On Sep 23, 1:33*pm, Jim Lux wrote:
Larry Gauthier (K8UT) wrote:
Art,

Funny that you should ask, because the October 2008 QST (just arrived a few
days ago) has a computer-based DIY spectrum analyzer project. Doesn't look
too difficult: *a couple of dozen parts and a software program that's
downloadable from the ARRL web site.

-larry
K8UT
"Art Unwin" wrote in message
....
S A s are usefull for antenna hobbyists. Some twenty years ago there
was a DIY *S A that used a t v tuner in
Ham Radio. Moving forwards some twenty years and most hams have
computors and there are 2.4 Ghz
spectrum analysers out there as well as audio set ups for computors.
So what is available today for hams
in the HF BANDS? There are a lot of older type audio S A s on E bay
but I haven't heard of anybody modifying thoseand with most having
computors it would seem reasonable to think that there were components
available that could performn between audi and 2.4 Ghz. So has anybody
seen any modern type DIY spectrum analysers
around for sale or kits? I have 141t and other types of SA which now
are considered bulky and I would really like something smaller or say
modify something like a audio setup as a project.
Comments

These days, the scanning receiver part isn't the hard part. It's
calibration and user interface.

For instance a Icom PCR1000 makes a fine HF,VHF,UHF spectrum analyzer,
although the resolution BW steps are limited and sweep speeds are limited..

What you get with a "real" spectrum analyzer is a fairly intuitive user
interface (with knobs!), well characterized and consistent RF
performance over a wide variety of operating conditions, and
calibrateability (i.e. stable and repeatable operation)

It's sort of like the difference between a real oscilloscope and a sound
card in a PC with an oscilloscope program. *The real scope probably has
wider applicability, more options arranged in a systematic way, etc.
But for some applications, the soundcard is just fine.

I have seen spectrum analysers the size of a hand held volt meter,
cost around 2 to 3 K
that tells me that the science is there and the chips are there. When
I see kids jumping their fingers all over the place with their hand
games
they have found a way around the knobs and wh
istles and bells so us old folks had better change up a gear. I just
want to see the shape of my transmission signal plus an idea what
bands are busy and which ones are not. For accuracy I can put a signal
on that of the SA and read out the frequency
on my radio. I do not want to replay my work years all over again!
Regards
Art