Wednesday, July 15, 2020

SpaceX is Apparently Having Falcon 9 Problems

Back in June, SpaceX had scheduled the launch of the 10th Starlink satellite mission for the 22nd, a Monday.  That launch was delayed 24 hours until Tuesday, then Thursday and finally Friday.  On that Friday, they simply said,
“SpaceX is standing down from today's launch in order to allow additional time for pre-launch checkouts in advance of its tenth Starlink mission.  Falcon 9 and its payloads, 57 Starlink satellites and 2 satellites from BlackSky, a Spaceflight customer, remain healthy.  SpaceX teams are evaluating the next earliest launch opportunity and will announce a new target date once confirmed.”
The “next earliest launch opportunity” was last week, originally on Wednesday the 8th, but that one was scrubbed due to afternoon thunderstorms.  Launch was reset for Friday morning, but when I got up and set to watch, SpaceX said it was further delayed until Saturday the 11th.  That in turn was scrubbed with a shorter statement; the first sentence of the paragraph above.  

During the Wednesday scrub, they did something unusual that caught my eye.  The launch was scrubbed with 10 minutes left in the countdown, but they opted to run the countdown, fueling the vehicle completely and running lots of other operations until the T minus 1 minute mark (when the Falcon 9's computers take over things), “for data collection.”  I've never heard them say that; I've never heard anyone say that.

Something seems wrong.  The booster for this mission, B1051, was to fly its fifth mission, so since only one has completed five missions successfully, attention focuses on the first stage.  Along the way, I had heard that there was a static firing of B1051 but that they never specifically said it had passed.  It's hard to imagine them proceeding if it didn't pass, but not stating it passed is just another oddity that people are noticing.  Are they seeing something in the data during a countdown test that isn't normal but doesn't really mean a failure?  Are they seeing something fail then start working, or something that fails sometimes?

Then, Monday the 13th, SpaceX announced that the mission to launch a South Korean military satellite called ANASIS II set for No Earlier Than yesterday, July 14th, had also been delayed indefinitely to allow teams to inspect the Falcon 9 rocket’s upper stage and potentially replace hardware. Upper stage?  That's different.  Since the upper stages are always new, do both of these upper stages have a problem?  Or not necessarily even a problem, just something that “don't seem right?”

Whatever it was they wanted to look at, they seem to have regained confidence in it.  Spaceflight Now reported today that:
Airspace warning notices associated with the Falcon 9/Anasis 2 mission indicated SpaceX might reschedule the launch for Sunday, July 19, during a launch window opening at 5 p.m. EDT (2100 GMT).
That mission, by the way, will use the booster from the first manned Crew Demo mission on May 30th, B1058.  If that mission flies on Sunday, it will be 51 days from launch, through recovery, refurbishment, and relaunch.  The previous record is 62 days.  

There have been eight announced launch dates for the Starlink 10 mission; I don't know if they consider all eight to be scrubs, but until now they've been going pretty much like clockwork, whenever the mission is scheduled.  Maybe they scrub due to weather or some typical little problem, but they don't scrub eight times, spread over most of a month.
As of July 1st, SpaceX has completed 11 launches in 2020 and has at least another 16 within tentative launch targets in the second half of the year. To complete all 16, the company would have to average almost three launches per month for the rest of 2020, a cadence it’s only managed to sustain for two or so months at a time.
Starlink mission 10 still doesn't have an announced launch date and appears to be holding up several additional launches.  It would be interesting to learn what caused the eight launch delays. 


An “experienced” Falcon 9, apparently ready for a Starlink mission from Pad 39A at the Kennedy Space Center.  (Richard Angle/Richard Angle/NASASpaceflight photo)  I'd like to say it's B1051 and the Starlink 10 mission, but it's not identified that way at the source. 



Tuesday, July 14, 2020

Seattle Takes Another Poison Pill

Seattle is struggling.  They were struggling before the riots started and now with the resultant costs from Covid and the Chaz/Chop, it has gotten worse.  Being a city council that's run by socialists, and therefore idiots, they've decided to punish upper middle class workers by instituting another city income tax.  Naturally, being idiots, they exempted themselves.
Nonetheless, the Seattle City Council has decided that now is the right time to impose a new tax burden on its residents. On July 6, the council passed the so-called “JumpStart” tax, which specifically targets middle-class jobs.

The council’s new tax will affect employees at medium-to-large companies, but not most small businesses. Applied to businesses with a total payroll of $7 million or greater, it will impose an additional 0.4 percent to 2.4 percent payroll tax on jobs that pay an annual salary of $150,000 or higher. This is on top of already steep federal and state payroll taxes.
...
According to OpenTheBooks.com, 601 city employees in Seattle earned $195,000 or more. Analysts found that “tree trimmers lopped off $160,604; the chief librarian made $197,704; electricians earned $271,070; electrical lineworkers made $307,387; and police officers earned up to $414,543.” The new payroll tax will not apply to any of these government employees or their peers otherwise drowning in taxpayer cash.
Now I realize that an annual salary of $150,000 sounds pretty high - if you're not working in any of those Seattle city jobs - but it's not the top 1% of salaries.  It takes close to $500,000 per year to make that, extrapolating from this 2019 piece, but $150,000 should be in the top 5%. 
According to Payscale.com, the average salary in Seattle is $79,000. It’s the fifth most expensive place to live in America, with the highest rents anywhere in the country outside of California. With this context in mind, workers making $150,000 are far from members of “the 1%.” More realistically, many of the targets of this new tax are middle class by Seattle standards. So while the tax isn’t massive, it does showcase an important trend: In their class warfare charge, left-wing officials aren’t constraining themselves to “soaking the rich,” but are quickly reaching down the income ladder for fresh wallets to tap.
You may have heard about Seattle telling Amazon that they didn't want them in the city anymore.  OK, that's not exactly how they said it.  They attacked Jeff Bezos by name, said, “we're coming for you” and one particularly idiotic councilwoman, Kshama Sawant, said she wants to “dismantle the deeply racist, sexist, violent, utterly bankrupt system of capitalism” and replace it with “a socialist world.” Sawant has also promised to “take into public ownership the top 500 corporations and banks that dominate the US economy.”  Sawant and fellow socialist city Councilwoman Teresa Mosqueda promise this new tax will be a “victory for working people.”

Doubtful.  They claim it will raise $200 Million.  Also doubtful.  The simplest thing for companies affected by the tax to do is to get out of the city limits.  When Seattle instituted a $15 minimum wage that was supposed to wonderful things, too, but reality is simply what it is.  Some restaurants went out of business and closed.  Others went outside the city limits.  Workers' hours went down, or they lost job flexibility and many ended up making less.   Prager University has a new video from a Seattle restaurant server talking about how the $15 minimum wage screwed up her world. 

If you were making just under $150,000 in Seattle and were due for a raise, would you want that raise if it went to the city?  Would the company want to give that raise, knowing you'd get a smaller piece of it than they had in mind?  Would you or the company look for ways around that?  It has been known for ages by anyone with the sense to observe cause and effect that revenue streams from soaking the super-rich dry up pretty quick - the world is full of these stories. So the “soakers” eventually must resort to soaking the less rich, and eventually the middle and working classes. 

I predict that they may take in some more revenue before the systems adapt, but in the second year, they'll lose money and the city will teeter closer to bankruptcy and collapse.  Seattle is in decline.  It could be terminal if they continue to elect socialists and other idiots.  


Twitter video is here.  I didn't really feel the need to watch it. 

