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Old 04-15-2017, 9:23 PM
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KG5HHS KG5HHS is offline
Join Date: May 2015
Location: San Angelo, TX
Posts: 426

Originally Posted by ka3jjz View Post
You should be (ahem) aware of RF safety rules and guidelines, so I won't go into them here. But to your 3 questions;

1. I suspect that 10 foot separation will at least prevent the transceivers (I am assuming a typical 2m/440 base/mobile here) from frying the front end of the scanners. However I would still anticipate that the scanners might start acting weird (locking up, etc.) due to any near field proximity. Personally I'd just make sure I wasn't transmitting while listening on the scanners. I had a somewhat similar situation just recently, except that all of my antennas were in an attic.

2. The further apart the antennas are, the better. Vertical separation is as important as horizontal in such situations

3. Listen carefully to your weaker aviation stations - or even better, pick an inactive frequency and see if there's a bit of hash (or worse, a little FM breakthrough) on the signal. If either is the case, then yes, I'd consider a FM trap. I've heard several second hand reports that it can help - it certainly won't hurt anything but your wallet (hi).. An example of one is linked below - the insertion loss at VHF air is very small, darn near undetectable unless you are chasing really weak signals...

VHF-FM Broadcast Filters | PAR Electronics | Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts

I probably don't know about RF as much as I should. I remember talking about human exposure in ham class two years ago. I'm also not very familiar with the front end on a scanner. I may need to come up with a different solution as these scanners will also be used for streaming. On another note, would using LMR400 coax for both the scanners and radios be a good choice or would it be over kill? I will be running coax in 3 bundle clusters if you will, 3 coax cables going out through the wall, and 3 coax cables going up into the attic. Would running them side by side be as issue?
John Longoria
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