Electroline Drop Amp/Multicoupler Problems

[hdralleiii]

I recently installed a 4 port Electroline Drop Amp / Mulitcoupler as an alternative to the expensive Stridsberg mulitcoupler offerings. I have 1 antenna feeding several radios used for live ATC and Railroad Feeds. The problem I am having is that even with the 25db isolation of the ports, the railroad radio is still bleeding over in to the airband receiver. I have a Motorola Maxtrac for the railroad feed and a Uniden BC350A for the airband stuff. I do NOT get air bleeding into the Moto and I am thinking that the Moto is just too much for the tiny Uniden scanner.

Anyone else using this type of amp and having these problems? I have a second 350A enroute from eBay and think that may solve my problem (to put in place of the Motorola). A brief test using my VX-6R in place of the Motorola seemed to remedy the problem a bit....

Any other suggestions?

Thanks!

 

[N_Jay]

Are you trying to transmit through it?

What do you mean by "bleed"?

 

[hdralleiii]

No transmit, strictly RX for feeds being sent to the internet for public listening. Basically if you are listening to the airband feed, you can faintly hear the railroad feed in the background. The sound cards and feed are running on different computers so its not internal to the PC. Shut off the railroad radio and all is well. Kinda puzzling. It was louder with a regular splitter, but I thought that the 25db port isolation would cure it altogether. Apparently not!

 

[smason]

Something definitely not right there. I don't think it's the coupler, I'd look at the audio connections.
Maybe a ground loop

 

[N_Jay]

Yes, it has to be something with the audio signal leaking on the ground or power.

It would have nothing to do with the antenna connections (except that may be where the grounds are tied together).

 

[hdralleiii]

Well, I did some in depth troubleshooting and determined that several things are wrong with the Maxtrac radio. The audio cable had a bad/loose pin, the antenna jack seems just a little loose and the internal speaker seems to have a short (without a jumper - should be silent). All of these things can and likely did cause some grounding issues, so I may have located the trouble source. I noticed my feed for Washington Center (ZDC) is much cleaner now on the 2 freqs that are scanned. I have pulled the Moto radio out of the mix pending further testing and possbile repair by a friend at the local Moto shop. I will just use the 2nd Uniden BC350 when it arrives next week.

I have now done a permanent install on the Electroline with all new RG-6 jumpers and compression connectors. Looks and works sweet. Now I just need several more radios!

Appreciate the help!

 

[N_Jay]

Well, I did some in depth troubleshooting and determined that several things are wrong with the Maxtrac radio. The audio cable had a bad/loose pin, the antenna jack seems just a little loose and the internal speaker seems to have a short (without a jumper - should be silent). All of these things can and likely did cause some grounding issues, so I may have located the trouble source. I noticed my feed for Washington Center (ZDC) is much cleaner now on the 2 freqs that are scanned. I have pulled the Moto radio out of the mix pending further testing and possbile repair by a friend at the local Moto shop. I will just use the 2nd Uniden BC350 when it arrives next week.

I have now done a permanent install on the Electroline with all new RG-6 jumpers and compression connectors. Looks and works sweet. Now I just need several more radios!

Appreciate the help!

Did you try a non-amplified splitter?

 

[zz0468]

Well, I did some in depth troubleshooting and determined that several things are wrong with the Maxtrac radio. The audio cable had a bad/loose pin, the antenna jack seems just a little loose and the internal speaker seems to have a short (without a jumper - should be silent). All of these things can and likely did cause some grounding issues, so I may have located the trouble source. I noticed my feed for Washington Center (ZDC) is much cleaner now on the 2 freqs that are scanned. I have pulled the Moto radio out of the mix pending further testing and possbile repair by a friend at the local Moto shop. I will just use the 2nd Uniden BC350 when it arrives next week.

I have now done a permanent install on the Electroline with all new RG-6 jumpers and compression connectors. Looks and works sweet. Now I just need several more radios!

Appreciate the help!

How are you getting audio out of the Maxtrac? If you're using speaker audio, be aware that both of the speaker leads are floating, and not referenced to ground. That could cause all manner of problems. The answer to that is to use an isolation transformer.

If it's a 16 pin radio, the jumper is required for the internal speaker to work. Sometimes, someone has put the jumper in, internally. If it's a 5 pin radio, I believe the speaker is connected without the use of an external jumper.