Date: Thu, 13 Dec 2012 14:15:57 -0500
From: Paul W9AC
Subject: Re: [Amps] Vacuum Relay
> A scope isn't going to tell all but it
> tells a lot about a signal. They're not difficult to use
> and don't have to cost a lot.
It doesn't take long to find some incredibly good buys on used Tektronix
scopes -- and at a price about half of the popular high-end wattmeters.
Folks have no problem paying $600 for a wattmeter with unnecessary high
accuracy, but seem to find no need for a scope. Is it the number of
controls that's so intimidating?
The dual trace function isn't required to determine if hot-switching occurs,
but is required to measure system timing. For station monitoring here, the
scope's Channel A is set to trigger on the keyer's output while Channel B
samples RF. This setup makes it easy to replicate the same CW waveform
measurement as shown in the QST Product Reviews. By triggering the scope
from the keyer, the waveform stays in place for timing measurements without
having to chase it with the scope's variable time-base control.
Paul, W9AC
Yeah, I don't understand why people choose to fly blind with just meters. A
'scope can tell you a lot more. I believe the only current manufacturer of a
graphic display instrument intended for ham use is Larry Phipps' LP500 Digital
Watt/SWR Meter, Waveform Monitor Scope and Spectrum Analyzer. Now, THAT looks
like a nice instrument.
For now, the LP500 is out of my price range. In the mean-time, my Tektronix
2236 ;scope (100 MHz dual trace) does the job. I paid $100 for it many years
ago, from my company's used equipment auction. I retired it from my test bench
after picking up a DOA Tek 2465B (400 MHz, quad trace) for free from another
former employer. Total investment = $500 for repair & alignment.
vy 73,
Bryan WA7PRC
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