GR500 repeater speaker

[Flameout]

I just picked up this old Motorola GR500 repeater and so far it works great. Pretty clean for its age and putting out about 24 watts on low and 43 on high. I was just wondering if that has a built in speaker? The on/off/volume has no effect other than turning the unit on and off and I always thought that since you can plug in a mic and use it as a base, that there would be a speaker

 

[Radioguy7268]

The GR500 wall mount did not include a speaker. You could add one by tapping into the rear connector. I haven't studied the manual in about 15 years, but there might even be handset audio available at the front mic jack.

Good info on pinouts and manuals should be available on batlabs and/or repeater-builder.com

One word of advice, do NOT run that unit at high power if you want it to live. The GR series of repeaters were sold as having a 50% duty cycle at high power. It was more like a 5% duty cycle. Fresh cool air helps, but it helps more if you can live with the idea of running at 20-25 watts. Even at the lower power settings, they're still not 100% duty cycle.

[Flameout]

1 hour ago, Radioguy7268 said:

The GR500 wall mount did not include a speaker. You could add one by tapping into the rear connector. I haven't studied the manual in about 15 years, but there might even be handset audio available at the front mic jack.

Good info on pinouts and manuals should be available on batlabs and/or repeater-builder.com

One word of advice, do NOT run that unit at high power if you want it to live. The GR series of repeaters were sold as having a 50% duty cycle at high power. It was more like a 5% duty cycle. Fresh cool air helps, but it helps more if you can live with the idea of running at 20-25 watts. Even at the lower power settings, they're still not 100% duty cycle.

Ok, thanks for that info. I couldn't find any info other than it was showing specs for an internal and external speaker. Although an internal speaker would be nice, certainly ( not a deal breaker. I'll figure something out.

I also had someone else tell my not to use high power. It gets very little use, but I will keep it on low (25 watt). Testing from the duplexer to antenna, on low power it was showing 1.03 SWR and 20 watts. On high power, it was 1.05 SWR and only 31 watts so that 11 watt difference isn't worth burning up this old radio prematurely (antenna is a CommScope DB404 and a 25' run ofLDF4-50 hardline)

[gortex2]

Only place on the GR1225 repeater that has audio is out of the 16 pin on the back. The GR500 was technically the chassis and was originally for the dual radius/maxtrac radios. When the GR1225 came out they sold an adapter for the 1225 head to mount in the chassis. Good unit. Good idea about the low power. I still have 6 in use that work fine on low power. If needed they would support an external controller but try to use the internal for simplicity.