Russell,
There is no better way to troubleshoot a rig than with a scope.
The fact is, almost any scope will do.
In our most recent case, the signal we were tracing was at 9 MHz.
In HF, worst case you will have 30 MHz.
So even if you buy a scope with a bandwidth of 20 MHz, it will still measure
to 30 MHz. It may not be perfectly accurate but it will be relatively
accurate and close enough to show you if a stage is amplifying or not.
Like Mike said, Outza must always be significantly more than Inza. :-)
Most of the time we are trying to isolate the stage causing the trouble,
not trying to do an exact measurement. One thing to know is that you do
need a good probe. That is not always included when you buy a used scope.
If Scott had begun with a scope, we would have been at the point we are at
now on the very first day.
Myself, I sold my scope before I moved across the pond.
Haven't replaced it yet and right now I am pondering whether to go the route
of an old used dinosaur or buy one of the USB digital front ends for a PC.
If anyone reads this and has any experience with these new methods, I would
appreciate some info. I worked for Tektronix 35 years ago, so my knowledge
on scopes is good but somewhat outdated - hi. (Actually, to be exact, I
worked for Rhode und Schwarz, who had the exclusive distributorship for
Tektronix here in Germany and I repaired and calibrated the 400 series
scopes / 465/475, etc.).
73
Rick, DJ0IP
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Hulett, Russell
Sent: Saturday, February 18, 2012 8:14 PM
To: tentec@contesting.com
Subject: [TenTec] OT: Scopes
I've avoided owning a scope, but the recent discussion about troubleshooting
low power from an Omni D has me rethinking. Most of the gear I own now old,
have managed to diagnose problems without owning a scope. In one case, the
problem with an old hollow-state receiver was found by poking around with a
wooden dowel to expose a poor solder joint. My main concern is spending
more money on a scope than my shack is worth, or alternately spending more
time fixing a used scope than is warranted.
Would be curious about thoghts from others who repair their own gear about
what minimum-required scope would be.
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