BCD536HP: Testing reveals why my 536 so often stops with no audio and then resumes

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wm8s

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Ever wondered why your x36 stops on a channel so often, but you never hear anything or maybe just a half-syllable, and then it continues scanning? Your suspicions are correct: you're missing stuff.

My 536 is holding on a single talkgroup, and holding a single nearby site on TxWARN Analog. I have the system's scan time set to 5 seconds (i.e., it holds on the system for 5 seconds, then does what I am now seeing people calling the "housekeeping sweep" where it drops the control channel for about 500 ms, then goes back to the system), which is even longer than it should need to be.

With 3-4 bars out of 5, the scanner misses the first between 1 and 3+ seconds of pretty much every transmission (as properly received with no problems on another radio sitting right next to it). The mean is around 2 seconds of every transmission. This has been the case since purchase, and while I haven't tested it, my 436 also stops on channels w/o audio then resumes, so I can only infer that it's got the same problem.

FWIW, the next time you listen to your scanner on a busy channel, count how many transmissions are under 2 seconds, or how many transmissions have a pretty important first 2 seconds. You'd be surprised how much of the total traffic you're missing. I'd estimate I'm missing 75% or more of the total traffic. For example, while typing this, I've missed many entire transmissions like "What is your location?" and "Twelve thirty-four southbound," and "Phone number is 123-456-7890" came out as "90."

I know that some people don't have this issue, but that lots of people have complained about this, anecdotally (i.e., they see lots of no-audio transmissions) and after testing. Are there any plans to fix this? Let's face it: it pretty much makes the scanner useless.
 

KevinC

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So you're saying holding on a TG and Site you miss calls?

I did tests comparing it to an APX7000 holding on a TG and site and never missed a single call.

Is Close Call turned on?
 

wm8s

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Yep, that's what I'm saying. CC off, holding one TG, one site, one system. I read the test results that you posted. You were testing the P25 layer. I am testing the analog layer. Perhaps you're referring to other testing you've done on the analog side.

"We can leave the dead birds there with the live ones, and they will take them back to Baytown," just came out "and they will take them back to Baytown." "I'm calling you now" came out "". It's amazing how many transmissions fall in the housekeeping cycle, no matter how long I make the system scan time ;(
 

KevinC

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Yep, that's what I'm saying. CC off, holding one TG, one site, one system. I read the test results that you posted. You were testing the P25 layer. I am testing the analog layer. Perhaps you're referring to other testing you've done on the analog side.

"We can leave the dead birds there with the live ones, and they will take them back to Baytown," just came out "and they will take them back to Baytown." "I'm calling you now" came out "". It's amazing how many transmissions fall in the housekeeping cycle, no matter how long I make the system scan time ;(
Let me try analog. What site are you using? I believe you're in the League City area, I'm in Ft. Bend County.
 

wm8s

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I was holding on League City. TG 51696 will almost always be carried on that site due to base radios near that site on that TG. Pearland is much stronger for me, but I don't want to affiliate that TG to Pearland and burn a voice channel there just to test a scanner....

[I'm pretty sure TG 23728 is always already carried from Pearland; if so, I will try that one so I can test the scanner on a 5-bars site. But the audio from League City is pretty good with 3-4 bars; honestly, it should decode that site just fine, and I certainly don't think having <5 bars is a good reason to miss 75% of the traffic.]
 

KevinC

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Odd, I'm holding on a Site and a TG and I never leave the control channel.

Now if I just hold on the Site it does the "Housekeeping" thingy and I sometimes miss the first letter or so of a word. But no where near what you are reporting.

I'll continue testing tonight.
 

KevinC

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Very strange, I'm not experiencing this. I do miss a letter or 2 sometimes like I said, but no late entries like you're reporting.

I'm holding on a "Site" and scanning a "Department" with about 25 TG's in it. System hold is 0 seconds.

Maybe I should try it on a weak site and see what happens.
 

wm8s

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No joy on Pearland analog, either. Solid 5 bars, still misses the first 1-3 seconds of everything.

"And twenty-three sixty-eight, we have..." in my right ear came out "xty-eight, we have..." in my left. A bit later, "Twenty-three sixty-eight" came out as nothing. "Clear me backup off duty" also got chopped entirely; nothing from the 536 at all.

I guess the silver lining is that my scanner now automatically edits out my favorite pet peeve, "That's clear"; those all get chopped completely ;)

[I wasn't clear earlier; I don't get the housekeeping when I'm channel-holding.]
 

KevinC

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No joy on Pearland analog, either. Solid 5 bars, still misses the first 1-3 seconds of everything.

"And twenty-three sixty-eight, we have..." in my right ear came out "xty-eight, we have..." in my left. A bit later, "Twenty-three sixty-eight" came out as nothing. "Clear me backup off duty" also got chopped entirely; nothing from the 536 at all.

I guess the silver lining is that my scanner now automatically edits out my favorite pet peeve, "That's clear"; those all get chopped completely ;)

[I wasn't clear earlier; I don't get the housekeeping when I'm channel-holding.]
This is really strange, I just tried a weaker site and I still don't miss conversations or even words.

