BCD436HP dropping transmissions

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wk5h

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I recently discovered that my BCD436HP has been dropping some transmissions. I really hadn't noticed it until I fired up DSD+ on a spare computer the other day to do some unrelated things, and noticed that I was hearing more PD traffic on it than I was on my scanner.

I think possibly my initial finding is due to the radio starting to scan again, and missing out on quick key'd events (such as a "10-4" 3 seconds after the last transmission on the PD channel)

What's interesting, is that during this time, I placed the channel on hold, and for the most part, it catches all the transmissions, until after 10-15 minutes - then it only receives maybe 2-10 transmissions. I can use the knob to channel up then back down, and it may or may not start receiving again. I can turn off the hold, let it scan, and it seems to start picking up more traffic again. It's like if it stays on hold for too long, it goes deaf?

I tried to capture it on video, but, being that it's a small town with sporadic traffic, it's hard to capture a vid of it.

The channel is a digital P25 channel of the local PD - no trunking involved.
 

jonwienke

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Program the frequency as a One Frequency Trunked system instead of conventional. That will give you the option to adjust the digital threshold for better decoding, and will also let you see what talkgroups are being used.
 

Rammel

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I recently discovered that my BCD436HP has been dropping some transmissions. I really hadn't noticed it until I fired up DSD+ on a spare computer the other day to do some unrelated things, and noticed that I was hearing more PD traffic on it than I was on my scanner.

I think possibly my initial finding is due to the radio starting to scan again, and missing out on quick key'd events (such as a "10-4" 3 seconds after the last transmission on the PD channel)

What's interesting, is that during this time, I placed the channel on hold, and for the most part, it catches all the transmissions, until after 10-15 minutes - then it only receives maybe 2-10 transmissions. I can use the knob to channel up then back down, and it may or may not start receiving again. I can turn off the hold, let it scan, and it seems to start picking up more traffic again. It's like if it stays on hold for too long, it goes deaf?

I tried to capture it on video, but, being that it's a small town with sporadic traffic, it's hard to capture a vid of it.

The channel is a digital P25 channel of the local PD - no trunking involved.
I had what sounds similar, but I'm in a big City using a BCD536. My problem was I needed Attenuation. Local stuff was over driving my receiver. Also a PRI setting was causing me to leave an active channel which seemed like dropout at first.

Mine was as yours - "The channel is a digital P25 channel of the local PD - no trunking involved."
 

jonwienke

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I don't think attenuation is the best solution. I live about 1500 feet from a transmitter tower and don't use attenuation for anything.
 

Rammel

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I don't think attenuation is the best solution. I live about 1500 feet from a transmitter tower and don't use attenuation for anything.
But ------ It corrected the problem. Might it depend on the power of the transmitter? Could that signal be "shooting" right over your receiver?

It's worth a try. If it doesn't help, remove it.
 

jonwienke

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Did you try programming as one frequency trunked? That allows additional adjustments to reception, as well as tracking talkgroups.
 

wk5h

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Did you try programming as one frequency trunked? That allows additional adjustments to reception, as well as tracking talkgroups.



I did, but I haven’t gotten a chance to sit down and listen to see if it’s still missing transmissions yet. Traffic comes in spurts, and my 3.5yr old had me tied up most of the afternoon. I’ll have a chance to listen a little tonight and compare it to my TX-1 (doesn’t seem to be exhibiting the same issue). I’ll be able to verify it tomorrow too at work where I have the machine with DSD+.


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wk5h

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Update

Squelch is good - any lower and it would break on the analog channels

I did set the PD frequency in it's own favorite list, and setup a department of single channel P25, and it appears that the drops have changed from being completely dropped, to missing only a small portion of the start of the broadcast in some transmissions.

I did check again, and it does appear that (at least on my radio and our local PD channel) that if you hold on a conventional channel that is a P25, after 5-10 minutes, it starts dropping the transmissions.
 

jonwienke

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By "single channel P25" do you mean a One Frequency Trunked P25 system?
 

Rammel

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wk5h

Did you check my posts above - #3 & #5 ?

I know I'm a newbie here but yours seems a similar problem to one I had. My fix was quick, and if it doesn't work, easy to remove.
 

wk5h

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Did you check my posts above - #3 & #5 ?



I know I'm a newbie here but yours seems a similar problem to one I had. My fix was quick, and if it doesn't work, easy to remove.



I haven’t tried the attenuation yet - I will try it tomorrow, see if it helps, and get back with you.


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jonwienke

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Do you have the battery saver enabled?

Battery saver periodically shuts off the receiver when you are holding on a channel. If it is turned on, that could account for missing transmissions during a channel hold.
 

UPMan

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Battery saver periodically shuts off the receiver when you are holding on a conventional channel. If it is turned on, that could account for missing transmissions during a channel hold.

I added emphasized word, above. Does not happen for trunked channels.
 

wk5h

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Well, I've done several things - for one, I updated the firmware. seems to have helped a little with catching conventional digital signals, even though I didn't see anything in the release notes dealing with it.

Setting global attenuation didn't change anything - changed it back to no attenuation.
Even setting the local frequency to P25 one-frequency trunking, didn't really help too much - still dropped a few transmissions.

I did turn on the battery save feature, and that did stop it from dropping so much when the channel was on hold (thank you Voyager).

On a side note - I borrowed a TX-1, and it does seem to catch a higher percentage of the conventional traffic. But I took it with me this afternoon to an area with a high traffic P25 II system, and it was... awful. Setup the BCD436HP and the TX-1 to scan the same exact trunked system, with the same site frequencies and talkgroups, sitting side by side, and the BCD436HP heard probably a good %25 more traffic than the TX-1 did. At one point, there was a long transmission that carried on for a good 45 seconds, and the TX-1 just scanned and scanned, until it finally picked up the last 5 seconds. Plus, the thing actually hard locked, and I had to remove the batteries and power cable to get it to reset.
Guess I'll stick with the BCD436HP until the SDS100 becomes available, and hopefully it'll do better on the conventional digital frequencies around here.
Thanks all for the help!
 

Voyager

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I did turn on the battery save feature, and that did stop it from dropping so much when the channel was on hold (thank you Voyager).

You turned it ON? Turning it on would make the RX sleep periodically which would increase lost transmissions.
 

jonwienke

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Yeah, that's backwards. Turning battery save ON would increase missed transmissions, not decrease them. Whatever is going on is an intermittent issue and the effect was coincidental to the setting change.
 

N0GTG

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I've also seen several instances of Close Call Priority, or Weather Priority accidentally turned on, which would cause periodic interruption of reception.
 
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