CDM Mobiles slow to open up RX audio.

QFL · Post by **QFL** » Thu May 15, 2003 11:24 am

I work in a MSS, and I am getting a strange complaint from one of my customers. I know I can come to you guys & get some good feedback! He says that his small fleet of CDM1550 radios are slow to open up the Receive audio - especially while scanning. I would naturally expect a small delay, but when I tested the CDM against an HT1550 I found that the mobile was indeed slower opening up than the HT. I have gone over the RSS in the radio completely, and minimized the size of their scan list. the primary channel also uses DPL for CTCSS. this helped some, but the customer is still complaining that the HT1550 is still opening up Approx. 600ms once in a while, and it is a growing nuisence. I have called the big /\/\ about this and they said "We will call you back"... I think you guys can beat them to the punch. I know you guys are a smart bunch and are eager to prove it. Please let me know if you have any ideas. Thanks!!!

-QFL

Znarx · Post by **Znarx** » Thu May 15, 2003 11:38 am

check to see if the Personality has an MDC system enabled.... if so reduce the DOS time or remove the MDC system if not required

.. DOS will mute the receiver for a set period of time once carrier squelch is detected (default 500ms I believe)

I'm sure someone else will have other ideas...Z

QFL · Post by **QFL** » Thu May 15, 2003 11:47 am

The DOS is disabled. However they are using POST MDC on Tx, Disabled on Rx.

nmfire10 · Post by **nmfire10** » Thu May 15, 2003 1:52 pm

I just ran through the CPS for my CDM1250. I am not able to find anything that would do that. In the MTSX (MTS-2000), there is a setting for "RX Unmute Delay". That is what that sounds like but there is no setting for that in the CDM settings that I can find.

QFL · Post by **QFL** » Fri May 16, 2003 5:04 am

UPDATE: just for fun I tried reprogramming the unit for Tone Squelch instead of DPL, and I found that this decreased some of the delay. this might be a small thing, but at this point I am willing to try anything.

-QFL

jim · Post by **jim** » Fri May 16, 2003 8:34 am

We had a local dept. that is dispathced on VHF and uses a DPL code on the frequency.

When the center would initiate a dispatch, the radio would sometimes skip a QCII signal. The 'A' tone was 1 second from the center. If you'd disable the tone in receive, the radio would activate the klaxon every time upon receiving a QCII tone set. When the center would dispatch, the instant the transmitter went on the air the tones would generate.

Solution: do away with DPL since these radios do take some time for a DPL decode or.....have the center program a delay between actual transmit keyup and the tone generation sequence. The delay is what they did and it solved our problem. These radios are slow compared to a GM300 or Maxtrac when decoding DPL.

I guess we need the 376th firmware upgrade for the Waris line!

Post by **wavetar** » Fri May 16, 2003 2:02 pm

jim wrote: I guess we need the 376th firmware upgrade for the Waris line!

Maybe...I guess my question would be what firmware version are they (the customer in this thread) currently running? The earlier versions did have several scan issues.

Todd

rrfd43 · Post by **rrfd43** » Sat May 17, 2003 4:24 am

I don't know if it is any help. but.....I use DPL on two freq's at our ambulance base. We noticed that most of the novice operators had problems. We would get the first part of the transmission chopped off. Apparently is takes just a little bit longer for the radio to decode DPL. Slowing the operators down helped out a bit. We have maxtracs, ht1000's, spectra astros, cdm's, MT1000's and MT2000 all do the same thing.

QFL · Post by **QFL** » Mon May 19, 2003 6:09 am

The Firmware in the radios were field upgraded to the latedt & greatest. (Leave it up to motorola to not touch an older version with a 10 foot pole.) That was the first thing we did so that the big /\/\ would attempt to assist us with some other issues we have.

ArmsonOeg · Post by **ArmsonOeg** » Mon May 19, 2003 6:50 am

I have had the same problem on my HT1550. But did fix it to some degree. I was getting up to a full 2 second of carrier with no audio, this was after i started adjusting things. It is mainly in the SCAN LIST section under ADVANCED. The HOLD TIME needs to be 300Ms or less. Disregard the HELP section that states it needs to be EQUAL or GREATER than MDC and PRETIME. Also go to the MDC system under DOS Coast Duration and make it 50 or 75 Ms.............Try this, i spent Many Hours to figure this one out

Gordon

QFL · Post by **QFL** » Tue May 20, 2003 6:53 am

I think I figured it out! The problem is most likely with the Non- Priority Scan members. The owner has loaded up his scan list and is also using priority scan. Whenever this person gets traffic that is important, but not priority, it can intermittently take up to and more than 2 full seconds before the radio will open up! By then, a good chunk of the conversation is lost. One easy fix would be to shorten up the scan list. but do you guys know if this is normal for a CDM (or any other radio for that matter?) 2 full seconds???