By the way, in the strange world of the Internet, it has happened more than once that people I've written about have stumbled across my blog.  Should that happen to you, Mr. Bezos, I think people in Florida would be happy to have your small but tasteful world headquarters of Amazon move into the state.  Putting it in Central Florida would put you that much closer to your Blue Origin operations on the Kennedy Space Center.  I do have to warn you about the oppressive, Crematoria-style heat and the mosquitoes that raped and killed the invading Murder Hornets, but air conditioning takes care of both of those.



Monday, July 13, 2020

U.S. Conference of Mayors Adopts Resolution in Favor of Reparations

The U.S. Conference of Mayors released a letter backing a Democratic plan to form a reparations commission to come up with a payment for slavery.  While the mayors didn't address the cost, one study by a small group of college professors has suggested it could reach $6.2 quadrillion.  For those people who aren't familiar with the word: a quadrillion is a thousand trillions or a million billions, so that's $6,200 trillion.
Bedard reported a study called "Wealth Implications of Slavery and Racial Discrimination for African-American Descendants of the Enslaved" recommended a payment of $151 million to each descendent of a slave.

He explained the study essentially calculates the unpaid hours slaves worked, a price for massacres and discrimination, and adds interest.

The study states, "Whether the full cost of slavery and discrimination should be compensated, or only a portion, and at what interest rate remain to be determined by negotiations between the federal government and the descendant community."
It's worth noting that's quite a bit more than "all the money on earth."  Wikipedia tells us that the Gross Domestic Product of the world for 2019 was about $88 trillion, making the reparations about 70 years worth of all the money in the world, assuming zero growth in world GDP and 100% of the world GDP going to the American descendants of slaves.  Of course, there have been no slaves in the US since the 1860s unlike today's middle east or lots of other countries.  The US produces 2/3 of the world's GDP, so since we'd be the only country paying this, it consumes our entire GDP for 105 years. 

Since only about a third of the American population pays income tax, or about 100 Million people, the tax bill due American taxpayers amounts to $62 million per taxpayer. 

Those numbers indicate it's impossible.  It'll never happen.  I can imagine no scenario in which the total economic output of the US could be collected for 105 years; that's at least four generations of people.  Then consider that all of these numbers are based on American people for the next 105 years not getting anything they work for.  Since letting them starve to death would mean zero tax collected, we couldn't collect 100%.  Which stretches 105 years out even farther.  They're saying they want reparations for slavery by enslaving the next six or seven generations of Americans?  That's not reparation, it's revenge.

What could they do?  If they played Liz Warren and stole every penny from every billionaire in the US, I don't think we could drop that $6200 billion bill down to $6,000 billion; most of that wealth is in the hardware of the companies they own, it's not like they're swimming in gold coins like Scrooge McDuck.  If they tried to create $6.2 quadrillion from thin air, as they've done with economic stimulus for the last (nearly) 50 years, the dollar would collapse to worthlessness.  It would literally be worth less than paper it's printed on.

WND concludes with this cheery thought.
If American taxpayers think, however, they're going to get by with paying only $6.2 quadrillion, they shouldn't put away their checkbooks just yet.

The same study claims the value of lost freedom to Japanese American World War II internment detainees could be $16 quadrillion.
I certainly hope there are some adults in the room that will tell them how insane these ideas are.  


The letter.  Screen capture from SCRIBD


Saturday, July 11, 2020

A Ham Radio Series 7 - Bigger is Better (Antenna Version)

Back when I posted my semi-serious three laws of antennas, I ended up with my third law saying: whatever you can put up won't be as good as you'd like.  Unless you have a Jeff Bezos-level budget including the property to match. I've heard several people say the rule of thumb "up north" of here (which is pretty much all of the US), is that if your antenna stays up all winter, it's too small. 

With that in mind let me introduce you to the hardware at Radio Arcala in Finland. 


That tower is topped with two antennas (which are constructed of towers themselves): the bottom one is a three element yagi (directional antenna with gain) for 160 meters while the top is a four element yagi for 80 meters.  Now, remember, the length in feet for a half wave dipole is 468/f with f in MHz.  That says the elements of the antenna need to be 134 feet tip to tip for the bottom end of 80 meters and 260 feet for the bottom of 160 meters.   And they need to be spread out with about 2/10 wavelengths between the elements (that number varies with the antenna design; it's very approximate to give an idea of size).

According to their website, the vital stats
  • Tower height: 100 meters or 330 feet
  • 80 m beam 90 m (300 ft) long
  • 160 m beam 80 m (270 ft) long
  • Total weight 39,600 kg (80,000 lbs)
They add that the tower is supported by four sets of guy wires.  Each of the four extends 120 meters or 400 ft from the tower – representing an area of 170 meters (550 ft) on a side, for a needed total space of almost three hectares.  Being in Finland, it's designed to handle more than its own weight in ice buildup on the structure.  The system rotates to point the antenna at the desired part of the world; I believe the entire structure rotates, not just the top where the antennas are.  There's a video of it rotating.

To give you an idea of the scale up close, here's a section of the 160m antenna where one of the elements meets the boom that holds the three elements.  With a prop for scale. 


This is tower number 7 of 7 at Radio Arcala.  All privately funded, lots of volunteer work, designed and built by a group of hams who wanted the best signal in the world on those two bands. 

In the comments to that video, one says, "now collapsed due strong gust wind" dated six years ago.  I guess that means it stayed up a few winters. 



Friday, July 10, 2020

Mars 2020 Rover Mounted on Launch Vehicle

The Mars 2020 mission Perseverance rover was mounted to the top of its United Launch Alliance (ULA) Atlas 5 rocket at Cape Canaveral Tuesday in preparation for liftoff this month, essentially completing the assembly of the launch vehicle and checking off another milestone along the way.
Omar Baez, NASA's launch director for the Perseverance mission, said Wednesday that the launch is on track for July 30. The launch window opens at 7:50am EDT (11:50 UTC), with launch opportunities available at five-minute intervals.
As we talked about here ten days ago, the launch was originally scheduled for July 17, the opening of an interplanetary launch period that extends into mid-August.  Like much of life in 2020, the mission was impacted by Covid-19 virus concerns.  This was during the critical phase of mounting the payload in the payload fairing and upper stage of the Atlas V.
Meanwhile, the Perseverance rover, its landing system and cruise stage — essentially three different spacecraft making up $2.7 billion NASA’s Mars 2020 mission — were prepared for launch inside the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center. The final steps to ready the rover for mating with the Atlas 5 rocket involved enclosing it inside its aerodynamic shell, which will protect it during entry into the Martian atmosphere, and then encapsulating the craft inside the Atlas 5’s payload fairing.

