Hi Paul,
I knew that. If you read what I wrote days ago, I was not writing about relay
timing. I was writing about using a scope as a waveform monitor during normal
on-air operating.
So far, I've not had a timing issue with semi break-in & my SB220 (I haven't
tried to operate full break-in). Even after the upcoming change to fast vacuum
relays, I doubt I'll use QSK or VOX... much. If I do, I'll be able to see any
abberations with my monitor scope.
Also, the Heath SB-610 you recommended first as a monitor 'scope isn't all that
great. I've owned one since the early 70s, and prefer my Tek 2236 lab 'scope.
Some of the SB610's issues:
* Itty bitty 3" CRT. Almost any lab scope has a larger CRT.
* No triggered sweep. It has a clamp function that pulls the beam off to the
side after a delay. But, the cathode is still emitting electrons. Without
clamping the cathode current, CRT life is no better. The only good thing is the
phosphor doesn't get burned.
* The step attenuator is on the REAR panel. That's fine if you always operate
using the same power and on the same band. I don't. I moved mine to the front
panel, centered on the VERTICAL GAIN pot. See
http://www.tinyurl.com/wa7prc-sb610 for text + photos.
* No astigmatism adjustment - the trace focuses only at one point. It's there
on my SB-620 'Scanalyzer'. So, Heath must've had an "oops moment" on the '610.
Now that the attenuator switch hole is vacated on my '610, I may add an ASTIG
pot when I get a round tuit.
* Cost. In working condx, they command high prices. A 60 MHz lab scope with
everything the 610 doesn't have can be had for less money. I bought my '610
when they were cheap.
vy 73 and FINIT,
Bryan WA7PRC
> From: Paul W8AEF
> Subject: Re: [Amps] Vacuum Relay
> To: Jim W7RY, Bryan WA7PRC , Amps
> Date: Wednesday, December 12, 2012, 9:46 PM
> When transmitting a series of dots,
> QSK, if you have relay timing issues you will observe ramps
> on the top and bottom of the waveform instead of a flat top
> and bottom rectangle.
>
> This is a result of the ALC in the exciter seeing no load
> during the switching period and instantly cutting back the
> power output, and when it sees the load the output of the
> exciter will ramp up. Depending on the speed and
> duration of your cw you may or may not ramp up to full
> output at the end of the cw element.
>
> de Paul, W8AEF
>
> -----Original Message----- From: Jim W7RY
> Sent: Monday, December 10, 2012 6:39 PM
> To: Bryan WA7PRC ; amps@contesting.com
> Subject: Re: [Amps] Vacuum Relay
>
> What would a waveform monitor scope have to do with a timing
> issue with a
> vacuum relay? You cant use one to check the other.
>
> It takes a dual trace scope to check relay timing.
>
> 73
>
> Jim W7RY
>
>
> -----Original Message----- From: Bryan WA7PRC
> Sent: Sunday, December 09, 2012 2:02 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Vacuum Relay
>
> > From: Paul W8AEF
> > Subject: Re: Vacuum Relay
> >
> >
> > ... for some reason not many hams use a scope as a
> > waveform monitor.
> >
> > de Paul, W8AEF
>
> That's unfortunate. 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. The vertical amplifier
> needs
> to respond at least twice as high as the highest radio
> frequency. At HF, this is about 60 MHz, and a usable
> unit
> can be found for about $1/MHz or so. Compared to the cost
> of
> an amplifier, it's peanuts. After I upgraded my lab
> scope,
> I "retired" my Tek 2236 (100 MHz) to use as a TX monitor.
>
> vy 73,
> Bryan WA7PRC
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