My understanding is that the RFI is generated by the variable speed
motor controls. In these systems, both the compressor and the forced-air
run at variable speeds. Which is the main contributor to the RFI? These
units will be maybe 30 ft from my tower; I shunt-feed my tower for 160
m, so they will be in a relatively high RF environment.
*IF* we replace our current units (and that's a *very* big if), I'll
make sure that the thermostat line is also filtered one way or the other!
Kim N5OP
On 2/7/2020 3:44 PM, Jim Brown wrote:
On 2/7/2020 1:11 PM, krgoodwin@comcast.net wrote:
The culprit was the thermostat line
(4-conductor) where installing an RF filter (LC circuit) on each of
the four
conductors in addition to some ferrites on the line easily solved the
problem. Next re-install I will put in a shielded multi-conductor
thermostat control line which was my baseline for the house LAN
(shielded
ethernet line). Shielded cat XX (ethernet) line costs more but I
think the
cost is worth it since my tower/beam is right next to the house
--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
/"A great second violinist plays second fiddle to no one." //– Robert C.
Marsh, Chicago Sun-Times./
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