HFU HF Underground
Technical Topics => Propagation => Topic started by: Rizla on September 12, 2020, 2306 UTC
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I found this:
The Signal Propagation Effects on IEEE 802.15.4 Radio Link in Fire Environment
https://www.researchgate.net/publication/232708332_The_Signal_Propagation_Effects_on_IEEE_802154_Radio_Link_in_Fire_Environment
and a PhD thesis from Australia. I don't know if they've experimented on the kinds of high altitude smoke atmospherics over CA and the SW right now, which are turning the sun orange, blotting out the stars, and making the sun disappear behind grey before sunset.
The studies were 50 meters and up, for emergency comms. I didn't find much on HF effects.
Also found this map of current air quality:
https://www.purpleair.com/map?opt=1/mAQI/a10/cC0#8.6/32.3781/-111.1294
Which is pretty lousy here, but nothing compared to the West Coast right now.
Mucho thanks in advance for any resources on the subject(s).
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Interesting!
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The air pollution here is worse than last night, and the night before. We're a good distance from the forests burning on the West Coast.
Subjectively on HF, it seems that reception may be up a bit, and transmission dampened, so to speak. There were a lot of contests on today, and I heard a lot of people, but only made as far as Alabama on 100 watts tx/QSO-wise. At least four contacts in that state. Now, whether that was due to lack of trying and/or the weird ash cloud hanging over parts of the southern/western US....? Dunno. I'll be talking on the radio tonight and hope to learn more about conditions out in CA.
[Edit: found typically curmudgeonly Eham discussion: https://www.eham.net/community/smf/index.php/topic,130877.0.html
AFAIK they were discussing the situation a few days ago. I wonder who has computer models for a situation like today? People who study
Volcanoes who are hams, maybe...?
Another Edit: It looks like a minor Mt. St Helens level out there tonight, and I am in Southern AZ...]
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I understand the effects on the microwave bands, but given the smoke particle size I doubt there's any effects on HF.
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So, you're saying that it might be my own incompetence and lack of killer antenna, rather than my proposal? How dare you? ;-)
I get it, I get it. I was on the local repeater last night, none of the guys there (none of them were HF guys, just repeater guys) wanted to talk about that the sky isn't blue these days.
My whole thing is that I don't think anyone's made a model for this stuff. I think HF/VHF/UHF is the least of our concerns and problems. That's a side issue to the real human damage going on.
My other thing is that it's only on a board like this one that I could even voice a concern. The straight laces of Ham Radio don't want to listen to pirates, how are they gonna care that the sky isn't blue?
By the way, I thought I'd said this before, but huge kudos to Chris S.... As you said, Chris, it's "interesting"....
[Edit: there is no forum/board like this one, and no community like the one here, on Earth AFAIK. Chris S got the job done. Again, kudos and a million thank you's that are thought all the time but too rarely said...]
Some of us have firefighter friends....
Thanks for putting up with my rants, as always!
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From NWS State College:
Smoke can filter out shortwave radiation from the sun resulting in cooler days, but is not as effective in absorbing longwave radiation (the smoke particles are too small), so it has less impact on overnight low temps
I know solar shortwave and longwave heat from the earth is not RF but it's all radiation.
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To truly affect ionospheric propagation, the smoke would have to be 50-100 miles up, I think.