“We were working simultaneously on getting the spacecraft encapsulated, and we ran into some issues with the crew,” Baez said. “A couple of the folks were suspected of having COVID, and actually had COVID, and with the precautions that come with that, anybody that’s been in close proximity to those folks either get tested or choose to stay out of work for however long they think is safe under the current guidelines.”
The source article on SpaceflightNow.com goes into the host of problems that they've had.  It's challenging enough to get a major mission to Mars under any conditions, but the pandemic adds another layer.  One that caught my eye was a problem with the Atlas itself.
Teams also encountered a problem with a liquid oxygen sensor line on the Atlas 5 rocket. Engineers discovered the issue during a countdown rehearsal June 22, during which ULA filled the Atlas 5 with kerosene, liquid hydrogen and liquid oxygen propellants to put the rocket through a thorough checkout before launch day.
The test found something that couldn't be found any other way (which is why they test). The sensor line can't get tested to real flight conditions until the Atlas 5 is filled with cryogenics. Naturally, they had hoped it was a loose connector or something easy. Instead it was a pinhole leak in a weld.
A welder from ULA’s rocket factory in Decatur, Alabama, traveled to Cape Canaveral to address the problem. The configuration of the sensor line while the rocket is standing vertical made the work challenging, with the welder entering a cavity inside the rocket and working “upside down” near the Centaur upper stage’s engine section, Baez said.
Our weather has been in a pattern that brings showers to the east coast most days.  Any given spot might have a 60 to 80% chance of rain, but the east coast is the focus of the rains.  That affects launch operations, too.  Launch Director Baez says teams will work weekends straight through until the planned launch date.  If everything goes according to plan, workers will take a couple of days off to “reset” before the Atlas 5 and Perseverance rover roll from the Vertical Integration Facility (VIF) to Cape Canaveral’s Complex 41 launch pad July 28.
Another significant step to prepare for launch will be the attachment of the Perseverance rover’s plutonium power source. The Multi-Mission Radioisotope Thermoelectric Generator will be installed through a port on the Atlas 5’s payload fairing.
A flight readiness review is scheduled for July 22, and launch readiness review on July 27.  Approval of both is required to get clearance to roll the vehicle to the pad on July 28, but at least for now they're on schedule and looking like they'll get there.




Wednesday, July 8, 2020

Less Like "Shock Poll", More Like "Well, Duh!"

You may have seen the story of the “Shock Poll” from Rasmussen about 50% of Americans agreeing with the statement that it’s at least somewhat likely there will be a violent attempt to overthrow the United States government within the next decade.  The poll results broke down like this:


You can see the top two groups Very and Somewhat Likely add to 50% vs. 42% saying it's Not Very or Not at All Likely.  There's the standard Not Sure response that always gets a few percent of responses.  Don't ask me why that adds to more than 100% (107%); unless it's a way of combining the +/- 2.8% uncertainty into one total.  (Note that 107 is 100 + 5 (number of categories) times 1.4 (1/2 of 2.8%))

To anyone shocked, I think you're avoiding the news.  I think there should have been an option for, “it's going on Right Now.”  One of my regular reads, Divemedic at Confessions of a Street Pharmacist has been running a series on the stages of an insurgency (good summary in part 2) and deep diving into lots of details.  Pollster Scott Rasmussen almost went there.
Rasmussen noted that Republicans are a bit more likely to expect such violence, but the gap is fairly modest. That may be due to a perception among some that the current civil unrest is heading in that direction.

"There is also likely a solid partisan distrust fueling such concerns," Rasmussen said. "Many Republicans fear the left will respond with violence if President Trump is re-elected. Many Democrats fear the same from the right if President Trump is defeated."
Saying there might be a violent attempt to overthrow the government in November isn't quite Right Now, but it's closer to Right Now than a decade from now.  

Count me as thinking we're in the early stages of a well-funded and organized attempt to overthrow the US government.  Yes.  Right.  Now.   



Tuesday, July 7, 2020

The “That's Funny” Story in Iran Comes More Into Focus

Back when I posted the original story last week, I deliberately avoided speculation that it was an Israeli operation.  That was when there was just the one incident in the Alborz mountains, just east of Tehran, seemingly from the Khojir Missile Base in Iran.  Still the topic came up in the comments.

Since then there have been more apparent attacks, some of which appear to have targeted allegedly civilian facilities (not that defense work can't take place in such facilities). They include an explosion on June 30 at a medical center in northwestern Tehran, a huge fire on July 3 in the city of Shiraz, and an explosion at a power plant on July 4 in the city of Ahvaz.  There have also been anomalous explosions and fires in Iranian military facilities and news is starting to come out.  That PJ Media story links to a story on Radio Farda, the Iranian service of the American Radio Free Europe/Radio Liberty broadcasters.
A mysterious explosion or fire in the early hours of July 2 destroyed a building at Natanz enrichment facility and many believe it was an Israeli operation, whether through a cyberattack or some sort of air strike. There have also been other mysterious explosion and fires both at military and vital economic facilities.

In one of the essential analysis, Israel's Channel 13 TV military analyst Alon Ben-David cited the country's officials as saying the explosion at Natanz nuclear facility has postponed Tehran's efforts to enhance its uranium enrichment capacity by two months.

"The facility, where Iran develops its more advanced centrifuges, took a substantial hit; the explosion destroyed the lab," Ben-David said, adding, "Those were centrifuges that were supposed to be installed underground at the Natanz facility; they were intended to replace the old centrifuges and produce a lot more enriched uranium, a lot more quickly."
Israeli military analyst Ron Ben-Yishai, told Radio Farda that “by using the new generation of centrifuges Iran could have acquired a nuclear bomb with staggering speed, within weeks or months.”  Instead, Iran is suddenly far behind their previous capabilities.
On Monday, Israel’s Channel 12 News said the “attack on the Natanz nuclear facility in Iran, credited to Israel, had managed to set back Tehran’s uranium enrichment program by two years, citing Western intelligence estimates.”
While Iran hasn't officially blamed Israel, they have apparently tried to “reach out” to a few Israeli officials.  Israel's premier intelligence agency, the Mossad, claims to have broken up planned or attempted Iranian attacks on Israeli diplomatic missions in Europe and elsewhere, according to a report Monday.

The main reason I was slow to go down the road of saying it must be Israel is the fact that nothing I came across last week had Iran blaming Israel or the US (the little Satan or the Great Satan) for the attacks.  There might be something else going on, too: anti-regime forces from Iran itself.  I'm reluctant to pass on this story because it's from the New York Times, a source I consider completely unreliable, but that sometimes, accidentally, does actual journalism.  Take it at face value.  Right after the Natanz blast, the Times reported, staff members of the BBC’s Persian service said they
received an email from a previously unknown group, which referred to itself as the Homeland Cheetahs, before news of the fire became public. The group claimed responsibility and said it was composed of dissidents in Iran’s military and security apparatus. They said [their attacks] would target above ground sections of…facilities so that the Iranian government could not cover up the damage.
Even if it wasn't this homegrown Iranian group doing the operations, but simply helping either Israeli or US operators, that seems it could be an important development.  We've heard that the Iranian people are fed up with the mullahs and want to be rid of them; could this be a turning point?


 Natanz centrifuges, 2019 photo. AP photo from Radio Farda.


Monday, July 6, 2020

Rocket Lab Loses A Mission

Rocket Lab, the company I keep wanting to refer to as the plucky New Zealand startup, had its first inflight failure for a paying customer this weekend, Sunday morning in New Zealand.  It was the 13th orbital mission of their Electron rocket from the company that regularly gives the current mission a whimsical name; this one was “Pics Or It Didn’t Happen.”  From the company statement:
The issue occurred approximately four minutes into the flight on July 4, 2020 and resulted in the safe loss of the vehicle. As a result, the payloads onboard Electron were not deployed to orbit. Electron remained within the predicted launch corridors and caused no harm to personnel or the launch site. Rocket Lab is working closely with the FAA to investigate the anomaly and identify its root cause to correct the issue to move forward.

