Programming 2 CDM1550LS+ UHF as repeaters

[Stryk1]

This is my first time to post. Hopefully I’m in the correct board. I am using 2 CDM1550LS+ UHF radios as a GMRS repeater. I would like to know if anyone has done this before and how did you program the radio. I have the correct CPS software and I’ve set up the radios as per a video online but I’m not seeing the “receive” radio receive light come on. I’m using a generic 16 pin eBay cable for the repeater patch cable that plugs into the 20 pin connector on the back of the radio. Any hep would be much appreciated.

[C17LVFD]

Hi Stryk1,

If you’re not getting any rx into the cdm, then the basic freq n pl programming of the rx radio is off or the subscriber radio transmitting in isn’t programmed correctly.

Without posting codeplugs for the cdms and subscriber, there’s a lot of missing information to be able to quickly drill down on what the issue may be.

Seth

[Stryk1]

Hi Seth

Thank you for the quick reply. I have uploaded the current code plug for transmit and receive. I am using these radios for a portable GMRS repeater. The GMRS channel frequency is 462.550 with a +5 MHZ shift. PL tone of 141.3. Let me know if you need anything else. I appreciate your help. I am not able to find where I can upload the code plugs.

[jackhackett]

You may have the frequencies mixed up. If the repeater receive doesn't match the portable transmit you won't see a receive light.

For a GMRS repeater you would use one of the repeater pairs found in this list (and remember, GMRS does require a license). The repeater output (TX) will be one of channels 15 to 22 and the repeater input (RX) will be the corresponding channel 15R to 22R.

So let's say you're going to use channels 17/17R, 462.6000 MHz and 467.6000 MHz. And you pick a DPL code of 134. Notice that these frequencies are 5 MHz apart, this is the standard for UHF repeaters.

We say that on UHF the repeaters transmit low and receive high, while mobiles, portables and control stations transmit high and receive low, so....

You would program the repeater transmit radio to transmit on 462.6000 MHz DPL 134 and the receive radio to receive on 467.6000 MHz DPL 134.
You would they program the portables or mobiles to transmit on 467.6000 MHz DPL 134 and receive on 462.6000 MHz DPL 134.

If the programming is all correct and you still get no receive it could be a bad receiver. If the receiving radio is known to be good you may have an antenna or duplexer problem (are you using a duplexer?). If that all checks out okay you may be overloading it by transmitting too close. There's also desense where the repeater output is interfering with the input.

check the programming and let us know if it's correct,

[Stryk1]

Thank you for your time and the information. I am going to check and make sure I have the e proper frequencies in the radios. I am trying to figure out the “Accessory Pin” programming for each radio. This has stumped me so far. Am using a tuned duplexer and I have the 16 pin patch cable connecting the radios together. What is the correct “ Accessory Pin” programming drop downs for the “receive” and “transmit” radios. I have tried 5 different settings on each radio and I don’t know if they’re correct. How can I upload a copy of the code plug for each radio. I do not see an “attach” icon I can click on. Again, I appreciate your help. I also have a GMRS license and I have my Technician class license.

[Stryk1]

I have the frequencies programmed in the radios. I am trying to figure out the “Accessory Pin” programming for each radio.

[C17LVFD]

Not knowing what type of interface cable you have makes things difficult. This video may help shed some light. I haven’t tried this config but it’s a starting point.

The cable you purchased should have come with some directions. May be worth reaching out to the seller for some.

https://m.youtube.com/watch?v=HW6jSSTvO ... dyYW1taW5n

Seth

[Stryk1]

Perfect, that’s exactly what I needed to know.