Loss of signal when using one antenna with two scanners

[n1chu]

Two BCD996P2 scanners fed by one antenna using a BNC “T” as the splitter. The antenna uses a “N” connector and the LMR400 coax has “N” connectors on both ends. An adapter was added (N to BNC) to feed the “T” connector and two runs of LMR400 feed the scanners.

While receiving a trunked P25 system one scanner hears this system but the other does not… it did when it was first added but now it doesn’t. Only one of the scanners if adversely affected-it’s always the same scanner. Both scanners are programmed identical-cloned. Any ideas why this happened?

It should be noted that while both scanners are programmed identically (cloned), and a simple extension speaker should be all that’s needed to hear the same in two different locations, it was decided a second scanner should be used in order to allow for lockouts for the two respective rooms being served. One room is a meeting room and the other is the dispatch center in a firehouse. It gives either location the ability to “Avoid” certain agencies, lower volumes, etc.

 

[bearcatrp]

I tried one of those a few years back. Enough issues like yours made me change course to get a stridesburg 4 port. Problem solved.

 

[kc2asb]

I tried one of those a few years back. Enough issues like yours made me change course to get a stridesburg 4 port. Problem solved.

Same here. I found that the scanners can interfere with each other as well. The distribution amp is the best solution.

Wish I had known about these 15+ years ago else I would not have installed multiple antennas!

 

[bearcatrp]

Thought about multiple antennas but decided a discone that covers up to 3Ghz covers my needs. Can always get a pre amp if needed but so far not needed.

 

[W9WSS]

T-connectors will cause issues between both scanners. Obtain a Stridsberg or equal quality pre-amplified splitter. Your problems will be solved. I own three Stridsberg's for various scanner configurations in two areas of my QTH.

 

[mmckenna]

Oscillator noise cross-mojonating between the two scanners, likely. Use a proper splitter with some isolation.

 

[KevinC]

While receiving a trunked P25 system one scanner hears this system but the other does not… it did when it was first added but now it doesn’t. Only one of the scanners if adversely affected-it’s always the same scanner. Both scanners are programmed identical-cloned. Any ideas why this happened?

Like everyone else said, a "tee" isn't the best choice, but since it used to work and now it doesn't something changed. I'd (obviously) suspect the cable from the tee to the non-working unit.

 

[wtp]

anyone touch the squelch setting, it should be on 2.
also if some of the stuff you listen to does not need an outside antenna, don't use it.

 

[n1chu]

Thanks for your inputs. The question was posted by myself on behalf of a friend who, after doing his own research became confused with the Stridesburg’s, Combiners/Splitters, in-line amps, with each having their own drawbacks such as the ability to isolate, db loss on numerous bands, not to mention the prices.

 

[exkalibur]

You can also "cheap out" and get a power divider. It isn't as good as the Stridesburg but if the received signals are decently strong, it'll work fine.

https://www.amazon.ca/Splitter-100-2700M-Frequency-Divider-Combiner/dp/B07SJL2XXD - as an example.

 

[buddrousa]

You get what you pay for and as I always say use the right tool for the job.

 

[exkalibur]

You get what you pay for and as I always say use the right tool for the job.

Absolutely true. Just saying that if someone doesn't want to spend hundreds, these may be a reasonable alternative.

 

[kc2asb]

Thought about multiple antennas but decided a discone that covers up to 3Ghz covers my needs. Can always get a pre amp if needed but so far not needed.

When Radio Shack was blowing out the #20-176 groundplane antennas, I bought several and installed them in one of the eaves in the attic and ran the feedlines down two floors. Out of sight and out of mind, and they work quite well.

I'm in RF Alley/NYC area, line of sight to Manhattan 5 miles to the northeast. Outdoor antennas tend to cause overload/desense issues.

 

[Brales60]

Been running a Stridesburg myself with a SDS200 and BCD996P2 with a Omni X. I love it, and no issues either.

 

[KevinC]

I still vote for something changed and I'd look at the cabling from the tee to the non-working unit seeing how it used to work. But I've only been troubleshooting things for 50 something years, so I could be wrong.

 

[kc2asb]

I still vote for something changed and I'd look at the cabling from the tee to the non-working unit seeing how it used to work. But I've only been troubleshooting things for 50 something years, so I could be wrong.

50 years? Wow. I didn't even think you were 50 years old. I agree with you here. If it was working before, check for problem components in the installation.

 

[KevinC]

50 years? Wow. I didn't even think you were 50 years old.

I may not be older than dirt, but I do remember when it was new.