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From: Old George KC5MU
Date: 11 Apr 2003
Time: 11:51:07
Remote Name: 207.113.129.156
Maurice Hately says that for the CFA to work it needs “two tuned circuits slightly off tune to get the necessary 90 degree of phase difference”, and that “it is hopeless looking for the action with a VSWR meter in the combined feed”. Then he says “only when the two circuits are correct can the feedline be seen to have a lowish VSWR”. The last two quotes would seem to contradict each other. Two tuned circuits adjusted “slightly off tune”( I call it titervating ) can give 1:1 SWR fed with coax or through a transformer to match a low impedance. I have done this often feeding various antenna configurations and on a breadboard with coils and variable capacitors. Two series tuned circuits connected in parallel (as in the dual loop) either connected directly to coax or through a transformer can be titervated for a 1:1 SWR. Connected directly to coax is more broedbanded, through a transformer is narrow banded , Both seem to “work” equally as well, down at least 1 S unit compared to a vertical dipole. Titervated Tuned parallel circuits connected in series does the same, as does a series tuned circuit in parallel with a parallel tuned circuit. When I have tuned against a field strength meter, the maximum reading has always appeared at the lowest SWR. So......? I would be delighted if my meters would show me some “CFA” activity and give me better then a “worked” reception of –1 S unit. Tell me how to do it, Maurice, and I’ll rerig my dual loops and read my meters. Old George