Dropout of specific subscribers when receiving through repeater

[otobmark]

This is more of a curiosity inquiry than something I need to fix. Using both Motorola and Kenwood (commercial grade) radios with pl decode on I get very short audio dropouts which seem to correlate with particular radios as they transmit through the repeater. The repeater is generating the PL which continues through hang time so I am mystified as to why my radio squelches on only certain radios. If I disable PL decode then no dropout. On one repeater there is a voice ID which has a dropout in the middle—worse on my Kenwood. What could a transmitting radio do that would close my squelch momentarily as I listen to repeater output? If it were every radio (input) having the problem then I’d suspect repeater PL dropping out or loosing sync.
I hate unsolved mysteries.

 

[a417]

they are out of tune/spec.

if they are specific radios, those radios need to see a service monitor for some TLC.

 

[nd5y]

What kind of repeater is it?
Low frequency audio that isn't being filtered from the repeater transmitter might be interfering with PL decode on your radios.
PL transmit on the repeater may be off frequency or improper level.
Maybe your receivers are defective.
Maybe other reasons.

 

[12dbsinad]

I'd first check the repeater and the PL deviation level, could be low. I'd also check to make sure it's on frequency and hasn't "drifted" as that can cause issues as well.

 

[otobmark]

I agree on check the repeaters (2 and counting) since whatever my radios (5 of them) don’t like is coming out of the repeater’s transmitter. It’s the fact that the up-linking subscriber radios are playing a part that beats me. If a repeater quickly stopped sending PL in response to loss of PL on input that might explain it but that’s not how they work (PL exists on part of hang time).

In distant past I had a squelch issue with commercial and amateur radios on a particular amateur repeater (ge master2). At the time I was one of the few who used PL decode on my radios. I went down to SHP radio shop and captured signal off the air with service monitor and found 2 separate problems. With my ham radios I would occasionally miss beginning of transmission and with moto I’d miss most of it. Turns out if repeater was idle for a few minutes (cooled down) the very next time it was keyed up the PL tone took a few seconds to stabilize frequency. If repeater stayed somewhat active PL would be OK. Second problem was deviation of PL was set low on purpose because their club engineer couldn’t stand to hear tone on his base station. I then tested my radios. Some of the ham radios would unmute on ridiculously low deviation (under 100hz) and were somewhat tolerant of off frequency PL. I’m guessing they were susceptible to false unsquelching. The commercial radios liked healthy deviation (around 300hz from memory) but were very selective of tone frequency.

 

[CanesFan95]

I once had MDC1200 decode on an XPR7550e that caused voice drop-outs and had to turn off MDC1200.

 

[techman210]

Users radios are likely the problem.

They are likely “talking-off” the PL of their radios. Voice and PL deviation need to be properly adjusted.

Too much voice deviation or too little PL deviation.

 

[12dbsinad]

The OP states the problem goes away if he disables his PL, which means the repeaters receiver is still opened up when the audio problem occurs. That's why my vote would be to check repeater first.

 

[otobmark]

Users radios are likely the problem.

They are likely “talking-off” the PL of their radios. Voice and PL deviation need to be properly adjusted.

Too much voice deviation or too little PL deviation.

I agree that the other user’s radios are or can set off the event. Also, it would seem that the repeater’s response to whatever the other’s radios are doing is incorrect. One of the repeaters can do it entirely on its own when voice ID’ing where I get audio dropout on any of my radios set to PL decode, including ham radios.

Users radios are likely the problem.

They are likely “talking-off” the PL of their radios. Voice and PL deviation need to be properly adjusted.

Too much voice deviation or too little PL deviation.

I wondered if there could be audio combining or cancelation on repeater output which interrupts my radios decode. I’m betting that the audio fed to repeater transmitter from repeater receiver is not high pass filtered (prior to PL insertion) and subscriber input tone is passing through. Two tones only slightly off combining could wreak havoc with decoder. It might even be the voice of the radio operator clashing with tone, especially if tone is low deviation. I was thinking the other users radio was the problem but maybe it’s the register of their voice!

I feel we are getting close lads…

 

[a417]

 

[otobmark]

What kind of repeater is it?
Low frequency audio that isn't being filtered from the repeater transmitter might be interfering with PL decode on your radios.
PL transmit on the repeater may be off frequency or improper level.
Maybe your receivers are defective.
Maybe other reasons.

You nailed it. I missed your post first time around. Filtering issues with repeater. If I can get repeater club to grant me access I will try to verify.

 

[Flyham]

You nailed it. I missed your post first time around. Filtering issues with repeater. If I can get repeater club to grant me access I will try to verify.

Site access and the transmitter version of a good chiropractor / spine alignment would probably work wonders!

 

[speedway_navigator]

Site access and the transmitter version of a good chiropractor / spine alignment would probably work wonders!

HHS would say the repeater needs a vaccine booster...