Diagonal lines on SLP/EP VHS recordings?
 

This isn't my capture, but I have seen this effect on quite a few SLP/EP playback test tapes that I have and I'm curious if there's a known cause or a best practice to improve it?

https://archive.org/details/wfaa-hom...ovement-finale

I am presuming that is an SLP/EP tape because I've never seen it on SP speed myself.

The diagonal lines are broadcast noise/interference, it's independent of the recording speed. I've seen this on an SP recording of an over the air antenna feed.

AviSynth DeFreq plugin (http://avisynth.nl/users/fizick/defreq/defreq.html) has been very helpful for me with this on multiple occasions. I suppose some other filters like Denoser/Degrainers may also reduce it, but it would also soften/smooth things you may not want to. I don't see that issue when I've used DeFreq.

Set the "show" argument and then try to define fx, fy, dx, dy arguments that put a box around the most noticeable dot(s) seen in the "show" window. May take some time getting used to it, but I find it rather intuitive once I got over that learning curve.

I'll have to give it a go sometime even though I'm not super familiar with Avisynth yet. Thanks!