Rick,
I think your friend already has the answer to the problem, but does not
realize it: the dish system power supply. I can not think of anything
within a sat dish system that could or should cause problems at 1.8 MHz
except harmonics of the switching power supply. Another tip off is the
drifting around - that's a variance by the PWM driver of the power supply.
If the power supply is a wall wart, have him check the label to see what
the output voltage and current is, then try to find a linear equivalent.
If the power supply is embedded within the control box, then he'll need to
figure out if the propagation of the birdies is via the AC power wiring or
from the cables to/from the dish. It sounds like it is the AC power
wiring, and that means doing some serious filtering right at the back of
the control box. Note that most commercial power filters have little or
no attenuation at or below 2 MHz.
73, Dale
WA9ENA
rick darwicki <n6pe@yahoo.com>
Sent by: rfi-bounces@contesting.com
01/15/2008 11:04 AM
To
rfi@contesting.com
cc
Subject
[RFI] DirecTV and DishTV
I have a friend that hears birdies on 160 M from various DishTV and
DirecTV systems.
He claims his own system has one at 1823 or so that drifts around. It
stops when he unplugs the AC but no when he disconnects the the cable at
the dish.
Has something been posted here or does anyone have info/cure ?
Thanks
Rick, N6PE
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