At 05:32 PM 09/11/09, Joe, K1ike wrote: >The average coax cable of 1985 vintage probably had a velocity factor of >66%. If you didn't figure this into your calculations the coax would >appear to be about 1/4 physical length, but would be an electrical 1/2 >wavelength. Did you use a velocity factor in your calculations? > >Would it be possible to scan the Motorola document that you have and >post it to the group? I've heard of it but I've never seen it.
It's been on the repeater-builder website for several years, on the Antenna Systems page, in the Mobile section. It's about the 5th one up from the bottom. I've been thinking about setting one up, as a future project is to set up a mobile, either a low band Syntor-X9000 or a Maratrac, with some channels on Red Cross and the rest on amateur 6m. I may have to go to a screwdriver antenna as a 1mhz wide window for 6m may not be enough.... We currently have active 6m repeaters from 51.24 to 53.76 Mhz. See <http://www.scrrba.org/BandPlans/51-54.pdf> And local Red Cross uses 43.00, 45.92, 47.42, 47.46, 47.50, 47.54, 47.56, 47.58, 47.62, 47.66 and a few high band and UHF channels. The 47 MHz channels will be no problem in a 1 mhz wide dual-whip system, the 45.93 and 43.00 channel will be a problem. The radio isn't the problem it would have been when I still had Motracs in a Ford station wagon with . It's going to be interesting to make a low band mobile antenna work across all the channels. And then to make a 99-channel MT1000 do it as well. Low band rubber ducks make better blackjacks than antennas, but that's the only thing that isn't fragile. It may take two separate rubber ducks - one for Red Cross, one for 6m. Or a UHF handheld talking to/from UHF to low band mobile crossband repeater. Mike WA6ILQ
