M1225 Repeater Build

[CChamblee25]

I'm building a GMRS repeater using two Motorola M1225 mobile radios and a Fumei 462/467 duplexer. I bought a repeater cable for interconnecting the two 1225's, and have it in-place. It's the cable most commonly found on eBay, with six conductors wired and the small blue trimmer pot on each end. I found a sample configuration for the M1225s on Bat Labs, but it doesn't work well. I have managed to get the radios configured so that when my 467.55 RX radio receives a signal from my portable test radio # 1, it shows receiving status, and I hear my voice when I turn up the volume on the RX radio. I can also see that the 462.55 TX radio on the other end of the repeater cable is transmitting (getting the lightning bolt on the left of the LCD), but on my portable test radio # 2 monitoring the 462.55 frequency I cannot hear my voice. I hear the dead carrier, and a slight hum, but no voice at all. All of the PL tones are matched up across the board. I've tried adjusting the trimmer pots on both ends of the repeater cable, but it doesn't make any difference. I am questioning the External Accessory port settings in the 1225 code plugs, and not sure which pins need to be configured, and how they need to be configured. Does anyone have a correctly-detailed code plug configuration list that they can provide for the M1225s to be used with this repeater cable to make it function properly? Or, some suggestions on how to fix the audio issue?

 

[N5XPM]

I'm building a GMRS repeater using two Motorola M1225 mobile radios and a Fumei 462/467 duplexer. I bought a repeater cable for interconnecting the two 1225's, and have it in-place. It's the cable most commonly found on eBay, with six conductors wired and the small blue trimmer pot on each end. I found a sample configuration for the M1225s on Bat Labs, but it doesn't work well. I have managed to get the radios configured so that when my 467.55 RX radio receives a signal from my portable test radio # 1, it shows receiving status, and I hear my voice when I turn up the volume on the RX radio. I can also see that the 462.55 TX radio on the other end of the repeater cable is transmitting (getting the lightning bolt on the left of the LCD), but on my portable test radio # 2 monitoring the 462.55 frequency I cannot hear my voice. I hear the dead carrier, and a slight hum, but no voice at all. All of the PL tones are matched up across the board. I've tried adjusting the trimmer pots on both ends of the repeater cable, but it doesn't make any difference. I am questioning the External Accessory port settings in the 1225 code plugs, and not sure which pins need to be configured, and how they need to be configured. Does anyone have a correctly-detailed code plug configuration list that they can provide for the M1225s to be used with this repeater cable to make it function properly? Or, some suggestions on how to fix the audio issue?

Good chance your 462.55 radio is desensitizing the portable. Best practice is to use a dummy load and turn down the transmitter power for this type of testing. There are many other possibilities here as well that I don't have enough information to address.

 

[CChamblee25]

I'm using a dummy load and low power. It seems as if the audio is not being passed from the receiving 1225 to the transmitting 1225 via the repeater cable. This is my first repeater build, so I have no experience to rely on. Wondering if I need another cable of some sort connected to the mic jacks on the 1225s. I had assumed that the repeater interface cable passed the audio from one radio to the other. I do need to make sure that I have the accessory pins and radio wide configs in the CP correct, if anyone can post a list of the radio settings that'd be great.

 

[petnrdx]

If your handheld is receiving the OUTPUT of the repeater at 462.55 then desense is not the problem.
Best guess is that your cable is wired wrong.
Your PL tone must be correct or it would not key the TX.
And same with the COR to PTT connection.
Narrows it down to audio connections.
From memory the audio pins I don't think were programmable, I would have to look.
RX audio out should be pin 5.
Transmit (MIC) audio in should be pin 2.
Look to see if there are pins present in those positions.
Maybe you have the cable installed reverse? (backwards)
I will look at the software and verify that the audio pins were not programmable.
I have made M1225 repeaters several times and it should be pretty easy.

 

[petnrdx]

Rx audio out should be 11.
Mic audio in is 2.
Flat TX audio in is 5.
In the programming of your TX radio on the EXTERNAL ACCESSORIES page there is a dialog box to select EXTERNAL MIC AUDIO or NO EXTERNAL MIC.
If you are using MIC pin 2, you need to select EXTERNAL MIC AUDIO (meaning mic pin 2 on)

 

[prcguy]

And don't forget to back the power down to the minimum the radios will go like 10 watts, otherwise you will not have a repeater for very long. It will also help with desense, which is almost ever present with this type of setup.