Plasma TV RFI wav files?

**ab1jx** · Wed 10th Nov 2010, 16:28

There's no forum for RFI so I'm trying this one. I'm wondering what plasma TV RFI actually sounds like. I live a fairly rural area (nearest houses are about 500 feet away) but I've got an S7 noise level on 80 meters, and 160, well, forget it.

Now that NTSC with a 60 hz vertical scan rate isn't in use anymore I suspect this is power line noise since it sounds 60 hz modulated, but I'd like to be sure before trying to track it.

Can anyone post a link to wav (or mp3, or au, or ogg) files that are samples of what plasma TVs actually sound like? I know there's one about 1/4 mile away (a relative) but do they carry that far?

Thank you,

Alan AB1JX

**M6NKA** · Wed 10th Nov 2010, 18:12

Hi,

My plasma is old model Pioneer and is very, very bad. Sounds similar to digital mode to me. It fully blocks the
160,80 and 40m bands. Sometimes PSK31 breaks trough the noise. The 20 meters and up doesn't seem that affected,
but i guess that is based on model of the TV. In my case the TV is 10 meters away from the antenna. Removing
the antenna connector at the back of the radio stops the noise, so its pure transmission from the TV that reaches the antenna.

If nobody gives you youtube link or something already online i will try to record and upload somehow for you.

BR

**M6NKA** · Thu 11th Nov 2010, 08:10

Here the files. Sorry it's wma format, the only recorder i had is one that comes with win7
as default.

BR

**ab1jx** · Sat 20th Nov 2010, 04:36

Thanks for the samples. I guess what I've got is just powerline noise.

I recorded a couple of samples by doing an audio capture in fldigi. Then I looked at FFTs done in Audacity (Linux user here). There's a strong 120 HZ component.

First the 80 meters, at about 6:30 AM on 3885 KHZ in AM mode:

Then 160, recorded just before:

The 80 meter one is more complicated and actually has some 60 hz, but still the biggest peak is at 120 hz.

Links to the wave files:

80 meters http://oldyashica.webs.com/ab1jx/rfi...5khz_20sec.wav

160: http://oldyashica.webs.com/ab1jx/rfi...5khz_20sec.wav

I'm using an end-fed wire about 150 ft long. I'm collecting parts for a couple of shielded loops instead.

Alan

**M6NKA** · Sun 5th Dec 2010, 17:04

Well, i hope that you can find a fix for your problem. With me it's not a big problem as i am interested only in 20m, due to not having space for really big antenna + the fact that i can only play the radio during day time. And for some reason my plasma is not affecting 20m band that bad (if at all)

**AE6ZW** · Sun 1st May 2011, 23:23

if you can power your receiver by battery, you might want to turn off main breaker of your house to see if noise go away, then turn on one sub breaker one at the time while listening receiver. I use AM radio ferrite bar's null to direction find noise source.