[RFI] DirecTV and DishTV

[dgsvetan at rockwellcollins.com]

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 at yahoo.com> 
Sent by: rfi-bounces at contesting.com
01/15/2008 11:04 AM

To
rfi at 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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