[RFI] impedance mismatching in coax
aaron at campusactivism.org
Wed Dec 28 13:02:32 EST 2016
Over Christmas I built a temporary/quick beverage antenna in a rural
area, but it had a very high noise level. I had chokes on everything
which helped, but as I hadn't a lot of planning - I ended up connecting
two pieces of coax together with 50 ohm and 75 ohm reactance.
Would this impedance mismatch cause any problems with the Type 43 toroids?
If not, then I'm guessing I wasn't far enough away from the house (50-75
feet away), and/or the house had a very dirty AC power. The location was
perhaps 20-30 acres - so I could get further away from the house and
The noise level at 500 khz was around 20-30 uV and below 100 khz there
were spikes up to S9 + 40 db. It was pretty clean above 3-4 mhz (so
this also points to the toroids working better at higher frequencies).
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