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.


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 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.   

Tuesday, June 23, 2020

Got Time for a Podcast?

To follow on to Bayou Renaissance Man's post about blogger Small Dead Animals.

Go to Glenn Beck Program Podcasts and at the top of the page click on Hourly.  This only holds the last few days; look for hour 2 of today, 6/23/20.  After stumbling around for a half hour, I found a link to embed here so that you can get it for the foreseeable future.  Once the audio starts it's worth skipping ahead to about the 5 minute mark to avoid some commercials (just click on a faux audio plot; the timer is on the right - or drag the slider across on the bottom of the linked page).  The part I want to direct you to is the first "half hour" of the radio show.  The podcast is all the content in an hour of broadcast radio, so the whole thing is 41 minutes long and the interview ends at about 23 minutes on the timer.  That means you have 18 minutes to listen to.

The topic is the Great Reset, a Top-down-driven, Crony Socialist Revolution that we seem to be living in the early days of.  The Small Dead Animals post leads into this.  The big picture idea is to crash the dollar as the world's reserve currency and completely wipe out the world's economy then replace it with a crony socialist system.  I get a couple of financial/economic email newsletters and they have been talking about the economic situation that's central to the story (sample here from Bill Bonner). 
In an article published on the World Economic Forum’s website, WEF founder and Executive Chairman Klaus Schwab said “the world must act jointly and swiftly to revamp all aspects of our societies and economies, from education to social contracts and working conditions.”

“Every country, from the United States to China, must participate, and every industry, from oil and gas to tech, must be transformed,” Schwab added. “In short, we need a ‘Great Reset’ of capitalism.”

Sharan Burrow, the general secretary of the International Trade Union Confederation (ITUC), said we need to use the present crisis to help “rebalance” the global economy.

“We need to design policies to align with investment in people and the environment,” Burrow said. “But above all, the longer-term perspective is about rebalancing economies.”

And they weren’t alone. Numerous other influential world leaders spoke at the WEF event, including Ma Jun, the chairman of the Green Finance Committee at the China Society for Finance and Banking and a member of the Monetary Policy Committee of the People’s Bank of China; Bradford Smith, president of Microsoft; and Gina Gopinath, the chief economist at the International Monetary Fund.

Specifics for the plan have yet to be laid out. Those will come at WEF’s meeting in Davos in January 2021, the theme of which will also be “The Great Reset.” But, like the Green New Deal, it’s clear that the purpose of the plan—as the quotes previously listed reveal—is to move the world economy toward socialism, using climate change and COVID-19 as justifications.
The podcast is an interview with Justin Haskins, whose "about the author" box reads:
Justin Haskins is editor-in-chief of Haskins is a widely published writer and political commentator, the senior editor and founder of The Henry Dearborn Institute for Liberty, and the editorial director and research fellow at The Heartland Institute, a national free-market think tank. Follow him on Twitter @JustinTHaskins.
Offered for your consideration.

Monday, June 22, 2020

The Roman Famine of 44 BCE and an Alaskan Volcano

Those of you familiar with Roman history around the time of the assassination of Julius Caesar know that event led to a couple of decades of turmoil and civil war that marked the transition from Republic to Empire.  History records that there was also a widespread famine due to crop failures in the same period.

A research team recognized the similarity to more recent volcanic eruptions causing cold growing seasons and failed crops, and started trying to determine if there was a volcano eruption that could be linked to this famine.  They found a likely culprit half a world away in Alaska.
Around the time of Julius Caesar's death in 44 BCE, written sources describe a period of unusually , , famine, disease, and unrest in the Mediterranean Region -impacts that ultimately contributed to the downfall of the Roman Republic and Ptolemaic Kingdom of Egypt. Historians have long suspected a volcano to be the cause, but have been unable to pinpoint where or when such an eruption had occurred, or how severe it was.

