Scanner is downtown at 40 feet. At the end of approximately 160 feet of LMR. Antenna (3 db gain 800 base)and cable check ok and shows signals across 800 MHz (target range). Scanner works everywhere but at the end of the cable. Thoughts?
Radio and antenna combination doesn't work
- Thread starter smurf8002004
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marksmith
Member
160 feet is a long ways. If your cable has any loss it could impact things
536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others
536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others
What variety of LMR? That's quite a run for 800mhz...
A 160 ft. run of LMR-400 will have around 6 db loss at 800 Mhz (give or take). You say you checked the coax. How did you check it? With an ohm meter or actually at 800 Mhz. Were the connectors attached by someone experienced? Is the antenna known to be good? The 3 db gain antenna will only offset half the loss in the coax. A 6db loss (in terms of voltage) is a loss of half the signal.
mmckenna
I ♥ Ø
If you are referring to Times-Microwave brand LMR cable there are many different models, everything from LMR-100 up to LMR-900, and they vary quite a bit.
You need to be more specific.
As was suggested, how did you test it? What type of test did you do, and what type of test equipment (again, be specific).
There can be a lot of reasons for a setup like this to not work well. Everything from cable issues to high RF levels near the antenna. Providing some background info would give us enough information to assist you in your troubleshooting.
You need to be more specific.
As was suggested, how did you test it? What type of test did you do, and what type of test equipment (again, be specific).
There can be a lot of reasons for a setup like this to not work well. Everything from cable issues to high RF levels near the antenna. Providing some background info would give us enough information to assist you in your troubleshooting.
JamesO
Member
Check resistance between the coax without an antenna connected, then put a resistor at the end of the cable and verify the connectors are properly connected.
Terminating of connectors and the proper connects are KEY to a decent RX set up.
Make sure you are not having problems with the center pins being too small in diameter or recessed for some reason. No physical connection is usually like a 30 dB attenuator.
I run a very successful set up using about 120 feet of RG6 cable with a very low noise preamp and FM filter at the base of my antenna. This is a really good set up that has no intermods and no overloading. I am running 8 radios off this set up with other higher noise figure to overcome the loss of the splitters. The KEY is to have a VERY low noise amp at the base of the antenna.
See this and search for my user name in the Scanner Antennas, Coax and Filter section - https://forums.radioreference.com/splitters-filters-multicouplers/338568-scanner-pre-amps.html
Terminating of connectors and the proper connects are KEY to a decent RX set up.
Make sure you are not having problems with the center pins being too small in diameter or recessed for some reason. No physical connection is usually like a 30 dB attenuator.
I run a very successful set up using about 120 feet of RG6 cable with a very low noise preamp and FM filter at the base of my antenna. This is a really good set up that has no intermods and no overloading. I am running 8 radios off this set up with other higher noise figure to overcome the loss of the splitters. The KEY is to have a VERY low noise amp at the base of the antenna.
See this and search for my user name in the Scanner Antennas, Coax and Filter section - https://forums.radioreference.com/splitters-filters-multicouplers/338568-scanner-pre-amps.html
It's not clear on what you are saying. Subject says "Radio and antenna combination doesn't work" Does that mean you tried another scanner and/or antenna and it worked? What do you mean by "Scanner works everywhere but at the end of the cable"? Is the scanner connected to the antenna cable the whole time during the test? Are you moving the scanner around to other locations? Any splice connectors on the cable? Battery or AC powered?
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