4 ms·

I don't like being around antennas. Especially when hiking trails take me past one of those microwave horns. Maybe it's a phobia, but I always wonder if hiking

I don't like being around antennas. Especially when hiking trails take me past one of those microwave horns. Maybe it's a phobia, but I always wonder if hiking trails were taken into account.

therein 5y ago
I sometimes feel the same way walking around in SF. There are just way too many buildings and fixtures that are actually antennas that are concealed to not look that way. I measured 20mW/m2 around 2nd and Harrison.
- strangus 5y ago
  Just curious, how did you measure that? Are you constantly scanning?
  - sytelus 5y ago
    I had bought Extech RF meter for $600. It seems to be the most reliable and accurate.
- formerly_proven 5y ago
  > I measured 20mW/m2 around 2nd and Harrison. For reference, on a sunny day the sun will dump 200+ W/m² on you in SF.
  - Gnarl 5y ago
    Q1: How much ambient RF spectrum intensity has there been during evolution vs. sunlight exposure? Q2: How much has ambient RF spectrum intensity risen today vs. natural background levels? A1: Virtually none. A2: 10^18
    - hypefi 5y ago
      this, it is not just about the intensity, it is that all organism have evolved to around sun exposure, not much around artificial light/Emf exposure...
myself248 5y ago
The microwave horns are incredibly, incredibly tightly focused, though. (That's why they made 'em so big.) If you're not literally between the two ends of the link, you're not getting significant energy. And if the beam actually touched the hill, it'd diffract badly and spoil the signal. Also I don't think any of those are still active, are they? Most of 'em that I've seen have the feed waveguides removed where they get near the ground. I always thought it'd be fun to make an adapter/coupler and stick a wifi card onto one of 'em because 2400Mc is within their passband, but I can't find a pair pointing at each other where both ends still exist.
EdwardDiego 5y ago
Yeah they are. The inverse square law is very real when dealing with non-ionising radiation. I used to work in radio spectrum governance, our inspectors who were clambering up towers on the regular made to sure to not stick their head or gonads in front of a focused microwave transmitter for more than 10 - 20 seconds (IIRC). All of those inspectors have retired now, and none of them have brain or testicular cancer, likewise none of their children had birth defects. So I think you'll be fine unless you're sticking your head in the dish :)
- kodah 5y ago
  When I worked in comms the running joke was that all of us that did things with high powered RF would only have girls. No idea if there's truth behind it.

I don't like being around antennas. Especially when hiking trails take me past one of those microwave horns. Maybe it's a phobia, but I always wonder if hiking trails were taken into account.

therein 5y ago

I sometimes feel the same way walking around in SF. There are just way too many buildings and fixtures that are actually antennas that are concealed to not look that way. I measured 20mW/m2 around 2nd and Harrison.

strangus 5y ago
Just curious, how did you measure that? Are you constantly scanning?
- sytelus 5y ago
  I had bought Extech RF meter for $600. It seems to be the most reliable and accurate.
formerly_proven 5y ago
> I measured 20mW/m2 around 2nd and Harrison. For reference, on a sunny day the sun will dump 200+ W/m² on you in SF.
- Gnarl 5y ago
  Q1: How much ambient RF spectrum intensity has there been during evolution vs. sunlight exposure? Q2: How much has ambient RF spectrum intensity risen today vs. natural background levels? A1: Virtually none. A2: 10^18
  - hypefi 5y ago
    this, it is not just about the intensity, it is that all organism have evolved to around sun exposure, not much around artificial light/Emf exposure...

myself248 5y ago

The microwave horns are incredibly, incredibly tightly focused, though. (That's why they made 'em so big.) If you're not literally between the two ends of the link, you're not getting significant energy. And if the beam actually touched the hill, it'd diffract badly and spoil the signal. Also I don't think any of those are still active, are they? Most of 'em that I've seen have the feed waveguides removed where they get near the ground. I always thought it'd be fun to make an adapter/coupler and stick a wifi card onto one of 'em because 2400Mc is within their passband, but I can't find a pair pointing at each other where both ends still exist.

EdwardDiego 5y ago

Yeah they are. The inverse square law is very real when dealing with non-ionising radiation. I used to work in radio spectrum governance, our inspectors who were clambering up towers on the regular made to sure to not stick their head or gonads in front of a focused microwave transmitter for more than 10 - 20 seconds (IIRC). All of those inspectors have retired now, and none of them have brain or testicular cancer, likewise none of their children had birth defects. So I think you'll be fine unless you're sticking your head in the dish :)

kodah 5y ago
When I worked in comms the running joke was that all of us that did things with high powered RF would only have girls. No idea if there's truth behind it.