A tracking generator is a sweep generator calibrated to track
to the center frequency of a spectrum analyzer as it sweeps.
Got it?
It is used to display the bandpass characteristics of a network
using a spectrum analyzer.
-Chuck
gw wrote:
"Ed Price" wrote in message news:tPmtb.4837$cX1.463@fed1read02...
"John Miles" wrote in message
...
In article ,
says...
johnm wrote in message
...
what is a good spectrum analyzer to have for a home shop in your
opinion, and also what is a good scope to have and do you have to
break the bank on this stuff? thanks.
SNIP
how about a 8569b ? some guy has one on ebay now for about
$3,000.00......i might pull the trigger on that one.....I would be
using it for hf work. I was considering a 141t from tucker . it cost
more but at least you know it works. i was going to get the 8552b and
8553b plugins with it. then you have to round up the connecting cables
and manuals for them. comments? oh by the way i have read good things
about the hp 8569b's. if they work.
My guess is that the 8569b would be a very passable unit. Its specs
seem competitive with an optioned-out Tek 492 in most respects, except
that it only goes down to 10 MHz (perhaps there's an underrange
capability that lets it see lower frequencies?) That might be a concern
if you're going to be using it mostly for HF work.
SNIP
The 141Ts at Tucker seem like a pretty good deal. I believe they all
come with new CRTs. I personally like to buy broken models on eBay and
fix them up. It's cheaper, you get really familiar with the gear inside
and out, and you always have spare parts on hand. But that strategy
isn't for everybody.
-- jm
As I have HP-141's, an HP-8569, an 8566B and an 8562A, let me drop a few
comments here.
The 141's are the best deal for a hobbyist. You can acquire the slightly
better 8552B IF section, and then get only the RF plug-in that suits your
needs (an 8556, with it's built-in tracking generator, for a few Hz to 300
kHz, or an 8555, for 10 MHz through umpteen GHz, assuming you also get the
external mixers). Unfortunately, by the time a hobbyist gets one of these,
it has been abused and neglected by its last commercial owner. CRT burns are
common, and the flood-gun analog memory may be very quirky. For an advanced
hobbyist, either get an associated Polaroid scope camera, or build your own
camera hood. You can capture a lot of transient things that way, and you can
scan the pixs to input into your computer. Also, HP made a line of
oscilloscope plug-ins that fit the 141 mainframe, so you can use the 141 as
a multi-channel analog memory oscilloscope too. 141's are a pain in two
ways; first, you have to externally store extra plug-ins, and secondly, the
hard side handles make carrying one a painful experience beyond about 50
feet. Also, you tend to injure your fingertips sliding those bulky plug-ins
in and out past the big metal front handles. The 141 may also be the last of
the hobbyist repairable analyzers; newer analyzers use proprietary chips and
are built too dense to let you get fingers and probes into them.
The 8562A is old (1987) but a superb analyzer, 1 kHz to 18 GHz, all digital
and synthesized. This will do everything you want, except drive a parallel
or RS-232 printer directly. If you're smart enough to talk to it by
IEEE-488, then you can do everything through the computer. Other 856x series
units have lesser capabilities, but are still great analyzers, and just
might be priced low enough for a very serious hobbyist. Also, the HP-859x
series are very good, although some have odd frequency, memory and IO
capabilities. All 856x & 859x series units are one-man portables, until your
knuckles turn white and numb.
The 8569 is, in my opinion, a transitional beast between the analog and
digital worlds. It's not as stable and simple as the 8562A, although it's a
leap above the 141. Since it's wide, it's also awkward to carry using it's
handle. I'm not much of a fan of the 8569.
The 8566B is HP's top-of-the-line analyzer. They threw down the benchmark
for everyone else to try to meet. Mine is customized a bit, covering 20 Hz
to 22 GHz, and with an external tracking pre-selector, optional detectors,
programmable attenuators, RF path switching and low-noise pre-amps. My
company has a number of somewhat more plain-vanilla 8566B's and 8566A's.
There isn't anything I need to do that these units fall short of (uhh, with
the help of some external IEEE-488 linked computers). OTOH, these are now
obsolete, non-supported by Agilent, and need two guys to carry one. Mine is
in a 60" tall dedicated rack. Typical used price is around $20k.
Most companies will be better served with one of Agilent's newer EPA or SPA
analyzers. Anritsu and Rohde & Schwartz are also making fine analyzers.
IIRC, Leader makes an analyzer that a hobbyist may aspire to affording.
I would say that a 141 is still the best hobbyist choice. A company needs to
be sure that they get a usable item for their money, so buying on eBay is a
gamble. A company should buy from some place like Tucker, where they get a
warranty backed by a reputable source. Yeah, it initially costs more. But
it's a lot safer than having to try to repair an analyzer when you need that
analyzer to do the real work of your company. A hobbyist can afford to spend
50 to 100 hours to get something going; in a business environment, where the
clock is always ticking, that's unacceptable.
Ed
wb6wsn
ed ...what is a tracking generator and how is it a advantage for a
home hobbyist to have one or is it really necessary? also what do you
thing about 8565a's
also what is the determining factor for pricing on these various units
on ebay? does it have anything to do with the options on each unit?
sometimes there would appear to be some flucuations on the prices on
either the same type unit or a similar unit.
|