I don’t know if this is helpful or not but every time I’ve heard someone use a Yaesu radio on a Motorola repeater with reverse burst enabled, they produce horrible squelch crashes. We’ve been aware of this for going on 2 decades.
Which is why I use Motorola radios and hit Yaasu radios with hammers… Seriously, we’ve always minimized this problem by adjusting the phase angle of the reverse burst if the radio supports it (ie. commercial Kenwood KPG software w/engineering features enabled)
Hi, im my case i made test using Yaesu, kenwood, motorola, icom radios and its the same problem with all of this radios transmitting to MTR3000 and MTR 2000 if we speak more loud with TPL tone in the repeater reception the repeater cuts reception, working on 12,5khz or 25khz in repeaters and also in radios. This is why im searching for a external rx tone detetor in the audio that comes out of the repeater and use this external rx tone detetor to control the tx on the repeater, working the repeater with no TPL RX. But its necessary a good tone audio detetor !
Thanks.
Paulo Lobo
Hi Paulo,
I don’t know if this will lead you to any answers, but I can share the following information. I ended up going all the way to engineering at Motorola and talked to one of the guys that designed the receiver in the SLR5700.
The bottom line is, the SLR series of repeaters and the MTRs that were released as DMR natively (MTR3000 for example) have a different receiver design than anything traditionally only analog and they do some tricks to make them work in analog mode. The problem with RTCM/Allstar and one of these repeaters boils down to how it does squelch. Much like a typical squelch circuit in an analog radio, RTCM/Allstar (it’s really Allstar… the RTCM is just passing digitized audio) is looking for noise or carrier above about 6000hz in the passband to determine if there is a carrier there (IE, carrier detected then unsquelch, noise detected then re-squelch). The SLR and MTR3K have significantly smaller audio passbands than traditional analog receivers that fall off very quickly on the high side above typically human voice range. This is easy to see with a service monitor and a tone generator on the input. Allstar doesn’t receive enough information in that area of the passband to make a good COR judgement and you get strange results with squelch crashes, delayed squelch opening etc… and it does change behavior with PL on or off…
So in summary, the answer (with the way the RTCM/Allstar combo works today) is that you can’t use the repeaters the way you want. The workaround right now is to use an external repeater controller that has COR input (like an SCOM 7K, 7330, etc…) and hook the repeater to that controller, then hook the RTCM/RIM/whatever you are using for A/D interface to one of the other ports and then tie the ports together. This works excellent. The repeater handles the squelch sense internally and passes that to the repeater controller as a COR line and your audio travels to Allstar via the interface you’ve selected on the second port of the hardware repeater controller. Obviously, the one thing you can’t do with this setup is voting receivers, but for a standalone repeater it works great.
I use (2) SLR5700s tied to ports 1 and 2 respectively of an SCOM 7330, and then a Repeater Builder RIM-lite on port 3 (Repeater Builder USB-RIM Lite) to talk to Allstar.
Just to clarify here, the MTR2000 has no such problem. We have dozens of those working directly with RTCM, both standalone and voted, and then work perfectly. If you are having problems with an MTR2000, you likely have some settings wrong in the programming or are using the wrong pins. The MTR2000/RTCM is an excellently performing combination.
Hope that helps
73
James
KI0KN
Hi
James ! KI0KN !
Thank you so much for your help, so the only way i have for MTR3000 is using a external repeater controller, but i need one that control the reception via tone TPL because in Portugal for legal stuff its necessary tone in reception. This controllers have that ?
“The repeater handles the squelch sense internally and passes that to the repeater controller as a COR line and your audio travels to Allstar via the interface you’ve selected on the second port of the hardware repeater controller.”
The repeater Mtr3000 is not able to handle with TPL tone, so the repeater must work reception with no TPL tone and the repeater controller must listten to the audio and search for the Tone, if it finds the tone it must be able to make the repeater ptt on with the audio, if tone is stoped the controller must unkey the repeater tx.
What repeater controller must i use ? Will a simple audio tone decoder with a relay works ?
Thanks
Paulo Lobo
Ct2gnh.
Will this do the work ?
Hi
James, im not using digital modes, just svxlink with mtr 3000.
I test the repeater with no svxlink, no raspberry boards, nothing, just working only the MTR3000 in analog repeater in a UHF frequency with TPL tone in recepcion and this issue happens all the time we speak a little loud to the repeater, it cuts recepcion. But if i remove the TPL tone and work only Squelch with no tone in recepcion repeater works perfect !
Is not a problem of out of frequency, is not a problem with the tone i choose, its not a problem in 12,5 ou 25khz, im starting to think that this is a real issue in motorola repeaters… And i need to find a external way to solve this. I think if i use a external tone decoder and control the repeater it can work, but i also think ill lose the repeater path configuration has the external decoder board will control the repeater and not the repeater itself !
If i find a person that works in Motorola making this repeaters, a engineer that was in the motorola factory building this MTR 3000 repeaters that will help to solve the repeater problem, but until today i didnt find anyone !
Thanks for your help and thanks for everyone trying to help !
And sorry but im not able to post answer back in the community…
Paulo Lobo
ct2gnh
Note: I’ve never used an MTR3000, but assuming it’s programming is similar to an MTR2000 and assuming that you can grab discriminator audio from either the native connector or a wireline board…
If you are trying to overcome poor analog squelch and/or CTCSS decode then you can use a Masters Communication SC-75DW. Roughly what you would do is disable the “repeater” aspects of the MTR3000, disable TPL on the Motorola receive channel, set it to do PTT via external signal, and open the squelch the whole way. Then allow the SC-75DW to detect COR/COS and CTCSS. Wire those sense lines into a sound card as well as the discriminator audio in, tx audio out, and external PTT (and of course ground!). Configure it with USBRadio and trigger on usbinvert for both COS and CTCSS Detect. Don’t use a PL/CTCSS decode frequency. Then configure USBRadio to encode the CTCSS/PL back out with the same input.
If MTR3000s support them and you have one, you can use a wireline board for audio in and use the MTR to encode TPL out directly. But might as well just use USBRadio.
Paulo,
I am thinking that your problem is not really the same as this threads original issue, but in case it’s related we can keep going here.
I am not sure I understand what the actual problem is with TPL decoding. The MTR3000 is absolutely capable of decoding and encoding PL without additional hardware. You mentioned that when you have PL decode enabled, the receiver is “cutting reception” when people speak loudly.
One question here… are you using the repeaters native hardware PL decode/encode via programming, or are you trying to use PL decode in Allstar? If you are using in Allstar, try removing the PL config in Allstar and instead program the repeater to decode and generate the PL. It’s very good at it, so why not let it? 
If you are using Allstar to decode PL, there is a wide variety of things that could be causing you issue. See if you can use the repeater hardware first and if that solves the problem, you should be good.
On the squelch issue, I am not sure if the Master Communications board will work any better than the RTCM. I think it works on the same principal, looking for carrier above the voice range in the audio passband and the MTR3000 will not pass that audio, even discriminator audio, to that board since it’s simply just not there in the passband. If I am off on this, anyone please correct me, but I think it will not solve the issue.
See if that gets you any farther.
James
KI0KN
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