In a new study published this week in Proceedings of the National Academy of Sciences (PNAS), a research team led by Joe McConnell, Ph.D. of the Desert Research Institute in Reno, Nev. uses an analysis of tephra (volcanic ash) found in Arctic ice cores to link the period of unexplained extreme climate in the Mediterranean with the caldera-forming eruption of Alaska's Okmok volcano in 43 BCE.

"To find evidence that a volcano on other side of the earth erupted and effectively contributed to the demise of the Romans and the Egyptians and the rise of the Roman Empire is fascinating," McConnell said. "It certainly shows how interconnected the world was even 2,000 years ago."
The discovery was initially made in a lab last year when McConnell and Swiss researcher Michael Sigl, Ph.D. from the Oeschger Centre for Climate Change Research at the University of Bern happened upon an unusually well preserved layer of tephra in an ice core sample and decided to investigate.  With this strong lead, the researchers looked for corroborating evidence on ice cores from Greenland and Russia, some of which were drilled in the 1990s and archived around the world.  What they found was evidence for two distinct eruptions—a powerful but short-lived, relatively localized event in early 45 BCE, and a much larger and more widespread event in early 43 BCE with volcanic fallout that lasted more than two years in all the ice core records.
The researchers then conducted a geochemical analysis of the tephra samples from the second eruption found in the ice, matching the tiny shards with those of the Okmok II eruption in Alaska—one of the largest eruptions of the past 2,500 years.

"The tephra match doesn't get any better," said tephra specialist Gill Plunkett, Ph.D. from Queen's University Belfast. "We compared the chemical fingerprint of the tephra found in the ice with tephra from volcanoes thought to have erupted about that time and it was very clear that the source of the 43 BCE fallout in the ice was the Okmok II eruption."
How bad was it?
According to their findings, the two years following the Okmok II eruption were some of the coldest in the Northern Hemisphere in the past 2,500 years, and the decade that followed was the fourth coldest. Climate models suggest that seasonally averaged temperatures may have been as much as 7oC (13oF) below normal during the summer and autumn that followed the 43 BCE eruption of Okmok, with summer precipitation of 50 to 120 percent above normal throughout Southern Europe, and autumn precipitation reaching as high as 400 percent of normal.
All from a volcano half a world away, reminiscent of the year without a summer in 1816 caused by Mt. Tambora in Indonesia; a year known as "1800 and froze to death" in Vermont and New England.

Alaska's Umnak Island in the Aleutians showing the huge, 10-km wide caldera (upper right) largely created by the 43 BCE Okmok II eruption at the dawn of the Roman Empire. Landsat-8 Operational Land Imager image from May 3, 2014. Credit: U.S. Geological Survey

It's worth noting that the eruption and the famines led to the end of the Ptolemaic Kingdom in Egypt as well as contributing to the end of the Roman Republic and ushering in the Roman Empire.  The ruler of the Egypt was Cleopatra, so in one post we get Cleopatra, Julius Caesar and Mark Antony (related).   I also have to say that while it's published on, which is a site for popularizing science research, that they talked about the affects to the climate.  No, a volcanic winter is no more a climate event than a nuclear winter.  It's a weather pattern.  If it doesn't last at least 30 years, and more like 50 years, it's weather not climate.


Sunday, June 21, 2020

What If I Trust Science, But Don't Trust Big Government Science!

If you pay any attention at all to the drivel coming from the leftist media (the vast majority of media) you'll have heard the idea that anyone who questions anything from authority is a "science denier."  That's an awful term, crafted to create a subconscious link to holocaust deniers.

This has been rumbling in my mind a lot, but credit (blame?) PJ Media author Stacey Lennox for bringing it into focus today with her piece, "What If I Trust Science and Don't Trust Dr. Fauci?"  Her emphasis is on Dr. Fauci and the Kung Flu crisis, but it's broader than that.  Let me go with a few of her points for a while.