“We are deeply sorry to our customers Spaceflight Inc., Canon Electronics Inc., Planet, and In-Space Missions for the loss of their payloads. We know many people poured their hearts and souls into those spacecraft. Today's anomaly is a reminder that space launch can be unforgiving, but we will identify the issue, rectify it, and be safely back on the pad as soon as possible,” said Peter Beck, Rocket Lab founder and CEO. “The launch team operated with professionalism and expertise to implement systems and procedures that ensured the anomaly was managed safely. I’m proud of the way they have responded to a tough day. We’re working together as a team to comb through the data, learn from today, and prepare for our next mission.” 
 Eric Berger at Ars Technica provides a little more context:
Before this weekend's failure, Rocket Lab had enjoyed an excellent run of success. The company's first test flight, in May 2017, was lost at an altitude of 224km due to a ground software issue. But beginning with its next flight, in January 2018 through June 2020, the company had rattled off a string of 11 successful missions and emerged as a major player in the small satellite launch industry. It has built two additional launch pads, one in New Zealand and another in Virginia, US, and taken steps toward reusing its first-stage booster.
Spaceflight is unforgiving.  Because of the sheer cost of lifting every pound of rocket, design safety margins are small.  Since Rocket Lab hasn't given any more details on the failure, it not only wouldn't be fair to jump to conclusions, there's no data on which to base such a jump.  We'll just have to wait for updates.


The start of mission 13, “Pics Or It Didn’t Happen” in that brief moment between lighting the engines and the rapid disconnect of that thick hose (probably fuel or oxidizer).   Rocket Lab photo.



Sunday, July 5, 2020

When It Rains All Day, Barbecue All Night

Like millions of folks, I like to barbecue on the 4th - or any day of the week that ends in -y.  We've been having several days of afternoon thunderstorms lately, though, and the forecast for the 4th was 70% chance of rain and today was 80%.  I had a pork butt in the freezer to make pulled pork from, though, and smoking one of those takes around 12 hours - sometimes as much as 16 depending on the particular hunk of pork you're working from.  These are animals, after all, and it varies with the individual.  It looked like chances of having 12 to 16 hours without rain lasting until an evening dinner time hovered right around zero.   

Yesterday, I hatched a plan to barbecue in the 12 to 16 hours between rain showers or from about 10PM Saturday night until the pork was done this afternoon.  I've done this sort of cook before, but usually starting later, like midnight or getting up at 3AM plus or minus an hour to start.  Sure enough, the rain let up to "chunky mist" before sunset last night and by 10 it was drying out (to the degree it can with humidity close to 100%).  I used my electric smoker for this, a Masterbuilt Digital Electric Smoker (like this model) and the side smoker box.  Everything was on the back porch with the pork butt in the smoker and heating up by 10:10PM.

Up for some barbecue engineering?  Doubtless you've seen pellet grills that use a motorized plunger (an auger?) to drive a calibrated amount of wood pellets in the heat chamber.  These advertise they can be run unattended - I don't have one so I don't know if that's real world or not.  The Masterbuilt side smoker is gravity fed.  The disassembled unit looks like this:


That little screen tray (bottom center) slides onto the wood chute (bottom left) which sits inside the big assembly, just above an electric heating element.  You fill that chute on the left with wood chips, the screen keeps them from falling through, they're heated until they smoke, and the idea is that as they give up their smoke, they turn to ash, which falls into the drawer (bottom right) and now gravity pulls the stack of chips lower into place so that the next layer burns.  The whole thing is supposed to provide continuous smoke for six hours, and pretty much does.   The problem is that the wood chips also release some resins and water vapor that rise inside the chute causing the chips to stick to the sides and each other, forming a clump or clot of chips that needs to be broken up every couple of hours. 

Which is why I get up every couple of hours through the night to look after the smoker.  The alternative, without the side box, is to refill the limited amount of chips the smoker itself holds, which means getting up a few more times through the night; perhaps every 90 minutes vs 120 to 150 with the side box.  Practically, it's not a really big difference but the side box gives us the ability to cold smoke, which the electric smoker itself can't do.

Since I'd made preparations to be done by no later than 2PM, expecting it could be raining by then, the rain held off another two hours.  The pork came out great and a splendid time was had by all.  And tonight, Mr. Kite is topping the bill. 


This is almost a stock picture to represent today's barbecue - a stock butt pic.  It's not today's barbecue because I didn't think to take a picture.  For once.  But it was like this.



Friday, July 3, 2020

Happy Independence Day - 2020

Just a note that a check of the archives shows that I've run this exact post all but one July 4th over the 10 year life of this blog.



IN CONGRESS, JULY 4, 1776

The Unanimous Declaration of the Thirteen United States of America


When, in the course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the laws of nature and of nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights, that among these are life, liberty and the pursuit of happiness. That to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed. That whenever any form of government becomes destructive to these ends, it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness. Prudence, indeed, will dictate that governments long established should not be changed for light and transient causes; and accordingly all experience hath shown that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same object evinces a design to reduce them under absolute despotism, it is their right, it is their duty, to throw off such government, and to provide new guards for their future security. --Such has been the patient sufferance of these colonies; and such is now the necessity which constrains them to alter their former systems of government. The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute tyranny over these states. To prove this, let facts be submitted to a candid world.

He has refused his assent to laws, the most wholesome and necessary for the public good.

He has forbidden his governors to pass laws of immediate and pressing importance, unless suspended in their operation till his assent should be obtained; and when so suspended, he has utterly neglected to attend to them.

He has refused to pass other laws for the accommodation of large districts of people, unless those people would relinquish the right of representation in the legislature, a right inestimable to them and formidable to tyrants only.

He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their public records, for the sole purpose of fatiguing them into compliance with his measures.

He has dissolved representative houses repeatedly, for opposing with manly firmness his invasions on the rights of the people.

He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the legislative powers, incapable of annihilation, have returned to the people at large for their exercise; the state remaining in the meantime exposed to all the dangers of invasion from without, and convulsions within.

He has endeavored to prevent the population of these states; for that purpose obstructing the laws for naturalization of foreigners; refusing to pass others to encourage their migration hither, and raising the conditions of new appropriations of lands.

He has obstructed the administration of justice, by refusing his assent to laws for establishing judiciary powers.

He has made judges dependent on his will alone, for the tenure of their offices, and the amount and payment of their salaries.

He has erected a multitude of new offices, and sent hither swarms of officers to harass our people, and eat out their substance.

He has kept among us, in times of peace, standing armies without the consent of our legislature.

He has affected to render the military independent of and superior to civil power.

He has combined with others to subject us to a jurisdiction foreign to our constitution, and unacknowledged by our laws; giving his assent to their acts of pretended legislation:

For quartering large bodies of armed troops among us:

For protecting them, by mock trial, from punishment for any murders which they should commit on the inhabitants of these states:

For cutting off our trade with all parts of the world:

For imposing taxes on us without our consent:

For depriving us in many cases, of the benefits of trial by jury:

For transporting us beyond seas to be tried for pretended offenses:

For abolishing the free system of English laws in a neighboring province, establishing therein an arbitrary government, and enlarging its boundaries so as to render it at once an example and fit instrument for introducing the same absolute rule in these colonies:

For taking away our charters, abolishing our most valuable laws, and altering fundamentally the forms of our governments:

For suspending our own legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever.

He has abdicated government here, by declaring us out of his protection and waging war against us.

He has plundered our seas, ravaged our coasts, burned our towns, and destroyed the lives of our people.

He is at this time transporting large armies of foreign mercenaries to complete the works of death, desolation and tyranny, already begun with circumstances of cruelty and perfidy scarcely paralleled in the most barbarous ages, and totally unworthy the head of a civilized nation.

He has constrained our fellow citizens taken captive on the high seas to bear arms against their country, to become the executioners of their friends and brethren, or to fall themselves by their hands.

He has excited domestic insurrections amongst us, and has endeavored to bring on the inhabitants of our frontiers, the merciless Indian savages, whose known rule of warfare, is undistinguished destruction of all ages, sexes and conditions.

