[TenTec] Slightly OT - oscilloscope question

Dr. Gerald N. Johnson geraldj at weather.net
Sat Jul 10 10:51:44 PDT 2010


While Tek made similar sized scopes with 50 MHz bandwidth, the Tek 465 
and 465A were a leap forward in performance and made in huge quantities. 
The delayed sweep switch can break though and Tek won't supply the 
parts. The 465 is flat to 100 MHz. The HP 1740 came out about the same 
time and the specification sheets are identical except for one line. I 
know ISU EE department preferred the 1740 as being a little easier to 
teach students to use. Long about that time I bought a new 475 for the 
greater sensitivity and bandwidth and I've not yet outgrown it. 200 MHz 
and 2 millivolts. Shows signals to about 460 Mhz, 6 dB down at 400 Mhz 
switchable to have the top end 100 or 20 MHz.

Probably today some USB based digital sampler hooked to the PC is as 
effective, new and far less costly than the vintage scopes.

Good probes are part of the scope package and need to match the scope 
bandwidth. After market probes tend to have narrower bandwidth than Tek 
scopes. Competitive scopes tend to be 3 dB down at their specified 
bandwith while Tek scopes are flat to their specified bandwidth as are 
their probes. A scope with a 3 dB bandwidth behind a probe with the same 
3 dB bandwidth results in a display 6 dB down at the bandwidth limit and 
that's OK for some things, but not for others.

On 7/10/2010 12:00 PM, Michael Goins wrote:
> Reworking the workbench to be a little more builder-oriented and a little
> less as a fix-it area, so I am considering a scope for the first time. I've
> used them very little in the past, but I'm relatively sure that a 50 MHz
> would suffice for me here as I don't operate higher than 6 meters. I do know
> that short probes with minimal capacitance can be important, but I need some
> help with knowing how much to get without overdoing or under doing it.
>
> What's out there that would work for joe average ham as a decent scope? Cost
> is always a factor, as is relative ease of use and learning curve (English
> major here). Single trace? Dual? Lots of bells and whistles? Few? Particular
> brands? Brands and models to stay away from?
>
> Especially fragile to ship, or should I stick to looking close to home?

Shipping is a concern, but Tek shipping them from Oregon when they were 
new. Probably packaged better than your friendly surplus dealer would pack.
>
> Mike, k5wmg
> Pipe Creek, Texas
> Fast cars, slow boats, big dogs, old trucks, little radios, and summers off
> to write
> _______________________________________________
>
73, Jerry, K0CQ


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