This forum is dedicated to discussions pertaining specifically to the Motorola ASTRO line of radios (those that use VSELP/IMBE/AMBE), including using digital modulation, digital programming, FlashPort upgrades, etc. If you have general questions please use the General or Programming forums.
Just seeking some ideas or opinions as to a certain problem we are experiencing on our system. Im not an astro expert ....
Units in the field are using xts3k portables and astro spectras
When heard on the centracom console at times the audio cuts out during a units transmission. The 'Select' and 'Call' lights flash and the unit ID is displayed when RX but the audio is none at times- its not so much that a unit 'drops out' its the actual audio seems to be muted. Units in the field can hear the transmission (obviously from the repeater).
The centracom is connected via phone lines to the tx/rx site and those were apparently checked out to be ok.
If you have a logging recorder and if it is connected to that channel at the BIM logging recorder audio output, then I would suggest that you listen to the recorded audio to see if the drop-out was recorded or only heard at the console speaker.
If you don't have a logging recorder - then have the maintenance person put an audio monitor at that point and run the test.
That should help identify if the problem is in the console or in the DIU/repeater. If the audio is present at the logging recorder but drops out at the console speaker, I would ask the maintenance person to check the level jumpers on the BIM - if they are set wrong the DLM can become confused.
Also, you should have them check the BIM squelch gate jumper setting - it might help to have that disabled.
Whenever Data 12 and/or Data 18 packets (unacknowledged and acknowledged, respectively) are transmitted on an ASTRO25 system, the DIU3000 will momentarily cut the voice audio whilst these ASTRO packets are being sent out. The DIU is perfectly happy with decoding D12 and D18 packets smack in the middle of an IMBE voice transmision. Of course, the voice path is momentarily interrupted. This may be your "problem."
This is an ongoing problem since the Centracom II consoles and MSF5000's. I have had techs in from two different shops on three different systems, and we find that when the person starts to speak softly, the audio is muted. That's the only time it drops, and yes, all the audio is still going thru the repeater and is picked up on the recorder. Its ANNOYING AS HELL, but comes down to training.
If you talk softly, or stop talking while xmitting, the console tends to mute the speaker, unless you are having some other problem.
So far, no one has been able to come up with a solution or adjustment that works well.
Lowband radio. The original and non-complicated wide area interoperable communications system
No its not an encrypted system
There is a voice recorder on this will have to check that out..
this is an IMBE system
also, as PJ pointed out/mentioned I have noticed with low audio transmission (at time NOT always)... YES annoying... ... we are having that issue occur as well... we have some people who are soft spoken or if they are using speaker mic at a far distance.. as well..... but it does also occur when you initally hear a clear/loud audio then it just mutes in the middle of RX'ing...
"does also occur when you initally hear a clear/loud audio then it just mutes in the middle of RX'ing... "
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These issues are almost always caused by improper system level setting. If the level setting isn't right, the DLM [Digital Level Memory = smart AGC] can be confused. In that case a loud transmission can cause a subsequent softer trasnmission to be heard at a much lower level.
If the BIM squelch gate function is enabled, this lower level transmission could be muted, however - if the BIM squelch gate function is disabled - the console CANNOT mute the audio.
Data 12 and Data 18 packets are tightly defined by the APCO 25 standard. D12 are unacknowledged packets, while D18 are acknowledged. ASTRO Dialing is an example of Data 12 packets.
hvacesu78 wrote:
I have noticed with low audio transmission (at time NOT always)... YES annoying... ... we are having that issue occur as well... we have some people who are soft spoken or if they are using speaker mic at a far distance.. as well..... but it does also occur when you initally hear a clear/loud audio then it just mutes in the middle of RX'ing...
thank you
John
As someone else pointed out, have your service people
check levels, particularly DIU "silent level". The proper
procedure is explained in the respective help screens.
Thank you.. to answer some ?'s