To begin with, she quotes Dr. Fauci himself from a US Department of Health and Human services podcast saying:
“One of the problems we face in the United States is that unfortunately, there is a combination of an anti-science bias that people are — for reasons that sometimes are … inconceivable and not understandable, they just don’t believe science, and they don’t believe authority,”
The problem is that this week, the same Dr. Fauci admitted that he lied to Americans about the effectiveness of masks. They decided to tell us masks didn’t work rather than tells us they were effective in preventing the spread, but please refrain from buying them until we have an adequate supply for healthcare workers.  Personally, I believe if they had simply said, "if you buy up all the masks and healthcare workers don't have them, we'll have to abandon hospitals because workers are required by law to wear them" that people would have been understanding and bought up fewer masks.

It's a lot easier to trust people who don't have a documented history of lying to you.  Could that be part of it Dr. Fauci?

Another topic that doesn't make sense and leaves me with Looney Tunes-style question marks in the air over my head is why is an old, well-known drug that was showing promise against the disease so politically divided?  The easy answer is that a couple of conservative commentators started talking about success with Hydroxychloroquine and then the president started talking it up.  Suddenly, liberal commentators couldn't acknowledge they might be right.  Dr. Fauci joined the liberal pundits against the drug.  Ms. Lennox (a Registered Nurse) says:
The debate over this generic drug that has been in use for decades is one of the most puzzling and ridiculous things about the entire pandemic. The medicine was politicized and became controversial. After researching it myself and listening to practicing physicians who were using it, I expected Dr. Fauci to step up and clarify why there was a reason to believe it may work in conjunction with the mineral zinc. He never did.

I found this odd since the drug’s older cousin, chloroquine had been demonstrated to inhibit the SARS virus, which has a 90% overlap with COVID-19. The NIH did this study in 2005, where Dr. Fauci is a director.
We report, however, that chloroquine has strong antiviral effects on SARS-CoV infection of primate cells. These inhibitory effects are observed when the cells are treated with the drug either before or after exposure to the virus, suggesting both prophylactic and therapeutic advantage.
Any doctor that was recommending the treatment recommended it be given with zinc. The properties of zinc on RNA viruses, which COVID-19 is, are also well known. Again a study from the NIH in 2010 shows that with a companion ionophore, or drug that allows more zinc to enter the cell, the mineral interferes with the replication of the virus. Both chloroquine and hydroxychloroquine are zinc ionophores.
When people see contradictory messages, they try to understand why one group of doctors currently treating patients with these combinations and reporting excellent success gets no press or negative press, while another group of doctors saying it's poisonous and will kill people gets all the media attention.  As result, people try to think of reasons and decades of experience with government at all levels brings thoughts of corruption to mind.  I really doubt that I'm the only guy who has heard people saying Dr. Fauci and the Anointed Health Experts must be in the pocket of Big Pharma.  After all, they argue, why use a very old, cheap, generic drug when there are newer, more expensive drugs, like Remdesivir that can be sold?   Why should they allow drugs that cost a couple of bucks per dose when there are drugs that cost a hundred or hundreds of bucks per dose? 

Again, it's easier to distrust people who have lied to you before.

Stacey Lennox's article contains more good information related to the virus crisis, but if you take the same thoughts and expand them to wherever government big Science! is involved, you get similar answers.  The easy one to cite is climate change.  The trillions of dollars at stake have attracted the grifters that humongous sums of money always attract and every claim has to be carefully examined. 

Another example is the USDA Dietary Guidelines.  The science behind the USDA recommendations is atrociously terrible - the King of Junk Food Science is an example of the kinds of stuff they're based on.  Part of that is because it's both ferociously hard and expensive to do the kind of experiments that can give the answers people want.  While, saying, "it's too hard" is a hell of a poor thing to say, it's better that they're honest about how tenuous their data is.  The committees drafting the 2020 Guidelines have been meeting this year and they've been more (apparently) corrupt than ever, prompting federal Whistle Blowers to come forward and report bad behavior on the part of the subcommittees involved. Full disclosure: I've donated to the Nutrition Coalition and think that their work is good.

