rjr@mgweed.UUCP (Bob Roehrig) (10/01/84)
To answer W3IKG, sorry, I don't know where there is a Matchbox for sale at this time. I have seen some at hamfests recently, mostly the smaller 275 watt version. I have the smaller one and use it with a 1000 watt (dc input) amp all the time with no smoke or arcing. Of course I tune up with just the 100 watt exciter first. The only real difference between the Matchbox and the balanced tuners in the handbook is Johnson's use of the dual differential capacitor which is an unavailable item. Without this cap, you have to tap down on the coil for proper loading and also be able to select series or parallel feed, but the handbook circuits work just as well. I don't know too many people using vertical dipoles but that is a good way to go. That reminds me of my experience with my low freq antenna which is a 40 meter inverted v fed with open wire line. The antenna works much better on 75 and 160 meters when the feeders are tied together and the system is fed like a single wire. It then becomes a top capacity hat loaded vertical. Naturally it is better if you have radials, or like they used to do in the old days, a counterpoise wire. A horizontal dipole just does not work well if it is under a quarter wave above ground. I remember an article in a 1920's QST that used a 3-wire open line feeder. The tuner also was used to shift the current point to different locations on the antenna to optomize the angle of radiation. I hope to find that article again and try it out. Bob K9EUI