Radio > EmComm/Emergency Power
CERT Coms Using Cross Band Repeaters?
16bravolima:
Our CERT group is looking for a way to provide EmComm County-wide during a disaster situation. We are in a mountainous area with ridges and peaks up to 4500 ft. Also, 75% of our County is National forest.
The local sheriff and FD have repeaters on two of the highest peaks and they do a good job of covering the entire County. We were considering building three EmComm Boxes using poly boxes large enough to hold 2-12V deep cell batteries, a 2M/440 mobile transceiver and a decent dual-band antenna. The "boxes" could then be driven to specific peaks and deployed during the emergency and then picked up later.
The strategy is to equip each CERT member with an inexpensive HT (Baofeng UV-5R) and have them TX/RX on 445.775 (simplex call). The cross-band repeaters would RX on 445.775 and repeat on 2M (147.510). The other two repeaters would receive on 147.510 and repeat on 445.775.
While I haven't tested this (I just bought a dual-band mobile capable of cross band repeat) I wanted to hear any thoughts or suggestions. The FD/EMA supports our efforts and thinks this would work.
bryanthegoon:
One of the more experienced guys will jump in I am sure but only concern I see is it seems like you would have a looping issue on 445.775 (ie the cross band repeaters picking up the signal from the other two repeaters). I believe you can fix this by playing around with PL tones (require a PL on the RX side on the cross band repeaters that the other repeaters wont be putting out on TX, and put that tone out on the TX on the HTs), other than that I don't see why it wouldn't work
16bravolima:
Good thought Bryan. I am assuming with the HT's only TX with 4W, they will only be heard by their local repeater. Depending on the size of the disaster area, we may only need two repeaters.
bryanthegoon:
On the HTs given the terrain you described you are likely correct unless you were near the top of one of the higher peaks.
kf4lne:
My thoughts would be to divide the county into zones that can be covered by a basic VHF hand held or mobile. Then use the repeaters as a remote base with a UHF link back to a centralized incident command center away from the action. Rather than trying to rig a repeater from cross band radios, make good use of the radios cross band functions as a remote base. If your disaster comms team is using a proper directed net, this should be all that you need. Its suitable for many public safety applications and should be suitable for any other emcomm need.
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