In every stage of these oppressions we have petitioned for redress in the most humble terms: our repeated petitions have been answered only by repeated injury. A prince, whose character is thus marked by every act which may define a tyrant, is unfit to be the ruler of a free people.

Nor have we been wanting in attention to our British brethren. We have warned them from time to time of attempts by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity. We must, therefore, acquiesce in the necessity, which denounces our separation, and hold them, as we hold the rest of mankind, enemies in war, in peace friends.

We, therefore, the representatives of the United States of America, in General Congress, assembled, appealing to the Supreme Judge of the world for the rectitude of our intentions, do, in the name, and by the authority of the good people of these colonies, solemnly publish and declare, that these united colonies are, and of right ought to be free and independent states; that they are absolved from all allegiance to the British Crown, and that all political connection between them and the state of Great Britain, is and ought to be totally dissolved; and that as free and independent states, they have full power to levy war, conclude peace, contract alliances, establish commerce, and to do all other acts and things which independent states may of right do. And for the support of this declaration, with a firm reliance on the protection of Divine Providence, we mutually pledge to each other our lives, our fortunes and our sacred honor.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Enjoy your day.  To those who serve - and have served - to provide this gift of liberty for us:  Thank You from the bottom of my heart.


Thursday, July 2, 2020

I Kinda Like This Kid

According to a story linked at FEE - the Foundation for Economic Education - an NBA player tweeted out a great idea on what to put on his jersey.  As the NBA is preparing to resume the finale of their season at the end of this month in Orlando, the NBA is expecting players to put Woke, Social Justice sayings on their jerseys; things that would make the arena seem like it matches protests outside.  Stuff like "Black Lives Matter," "I Can't Breathe," and “Congratulations George Floyd - One Month Drug Free.”  OK - not that last one.

The player, Spencer Dinwiddie of the Brooklyn Nets, tweeted an idea for his jersey that will make him the only person in the arena to say it or (probably) to understand it.
“If you’re wondering what I’m gonna put on the back of my jersey it’ll be ‘Trillion,” Dinwiddie tweeted
Young Mr. Dinwiddie, at the age of 27, wears jersey number 26 and realized that the phrase “26 Trillion” is the current national debt!  USDebtclock says it's $26.5 Trillion, to round it to the nearest one hundred billion.

Naturally, predictably, and as always he drew attacks from the other Twitter users for not falling in line with their predictable desires.
Woke up at 4am to see that I’m getting lit up in the comments for talking about the Global Debt. Comments ranging from massive amounts of debt are good (which I disagree with), to its not personal debt (obviously), to its a waste of a platform, amongst others …

To those I question, what is the purpose of putting a social issue on the back of the jersey? To inspire change right? Considering that nobody opts out of the complete global financial system and the USA weaponized the dollar that means you need leverage within the system.

In my opinion like it or not, change for us comes down to Group economics. Rethinking how we approach finances. Acquiring hard assets. Recycling dollars etc. Til then the slow burn of marches/protests will produce progress but will still yield similar results...
Of course, people are free to criticize.  The problem is simply that he's the only one even referring to the debt bomb.  You just don’t find students carrying signs emblazoned with “$26 Trillion and Counting!” or “End the Fed!” at political protests.  That's something only old people worry about - yet it's a problem that our politicians are creating for Mr. Dinwiddie's generation. 
Baby boomers and Gen Xers have much less to worry about when it comes to surging debts that will require massive interest payments—$1 trillion annually by 2029, if not sooner—in the coming decades. Most of them also already have lots of job experience and decades of work in the bank. Many have accumulated assets and retirement savings.

The economic futures of young people, however, depend on a vibrant economy that offers similar opportunities—jobs, entrepreneurship, and the chance to get ahead. Unfortunately, that’s going to be much more difficult with a $26 trillion national debt that is rapidly growing.
While there's an ongoing attempt at a communist overthrow of our country that will almost certainly fail, that's the only possible threat to the future of Spencer Dinwiddie and his generation that's bigger than the threat posed by the way the Federal Reserve creates money out of thin air. 


Spencer Dinwiddie.  YouTube screen capture from FEE article.

Just six weeks ago, May 12, I wrote that the National Debt was $25.1 Trillion.  Having grown $1.4 Trillion in 7 weeks says the debt is growing at $230 Billion per week; almost $1 Trillion per month.  If the debt keeps growing at that rate for the rest of this year, by 2021 the National Debt will be $32.6 Trillion.  That's so stunning I went back to make sure I hadn't miscopied the $25.1 Trillion debt in mid-May.  I hadn't.  Buckle those seat belts, it's going to get bumpier.




Wednesday, July 1, 2020

A Ten Year Old Post Relevant Today

While doing some searches for something I knew I had written here, I stumbled across this post, almost 10 years old to the day.  I had a surprise while going through it, when I clicked on the link to a 12 year old, nearly 10 minute long YouTube video, linked in the second paragraph.  It's worth some time to look around in that video, even if you don't sit for the full thing. 

I repost it here because on its 10th birthday (almost), it's as true as it ever was.  Earlier in the year I thought of repeating more 10 year old posts, but finding them isn't always easy.  

The Atomic Bomb of Argument



In the world of the Internet, a law of argument has been recognized, called Godwin's law of Nazi Analogies, which says that any argument long enough leads to an invocation of Hitler or Nazis.  As usually stated, "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1."  The idea is that the accusation of being a Nazi is so outrageous, and Nazis are so socially unacceptable, that when charged with being one, the accused will drop whatever they are arguing to counter that they are not a Nazi.

This idea, while not specifically the Nazi allegation, is widely used in domestic politics and is the part of the reason behind negative attack ads.  If candidate Phlegm says that candidate Halitosis has done some negative thing, Halitosis generally has to issue an ad showing how he hasn't done it.  For Phlegm, it's a win-win scenario.  He gets Halitosis to spend money and time on the made-up charge, and it gets the opponent "off-message."  Halitosis is not talking about what he really wants to talk about, but is instead talking about what Phlegm wants him to talk about.  As for the dumb voters, who don't really pay attention anyway, they become vaguely aware that Phlegm and Halitosis are both talking about this negative thing and learn the association that Halitosis is the bad guy ("where there's smoke, there's fire!"). 

If the Nazi charge is the WMD of online argument, the charge of Racism is the atomic bomb of daily discourse.  So when the NAACP raised the charge of racism against the Tea Party, this was the purpose.  It made people trying to reduce the insane government spending get off their message and address the fact that they aren't racist.  It made some people waste time and money to respond to it.  It made headlines that stupid voters will notice without reading any details to, and may influence them.  It's a blatantly transparent political move in what has become simply a "wholly-owned subsidiary" of the Democratic Party.

