Some radios get Call Failed indication (2024)

John

We have had the STM32-DVM-MTR2K card running since January 2020 in an MTR2000 successfully. Something has happened in the last couple of weeks which has me puzzled. I have a Connect Systems CS-800D which consistently gets Call Failed when trying to access the repeater where it worked fine up to about 2 weeks ago. I have an Anytone AT-D878UV which can access the repeater. I have tried a clean code plug in the 800D and still get the call failed indication. I have tried high, middle and low power with the same response. The 800D can access other repeaters (e.g. Motorola XPR8300) in the area and can access the network via an OpenSpot 2. I am therefore calling this an MTR2000+MMDVM problem.

Thinking that the repeater might have gone a bit deaf we made some measurements RL from antenna approximately 19 dB not great but good. Receiver sensitivity on the MTR2000 via an ANRITSU S431 LMR test set was 0.25 microvolts so the MTR2000 receiver side seems ok. There is no problem hearing the output of the repeater when the data is coming in from the network so the transmit side is ok. The repeater was pulled out of service on 19 December and is on my workbench with the duplexer connected to a small antenna. I have upgraded the mmdvm modem firmware and the MMDVMHost software as of 19 December 2020 from Github. There has been no change in the behavior of the repeater. I have rechecked the MTR2000 receiver gain setting and it is at 119 when the clipping led stops flashing and this was the value that was set before moving to the bench. I have just about run out of ideas as to what it can be so I am asking the collected wisdom of the group for ideas.

John
VK2DLP

On this latest build with a MTR2000, and the STM32-DVM-MTR2K board, I had to reduce the TX level to get my Kenwood NX5300 to work successfully. Even though everything had been set as per the instructions regarding deviation etc..

So it could be either way, and it may have been "just about" right before, but has tipped over the edge now.

Seasons Greetings

Also, be sure you have both the TX and RX channel widths set to "wide" 25KHz channels. But again, if it *used* to work, what changed.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

John,

...so I am asking the collected wisdom of the group for ideas.

I don't know how many folks are subscribed here, but I'll help you out as I can.

Something has happened in the last couple of weeks which has me puzzled.

If it *was* working and is now not, one must ask "what changed"?

If the answer is nothing on your end, I would start thinking outside the box. I think you made a good first step on bringing the machine to the bench to test. If you run the repeater's transmitter on a dummy load, does it work? I'm suspecting duplex noise/desense is the culprit, however the fact that another radio works OK, sort of discounts that theory.

Do you have a way to check the TX and RX frequency of both the radio and repeater? It could be that one or the other is off frequency slightly. DMR is pretty sensitive to RF frequency.

Unfortunately other than the above, I am stumped as well. Sorry.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

On 12/19/2020 10:00 PM, John wrote:

We have had the STM32-DVM-MTR2K card running since January 2020 in an MTR2000 successfully. Something has happened in the last couple of weeks which has me puzzled. I have a Connect Systems CS-800D which consistently gets Call Failed when trying to access the repeater where it worked fine up to about 2 weeks ago. I have an Anytone AT-D878UV which can access the repeater. I have tried a clean code plug in the 800D and still get the call failed indication. I have tried high, middle and low power with the same response. The 800D can access other repeaters (e.g. Motorola XPR8300) in the area and can access the network via an OpenSpot 2. I am therefore calling this an MTR2000+MMDVM problem.
Thinking that the repeater might have gone a bit deaf we made some measurements RL from antenna approximately 19 dB not great but good. Receiver sensitivity on the MTR2000 via an ANRITSU S431 LMR test set was 0.25 microvolts so the MTR2000 receiver side seems ok. There is no problem hearing the output of the repeater when the data is coming in from the network so the transmit side is ok. The repeater was pulled out of service on 19 December and is on my workbench with the duplexer connected to a small antenna. I have upgraded the mmdvm modem firmware and the MMDVMHost software as of 19 December 2020 from Github. There has been no change in the behavior of the repeater. I have rechecked the MTR2000 receiver gain setting and it is at 119 when the clipping led stops flashing and this was the value that was set before moving to the bench. I have just about run out of ideas as to what it can be so I am asking the collected wisdom of the group for ideas.
John
VK2DLP

John

John,

BTW I did widen the deviation setting on the MTR-2000 out to 5K and it made no difference.

Did you re-calibrate the transmit deviation levels once you changed the channel settings?

It's also possible that one radio is more particular than another when it comes to deviation levels. you may just need to bump it a notch or two one way or the other. You might also try playing with the DMRDely setting. Most times it's somewhere between 162-165.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

On 1/4/2021 3:06 PM, John wrote:

Scott,
On the bench it still fails. I can see the repeater key up with both the 878 and the 800D but it is the 800D that gets the call failed. We did change the deviation setting on the MTR-2000 down to 2.5KHz some time ago but the problem occurred several weeks after that change. The only thing that correlates with the change is a severe thunderstorm although that might be a red herring. My plan of attack is to wait for the arrival of a replacement STM32-DVM-MTR2K from Cort and see if the problem remains. Before that happens I will go back over the deviation set-up. BTW I did widen the deviation setting on the MTR-2000 out to 5K and it made no difference. It is a mystery and I love mysteries. Hi Hi.

John / Scott

I found the dmr delay setting in the instructions for the MTR was pretty much spot on.

Using mmdvmcal, I set the MTR deviation as per the spec.

With some of the radios in use around here the DMR TX Level needed to be set higher than the out of the box setting of 50. I found TYT MD380's wanted it up to 70 before they would decode / handshake and key up. Anytones also like that kind of level.
My own Motorola DM4601 needs more than my DP3600 (XPR6550) - the latter worked fine at the "factory" setting of 50, but the DM needed 60 actually decode / handshake and key up.

It's a real case of trial by ordeal! Get someone with a problem radio out there and gradually increase the DMR TX level in the MMDVMHost config, but 5% at a time, until you get them all to work successfully.

vy73
Rob
M0ZPU
In not so sunny England.

John

Rob,
The problem is that the repeater has been working for almost a year just fine with a wide assortment of radios. It is only just recently that the change in behavior occurred. I did not redo the deviation calibration when we shifted the MTR-2000 to 2.5KHz but the 800D still worked with the repeater when that change was made. The problem arose a week or two after the change and after a major electrical storm in the area. BTW the 800D works fine into a Motorola XPR8300 repeater which also covers our local area so the 800D is not the problem. Another data point is that before I got my 878 I had the loan of a Motorola 4801 hand held and it worked just fine into the repeater and several days later it didn't so something changed and that is why a known good card will help sort out where the failure lies. Like I said I love a good mystery. Just got notification that the card has arrived in Australia so it should show up here in a week or so.

John
VK2DLP