I'm not doubting you at all, it's just strange.
 

AZScanner

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There has to be a logical explanation. There's no reason why your scanner would do that and Kevin's scanner (or mine, when holding on an analog talkgroup on the Maricopa County Smartzone) doesn't.

ETA: Something to check - what is the P25 wait time for that site? I'll set mine up same as yours is and see if I can make my scanner do the same thing yours is.

-AZ
 
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AZScanner

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Right, I know. But you're monitoring this system, correct? Texas Wide Area Radio Network (TxWARN) Motorola Trunking System, Metro Houston area, Texas - Scanner Frequencies

If so, that's a Smartzone system and Sentinel would have programmed it as such, which means under the site in question you'll have a setting for P25 wait time. The default is 400ms. Set it to 0ms and see if you still miss parts of transmissions or not. I don't know for sure if that will fix it or not, but that's the setting I'm using on the Smartzone system I monitor and I'm not missing a word on any of the analog talkgroups or the digital ones.

-AZ
 

wm8s

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Right, I know. But you're monitoring this system, correct? Texas Wide Area Radio Network (TxWARN) Motorola Trunking System, Metro Houston area, Texas - Scanner Frequencies

If so, that's a Smartzone system and Sentinel would have programmed it as such, which means under the site in question you'll have a setting for P25 wait time. The default is 400ms. Set it to 0ms and see if you still miss parts of transmissions or not. I don't know for sure if that will fix it or not, but that's the setting I'm using on the Smartzone system I monitor and I'm not missing a word on any of the analog talkgroups or the digital ones.

-AZ
Good point. I'll try that. And also ensure that the sites are NFM instead of Auto.

I have noticed that recording REALLY hits the CPU. Button responsiveness is terrible when recording is on. Turning it off improves things. That has to be affecting the scanning performance, as well. I'm using a Sandisk uSD card; perhaps it's causing part of my problems. I'll revert to the factory card. Let's see how many variables in my experiment I can change at once!
 

AZScanner

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Good point. I'll try that. And also ensure that the sites are NFM instead of Auto.

I have noticed that recording REALLY hits the CPU. Button responsiveness is terrible when recording is on. Turning it off improves things. That has to be affecting the scanning performance, as well. I'm using a Sandisk uSD card; perhaps it's causing part of my problems. I'll revert to the factory card. Let's see how many variables in my experiment I can change at once!
Heh! Wait until you try listening to Phase II. The PCWIN system here in Arizona REALLY bogs down the scanner - lots of lag between keypress and action I noticed.

I would definitely get the scanner back to as close as stock as possible, although I don't think the SD card would cause the issue you're having.... but maybe! It's certainly worth trying to eliminate it as a possible cause.

Let us know how it goes.
-AZ
 

wm8s

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95% of the Phase-II stuff here is encrypted, so no worry there ;(

Here's what I did:
- I've changed the P25 wait time to 0 for every site, and I've set them all to NFM
- I've turned off recording
- I've reverted to the stock card

So far, the delay is now very short (I'd like it to be 0, but it's tolerable). I'll figure out which one was the culprit and re-post.

And THANKS to both of you for the "control group"!

...R
 

troymail

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This all sounds VERY familiar.

I'm a bit surprised you're seeing it on analog systems though.

I suspected all along that the digital decoding is putting a serious strain on the 536 processor to the point that button pushes are ignored quite often (can be pretty frustrating). When there is silence on a digital talkgroup or it's analog activity, the buttons respond immediately (I enable recording on power up by default).

Kevin did some testing the other day and one of the questions I had was if he had recording enabled - wondering if that along with other things were also putting stress on the processor. I sense the radio doesn't see button pushes as a priority but I would have though the user interaction with the radio would take priority over other things the radio is doing.

I think I've also determined that once you take a system from the database and start adding favorites lists and other quick keys, the performance seems to be affected. This could be perception but I'm pretty sure I see a difference.

Having said all of this, I've been experiencing what I believe is a loss of as much as 50% or more activity that my other radios pick up. Clearly there are many variables - and I'm not too much into the idea of doing all this "tweaking" to make things work. However, given this thread, tomorrow I think I will revert back to default settings and stop using recording for a while and see what happens; I may even program in just a couple of talkgroups for one given system/site and nothing else (no avoids, QKs, etc.) to see what happens.

Following that, there seems to be some NFM vs. FM tweaks everyone has found to be an improvement. Can you enumerate these for 770 and 850 mhz?
 
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kb8rvp

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BCD536HP Testing reveals why my 536 so often stops with no audio and then resumes

Not seeing any issues with delays or missing anything. I am using it on the Michigan 800MHz digital system along side my PSR-800 and once in a while one will beat the other but they are very close. I have all of the delays turned off for each system.

Good luck finding a fix for your issue... One other thing are you using the zip code programming or favorites? I did notice using the zip code was a lot slower scanning than using favorites.

Mike
 
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