-QFL

nmfire10 · Post by **nmfire10** » Tue May 20, 2003 7:09 am

Well, I have the whole 16 slot scan list filled on mine and I use Priority. It works fine, it hardly cuts anything off at all.

ArmsonOeg · Post by **ArmsonOeg** » Tue May 20, 2003 7:47 am

Well like i said i too was getting a full 2 seconds and even caught a couple at about 8 seconds. My partner has a 1550 but his does not seem to have the problem,mabe it's the software: mine is R05.00.03
I remembered what i did and changed things as my above post said. Im also using PRI 1 and PRI 2 and that is one of the problems. One more thing is when a full scan list (16) and both PRI's do not use the sample rate of 750 ms, actually do not even program the priorities on the computer have the user set them up via the keypad. Even though i got mine working better Please let Me/Us know what M says i may need to have mine serviced.

QFL · Post by **QFL** » Tue May 20, 2003 1:03 pm

I spoke with /\/\ about it and here is what they had to say:

"If there are priority members, it essentially doubles the time to scan, and a 10-member list could possibly take close to 2 seconds to land on a non-priority member. With signaling or PL, possibly over 3 seconds even."

When I asked for the speciffic sample times, this is what I got:

It "is technical information that I do not believe we have readily available" for distribution. If we see the codeplug, we can estimate the max time to wrap around and hence determine if they are seeing normal behavior or not."

This just comfirms what I thought. Oh well. back to the drawing board.

ArmsonOeg · Post by **ArmsonOeg** » Tue May 20, 2003 6:31 pm

Well thats nice...... Here is what mine was doing. I have 16 ch in the scan list and two Priorities, while scanning it stops on Pri 2 but u just see signal no audio on PRI 2. This has been as long as 7 or 8 seconds just depends on ??, by that time the transmission is complete. This also happens on other scan list members although they may not have been as long. I may have mine sent in so they /\/\ can play with it. But like i said i have taken care of it on my own (Previous Post)

Gordo ô¿ô

SonicSounds · Post by **SonicSounds** » Tue Nov 13, 2007 11:03 am

I'm going to bump this. I have a WHOLE BUNCH of CDM mobiles that are driving their users absolutely crazy with slow PL decoding. If a CDM and a Maxtrac are put next to each other, the Maxtrac is MUCH faster at decoding the PL, and opening the receiver. The CDM also (not surprisingly) has a long delay on the COR output, which makes it very irritating to use in bi-directional repeaters, because the first part of even the most careful user is cut. Regardless of the application, I'm noticing long lags with these radios. They are NOT scanning and they DO NOT have any MDC systems in use.

Ideas?

Thanks,
Jon

Post by **wavetar** » Tue Nov 13, 2007 5:52 pm

Can't say I've ever noticed slow PL decode in a CDM as compared to a Maxtrac. I've also used CDM radios in bi-directional repeaters with no noticeable delay on the COR output either. Could you send me a codeplug to have a look at?

wavetar@eastlink.ca

Also, what firmware version(s) are the mobiles using?

Todd

Wile E. Coyote · Post by **Wile E. Coyote** » Thu Nov 29, 2007 6:18 am

I remember hearing a radio urban legend a while back that using higher frequency PL tones will help the radio open up quicker. That may have been true in the vibra-sponder days, but because the CDM uses software to decode the PL/DPL, I would think that it would take the same amount of time regardless. Still, it wouldn't hurt to try it if you have some radios lying around.

-WEC

a_j_b · Post by **a_j_b** » Thu Nov 29, 2007 8:21 am

If your users are NOT using signalling with Data on Squelch (DoS) change this setting. This will keep the radio from trying to detect signalling data before deciding to unmute. This will only effect unmute delay time while in Scan though.

Scan List -> Advanced tab -> Signalling -> Type set to None

KG4LHQ · Post by **KG4LHQ** » Fri Nov 30, 2007 11:22 pm

We had the same problem with our CDM's... I just backed down the DOS Mute Time and all that in that tab

I think I have it set to 25 and 25 and it works flawless now

No delay at all.

CDM Mobiles slow to open up RX audio.

CDM Mobiles slow to open up RX audio.

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