[Lowfer] HDTV RFI, request recommendations for reduction of noise

[Douglas D. Williams]

That sounds like a tough nut to crack, Andy.

Are you using the same antenna for HF that you do for LF? If I recall
correctly, it is a large wire antenna. Is it close to your house? Do you
use the same antenna for RX that you do for TX?

I still have that Wellbrook Loop, if you need to have a separate receive
antenna, placed further from your house, as many 160 meter ops do. Free to
you, of course.

I wonder if the interference is being radiated through your house wiring?
If that is the case, perhaps a faraday shielded line isolators, such as
this:

http://www.tripplite.com/en/products/model.cfm?txtModelID=229


73, Doug KB4OER


On Fri, Jan 4, 2013 at 12:59 PM, Andy - KU4XR <ku4xr at yahoo.com> wrote:

> Greetings all:
>
> As you are all very aware.. The noise we deal with on MF / LF
> frequencies can be terrible, and sometimes curable, sometimes not..
> PC's, switching power supplies, especially cheap Wall-Warts, and
> for sure the lovely HDTV's of today.. Here is my current delimna..
> My old HDTV had a low frequency refresh rate, and just ripped to
> pieces many frequencies in the 600, 630, 1750, and 2200 meters bands..
> After replacing 3 defunct power supplies in it, I finally retired it..
> I then went thru the process of finding a new " radio friendly " HDTV
> for the family room.. My wife is the TV-aholic, as for me; I would
> rarely have one on.. I purchased a Zenith 42 inch LCD with a
> Refresh rate of 600 KHz.. As I expected, the interference to
> frequencies below 500 KHz was either eliminated, or greatly reduced..
> However... I did not at the time, consider the regular ham bands..
> Well of course 600 KHz times 3 equals 1.8 MHz ... Yaaaayyy
> The TV does cause interference at lower frequencies, but it is
> tolerable.. 160 meters though is another story.. 20 dB over S-9
> growl, and garbble.. My noise blanker will reduce, mask, or whatever
> it does to it, and drop it down to S-9, but 160 meters is un-usable
> except to transmit in beacon mode... I have thru the years built
> heavy filters for power supplies, and been able to eliminate lots
> of noise.. But, I am not sure that this type of noise has a remedy..
> The refresh rate is fixed, and cannot be changed thru the setup menu..
> I have tried putting a home-brew, heavy duty line filter on the TV
> with no sucess at all.. I can disconnect the coax from the TV and the
> noise is still there, but does not change in frequency until I
> reconnect the cable and the picture comes back on.. The old Rat Shack
> inline caox RFI filter does nothing.. SO; I'm stuck as to how to deal
> with this type of interference.. We all know that hind sight is 20/20,
> and had I thought it thru better, I would have saw this issue beforehand..
> Yes, turning the TV off, it does go away, and a nice S-2 meter reading
> on 160 meters.. Any thoughts, ideas, recommendations, etc. will be most
> appreciated..
>
> 73 to all:
>
> Andy - KU4XR
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