BCD436HP: Missing calls...or not

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KevinC

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I was curious whether my BCD436HP was missing trunked calls as reported by others, so I did a little test (and no, I'm not part of any Gamma test team).

Here's the setup...

BCD436HP with a FL consisting of 1 system, numerous departments and 2 sites. I disabled one site and did a "Hold" on a department, consisting of around 15 TG's.

APX7000 authorized to be on the system, locked to one site (same site as the 436) and sitting on one TG (included in the "Department" of the 436).

I figured this would give the disadvantage to the 436 as it's "scanning" numerous TG's and will leave the CC during the "housekeeping" cycle.

This is a P25 simulcast trunked system and I'm testing with a Phase 1 TG.

Other than the times the 436 was listening to one of the other TG's it was scanning, it never missed any of the calls the APX received. It did however unmute late sometimes, maybe missing the first letter or two of a word at most.

Others may not get the same results I did (and I'm waiting for the replies denouncing my test), but this is what I experienced.

As usual YMMV. :D
 

Ghstwolf62

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I don't know if it'll help you but with the clipping thing I followed, I believe, DaveIN's advice about lowering the threshold level from 8 to a lower setting. He recommends 5 and I got it mixed up when I set mine so it was set to six but since then I haven't had that problem anymore. Turning mine up actually decreased reception/performance.
 

troymail

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Couple of questions:

1. For the site you held on, are you between towers or outside of that site's footprint?

2. Were you running in ID SCAN or ID SEARCH mode?

3. Was recording enabled?

4. What antenna are did you use?

5. Were any tweaks (P25 threshholding, etc.) being used?

6. Any ability to perform the same type of tests on Phase 2 activity?

I'd sure hope things work well when holding on a single system & site with 15 talkgroups. Run a similar test scanning multiple systems. When your APX is active on a talkgroup, does the radio always stop on the active talkgroup in scan mode or does it sometimes scan right through the system without stopping?

EDIT: FWIW - Reception on my 536 changes drastically by simply moving the radio a few inches. To be fair, this location or "placement" issue was similar (probably worse) on my PSR800
 
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KevinC

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Couple of questions:

1. For the site you held on, are you between towers or outside of that site's footprint?

2. Were you running in ID SCAN or ID SEARCH mode?

3. Was recording enabled?

4. What antenna are did you use?

5. Were any tweaks (P25 threshholding, etc.) being used?

6. Any ability to perform the same type of tests on Phase 2 activity?

I'd sure hope things work well when holding on a single system & site with 15 talkgroups. Run a similar test scanning multiple systems. When your APX is active on a talkgroup, does the radio always stop on the active talkgroup in scan mode or does it sometimes scan right through the system without stopping?
1. The site is 3 subsites and I'm about equal distance from each, as in the middle of a triangle.
2. ID scan,scanning about 15 TG's as I said.
3. No recording.
4 .The R/S 800 for the 436
5. No "tweaks".
6. I can do P2, probably tonmorrow. This will be a much more hostile RF enviroment as the sites have between 9 and 11 subsites.

The 436 stopped every time the APX was active, except as I said when it was receiving another TG. I was just trying to determine if a "core" issue exists with the P25/simulcast/CC decoding, it appears it doesn't. I'm sure scanning multiple sites/systems would yield different results.
 

KevinC

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Did a P2 test...

APX7000 locked on a site, sitting on 1 TG (which is in the 436 Department)

436 scanning 1 system, 2 sites, one department with about 20 TG's (the APX TG is included), no system/dept/site hold.

The 2 sites are simulcast, between 9 and 11 subsites each. I'm "outside" one site and deep inside the other site.

Pretty much the same results as the P1 test, the 436 never missed a call that the APX heard except when it was receiving a different TG. As a side note the 1 TG was allowed and active on both sites, so the chance of catching it was greater since the call assignments were on both CC's.
 

KevinC

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And I better qualify my test results..

I know others will get different results and every system is different (or is it??).

The systems I tested on are very well maintained and setup properly (yes, I'm positive of this).

So, does this really help anyone else? Probably not, it's just my tests and my results.

Let the lambasting begin.
 

redburgundy

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I think you indicated you made no change to the P25 Threshold setting (auto), right?
Did you notice the ERR values that came up?

Could you try again with the auto setting and note the ERR values, then try again with a manual P25 Threshold of 5 and again with a manual setting of 12 and note the ERR values?

