Amps
[Top] [All Lists]

Re: [Amps] Vacuum Relay

To: Jim W7RY <w7ry@centurytel.net>, amps@contesting.com, Paul <w8aef@q.com>
Subject: Re: [Amps] Vacuum Relay
From: Bryan Swadener <bswadener@yahoo.com>
Date: Wed, 12 Dec 2012 22:45:45 -0800 (PST)
List-post: <amps@contesting.com">mailto:amps@contesting.com>
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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>