Maybe I've been triggered because I'm sensitive to the topic, maybe I'm sick
of the same old ... stuff, but I saw something supposedly coming from Bobby
Kennedy and
the MAHA folks. I've spent hours looking for it between yesterday and today but
couldn't find it again. Which makes me doubt talking about this, but
it's a slow news day.
What I'd swear I saw was a list of things that they're supposedly interested
in looking into the health effects of the High-frequency Active Auroral
Research Program (HAARP). Coming from a career in radio design -
transmitters, receivers and all the major subsystems in them - I've heard
absurd fear of radio signals for so long, I start subconsciously twitching
when I come across a new story.
Let's start here. Most people don't think this way but every minute of
every day you live immersed in a constant soup of radio signals. Forget
about your phone or your home WiFi router, the things you usually think of,
there are sources from almost audio frequencies through broadcast radio,
shortwave broadcasters, TV over the air, police radios, taxi radios, weather
radios and on and on up into the microwave spectrum and beyond that into what
are called millimeter waves that you're exposed to every day. Some of
them all day, some of them irregularly or intermittently. Unless you
take absurd steps to prevent this - forget the tin foil hat, it's more like a tin foil 100% cover - you live in this every day. If you turn off your phone, you turn
off what it produces; the signals from every other phone and every cell tower
are still there.
So let's think of it in another way the most people won't. The first law
of Toxicology - the study of toxins or poisons is "The Dose Makes the Poison" and the guy who started the field said a big enough dose makes something
toxic that isn't usually thought of that way. The classic example is
oxygen; not just nontoxic but essential to life, as in without it we
die. At a high enough partial pressure, it's toxic. That's why
really deep sea diving doesn't use compressed air but exotic mixes of other
gases and oxygen.
A big enough "dose" of radio will burn you. Since radio is just very, very far infrared light, it immediately brings to mind a laser.
Lasers are high power lights and dose is the power. Can high power radio
hurt you? Absolutely! That's why there are limits imposed on the power that systems can produce that people can be exposed to. The power required to hurt someone depends
somewhat on the physical size of the radio waves; the allowable power for a
system to expose the general public to is lowest around the FM broadcast band
because people are similar in size to 1/4 wavelength at some point in the FM
band, depending on how they're sitting; 234/freq. in MHz gives 1/4 wave, so
2.66 ft @ 88 MHz and 2.17 ft @ 108 MHz.
The saving grace of all that radio soup we live in is that it's all low power by the time it
gets to us. Radio signals drop off in power very fast. It drops
to 1/4 of the power every time you double the distance from the
transmitter. A relationship I've shown many times here is a bit less
accurate than the fully rigorous calculations, but it's easy to stick in a
spreadsheet somewhere and use it when you need it.
Path loss in dB = 37 dB + 20log(f) + 20log(d) where f is the frequency
in MHz and d is the distance in miles.
What's a dB? It's a decibel, a power ratio. A loss of 3 dB is 1/2 the
power, -6 dB is 1/4, -9 dB is 1/8. So imagine you're calculating how
much power you're exposed to from an FM broadcaster in town.
Path loss in dB = 37 dB + 20log(100) + 20log(10) where f 100 MHz and d
is 10 miles
Path loss is 97 dB
Now 97 dB is a lot of loss, but FM broadcasters often start out with high
powers. I have a local FM station here in town that says they start out
at 1000 watts. Us Receiver guys refer to that as 60 dB more than 1.00
milliwatt or +60 dBm transmit power (dB is ratio, dBm is a power ratio to 1
milliwatt). Taking away 97 dB of that gives me -37 dBm. That's a
perfectly usable signal to a radio receiver, but it's 3.2 millivolts RMS or
.0032V on digital voltmeter. That's not going to hurt anybody or
anything.
So let's do the same thing with
HAARP, according to their documents. The frequency is 2.7 to 10 MHz, and the distance depends on where you
are with respect to the transmitter. Essentially the distance is up to
the ionosphere and out to your location. The ionosphere covers a fairly
wide range of altitudes, but at most is in the "couple of hundred miles" range
(photo below) and the altitude will drop out of the equations for a path to
the center of the country. Some web searches show
the center of the US is just outside of Lebanon, Kansas, and that it's close enough to say 3300 miles from HAARP.
Path loss in dB = 37 dB + 20log(10) + 20log(3300) where f 100 MHz and
d is 10 miles
Path loss is 127 dB
The power of HAARP is variable, the antenna pattern can change plus there are other differences depending on what the experiment is. That said, 3.6 Million Watts is 95.6 dBm and after the path loss
the level is close to previous example - a bit stronger at -31.4 dBm or closer
to 6mV, .006V.
Atmospheric layer heights from Wikipedia
I tried to pick numbers for the distance that weren't too far from or too close to Alaska to be reasonable, but it's a bit surprising that these numbers ended up being within a couple of dB for a local, low power FM station and HAARP. Bottom line is I still see nothing about that situation that's remotely scary. As a general rule, the only time a radio signal can be dangerous is if you're close enough to touch the transmitter.