Get my GM1200 to transmit constantly

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jens ledet
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Joined: Mon May 26, 2014 4:12 am

Get my GM1200 to transmit constantly

Post 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
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fineshot1
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Re: Get my GM1200 to transmit constantly

Post 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.
fineshot1
NJ USA
jens ledet
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Re: Get my GM1200 to transmit constantly

Post by jens ledet »

Do you now can the gm 900 do it then ?
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Astro Spectra
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Re: Get my GM1200 to transmit constantly

Post 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.
Karl NVW
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Re: Get my GM1200 to transmit constantly

Post 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.
Karl - WA8NVW AFA5VB
SHARES + NCS
jens ledet
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Posts: 28
Joined: Mon May 26, 2014 4:12 am

Re: Get my GM1200 to transmit constantly

Post 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 :-)
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