Kent,
Never tried it, but I doubt a preamp would be worth the expense if mounted at the rig in a mobil set-up. I assume the feedline is only 10' or so. The preamp helps most when the feedline is lengthy, especially if cheap coax is used.
If you want to try a switching preamp, the ARR SP432VDG is a good one, see http://www.advancedreceiver.com/page7.html
For about the same price, you could buy an Arrow handheld yagi antenna, which would substantially improve both reception and transmission. See http://www.arrowantennas.com/146-437.html , although if the rig is fixed inside your car if might not be convenient to hold the Arrow, unless your mike cord is long enough so you can stand outside the car.
If you are limited to operating from the car, try driving to a hilltop or somewhere with a clear view from horizon to horizon.
73, Bill NZ5N
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On Mar 31, 2008, at 8:01 AM, Bill Dzurilla wrote:
Kent,
Never tried it, but I doubt a preamp would be worth the expense if mounted at the rig in a mobil set-up. I assume the feedline is only 10' or so. The preamp helps most when the feedline is lengthy, especially if cheap coax is used.
Agreed with all of Bill's comments, snipped to save space.
The "dollars to dBs" value proposition for pre-amps in a mobile installation with short coax runs doesn't work out until after you have an incredibly large antenna system.
A higher gain antenna and a way to point it "buys" you a lot more signal at the receiver, and is probably cheaper -- up to a point. It also helps you out on transmit, so you get "double-duty" out of antenna system upgrades.
(One can always look at some of the papers from organizations like the Southeastern VHF Society, from weak signal VHF terrestrial enthusiasts, especially "rover" stations in this particular case to see the math to engineer the "best" system one can for mobile weak- signal operations, since that's all Satellite work really is... weak- signal operating with a need to point the antenna more critically and more often, in both a horizontal and vertical plane, and different operating techniques. At the end of the day, other than Doppler shift, the RF physics are the same.)
-- Nate Duehr, WY0X [email protected]
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Bill Dzurilla -
Nate Duehr