GR1225 Repeater Clipping Off MDC

Larry · Post by **Larry** » Mon Sep 13, 2004 10:40 am

I've got a GR1225 repeater. My mobile and portable units are programmed with an MDC signal. For some reason the repeater is cutting out the MDC pre-tone, I no longer hear the MDC signal as I did when radios are in direct mode. The repeater seems as if its not re-transmitting the first second of the field radio's transmission. subsequent transmissions on the repeater while taking advantage of the hang-time, I hear the MDC signal.. Do I need a different controller to capture all the TX signal of a radio?

Jay · Post by **Jay** » Mon Sep 13, 2004 10:59 am

Larry it just sounds like the reciever / controller is a littlel slow to wake up. You can test this theory by getting rid of your MDC pretone, and seeing if it cuts off part of the first part of the first word.

Possible solutions that do not involve hardware changes: increase MDC pretime in all of your user radios - use MDC post tone, or use MDC pre / post tones.

Jay

Post by **alex** » Mon Sep 13, 2004 11:01 am

I've never programmed a GR before, however, if it's two seperate radios that you can program, it may very well be that MDC decode is on the reciever radio, and therefore, the radio trapps it as being MDC, and mutes the audio.

Just an idea.

Moved to infrastructre forum.

-Alex

Larry · Post by **Larry** » Mon Sep 13, 2004 11:30 am

I believe that the controller is slow to wake-up and it cuts off the first milliseconds of the transmission. I've got the repeater set with a hang time of 3 seconds and each radio that transmits during the hang-time has no probelm sending the MDC signal through the repeater and is heard on recieving radios....

Not sure why it's slow, but I will try slowing down the MDC pre-signal on the radios....

jackhackett · Post by **jackhackett** » Mon Sep 13, 2004 11:35 am

GR1225s are a single radio with built in controller. They should work for passing MDC, we have several systems that use GRs, with the base radios set up for MDC decode. I think we had a similar problem, you might have to change some of the settings, I believe we have the pretime set to 750ms in the mobiles. Try that and see if it works.

Post by **HumHead** » Mon Sep 13, 2004 2:02 pm

I've run into the same thing. It's just the nature of the GR1225's receiver.

I've found that 400-500 mSec of MDC pretime is usually enough to get the data through consistently.