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Get my GM1200 to transmit constantly

Posted: Thu Feb 25, 2021 6:42 am
by jens ledet
Hi, i want to get my gm1200 to transmit alle the time when it is on, without someone pressing the ptt.
I think I can do it in the accessory connector ? but I can't get it to work by shorting ext ptt2 to ground. Anyone know what I am doing wrong here ?

Regards Jens

Re: Get my GM1200 to transmit constantly

Posted: Mon Mar 01, 2021 6:45 am
by fineshot1
Even if you could do so - why would you need to do that?

This type of mobile radio is NOT made for 100% duty cycle and this would likely burn it up sooner or later.

Re: Get my GM1200 to transmit constantly

Posted: Mon Mar 01, 2021 7:45 am
by jens ledet
Do you now can the gm 900 do it then ?

Re: Get my GM1200 to transmit constantly

Posted: Thu Mar 04, 2021 12:00 pm
by Astro Spectra
Both those radios are designed for ICS, that is intermittent commercial service with a low transmit duty cycle. If you want to use them to transmit continuously then you would need a number of modifications including a fan for the heat sink and some work around the PA to reduce the output power quite a lot. Maybe even bypass the PA entirely. For continuous duty cycle you should look at a product designed for repeater service.

Why do you need to transmit continuously? There are low lower radios specially designed for continuous audio or data service. Also, many countries have regulations that do not allow continuous transmissions in mobile radio bands.

Re: Get my GM1200 to transmit constantly

Posted: Sat Mar 06, 2021 9:37 pm
by Karl NVW
Confirming, the GM1200 mobile transmitter is designed to a 20% duty cycle, maximum 60 seconds transmit followed by 4 minutes receive. The heat sink will not even provide sufficient cooling during 50% DMR or analog transmit duty cycle.

Re: Get my GM1200 to transmit constantly

Posted: Tue Mar 23, 2021 11:13 am
by jens ledet
Thank you for the reply :-)
I need the to send continuously (at low power) Because the radio is going into a OB van, and we need the people on the floor/stage to hear the producer at all times. I know some of the radioes is being used for this purpose, but I can't remember the model number. And the 900 and 1200 was on the shelve here :-)