RadioBanter - View Single Post

January 14th 06, 03:39 AM posted to rec.radio.shortwave

wrote:
I'm not sure why the XY display, but seeing 40db is about the limit.
You really need test equipment to get any meaningful results. Network
analysers that cover a few MHz aren't that expensive. You can also
just use a RF generator and power meter, which is a cheaper solution
since you don't need phase measurements to see attenuation.

If you DON'T have a spectrum analyzer (most don't) or if you DON'T have
expensive test gear, a decent Oscope with x-y and a sweep generator can be
used as a poor man's spectrum analyzer. 50 years ago, there was no other
way to do it, in fact. If you look at, say, a Hammarlund receiver manual,
that's exactly the recommended way to adjust the IF filter response curve.
You don't have to go down to 60 db to see a bad shape factor.

--
Brian Denley
http://home.comcast.net/~b.denley/index.html