Tucson GMRS Repeater Changes

Howdy! David 960 here:

As of yesterday (5/28) we’ve completed the necessary hardware changes at the Lemmon 650 site to enable voting/simulcasting capabilities and have moved a few area repeaters around as a result. We’re not changing the frequency or tones on the Mt. Lemmon machine, but if you use the SWCRS machines covering the northwest side of Tucson (formerly on 575), you’ll now need to dial into the Lemmon 650 instead (now named the Simulcast 650). Fundamentally there should be no other changes required on your part. Should you need the programming information; you can grab it here: SWCRS Programming Info.

Since simulcasting requires the use of a delay to precisely time the audio at all sites, you may also hear the last fraction of a second of your own transmission depending on how fast your radio switches between transmit and receive; this is normal – think of it as a complementary radio check (copy that!). You’ll get used to it.

Simulcasting essentially merges coverage from several repeaters onto one channel, eliminating the need to switch channels when moving through their cumulative coverage zones, and is a much more efficient use of radio spectrum that will allow more local repeaters to come on the air and leaves more space for simplex users (since GMRS only has 8 repeater/simplex shared channels). As a result of developing, testing, and rolling out this system over the past few months, we’ve cleared off of 462.575Mhz and 462.675Mhz in the Tucson area which are now open, with plans to eventually clear off 462.550Mhz as well (putting that machine in standalone).

This change required procurement of new repeater controllers and GPS disciplined reference oscillators to discipline the existing repeater hardware and the controllers themselves, providing the timing accuracy required to pull this off at each of the repeater sites. If you enjoy using the repeater system and have the means to, please consider making a small donation to the group to help out! We’re trying our best to make this system as best as we can make it for the folks it serves, and that comes with real equipment and operating costs, every bit helps!

That’s all for now!


David WQVS960 / K6DSA