This may shock some people, but I don't really believe there is such a thing as race.  I believe there are nationalities, and people from different areas of the world look different, but those differences are superficial and go away as cultures blend.  As I was doing my little research to help gel my thoughts for this article, I was surprised to see PBS (of all places) basically doing a program that sums up where I am, to about the 75% level - Race - the Power of an Illusion.  I'll add a few notes in this edited summary from that web site, and I remove things that I think are just PBS being the liberal spin machine they are. 
1.  Race is a modern idea....The English language didn't even have the word 'race' until it turns up in 1508 in a poem by William Dunbar referring to a line of kings.
2.  Race has no genetic basis. Not one characteristic, trait or even gene distinguishes all the members of one so-called race from all the members of another so-called race.
3.  Human subspecies don't exist. ....Despite surface appearances, we are one of the most similar of all species.
4.  Skin color really is only skin deep.  Most traits are inherited independently from one another. The genes influencing skin color have nothing to do with the genes influencing hair form, eye shape, blood type, musical talent, athletic ability or forms of intelligence. Knowing someone's skin color doesn't necessarily tell you anything else about him or her.
5.  Most variation is within, not between, "races." Of the small amount of total human variation, 85% exists within any local population, be they Italians, Kurds, Koreans or Cherokees. About 94% can be found within any continent. That means two random Koreans may be as genetically different as a Korean and an Italian.
6.  Slavery predates race. Throughout much of human history, societies have enslaved others, often as a result of conquest or war, even debt, but not because of physical characteristics or a belief in natural inferiority. Due to a unique set of historical circumstances, ours was the first slave system where all the slaves shared similar physical characteristics.
7.  Race and freedom evolved together. The U.S. was founded on the radical new principle that "All men are created equal." But our early economy was based largely on slavery. How could this anomaly be rationalized? The new idea of race helped explain why some people could be denied the rights and freedoms that others took for granted.(SiG answer: but you do know that the whole 3/5 of a person thing was intended to end slavery, right?  To put pressure on the deep south to free their slaves, and get more representatives right?)
8.  Race justified social inequalities as natural. As the race idea evolved, white superiority became "common sense" in America. (SiG answer: not anymore, and not for my life)
9.  Race isn't biological, but racism is still real.  Race is a powerful social idea that gives people different access to opportunities and resources. (SiG: liberal bullsh*t diatribe deleted)  
item 10 deleted.  I think it's complete bullsh*t, and is there simply because PBS can't shake their liberal mentality.
Rather than the item 10 PBS used, I would much prefer to envision the world Martin Luther King did, in his famous, "I Have a Dream" speech.  I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character. - Martin Luther King, August 28, 1963

Are there really racists?  Undoubtedly - as I've said before, if 5% of the people don't believe we went to the moon, some small percentage are going to believe anything.  Are there any in the Tea party?  If the Tea party is a random sample of the population, there would be some, sure.  I would bet there's at least as many racists in the NAACP itself.



Tuesday, June 30, 2020

NASA's Next Mars Rover Slips - Has Burned Half The Launch Window

I haven't posted much about it, but NASA had scheduled the launch of its next rover, named Perseverance in a national contest, for the beginning of the opposition launch window in July.  It's a 20-day window opening July 17.

Ars Technica's Eric Berger reports today that the launch has slipped to No Earlier Than July 30. Thirteen days is over half the 20 day window.  Worse, an official launch date has not been named.
A problem arose during a Wet Dress Rehearsal test earlier this month. During this standard prelaunch test, an Atlas V rocket is fueled with propellant and a countdown is conducted until the final moments before ignition. So what happened? "A liquid-oxygen sensor line presented off-nominal data during the Wet Dress Rehearsal, and additional time is needed for the team to inspect and evaluate," NASA said in a statement on Tuesday afternoon, in response to a query from Ars.

A source in Florida indicated that the issue was related to the Atlas V rocket's Centaur upper stage, which is fueled with liquid hydrogen and liquid oxygen.
It's clear from the text that United Launch Alliance (ULA) hasn't resolved the issue with the liquid oxygen sensor.  The spacecraft had not been stacked on the launch vehicle, an Atlas V in the 541 configuration (five is the fairing diameter in meters, four is the number of solid rocket boosters, and the one is for the single engine Centaur upper stage).
The $2.1 billion rover is similar to NASA's Curiosity rover but contains several upgrades, including the addition of a small helicopter, and it will launch on the 541 configuration of the Atlas V rocket. NASA originally set a launch window from July 17 to August 11, the optimal period for the rocket to launch, and for Perseverance to reach Mars within about six months.

The launch has since been delayed from July 17 to July 20 due to a crane issue during the stacking process; it was again delayed from July 20 to July 22. NASA attributed the latter setback to "a processing delay encountered during encapsulation activities of the spacecraft."
The small helicopter intended to fly on Mars was covered here in May of 2018.  

This third delay now starts making the end of the launch window look scarier and NASA has started to evaluate how far into August they could launch and still make their mission.  So far they extended the window until August 15 and are examining whether the launch window can be extended another few days.
If the Perseverance mission misses this launch window, it would be delayed 26 months, at a cost of hundreds of millions of dollars, until the next Earth-Mars conjunction in 2022.

The Atlas V with Centaur Upper Stage, but no Mars Perseverance rover and no launch fairing.  This is around the day of the Wet Dress Rehearsal within the last week or so.  ULA Photo.

Here's hoping ULA figures out what needs to be done and gets this launch off in time.



Monday, June 29, 2020

One of Those “That's Funny” Stories

Every so often you see stories in the news that make you say, “that's funny” and then disappear.  You wonder what's really going on but while you'd expect more followup stories, those just don't show up. 

There was a story like that over the weekend but today I'm only seeing it on PJ Media.  The Associated Press reported on Friday that a huge explosion had occurred that rattled Tehran and lit up the horizon. The site of the blast was a region where many nuclear experts believe Iran conducted high-explosive tests relating to its nuclear program. 

The explosion happened in the Alborz mountains, just east of the city and appear to have come from the Khojir Missile Base in Iran. There is some Twitter back and forth about it, saying that the Iranian regime is trying to say it was somewhere else, when open source, commercial satellites clearly show some differences at the Khojir Missile Base.


If that's what happened, 5,000 liters (about 1,300 gallons) of propane could make quite a boom, but propane isn't typically used as a rocket fuel.  That's not to say that it couldn't be used with the proper design trades, just that generations of actual rocket scientists have looked at the trades and don't consider it a worthwhile fuel.  If it's the only fuel you have, it can burn, it's just not as good a rocket fuel as methane.  The most up-voted answer at that previous link is:
Propane, with ~5-7 bar vapor pressure at ambient temperatures would require a pressure tank (not acceptable on a rocket due to mass), or needs to be cooled to at least -42oC. This combines disadvantages of cryofuels and complex hydrocarbons, giving a very small specific impulse rise over RP-1, and while rather large, still insufficient boiling point rise above methane. 
In my limited perspective the pieces don't add up here.  I think it's entirely possible that thousands of liters of propane went boom, I just don't think that it's likely they're developing rockets based on it.  I'm assuming that if there was any indication that was nuclear, somehow that news would leak out, but there are uses for other explosives in a nuclear warhead that could also have gone boom.  I'm left where I started, with a “that's funny.” 



Sunday, June 28, 2020

June Won't Be a Four Launch Month for SpaceX

A few weeks ago, I reported that SpaceX watchers were commenting that there were four launches scheduled for the month of June, which would give the company their first four launch calendar month ever.  That milestone slipped away two days ago, when the 10th Starlink launch was postponed - after having slipped from Tuesday, to Thursday and finally Friday.

The new launch date has not been announced, nor has any detailed reason for the delays been offered.  On Friday, their statement simply said, “SpaceX is standing down from today's launch in order to allow additional time for pre-launch checkouts in advance of its tenth Starlink mission.  Falcon 9 and its payloads, 57 Starlink satellites and 2 satellites from BlackSky, a Spaceflight customer, remain healthy.  SpaceX teams are evaluating the next earliest launch opportunity and will announce a new target date once confirmed.”

Moving to the front of the queue, with launch scheduled for Tuesday, No Earlier Than (NET) 3:56 pm EDT (19:56 UTC) is the GPS III SV03 mission.

