[time-nuts] Test Equipment

Didier Juges didier at cox.net
Thu Jan 21 22:34:12 UTC 2010

I agree, the TM-500 series has a lot of good plug-ins like DMMs, power
supplies, function generators, pulse generators and frequency counters, that
are quite useful and as good as economy stand-alone equipment, often for
much less.

One relatively deceptive instrument in the TM-500 series is the SG-503 (and
its big brother SG-504). On paper, it sounds very useful, with 250MHz max
frequency and very stable output level with a frequency counter built-in in
a single TM-500 drawer. But its frequency stability is insufficient to check
receivers, the frequency control (and counter) is too coarse, and the
attenuator has very limited range (high level only). It is perfect for what
it was designed for, which is checking the bandwidth of oscilloscopes, but
is not really useful for much else, particularly not for checking receivers.
I have one in perfect condition, and I never use it.

If you do RF work on a budget, don't buy an SG-503. They are still
relatively expensive, and not very useful. Keep your money for a true Signal
Generator, like an HP 8640 (manual tuning) or an HP 8657A (synthesized), or
a Communication Test Set.

This was my $0.02 for today...


> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster
> Sent: Thursday, January 21, 2010 3:46 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Test Equipment
> One thing to look at is the Tek TM500 stuff. When I lived in 
> a small appartment, it was very helpful. There are a wide 
> variety of modules available, often in the $20 to $30 range. 
> They are also mostly pretty easy to fix and use mostly 
> standard OTS parts.
> The TM500 stuff is NOT a substitute for high end instruments, 
> but is well above hobby grade. BTW, the RF generators are not 
> very good on frequency stability. You can get 6 lab grade 
> instruments in a box about 9" wide x 14" high x 18" deep.
> -John
> ================

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