Jump to content



Motorola M1225 repeater build with msf-5000 pa

repeater PA output power msf-5000 pa

  • Please log in to reply
3 replies to this topic

#1 wqzw301



  • Members
  • PipPip
  • 23 posts
  • GMRS Callsign:WQZW301

Posted 13 April 2020 - 11:58 AM

Hello all,


Does anyone know if it is possible to lower the wattage output on a radius M1225?

I read in repeater-builder that an m1225 was a good exciter for a (stand alone) msf-5000 pa .

The Msf-5000 has an input of >5watts give or take....

I do have the rss (windows xp) for the Motorola m1225, I'm thinking, there might be a way, to adjust output wattage, in the service feature?

Also I've read in forums (years ago) that people would adjust the m1225 potentiometer, when programming out of band, for ham use....

I'm putting together a repeater in the vhf business bands.

I was also thinking an inline attenuator, but that kinda defeats the purpose of increasing the duty cycle, even on low,15 watts...just more heat generated that needs to be exhausted.

Please and thank you for any help you can give me in this matter.



#2 kb2ztx


    Advanced Member

  • Members
  • PipPipPip
  • 379 posts
  • LocationEast Coast
  • GMRS Callsign:WQLY948
  • Ham Callsign:KB2ZTX

Posted 16 April 2020 - 08:11 AM

I don,t think you can get the GR1225 that low and be stable. I never had any turned down below 10 watts. There is alot of info out there on the GM300 and maxtrac radios that used very similar PA's and would wander on really low power. I run the TPL amps on my GR1225 repeaters in both UHF and VHF and have had good luck with them.

#3 berkinet


    Senior expert on absolutely nothing

  • Members
  • PipPipPip
  • 909 posts
  • GMRS Callsign:WQYR510
  • Ham Callsign:WB6TAE

Posted 16 April 2020 - 09:02 AM

Couldn't you just remove the PA? On many GR1225s they are already blown out anyway.

Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth.

-- Marcus Aurelius

#4 jbecraft



  • Members
  • Pip
  • 6 posts
  • GMRS Callsign:wrfu821

Posted 14 May 2020 - 08:51 PM

wqzw301, I sent you a private message

Also tagged with one or more of these keywords: repeater, PA, output power, msf-5000 pa

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users