Teslarati SpaceX correspondent Eric Ralph had this truism to relay.
Additionally, SpaceX’s willingness to delay an internal Starlink launch by a substantial amount serves as a confirmation that the company continues to prioritize reliability and established procedures over expedience. Given that any Falcon 9 failure would severely impact all SpaceX launches, including internal Starlink missions and commercial launches for customers, that should come as no surprise. Still, SpaceX’s Starlink missions pose a perfect storm of low cost and high launch frequency requirements that could incentivize corner-cutting in the short term.

At the same time, it’s not actually clear whether Starlink V1 L9’s delay was SpaceX’s decision or something decided (or heavily influenced) by the US military. Shortly after SpaceX announced the delay, new regulatory filings suggested that June 28th was the new target, but they were quickly rescinded. It’s possible that the US military asserted its desire to be SpaceX’s immediate priority ahead of the launch of an extremely expensive GPS III satellite.
Another point of interest for the military is that this is the second launch of a GPS III satellite and will be the first one in which the military will allow SpaceX to recover the booster.  The first GPS payload flight was in December 2018 when SpaceX was new to successfully recovering boosters.  I suppose the military was too concerned it might inhibit the booster performance to allow enough fuel to do the landing burns.  The never-flown booster for this mission, B1060, should land on recovery drone ship Just Read The Instructions (JRTI) by about 4:05 PM EDT if all goes well.


The business end of B1060 during tests earlier in the month.  It is currently vertical, stacked and on the pad at Launch Complex 40.

I should point out that with last Friday's Starlink launch moving into July, there are now four launches scheduled in that calendar month making July their possible first four-launch month. 
Starlink-9 (early July), ANASIS-II (mid-July), SAOCOM 1B (late July), and Starlink-10 (late July). Once again, with two launches scheduled near the end of the month, the odds that one or more missions will slip into August are substantially higher, but the possibility remains.
The once a week launch cadence seems to be tough to keep up.  To my knowledge, there's no one on Earth that can advise on how do that.  Most of the other big contractors have a once or twice a year cadence.


Saturday, June 27, 2020

A Ham Radio Series 6 – Choosing an Antenna

So far in this series, I’ve mostly talked about HF and low VHF propagation and some antenna overview topics.  My slightly snarky three laws of antennas have truth embedded in them.  If you don't have an antenna anything you put up will get you contacts.  There's a group of hams who try to operate with the lowest power or most meager antennas they can and sometimes with both low power and "compromise" antennas at the same time!  They measure miles per watt for bragging rights.  1000 miles per watt will get you a certificate suitable for framing, and the records are many times that.
The current QRP miles per watt record is 1,650 miles from Oregon to Alaska on the 10-meter band using 1 microwatt! That’s the equivalent of 1.6 billion miles per watt.
The second law was that nothing is best at everything, and it's pretty common to want to upgrade your antennas.  A saying that I agree with more almost every year is that if you suddenly got a windfall chunk of change and really wanted to upgrade your station, look at your antennas first.  

For the past several months, I’ve been looking at antennas I can put on my suburban lot that would give me better coverage on two different bands, and I thought some of you might be interested in what I’ve been doing to evaluate options.  For this post, I’m going to talk about the amateur allocation on 30 meters; or 10.100 to 10.150 MHz.

For antenna work, if you go with a resonant, full-sized antenna, there are a couple of formulas you need to know.  For a half-wave dipole, the length in feet for a half-wave at a frequency (f) in MHz is given by:
L = 468 / f
Since a monopole is one half of a dipole (one pole is half of two poles), it’s length is half of the dipole's or L = 234 / f. 
For the middle of the band, that tells me a half-wave dipole is 468/10.125 or 46.22 feet (that’s 46 ft 2.6 inches).  A monopole is 23 ft 1.3 inches.

Which one do I use?  As always, the answer is “it depends;” in this case it depends on what I want it for.  My preference for this antenna, as with all of my antennas, is for distant contacts.  That means I want a low angle of radiation.  Which antenna should I try to put up?

Let me stop here for a moment.  Why is there a choice between one or two “poles” and what does that even mean?  A half-wave dipole antenna has a length that closely matches the physical length of the radio waves.  As mentioned in the Antennas 101 Part 1, the voltage and current physically fit on the dipole like this.  Current is zero at the ends because there’s no where for the moving electrons to go.  Voltage is high were current is low because the power (voltage times current) is constant.


To show that conceptually for a monopole, you cut it in half at the middle, and rotate it so that it’s vertical.   Here, I cut off the right half and the left half is now vertical.


This antenna works because there’s a virtual second monopole; a reflection of the top monopole in the ground making it a virtual dipole.  In reality, if you’re mounting a monopole vertically like this, you need a better ground than most people get out of their actual ground.  AM broadcasters do this by burying a radial array of wires centered under the vertical.  In practice, four quarter wave long wires arranged radially just below the grass is pretty common.  Note that this sometimes called a ground plane antenna although usually just called a vertical.  If you live on a saltwater marsh (really, any body of water) you're good to go without putting down radial wires.

I’ve simulated several antennas in EZNEC 6 (freebie equivalent), and have some comparison plots.  First off, here’s a 30m dipole situated 20 feet above ground, so just under ¼ wave up.  This is an Elevation plot, that shows which direction the signal is strongest, marked from horizontal to vertical.  The farther out the red trace is, the stronger the signal is.  The antenna is conceptually at the bottom where everything converges, and you’re looking at one end of the wire sticking out of the screen at you. 


Notice that the strongest signal is going straight up.  The performance at 45 degrees from the ground isn’t that bad, it’s only down a little over 1 dB, but I can move a marker on the plot and find that the half power point, -3dB, is at 32 degrees elevation.  This dipole will be better for local contacts than those distant stations.  Very little power radiates at low takeoff angles.

Given that, let’s see how the vertical compares.


Because of the way EZNEC presents this data, I drew in a green line to represent the ground.  The radiation is strongest right along the ground.  This is close to ideal for those distant, DX stations I want to work.

There’s a gotcha.  Notice the gain figure on the right in both plots.  The dipole has more gain than the vertical but a worse pattern.  Even with the lower gain, the vertical puts more power into take off angles below 20 degrees than the dipole does.

To get a lower radiation angle from the dipole you need to put it up higher.  A half wave is better than a quarter wave. This is the same antenna when it’s 46’ up instead of 20.  Not many people have the real estate to support both ends of a 46' long dipole held 46' up in the air by two towers. 


I should point out something important.  All antenna modeling programs present impressive results that won’t match reality exactly because the world is much more complicated than the models.  The only thing in the universe of these models is what you model.  There are no buildings, no metal roofs, no towers, no cars parked across the street, nothing.  What that means is that this is an indication of performance, not an absolute model of what you’ll get.  The world around the antennas makes the patterns lumpy and asymmetrical.  The patterns are distorted, but reality resembles the model. 

You might ask if an electrically shortened antenna using loading coils or traps (parallel resonant circuits) effects gain.  It affects signal radiated but not the pattern so much and not by large amounts.  If you use an antenna tuner and a random length of wire, as many people do, you will lose power and received signal in the tuner.  If it gets you on the air and gets you contacts, you can worry over every milliwatt you might lose, but remember the ionosphere isn't constant and power levels flicker all the time, too.  My personal take on it is not to worry about loss in the tuner if the ionosphere takes out six or seven dB in a flicker.   If the radio's happy, I'm happy. 

