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On Wed, 1 Oct 2003 15:11:29 -0500, "Crazy George"
wrote: Roger: I think you are trying to make a simple task difficult. Think about why you can't just hook a feeder to the base of the tower. Actually, you can, except matching it is a bitch because of the verrrry low impedance. So, go up a few feet (I use 20', as it is a common tubing length), and make it a gamma, delta, or whatever is convenient. Then use a "tuner" to match That's kinda, sorta, something like I'm thinking of doing. Other than at 160 meters the tap will probably be some where around 70 feet with a spacing of (SWAG here) of 18 to 24 inches. Then a series matching cap, just like in a gamma match, Then check with noise bridge and adjust accordingly. whatever appears to 50 ohms. Mine is a few microhenries of series inductance, with a few hundred picofarads of shunt capacitance at the 50 ohm I'd like to get it set so I don't need any series inductance, just a little capacitance. I'm currently trying to finish up a rebuild on the old Henry 2K4 in the shop, repaint the cabinet on an HT-33 that has a great front panel and nice chassis, and unfortunately I'm waiting for the wind to let up so I can let the top mast down to check the antenna hardware as well as replacing the pigtails. (That means about 6 to 7 hours on the tower). Oh..I forgot the HyGain AV640 that is ready to go on top of the 32 foot tower at the end of the shop. (which naturally has a big tree limb in the way which is too high to reach even with a big extension ladder) Roger Halstead (K8RI EN73 & ARRL Life Member) www.rogerhalstead.com N833R World's oldest Debonair? (S# CD-2) end. I actually use a fixed inductance and a series capacitor instead of a variable inductor, but that is a construction detail. |
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