On Fri, 20 May 2005 11:57:37 -0400, Chuck Harris
wrote:


No, your data sheet is wrong. The slowest automatic sweep is 10 secs per
division. The slowest sweep is manual. This specification exists across
the entire 7L line.



That's not what this says:

http://www.tucker.com/images/images_spec/00000453.pdf

I pulled out a 1981 Tek catalog, and I am indeed remembering wrong.
This is yet another reason why I discounted the 7L12 as a credible SA.

Here is what Tek is expecting you to do. There are timebase positions
for 5ms through 0.01us. These are for use when the SA is being used as
a receiver (time domain mode), and you are looking at a received pulse
train.

The "SA" mode is *variable* from 10ms through 5ms/division. You are expected
to manually adjust the sweep rate to get a clear picture.

So, how can you get 300Hz filter resolution? Well, simply by not scanning
the full bandwidth of the SA plugin. Reduce the sweept bandwidth to 10KHz,
and 300Hz is easily achieved with a 5-10ms/division sweep rate. Not a great
way to go, but usually if you are interested in the narrow resolutions, you
are only looking for signals over a narrow bandwidth.

Well, you can always just use an hf receiver with a stepped attenuator
and a narrow CW filter, but it's not so handy.


As I said earlier, get a 7L13, or 7L14. The 7L12 wasn't fully incubated
when it was hatched.

When you go looking at the 141T, remember, it is a mid 1960's SA design,
and it feels like it when you use it.

Hey, if you started using SA's in the 60's it's perfectly natural. [g]
We had one (don't remember the no.) that predated the 141's. Two
boxes that took up about three feet of rack space. Drifted like crazy
and used harmonic mixing so you didn't know what the hell you were
looking at.


The 7L5, 7L13, and up were designed in the
very late 1970s, and take advantage of things like microprocessors to help
with house keeping operations. They are smaller, quite reliable, and just
plain work better than the 141T family. (And, yes I have owned, used and
repaired both.) The 141T storage tube is a nightmare. Very short life.

Not when used properly, which most weren't. The ones in my lab worked
flawlessly until we upgraded. I auditioned a TEK 492P when they were
first issued. Never liked it even tho I had a capital acquistion
approval for it I didn't buy it. Bought an HP8566 instead. Of course
there was no comparison size and weight wise, but the HP was
rack-mounted and wasn't going anywhere. Programming was *much*
friendlier.


Another SA line that is usually very inexpensive, and much better than the 141T
family, is the Eaton/Ailtech 727 and up. I was told (in the early '80s) by an
HP FAE (who specialized in HP's SA's and other RF gear) that the Ailtechs were all
over the place in HP's internal R&D labs. They were the SA's that HP used in
designing their own product line.

My only Ailtech experience was with their NF boxes and that goes back
to when we were using gas tubes in waveguide [g].

(flame suit on, helmet latched, as I await the onslot of rebuttles from HP guys..)

No offense to Roy Lewallen and Wes Hayward, but at Hughes it was an
unwritten rule, you want a 'scope, buy Tek; you want a network or
spectrum analyzer, buy HP. You want a DMM, "If it works, it's a
Fluke." I did buy a Wiltron scalar network analyzer once for a
dedicated test position.

If I was to have a SA at home just for hf work I would love an HP3585.

And until the N2PK network analyzer came along, I lusted for an
HP3577.

http://users.adelphia.net/~n2pk/index.html#TR