Quantar Muting Audio

[rescue161]

I have a Quantar set up as a mixed-mode repeater on the UHF ham band and I'm using a Northcom controller. During the weekly nets, some transmissions go silent/get muted. The transmission stays muted until the person talking unless. Then the controller emits an invalid boop and the repeater works fine again. At first, I thought it may have been the time out timer, so I turned that off, but the problem persisted. Then I thought the controller was hearing or otherwise misinterpreting a voice for a DTMF tone, because the controller instantly mutes the audio when it detects DTMF. It kept randomly happening, so I thought it may have been a Baofeng problem, but then it happened to me and I was talking through a Quantar as a base. Both Quantars are aligned. The folks at Northcom are looking into it, but I'm beginning to wonder if the Quantar repeater may have a problem. Northcom said to set the priority to R before W and it would not mute, but it does.

 

[wiredwrx]

Does the carrier drop as well, or does the audio drop only? Perhaps this is the start of U306 on the SCM failing. When U306 fails (and there may be others, though U306 seems to be common on some SCMs) it will not pass audio/modulate the signal.

 

[rescue161]

Phone keeps posting before I was finished typing...
Carrier stays as long as they hold the PTT, just no audio.

 

[rescue161]

Thank you. I'll schedule an appointment to replace the station controller.

 

[moetorola]

Check Station Log before, just in case.

 

[CARC383]

Interesting, I use several mixed mode Quantars with the Northcomm controller and have never seen that happen. The wild card list used by those controllers is extensive, maybe go through all the pages and verify everything is as recommended.

I did change one station setting from what was recommended by Northcomm. They say on the channel information tab to set "analog RX activation" to "S=carrier squelch". That caused some problems on carriers with the wrong tone making the courtesy beep go off. We happen to run two repeaters on the same pair, one a very high site and one a low neighborhood site with different input tones and the same output tone. The fix was to set "analog RX activation" to "SC=carrier and PL/DPL".

You might try that anyway in case the repeater is somehow thinking its in analog when you are using P25, or vice-versa due to the settings Northcomm recommends.

 

[rescue161]

I did mine the same way with "SC=carrier and PL/DPL." Everything else way by the book. I just verified the codeplug and it is spot on as to what the manual shows.

Would the station logs show an error for U306, or just the SMC in general? What is strange is that the repeater gives the low boop after the muting occurs. I can force it to repeat the error by keying up and hitting a random key on the keypad and continue to talk. Of course, after I hit the key, my audio is muted and it gives the low boop when I unkey, which is why I was thinking it was the controller. Would a failure of U306 cause the controller to boop or is the boop coming from the Quantar/wildcard settings? Did you set up wildcard table 20 by the book? What is the purpose of "MUTE TX" under the "HANG TIME ENABL" (wildcard table 20)? Same goes for "UNMUTE TX" on wildcard table 21. If the logs don't show any errors, would removing the mute/unmute lines on 20/21 create any problems?

I hate not having access to the site as I have to schedule everything with the folks from the state and that gets old when I don't know the exact problem. I've already scheduled one visit to reprogrammed it to remove the TOT, but that did not fix the issue. I was going to schedule another one to remove the controller, so I'm glad I hadn't done that yet. I will probably set another Quantar/Northcom controller up on the bench and program it the same way, so I can quickly do a swap at the site.

 

[wiredwrx]

Would the station logs show an error for U306, or just the SMC in general?

No, the log won't show a bad U306. I have never used the northcomm cable and/or controller, so can't answer anything about them. However, the issue as presented seems consistent with a bad U306. What you are experiencing may be a result of the interaction of the wildcards and the non oem controller and the SCM.

 

[d119]

Then the controller emits an invalid boop and the repeater works fine again.

What is an invalid boop, and what causes it? That's what I would start looking at.

Additionally, is the time out timer in the Quantar itself turned all the way off, both for repeat and wireline? The way the Northcomm controller works, it appears to the Quantar as some sort of external/wireline device, so you may want to make sure that the wireline time out timers are set to 0 as well.

 

[rescue161]

Yes, all three time out timers on the Quantar are set to zero. All of my other Quantars are run strictly in P25 mode without an external controller, so I have never heard one boop before, but this one does when an invalid DTMF string is detected.

 

[rescue161]

Swapped out the SCM and all is good so far. Thank you the info.