TRC-455 weird problem

[Deleted]

This is my main base unit. I have noticed lately that I am hearing electrical noise when someone keys up and talks. Happens to anyone that is talking, and only when they are talking. Almost sounds like electrical ignition noise, except this is in my house. Does not occur when no one is rag chewing on the channel. IOW, it's there during their key-up only. Someone said it is because it is winter and cold, which made no sense.

And yes, my ANL and NB are on !

[Sandbagger]

Nov 25, 2008 21:12:38 GMT -5 @vinnies said:

This is my main base unit. I have noticed lately that I am hearing electrical noise when someone keys up and talks. Happens to anyone that is talking, and only when they are talking. Almost sounds like electrical ignition noise, except this is in my house. Does not occur when no one is rag chewing on the channel. IOW, it's there during their key-up only. Someone said it is because it is winter and cold, which made no sense.

And yes, my ANL and NB are on !

That sounds weird, but I do have a few possibilities to throw at you. One theory is that one of the A.C. switches in the radio (Usually the one connected to the clock) gets dirty and arc's which shows up on receive signals. My Royce 640 was doing this. A quick test would be to run the radio off of an external power supply to see if the problem goes away.

Another possibility, and this one is a bit of a stretch, is that you are getting interference from triac heater controllers. Is your home heated with electricity? Or perhaps some other electrical device on your electric line.

Lastly, it's also possible that the loop filter in your PLL VCO is breaking down and the error pulses are leaking through and modulating your VCO causing it to FM at the pulse rate and when it beats with an incoming signal, you hear the pulses. Of course if this is the case, you should have a similar effect on your transmit as well.

[Bus Driver]

Happy Thanksgiving to all

[Deleted]

Dave,

I will take a look. I have some other radios I can try it with. I have a Uniden Grant LT, but the receive is not as good as the TRC-455, and it's hard to distinguish. I do notice that when i do turn the ANL abd NB off, the noice is unbearable (just like that Cobra 1000 GTL I was talking about). However, with the switches on, it appears only when someone is keying.

[Sandbagger]

Nov 26, 2008 9:09:38 GMT -5 @vinnies said:

Dave,

I will take a look. I have some other radios I can try it with. I have a Uniden Grant LT, but the receive is not as good as the TRC-455, and it's hard to distinguish. I do notice that when i do turn the ANL abd NB off, the noice is unbearable (just like that Cobra 1000 GTL I was talking about). However, with the switches on, it appears only when someone is keying.

I would think that that fact that you had similar issues with the Cobra 1000, might be a clue that your problem is environmental and not within the radio itself. The exception to that, is the arc'ing AC switch, the interference from which actually conducts down the AC cord and "pollutes" into other radios giving the impression that the problem is "out there" rather than right on your bench.

So in order to test for the source of such a signal you would have to run a known good radio off of a clean DC source, and unplug all the base radios from the AC source so that they don't generate interference. If the problem goes away, you can then plug them back in one at a time and when the problem comes back, you know which radio is the culprit. This is the method I used to identify my horribly dirty ethernet routers and other computer "stuff". And since we're on that subject, if you recently added network gear (or a Plasma TV) nearby to your radio bench, there's another potential source for interference.

[Deleted]

Well, the problem is now gone, so it is environmental. I must have shut off everything, but could not pinpoint it.