Not as fast as the speed of light, it takes 2 handed coordination(-; Or 2
people if you also want to immediately kill amp power, take the shot and
then power up again for normal cooldown.
Carl
KM1H
----- Original Message -----
From: "Jeff Blaine" <keepwalking188@yahoo.com>
To: "Carl" <km1h@jeremy.mv.com>; <amps@contesting.com>
Sent: Thursday, April 07, 2011 12:56 PM
Subject: Re: [Amps] Alpha vs Henry
> Carl,
>
> You are right on the affected reading.
>
> On the couple of IR guns that I have, they seem to be affected by some
> frequencies more than others. So I try to check it while the
> rf is rocking by picking a different band.
>
> The problem I see with the key-up measurement is that, with an efficient
> cooling, the change in temp vs. time is very fast. So you
> are left to interpolate the slope of the temp drop and estimate the peak
> anode temps to an extent.
>
> 73, Jeff ACØC
> www.ac0c.com
>
> -----Original Message-----
> From: Carl
> Sent: Thursday, April 07, 2011 9:16 AM
> To: Jeff Blaine ; amps@contesting.com
> Subject: Re: [Amps] Alpha vs Henry
>
> I was referring to an IR gun for actual anode temp. Do it right after key
> up
> as RF has a tendency to affect the gun.
>
> You may be surprised at how cool the anodes are often run. Another thing
> to
> look at is the color of the anode and the fins; if they are not discolored
> you havent reach anywhere near the danger point yet.
>
> Ive had many tubes of the 8874, 8122, 8877, 3CX800 variety, and others,
> come
> thru here that are severely heat discolored yet are perfectly fine.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Jeff Blaine" <keepwalking188@yahoo.com>
> To: "damon stewart" <wsmc551@gmail.com>
> Cc: "Carl" <km1h@jeremy.mv.com>; "Al Kozakiewicz" <akozak@hourglass.com>;
> <amps@contesting.com>
> Sent: Wednesday, April 06, 2011 9:55 PM
> Subject: Re: [Amps] Alpha vs Henry
>
>
> Sorry Damon to confuse.
>
> The exhaust temp is only good for determining how long it takes the
> tube/exhaust to get up to a steady temp. The actual temp around the tube
> cannot be easily deduced from this, as far as I can tell although I think
> it
> should be in theory.
>
> A decent but not perfect solution is measuring the anode temp with an IR
> gun
> at the end of a run just prior to key up. And that will be much higher
> than
> the exhaust temp.
>
> 73, Jeff ACØC
> www.ac0c.com
>
>
>
> From: damon stewart
> Sent: Wednesday, April 06, 2011 8:41 PM
> To: Jeff Blaine
> Cc: Carl ; Al Kozakiewicz ; amps@contesting.com
> Subject: Re: [Amps] Alpha vs Henry
>
> You dont want the exhaust temp to get anywhere close to the seal temp!
> By that point your seal temp is way past the limit. On an 8877 the seal
> temp is rated at 250 deg C max (480 deg F). Id try to keep the exhaust
> temp below 300 deg F.
>
>
>
> On Wed, Apr 6, 2011 at 6:33 PM, Jeff Blaine <keepwalking188@yahoo.com>
> wrote:
>
> RTTY contest duty is the worst for the transformer - not for the tube.
>
> The thermal mass of the transformer is huge and if it starts out with a
> low temp the gradient will keep the innermost windings from
> heating to max in RTTY service until you've been running for an hour or
> so. And as the guys mentioned earlier, any air circulation
> on the transformer (even really minimal levels) will have a huge impact
> on
> the final temps the tx reaches.
>
> If you want to whack the tube, a good 5 minute RTTY transmission is the
> way to go. The tube heats up to it's max after maybe 15-30
> seconds - just stick a probe and watch the exhaust temps stop rising at
> some point the system is stable and if you have not pushed
> pass the tube op temps (seal limited) then it's probably going to be
> fine.
>
> 73, Jeff ACØC
> www.ac0c.com
>
> -----Original Message-----
> From: Carl
> Sent: Wednesday, April 06, 2011 7:44 PM
> To: Al Kozakiewicz ; amps@contesting.com
> Subject: Re: [Amps] Alpha vs Henry
>
> Maybe time to see what the anode temperature is but Id think 1000W out
> would
> be fine.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Al Kozakiewicz" <akozak@hourglass.com>
> To: <amps@contesting.com>
> Sent: Wednesday, April 06, 2011 8:35 PM
> Subject: Re: [Amps] Alpha vs Henry
>
>
> > 1500 watts continuous for 30 minutes; 2500 for 30 seconds.
> >
> > Even if I do nothing but call CQ every 2 seconds, that's probably
> "only"
> > about a 60% duty cycle. I'm just trying to get a feel for how much
> > derating is prudent when using the thing for extended periods of time.
> >
> > 73
> >
> > Al
> > AB2ZY
> >
> > -----Original Message-----
> > From: Carl [mailto:km1h@jeremy.mv.com]
> > Sent: Wednesday, April 06, 2011 5:37 PM
> > To: Al Kozakiewicz; amps@contesting.com
> > Subject: Re: [Amps] Alpha vs Henry
> >
> > What does Ameritron say?
> >
> > Carl
> > KM1H
> >
> >
> > ----- Original Message -----
> > From: "Al Kozakiewicz" <akozak@hourglass.com>
> > To: <amps@contesting.com>
> > Sent: Wednesday, April 06, 2011 5:05 PM
> > Subject: Re: [Amps] Alpha vs Henry
> >
> >
> >> Can anyone tell me how much power an AL-1500 is rated to produce at a
> >> 100%
> >> duty cycle?
> >>
> >> During RTTY contests and outputting about 1000 watts, the tube side of
> >> the
> >> cabinet gets mighty warm. The power supply side seems cool - but
> then,
> >> that's with the cover on. I don't know how hot is too hot and it
> would
> >> be
> >> useful to know at least how much continuous power the supply is rated
> >> for.
> >>
> >> Tube cooling is probably another issue...
> >>
> >> Al
> >> AB2ZY
> >> _______________________________________________
> >> Amps mailing list
> >> Amps@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/amps
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
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>
>
>
>
> --
> Damon Stewart, KJ7E
>
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