Zombie wrote:
if you goto http://labvolt.com/product.asp?id=163&Line_Id=64 they do have a
device there to convert an ordinary scope into a somewhat crude spectrum
analyser ( i believe it maxes out around 127Mhz), but im not sure if they
sell that device seperatly, and the whole Fm/Am training suite which the
link goes to is around $250,000 CDN.
"dbu" wrote in message
...
In article ,
Panzer240 wrote:
"Pete KE9OA" wrote in
news
I would buy both of them. An oscilloscope is something you really need
for doing signal tracing, etc. while a spectrum analyzer is a must if
you are doing synthesizer/oscillator/transmitter design. I have both
of
them and use them all of the time. Other good things to have are an RF
power meter, modulation meter, frequency counter, broadband noise
source, RF generator, DVM, VOM, and a good variable power supply. This
just scratches the surface, depending on your needs.
Pete
The choice between the two depends on what you are most interested in
doing. Since both these instruments are designed for different tasks.
However if you are looking for a good all purpose Swiss Army knife sort
of
tool for general ham useage, I would look at a gadget called a service
monitor. Depending on make and model, you can find one that combines the
features of most of the instruments on Pete's list 
They usually have
a
scope that will do af and also act as a spectrum analyzer along with
power
meters,signal generator,frequency/modulation meter perhaps a DVM etc.
All
in one handy dandy portable package.
Here is an example of one of the many on Ebay at present.
http://cgi.ebay.com/ws/eBayISAPI.dll...8784288 71&rd
=1
As a general purpose test and troubleshooting tool I find these hard to
beat!!
I already have a scope which I use on my work bench, but it sits a lot
not being used, so it would be kind of handy to plug in a device which
would enable it to be used as a SA or panadapter type scope for the
shack. This would make my scope much more useful. Anything like that
around?
Spend some time to think VERY carefully about your requirements.
I have a DSO with an FFT display. I find it interesting on occasion.
But if you need a spectrum analyzer, you need a spectrum analyzer.
The key parameters are resolution bandwidth and dynamic range.
In most cases requring a SA, a toy isn't nearly good enough in those
areas. You can't look at a signal when the thing is overloaded or if
there's another signal too close. Toy spectrum analyzers have very WIDE
bandwidths. If they don't, they're not toys and not cheap either.
A SA with a tracking generator is very useful if you need to design
filters or align repeater cavities.
Remember that the dynamic range of a scope is very low. It's not
shielded. When you try to hook an external box to it, all sorts of
stuff finds its way into the scope. And the scope radiates the signals
you stuff into it. Not good if you're trying to measure something 100dB
down.
Service monitors CAN have very good spectrum analyzers, but the ones you
can afford probably don't and have all the bad characteristics of a toy
spectrum analyzer.
I have a TEK 492 with tracking generator. I use it rarely, but when I
need it, I'm glad its there.
It's all in your requirements...no free lunch here.
mike
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