Batboard

Hello to the group,

My interest lies in modifying a UHF repeater, a GR300, using the GM300 radios at which I am new to. Actually I’m new to all Motorola radios.

I read on the main page about programming the GM300 for out of range frequencies using the ‘hold the shift key and enter the frequency’ thus my questions.
The GM300 has a number of UHF ranges and looking up part numbers, there is a different board for the power amp and one for the RF board for each range. So if I understand this correctly if my radio has the range of 465 to 490 MHZ, (because of the model number says it is) I could program it to operate in the ham bands of 440 to 450 MHZ. True / False?
But if true, what are the trade offs? Lower power out because I am not in the boards filter’s range, etc? And for the RF board are there receive issues?
There must be a reason for having the ‘ranges’….

If I missed a tutorial that would answer my post, I apologize and please point me in the right direction.

Tnx in advance, Pete NØOY

Worldtrek,

Let's solve your problem before you create one. Don't even bother trying to use the radios that you have for this project. You may be able to force frequencies into these range three radios but the chances of the VCO locking are about zero. We are not even going to discuss the ineffencies in the out of range power amps nor will I mention a front end that doesn't have a chance of hearing a signal short of connecting a mobile to the antenna input and keying directly.

That having been said, your best bet is to pull those radios, find a T band user and dump them. Hopefully you will get a few dollars and you can buy the 449 to 470 version. I may be slightly off in my ranges, but you want the range two radios. There should be plenty on ebay and I seem to see the VHF commanding more than the UHF in price. I hope you don't have a lot of money in these and can get what you need reasonably priced.

You do have some other options like scrapping these radios for the logic boards and trashing the remainder. Maybe the plastic on the front could be useful if they are beyond two frequencies with the digital display. But you also have indicated a limited skill set with this equipment so my conclusion is you are better off getting the radios that you need rather than arguing with what you have or trying to piece together equipment pieces and parts. The real question is, how much pain do you want? I suspect, not much. Go find some radios and have fun.

Yes, I am an obnoxious cuss tonight. I am tired.

Good luck.

George

I second George's post...

Trade the T band range GM300's for the 438-470 range radios.

Thanks George & Will,

I have not bought the radios yet, in fact they are in a GR300 with the owner unable to provide the model number of the GM300s. So I don't know for sure if they are the 438-470 or other ranges. My thinking was if I took a chance and they are not the range 3 radios would I be able to salvage some usefulness. With that said, your posts will save me some headaches and shorten the learning curve.

Thanks, Pete