John Barrett wrote: > Yes - this is going on an 16ft boat trailer converted to a flatbed with a > 38ft crank up tower mounted on a tilt base that I built. the tilt base, > hydraulic system, and generator are towards the back of the trailer, with a > 9ft x 5ft x 3.5ft cargo box system forward of the tilt base. The forward 5ft > x 5ft x 3.5ft of the cargo section is split into 2 shelves for cargo, the > rear 4ft is split with 2 18" deep shelves on each side, and a 65 gallon fuel > tank for the generator in the middle. The bottom shelf on each side holds 10 > each 100ah SLA batteries. The top left (drivers) side is power electronics > (transfer switch, 3000W inverter, 140A battery charger, AC distribution > panel, Primary 300A DC power Bus, and the high current DC breaker panel. The > top right side is radio and computer gear to implement local area and point > to point WiFi networks, APRS beacon with optional digipeater capability, > WinLink Telpac and PacLink Postoffice capability, Voice Repeater, and > eventually a 1.2hgz D-Star link. If the repeater ends up on VHF, then I > might consider setting an ATV system on 440, since I won't be using 440 for > anything else on the trailer. Call it the "ham shack on wheels" if you like > :-)
Well, I was thinking a RV-type comm. van, but that's not important. It does sound like a nice setup to haul into a scene and get comm's into a bad RF area. I think where your going to run into issues is the repeater. Putting a 144.39 and a 145.05 transceiver should be do-able with a standard 2M duplexer. Feed 144.39 into one leg, 145.05 into the other, making sure the duplexer construction is such that it will pass RF in both directions on both legs-some don't. (Some can't handle much power on one leg-it was assumed that would be a rx leg.) You might even be able to get away with a 3-leg duplexer-like combiner for the 3 tx's. But it would not be real cheap, and will take up space. The repeater rx would need to be on a separate antenna above the other one-as far apart as possible. Not sure 30' is enough...it will likely get desensed by the 144.39 tx. But trying to save space by using an isolator instead to combine everything onto one antenna isn't going to work. Just too many freqs too close together. -- Jim Barbour WD8CHL
