[ADXA] The Never Ending Battle With ^&%$*# Noise

[w5zn at w5zn.org]

Yesterday I began the process of getting my low band RX antennas all set 
up for the upcoming season. It takes about 3 or 4 days to get the 
current system of short vertical arrays all going. Some of them are 
completely removed for the summer and hay cutting, a couple other short 
vertical array elements are left out and the electronics just all packed 
up.

Yesterday's work was on the HiZ-8 160 meter array. For those of you who 
were here a year ago for our ADXA BBQ it is one of the arrays east of 
the house along Miller Rd., centered 800 ft from the shack. This doesn't 
take too long given the vertical elements are already out. Just getting 
the individual signal cables from the center control unit to each of the 
elements and connecting the high impedance amplifiers. The longest time 
is spent running over 800 ft of signal cable (1/2") and DC voltage 
wiring (3 - #12 wires) from the shack out to the control unit. I had it 
working after about 4 hours, just in time to catch the football game 
yesterday.

What I noticed when I fired it up last night was my noise floor was 
about 10 dB higher than when I disassembled it last March and I had some 
broad "goober" signal around 1827 KHz that was 20 dB above the noise 
floor. Time to start searching for the source. It seems to never fail 
that during the summer months something seems to increase the noise 
floor.

So I started turning things off and when I turned off one of the shack 
computers it went away. What I discovered as the specific source was the 
USB connection at that computer from the Elecraft K3S I use on 160. This 
connection is necessary for all of the communication between the radio 
and computer so simply leaving it disconnected was not an option and 
replacing the USB cable did not solve the problem. I'm not sure what 
changed over the summer to create this new noise source. I grabbed a 12 
ft USB cable and a couple of #31 cores (We've talked about this during 
an ADXA technical presentation before) and wrapped the USB cable 
completely around a core at each end of the cable (see attached photo). 
Goober gone and noise floor back down to -130 dBm!!!!

Now to get the 160 BSEF and 80 meter BSEF vertical arrays put out and 
connect the YCCC-9 along with a couple of Beverages.

VK sigs on 160 were decent this morning.

73 Joel W5ZN
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