On Sat,9/24/2016 7:15 AM, Steve London wrote:
How much better would the performance be with a multiturn choke ? Over
real ground, in the presence of real, possibly interacting structures
within N wavelengths, isn't there a finite limit to the performance,
regardless of your choice of "excellent" vs. "superb" common-mode
chokes ?
Hi Steve,
The primary reason for using common mode chokes in our antenna systems
is to reduce RX noise. A string of beads choke is NOT a good choke at HF
for the reason cited -- it's effectiveness is strongly dependent on the
electrical length of the feedline considering it as an antenna (that is,
considering it as a wire, not a transmission line). This is not a matter
of "excellent" vs "superb," it is whether it is effective at suppressing
RX noise, and whether signal pickup on the coax fills in the nulls a bit.
73, Jim K9YC
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