[SEDXC] K9AY receiving loop
k4sb at comcast.net
Thu Sep 7 18:16:55 EDT 2006
Tad and John, you may be making it a little more complicated than
First of all, you can get pretty good performance IF you use a
device at the input to the loop , and also a low pass ( I think )
filter, both made by ICE. The The matching device has 4 different
choices for the input impedance to convert it to 50 ohms.
The low pass filter has a cutoff at 1.6 mHz and the drop-off curve at
that point is almost unbelievable. I can tune in an AM station which
is 40/9. cut the filter in, and it's in the mud. You will also find if
you just listen to an empty frequency on 160, and then cut the filter
in , you will see a decrease in noise level of about 3 S units.
Now, when I used my home-brew version with the Vactrol, it seemed a
waste of time. So, I mounted the loop on a 2" piece of PVC at about
6 feet, put a cheap radio shack TV rotor on it, and rotated the entire
One more thing. IF you are using a vertically polarized antenna for
transmit, you MUST ground the antenna on receive. That's worth about
3-5 S units down on the noise scale. Learned that one from K6LL, and
the reduction is amazing.
Just some thoughts..
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