On 4/12/2018 4:02 PM, David Eckhardt wrote:
Ferrites are better suited at reducing RFI at 30 MHz than low HF. I am far
more concerned about 160, 80, and 40-meters, and of course, 20.1 MHz that
30 MHz.
Not even slightly true! I suggest that you study
k9yc.com/RFI-Ham.pdf I'm currently working on a major update of
recommended chokes for use below 10 MHz, extending recommendations to
the new 630M band, and providing more detailed plots of choking Z, Rs,
and Xs .
Inverters and built-in or added after the fact optimizers produce
less and less energy as the frequency is increased. Ferrites become less
and less effective as the frequency is decreased. Yes, there are special
mixes of ferrites that are effective at lower frequencies, but not easily
available from your corner store.
Not all that difficult to find if you know what you're looking for. My
website includes Fair-Rite part numbers for useful parts and a list of
vendors. There's an update to that list in my more recent tutorial on
chasing and killing receive noise. k9yc.com/publish.htm Another ham
recently pointed me to Arrow Electronics as a good source for small
quantity orders -- decent prices on stuff they stock and free shipping
for a $20 order.
73, Jim K9YC
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