It would be better for the USDA guidelines to be shut down and the government to get out of the business of telling people what to eat, but right now that would require many laws or regulations to be revoked because the dietary guidelines influence military meals, school lunch (and breakfast) programs, hospitals, nursing homes and all sorts of institutional programs that feed people.  

Real science is a rigorous process for learning.  It's never preaching from a standpoint of "I'm all-knowing" and it's never "settled" except in the rare cases of physical law and one way you can be sure it's settled is that nobody is doing research into a field.  Nobody disputes that gravity exists; there might be research into fine details of the subject, but the fact that gravity exists is settled.

In the case of a new disease, nobody can be expected to know enough about it when it first appears.  It was quickly apparent that the doctors on front lines treating patients knew far more about it than the Experts.  Consequently, if people don't flock in admiration to the Anointed Experts, it's not that people have "an anti-science bias," it's that they know they've been lied to before or that their life's experiences tells them something funny is going on.  You see, Dr. Fauci, it's not "anti-science bias" to question things.  Questioning things is the essence of science.  Just accepting things the scientists say is the essence of religion. 

Dr. Fauci and Vice President Pence, April 19 Covid-19 press conference.  (AP Photo/Andrew Harnik)

Saturday, June 20, 2020

A Ham Radio Series 5 - Antenna Polarization

One of those questions that comes up from time to time is from someone who has heard antennas are polarized and wants to know if that matters.  The answer, as always, is that it depends. 

The polarization of the radio waves from an antenna is ordinarily given as the polarization of the electric fields.  As a recap, a radio wave is an electromagnetic wave, like ordinary light but lower in energy.  In the 1800s, you may recall from reading or a class at some time, it was thought that light propagated in a medium called the Luminiferous Aether because there was ample evidence light traveled in waves and how can there be waves that aren't waves of something.  Without spending too much time here, the presence of the Aether was disproved by the Michelson-Morley experiment and then finally buried by early 20th century advances.  Long before that, Maxwell described how an electromagnetic field can propagate forward as a changing electric field created a changing magnetic field which created a changing electric field ... repeating forever. 


Animation of EM wave propagation; by convention the electric field is called E while the magnetic field is B.  The important part to notice here is that both fields maintain the same orientation as they propagate.  

The general rule is that horizontal antennas produce horizontally polarized radio waves while vertical antennas produce vertically polarized antennas.

Why do we care?  Anytime radio propagation is local or line of sight, the polarization will be maintained and various radio services have established preferences for polarization.  An antenna set for one polarization rejects the other.  The theoretical attenuation on a cross polarized signal, like a horizontally polarized signal on a vertical antenna, is infinite.  You never get truly infinite rejection because that depends on the antennas being perfectly perpendicular to each other, and very small angular differences matter.  A cheap and dirty workaround, although you lose signal compared to antennas in alignment, is to rotate one antenna 45 degrees to the vertical.  This loses 3 dB compared to perfect alignment, but is an easy workaround if you were to be unsure of how signals would arrive at your antenna, vertically or horizontally polarized. 

Virtually any service that uses vehicle mounted antennas or handheld radios is based on vertically polarized signals - taxis, police, fire, emergency medical, and ham radio FM services (most popularly the 2m or 440 MHz handhelds or car mounted radios) come to mind.  I know of no exceptions.  While vertical polarization is the default on the 2m repeaters, if you drop down to 144.200 and switch over single sideband, the default there is horizontal polarization.  A few times over the years, I've heard guys just getting started on sideband using their vertical 2m FM antennas and being disappointed until they rotate the antenna. 

If the propagation is ionospheric, the polarization gets "scrambled "in the ionosphere by a phenomenon called Faraday rotation.  This goes for your attempts at working the other side of the world or the guy behind the next hill by sending your signal straight up.  If you're using a vertical to work some remote island and they're using a horizontally polarized beam (or dipoles) polarization doesn't matter. 

