436HP TDMA crackling

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N0UDG

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Anybody experiencing this with systems other than the Loudoun County one?


TDMA crackling on Loudoun Co system - YouTube
The video you made did a fine job of showing what you were talking about, much better than trying to describe it with words.

If appeared to me that the "crackling noise" seem to be associated with problems with the decode or signal strength/interference. Have you ever heard the "crackling noise" during a good decode?

Is this problem new? If it is maybe your system has a problem. Others could help us answer this question so you might consider posting in the State Tread you are in to see if other people with your radio and this system are experiencing the same problem.
 

freqhopping

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The signal strength doesn't waver in the least. I can monitor system perfectly fine with no antenna even. The error is typically 0.
It doesn't happen with the FDMA transmissions.
It is not heard when I replay recorded .wav files on my computer.
It is heard through ear buds.

I just watched for the error rate on some TDMA transmissions. Crackling is heard whether the error rate is 0 or 18, though maybe a little more at higher rates.
 

freqhopping

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Is this problem new? If it is maybe your system has a problem. Others could help us answer this question so you might consider posting in the State Tread you are in to see if other people with your radio and this system are experiencing the same problem.
I already know of someone else reporting this about Loudoun because they posted about it in the VA forum. I'm posting here for outside comparisons.
 

N0UDG

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I already know of someone else reporting this about Loudoun because they posted about it in the VA forum. I'm posting here for outside comparisons.
I see you are way ahead of me, very good!

I hope it is the Loudoun site and not the radio since I own a 436, if you know what I mean.

Good Luck.
 

n4yek

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Do you have the digital AGC turned on? try it with it turned off. Also try attentuating the signal, maybe overloading.
Just some thoughts.
 

troymail

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It does it on Phase 2 systems in central Maryland also on my 536. I've always suspected it's that point when the radio starts to get confused by the simulcast....it sometimes "pops and cracks" but usually seems to recover quickly.
 

KevinC

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It does it on Phase 2 systems in central Maryland also on my 536. I've always suspected it's that point when the radio starts to get confused by the simulcast....it sometimes "pops and cracks" but usually seems to recover quickly.
I'll attempt to try it on a non-simulcast P2 site this weekend and see what happens.
 

policefreak

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troymail said:
It does it on Phase 2 systems in central Maryland also on my 536. I've always suspected it's that point when the radio starts to get confused by the simulcast....it sometimes "pops and cracks" but usually seems to recover quickly.
Yes I hear it on some transmissions on Camden County NJ phase 2 audio and also suspect it to be a reception issue. S Meter fluctuates at that point. Also did it when I purposely overloaded the signal using a GRE Super Amplifier turned up. When I hear this error rate is between 5-8 as opposed to 0-3 on clean transmissions.
 

freqhopping

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Everyone, record the crackling comms with the scanner.
Copy the .wav files to you computer and play them.
Do you still hear the crackle?

I don't. That and other reasons are why I don't think this has anything to do with reception or simulcasting.

There has to be something funky going after the time the TDMA audio gets recorded to the memory and it coming out the speaker or jack.
 

policefreak

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Yea i notice you dont even hear it when youre playing back audio recorded straight from the scanner. So I have investigated further. Since it is happens to me only in an area where reception is questionable, on frequencies my PSR 800 has trouble handling, that seems to have some play in it, at least for me. To me, and i certainly could be wrong, but it seems as if on phase 2 audio, the radio is set to slow down digital audio processing when reception gets questionable. I see that while, sitting side by side with a PSR 800, the 800 will cut out, the 436 will continue with copyable audio but with the popping, then when the 800 comes back, it seems to be a split second ahead of the 436. Its like slowing down the digital processing, while it greatly reduces the audio from cutting out, it just degrades audio quality somewhat. And in playback mode, the radio just discards those very split seconds of "missing" audio so it seems to play back in one continuous, clean transmission. But if you listen closely, there are very tiny cutouts in audio where words get snipped off or half syllables are missing. It plays so quick it is hard to notice. Any thoughts on this?
 
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