Our ARES group is planning to deploy cross-band repeaters for an upcoming exercise in hilly terrain where HT coverage is marginal. We'll be using dual-band mobiles to link 70cm simplex with our 2m repeater system. What are the key configuration points to avoid interference and ensure reliable operation?

Particularly interested in:

• CTCSS tone strategy for both sides
• Power level recommendations
• Frequency coordination between multiple cross-band units

The receive sides of both VHF and UHF on the cross-band should have CTCSS tone encode set to minimize the chance of false triggering by other signals. Also coordinate your 70cm simplex frequencies between units - Make sure each CBR is configured to use a different 70cm simplex frequency. Coordinate your choice of frequencies with the Net Control Station to avoid interference to the net.

NEVER CROSSBAND REPEAT TWO REPEATERS TOGETHER!! By doing so, you run the risk of a signal loop, causing both repeaters to remain up, and rendering the systems useless. Keep power levels low to manage heat and battery drain. I typically run 5-10 watts max on the mobile units.

From a technical standpoint, even though it is a low-power device, it must conform to all repeater rules. You must "plug in" the necessary Part 97 rule sections including sections on auxiliary operation and control. Identification requirements also apply and you must be sure not to cause harmful interference to coordinated repeaters. Make sure you understand the control operator requirements for unattended operation.