Fixed Loop On-a-Roof - Great for Monitoring that Hard-to-Get AM/MW Radio Station
Telamon wrote:
In article .com,
"N9NEO" wrote:
Does higher bands mean like 160m is higher than 75m or 3.885MHz is
higher than 1.945MHz?
Would your Idea be practical Telamon considering the reverse voltage
capacitance of a varactor is limited to a small swing in PF? Maybe
lots of diodes in parallel?
Ack Ack, 12:59, back to work.
Well a couple of things come into play.
Local noise goes up, along with atmospheric, and loops tend to have
greater local noise rejection over a voltage type. This is especially
true for a shielded loop. There is no loop advantage in atmospheric
noise save for lightening storm noise so it might make a better summer
antenna.
The lower in frequency you go the signals tend to be directionally phase
stable and so with a loop receive pattern you can null signals.
The higher in frequency you go the less advantage there is in a loop
over a dipole but it will work just fine.
I think paralleling diodes to get more capacitance than what one diode
can provide will work. Can't think of a reason why it would not work.
There are available diodes that can provide swings of more than 300 pF.
What is important, if you want tuning range, is the ratio of maximum
capacitance to minimum capacitance. Paralleling many identical diodes will
not change the ratio. Selecting the appropriate diode is better.
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