Building GMRS repeater

[Guest Chris]

Hi.  A little background is in order.  I am a licensed amateur extra (WA7ZAF) and I am part of a group of emergency communications group in my county.  We are all SAR members and comprise their communications team.  I am currently piddling around with building a UHF repeater for use on the county's licensed public safety frequencies.  I would like to first build a GMRS repeater as proof of concept before GMRS frequencies so I'm not tying up the active emergency frequencies with testing.  All of the gear I am using is both part 90 and part 95 certified.  The repeater will be a pair of Motorola Radius M1225 radios and I have a Kenwood TK-370 to talk to the machine.  I have NOT gotten my GMRS license yet, which is why I haven't registered here yet.  I will be doing that soon.

 

That's a LOT of background for a little question.  I have figured out how to field program the TK-370 but I can't find anything that will tell me which CTSS codes in the Kenwood correspond with the GMRS privacy codes.  These are in the second and fourth programming operation.  There are two options for these codes.  One corresponds with the amateur radio tone frequencies that I am familiar with, 67.0, 69.3, 71.9, etc.  The other is a bunch of numbers that don't mean anything to me.  They start at 023 and go up to 754.  What are these numbers and what is each set of numbers used for in GMRS?

 

BTW, the silly "security check" took me over 7 tries.  Uuuugh!

[Radioguy7268]

If you're doing Search and Rescue using a pair of M1225's for a repeater - you should stop and re-think your budget. M1225's are NOT meant for repeater duty. They do not have a good duty cycle rating, and they suffer from de-sense. Do those you're searching for a favor, and get a repeater that's built to do the job, instead of one that might fail in the middle of the job.

 

As for your question - if you designate a TPL - Tone Prive Line, that will be equal to your CTCSS standard tones that you're familiar with. You can choose either TPL, DPL, or CSQ (Carrier Squelch).  It's really poor practice to put a UHF repeater on the air using Carrier Squelch.

 

The other numerical values 023 to 754 are Digital Private Line - DPL codes. You'll find plenty of information over on repeater-builder.com if you go searching for information on DPL, maybe even to the point of information overload.

 

Hope that helps.