Horizontal and vertical polarization are just the basics, there are other kinds.  Circular polarization, (the general case is elliptical polarization) is a natural phenomenon - see the previous link on Faraday rotation - and is commonly used in some satellite downlinks.  Quadrafilar helix or turnstile antennas are common amateur approaches to receiving weather satellites.  The tricky part here is that there are two types of circular polarization, too: Right Hand and Left Hand Circular Polarization (RHCP and LHCP).  Those antennas reject the other polarization and I don't know of a trick like mounting the vertical or horizontal antenna at 45 degrees. 

If you're interested in HF, polarization is less important than the antenna pattern you get from either a horizontal or vertical antenna.  The effect of antenna height is talked about in this post from February of 2018.  

The same 40 meter dipole mounted at 66' above ground (left) and one foot above ground (right).  On the left it's a respectable pattern for long distance contacts.  On the right, it's an NVIS (Near Vertical Incidence Skywave) for local contacts.  Vertical antennas tend to have low angles of radiation, like the dipole at 66' but with even lower take off angles. 

Friday, June 19, 2020

Shop Update

It has been almost three weeks since I posted an update.  I ended up spending more time than usual in the ham shack instead of the metal shop last week.  The parts I'm working on are either small or fiddly or both.  Let me show you some of what I've been up to.

The top piece is the simplest, but still a fiddly bit.  It's a washer made from brass rod that's 1/4" OD with a 1/8" hole down the center.  It's easy to do this; the only touchy operation is cutting off a .015" thick sliver of a brass rod with a 1/8" hole down its center.  The cutoff tool usually leaves a nib that has to be trimmed off and then the whole thing needed to be lapped on sandpaper to bring the thickness down about .003".  I could make washers like this and sell them, but one of these would cost you the same as a box of 1000 stock washers.  It's kind of silly to make things like this.

The piece of bar at lower left is straightforward cut a piece of 1/4" drill rod to 0.938" long and then move it to the mill (or good drill press) to drill a 1/16" cross hole through it 0.844" from one end. 

The piece at the lower right is the blank for the cam pictured just to its left.  I've never made a cam like this and there's a couple of ways to make them.  The plans I'm using recommend using a method developed by a guy named Hamilton Upshur, which requires building a fixture to turn the cam eccentrically - that is, off the centerline of that big 3/8" reamed hole in the center.   I had no idea what that fixture needed to be until I found a video that's one of a series where this guy takes you through building an entire engine that Upshur published.  Late in the video, I got a good look at some prints he kept using, paused the video, screen captured the frame and improved its appearance. 

The fixture I'm making is at the upper right.  In the first picture, the 3/8" "peg" the designer calls out is lying on the top right edge of the print; the big 1" diameter cylinder that holds the peg is waiting to be drilled for it on the mill.  The peg is through-tapped, 8-32 instead of 6-32 because I prefer 8-32 screws.  Tomorrow, I should be able to complete the fixture and maybe make my first attempt at the cam.  A finished cam is in the middle of this screen capture, and it looks very much like the one I'm trying to make.  With this method, the cam is largely machined by hand; the fixture just makes it easier to hold the work for those odd cuts.

There's another method for cutting cams that has been shared by a home engine modeler named Chuck Fellows, and his video details how he got there.  It seems a bit fussier to set up than this, but probably gives a more controlled shape.  Fellow's method fixes the cam blank on a rotary table which then moves for all the cuts while Upshur's method uses a lot of hand work; tighten down the screw that holds the blank in place, make a cut, loosen the screw, change the blank's position, tighten the screw, make a cut, and repeat.  Over and over.  
The topic of making cams is of great importance for engine manufacturers, especially generating the curves mathematically.  I've read several things on this, including equations that can be plugged into an Excel-compatible spreadsheet.  Take this exercise:  the green circle is the starting blank; the big white circles cut the left and right flanks; the center points where the center of a boring head should sit while rotating to cut those big white circles are computed and displayed.  The boring head is cutting an inside diameter, not an outside diameter. 

This rabbit hole is as deep as you want to go and as techno-geeky as you want to get.