I'm working on a new matching network for my vertical. The vertical is a wire cage of approx. 82 feet high, and I use it on 160, 80 and 40 meters. The matching network is a low-pass L network. The new matching network is remotely tunable with 5 different capacitors selected by vacuum relays and two tapped inductors adjusted with motorized rotary switches. One inductor is large (about 45 uH), most of which is needed for loading on 160 and less is needed on 80 but I have 6 taps to choose from. The smaller inductor (about 2 uH) is used mostly for 40, but also to "fine tune" the large inductor since the large inductor is almost 2 uH per turn. The inductors are in series between the antenna and feed with motorized rotary switches to select the taps, one switch per inductor, 6 taps per inductor. Taps are set to be "about right" for the bands I use on the antenna so the matching network is adjustable but within certain ranges - it's not a "match anything" network, it's specific to t his antenna.
Here's my question: the large inductor is much higher Q on 160 than the small inductor (large inductor is about 4.5" diameter, small one about 2" diameter). Would it be better to have the large inductor connected to the antenna and the small one to the feed (the two inductors would still be in series), or the other way around? My original thinking was that it wouldn't really matter since they're in series, and due to the tap selection arrangement the same distributed capacitance is in the circuit regardless. Can anyone think of a reason why the arrangement of which inductor was in which position would make any practical difference in this system that I may have missed? -Bill _________________ Topband Reflector Archives - http://www.contesting.com/_topband