I'm getting much better performance with a setting of 11 or 12, but others seem to get better performance with a setting of 5. There seems to be a consensus that the auto setting is not converging automatically to the optimum setting.
 

KevinC

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I think you indicated you made no change to the P25 Threshold setting (auto), right?
Did you notice the ERR values that came up?

Could you try again with the auto setting and note the ERR values, then try again with a manual P25 Threshold of 5 and again with a manual setting of 12 and note the ERR values?

I'm getting much better performance with a setting of 11 or 12, but others seem to get better performance with a setting of 5. There seems to be a consensus that the auto setting is not converging automatically to the optimum setting.
My error rates are almost always between 0 and 4-5.
 

gjhamilton

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Every once in a while my 536 will unmute late. As far as missing conversations it will occasionally. My radio too would not rx at all, even with a full signal strength. And moving a couple feet in either direction would cause the radio to start receiving again. With all this being said this radio works very well considering the only other option is an apx radio.

Sent from my SCH-I545 using Tapatalk
 

KevinC

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Every once in a while my 536 will unmute late. As far as missing conversations it will occasionally. My radio too would not rx at all, even with a full signal strength. And moving a couple feet in either direction would cause the radio to start receiving again. With all this being said this radio works very well considering the only other option is an apx radio.

Sent from my SCH-I545 using Tapatalk
Stop sitting at 610 and Braeswood. :D
 

SCPD

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question

I was curious whether my BCD436HP was missing trunked calls as reported by others, so I did a little test (and no, I'm not part of any Gamma test team).

Here's the setup...

BCD436HP with a FL consisting of 1 system, numerous departments and 2 sites. I disabled one site and did a "Hold" on a department, consisting of around 15 TG's.

APX7000 authorized to be on the system, locked to one site (same site as the 436) and sitting on one TG (included in the "Department" of the 436).

I figured this would give the disadvantage to the 436 as it's "scanning" numerous TG's and will leave the CC during the "housekeeping" cycle.

This is a P25 simulcast trunked system and I'm testing with a Phase 1 TG.

Other than the times the 436 was listening to one of the other TG's it was scanning, it never missed any of the calls the APX received. It did however unmute late sometimes, maybe missing the first letter or two of a word at most.

Others may not get the same results I did (and I'm waiting for the replies denouncing my test), but this is what I experienced.

As usual YMMV. :D
<<what the Jesus is YMMV?
 

davenlr

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Ive found most of my "missing" transmissions are caused by extremely high error rates. It will stop, but the error rate is just to high to decode. Adjusting the threshold to 5 or 6 improves this alot. It happens most often when stopped on a "simulcast" site where two or more sites are transmitting on the same frequency and are of about equal strength.

Its especially noticeable when driving, listening to a long fire dispatch. The scanner will just stop putting out audio for 2 or 3 seconds, then resume, then cut out again. The whole time the signal level is full. Once I get out of the simulcast sites range, into the range of single sites, I dont miss any transmissions anymore other than an occasional second at the beginning.

I hopefully believe this will be made better with firmware upgrades over time.
 

Bolt21

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I found this thread while researching 436HP missed transmissions and late unmuting. My 436 does this mostly on P25 Phase II and EDACS systems, with full signal strength and low error rates. Tweaking the P25 threshold level doesn't help either for P25. This shouldn't be happening on a high-dollar, high-tier radio. This was never an issue with my 396T.

I'm debating on sending it back for warranty replacement, but I'm afraid I'll just end up with another unit that performs just like the one I currently have. Also wondering if a firmware fix for this issue is in the works.

Has anyone else sent a unit like this back and received one that performs better? Or should I just hold out for a firmware fix?
 

redburgundy

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I found this thread while researching 436HP missed transmissions and late unmuting. My 436 does this mostly on P25 Phase II and EDACS systems, with full signal strength and low error rates.
All of today's scanners have a problem with simulcast systems.
Simulcast digital distortion - The RadioReference Wiki
If the systems you are having problems with are not simulcast systems, then possibly your radio could be at fault.
 

Bolt21

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I have battled simulcast distortion for years with my 396T. I believe this is something completely different. My 396T never flat out ignored short ("10-4") transmissions like this 436HP does, on both P25 and EDACS.

Hence my questions about firmware and/or warranty return.

Upon closer observation, it seems that after every transmission stops, there is a a second or two delay where the scanner mutes, where the signal strength meter disappears, which would explain the missing short replies. Is anyone else experiencing this?
 
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