Which way am I going for my 30m antenna?  I'm not really done with trying options, which is more about looking at my lot than running simulations.  My current antenna is a commercially made electrically short (trapped) vertical for 80 and 40 meters.  It's electrically long on 30m, and tuned with the radio's antenna tuner.  I've been using it on 30m since I got it in 2008, so it works, I just would like better.  Without dropping large sums of money on it. 



Friday, June 26, 2020

The Continuing Chronicle of the Cam, CNC and CAM

My last shop update post, a week ago, mentioned that one my next parts for my Webster engine was to be the exhaust cam.  I mentioned that the plans I'm using recommend using a method developed by a model engine designer named Hamilton Upshur, which requires building a fixture to turn the cam eccentrically.  It wouldn't work to just turn it off center with a four-jaw chuck because the cam gets rotated a bunch of times and just a little metal taken off.  This fixture is turning it off center twice.  This is interrupted cutting; it only cuts for a few degrees of rotation so the lathe has to not shake itself apart while doing this.

Last Saturday I finished the fixture:


Right below the socket head cap screw is a 1/2" diameter washer.  The next thing down is the cam blank: turned on the lathe to an Outside Diameter of 0.712" and the Inside Diameter reamed to 0.375".  Lacking solid step by step directions, I realized I needed to turn this on the outer diameter until I could verify that the bottom would be the right thickness; the OD minus ID of 0.094".  I just didn't see quite how to get from that first step to a complete cam.  As a result, my cam came out with a cam-like shape (or egg-like), but any outside dimensions that matched were purely a coincidence.


After posting my picture to the Home Model Engine Machinist forum, one of the wizards sent me a pdf he had previously posted of how to cut these.  The biggest mistake I made was starting from the center and trying to work to some lines I had scratched on the blank (coated with blue Dykem), then flipping it over and going back to the bottom center and trying to do the same thing going the other way.  The way to do this is to start at some point, and then rotate the blank 5 degrees at a time until it starts to look like a cam and then measure the top of the cam and stop when you get to the desired width.  For this cam, that's 43 steps.  For each step, I unscrew that cap screw, rotate the blank 5 degrees (where the tool is cutting, that's about .024"), tighten the screw and turn it again.  This time it came out much better.


You can see it's less lumpy, and in fact better than the first in just about every measurement.  The problem is that the bottom 3/4 of the cam is too thick.  Instead of 0.094", it was 0.125".  So back to the fixture to try to resize the rest of the cam.  That failed - one time when I tightened the screw down I guess I didn't tighten it enough and it slipped.  The top section of the cam got undersized by almost 1/16". 

Now what?  Do I proceed to cut a blank and do this again, or like an anonymous comment said to the last post,
Cam looks like a job for the cnc mill to me. Bolt the blank down to the table, through the hole, on top of a sacrificial piece of aluminum.
I was interested in doing it with this fixture for two reasons:  first, to be honest, just to do it manually (which is because) second, the guys on that forum seem to be completing their projects at least a thousand times faster than I do.  That implies CNC is holding me back.

It just seems that if CNC is holding me back, and if CNC is a strong feature of my shop (maybe the strongest) maybe I should be trying to get better at CNC programming.  So instead of using my CAM program (Computer Aided Manufacturing) to create the tool paths to make the cam, which has a simple outline, maybe I should write the program by hand.

I started out like this:


Each of the turquoise colored circles is the end profile of a 3/8" diameter end mill.  The centers of the four at the top are listed in the lower right.  The tool path is to start at number 1, move in a straight line to position 2, then do a section of a circle that takes the cutter to 3.  From there, do a straight line to 4 and then straight to 1. The gold outline is the cam drawing, and the almost white circle is the blank.   For some reason I don't understand (but that I had read could happen) the Mach3 interpreter didn't understand my code to go from 2 to 3 and almost went straight across.  After troubleshooting for a while, I thought I'd add that unnumbered position at the middle bottom, cutting the arc motion into two movements.  After that, the test cuts (air cuts) looked perfect and I cut this. I cut this in .031" thick slices, from top to bottom, making the entire file six copies of this with one modification (the first line goes .031 deeper each pass):
G01 X0.220 Y0.828
G01 Z-0.031 F2
G01 X0.427 Y0.476 F5
G02 X0.000 Y-0.188 R0.470
G02 X-0.427 Y0.476 R0.470
G01 X-0.220 Y0.828
G01 X0.220 Y0.828
This file is 42 lines long because of the two G02 (cut an arc clockwise) commands.  The file my CAM program made, which is entirely small steps from one point it chose along the side of the cam the next point it chose instead of G02 statements, is over 10 times as long.

Here are all three cams with the CAD/CAM/CNC cam on the right.   This is right off the fixture with the barest amount of deburring.


Clearly, I would have wasted less metal and been done faster if I hadn't spent a few days trying to turn it on the lathe fixture.  The question is whether or not sitting down to make the cam with CNC from the start would have gotten me done faster than if I knew how to do it with the fixture in the lathe. I think the answer is yes. 

The reason why some of the wizards on the HMEM have done three engines since the first of this year and I've been working on this one for over a year is that for me, just about every part is the first of a kind and I've never made one before.  My second cam is virtually guaranteed to go faster than this one.  I don't know enough about engines to really see how this goes together so I spend too much time thinking about most parts.  If someone wants to make model engines, they'd probably be better off working on small engines and antique farm engines than learning how setup a CNC mill and lathe. 



Wednesday, June 24, 2020

Yesterday's SpaceX Tank Popping Was Deliberate

For the second time, SpaceX Starship test article Serial Number 7 was tested until the new steel structure failed.  This was a deliberate test to failure, unlike the first test nine days ago, which just popped a leak. 


That's a screen capture from this NASASpaceflight.com video.  A look at the wreckage from up close later in the day shows that the bottom of the tank blew out pretty extensively.  You can see the tank and test stand lift off and fly to the left in the video (and in that picture above).  The two dark objects sticking out of the highest spot in the white cloud is a pair of valves that were releasing LN2 vapor.  The test consisted of closing those valve and then monitoring the pressure build up until the tank blew.  This was deliberately destructive test to see what fails and at what pressures.


There is no SpaceX data release telling us how well the tank performed.  The working pressure that tanks have been tested to is about 125 pounds per square inch (PSI), which is a 40% safety margin over the worst anticipated flight conditions, but those are not intended to be destructive tests.  Whether or not the tank survives that pressure for some time is the criteria.  This is more a test of everything, the sheet steel, the processes, and their understanding of all of those. 

The destructive test was yesterday around lunch time; I missed the failure but had kept the tab open in my browser.  When I went back the tank didn't look as good as the second picture and I rewound the video to see the pop.  Early this morning, the full sized test vehicle SN5 was rolled out to the test stand and mounted on the stand while the remains of SN7 were being cleaned up.   There don't appear to be any road closures for another several days, which indicates no testing at least until then.  The next road closures are for Jun 29th through July 1st.  I've watched the channel enough to know those dates are extremely fluid.

Meanwhile the third Starlink mission in as many weeks is scheduled for tomorrow at 1639 EDT, 4:39 PM.  This has slipped a couple of times, with no explanation I can see.  Like the last mission, this will be a ride share flight, and a couple of Starlink satellites will be pushed off to a later mission to accommodate the first two BlackSky satellites from Washington startup LeoStella.  Those ride sharing photographic satellites are believed to weigh around 55 kg (~120 lb) each.  The booster for this flight is B1051 and is scheduled to become the third SpaceX rocket to launch five times when it lifts off.  Only one has successfully landed and been recovered; B1049 from the first Starlink mission of this month is in the inspection and refurbishment process now.