[RFI] Re: RE: RF resistant TV, DVD, & Surround Sound ?

Dave Hachadorian k6ll@juno.com
Sun, 22 Dec 2002 23:14:56 +0000

On Sun, 22 Dec 2002 22:12:54 -0500 "WW3S" <ww3s@zoominternet.net> writes:
> The S video connection is lousy if you use 40m much. I think the S 
> video
> signal is just below 7mhz.

Actually, composite video and s-video are both "baseband" signals,
extending from 0 to about 5 Mhz. The only real difference is
that in s-video, the luminance and color are carried on two
different coaxes, thus the four pins (luminance, color, and their
two shields). The advantage of using s-video is that you don't get
"rainbows" on striped ties, herringbone jackets, and other
complex patterns.

Running 1500 Watts, I don't have any interference to either mode
on my video setup. However, when I'm on the treadmill (a great QRN
S-video shows no interference, where composite shows mild interference.
That was the only basis of my statement that I thought s-video was better
from an rfi standpoint. The rfi susceptibility of each should be about
equal, with differences showing up because of cable lengths, grounding
differences, or other unpredictable effects.

The worst thing you can do is to use the RF connection, especially
using the channel 3 output of VCR's, Satellite Receivers, and cable
boxes, because channel 3 is the third harmonic of 15 meters. Even
if your harmonic transmission levels are zero, the RF amps in the
video chain can overload from 15m rf, generating harmonics on
channel 3, which will affect all channels, since channel 3 is the
output for them all.

Dave Hachadorian, K6LL
Yuma, AZ