If you must go down the tube route, and the possession of a nice new pair of
tubes might even make me consider it, a pair of '350s will work well in a
W1SL-type amplifier on 144. Get hold of a copy of the VHF/UHF DX Book and
read G4FRX's chapter on 2m tube PAs. John spent a great deal of time
refining the art of the 2 x ceramic tetrode 2m/70cm amplifier back in the
1970s and 80s, and his notes in the book, edited by G3SEK, are well written
and amusing, as well as authoritative.
73
Chris
GW4DGU
----- Original Message -----
From: <amps-request@contesting.com>
To: <amps@contesting.com>
Sent: Thursday, August 28, 2003 2:27 PM
Subject: Amps Digest, Vol 8, Issue 30
> Send Amps mailing list submissions to
> amps@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/amps
> or, via email, send a message with subject or body 'help' to
> amps-request@contesting.com
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>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Amps digest..."
>
>
> Today's Topics:
>
> 1. Re: PS Theory ? (rlm)
> 2. None (Thomas Hix)
> 3. Re: anyone else been contacted? (Tommy/Barb Taylor)
> 4. Re: anyone else been contacted? (Dan Evans)
> 5. Re: PS Theory ?
> 6. Re: PS Theory ? (Bill Turner)
> 7. 4CX350A for VHF? (ad5gb)
> 8. Fw: Re: [Amps] anyone else been contacted? (skipp isaham)
> 9. Re: PS Theory ?
> 10. Re: PS Theory ? (rlm)
> 11. Re: anyone else been contacted? (tongaloa)
>
>
> ----------------------------------------------------------------------
>
> Date: Wed, 27 Aug 2003 09:01:28 -0700
> From: rlm <r@somis.org>
> To: "Mike, K8LH" <k8lh@kramerairtool.com>, "AMPS" <Amps@contesting.com>
> Subject: Re: [Amps] PS Theory ?
> Message-ID: <200308271551.h7RFpNgq018678@contesting.com>
> Content-Type: text/plain; charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Precedence: list
> Message: 1
>
>
>
> >
> >Please excuse the dumb question... I'm trying to figure out how to
> >determine the power handling capability of transformers (I did take a
> >quick look through the ARRL Handbook last night)...
> >
> >Questions:
> >
> >How can you determine the power handling capability of a transformer???
> >
> ? primarily by measuring the resistance of the secondary winding.
> Look in "Amplifiers" on my Web site for some rule of thumb formulas.
>
> >For example, the secondary on the transformer in my Heath SB-201 is
> >rated at 800 VAC at 0.5 amps... I would think this transformer would
> >only be good for about 400 watts of power (800 x 0.5) but it seems that
> >if you feed this secondary into a full-wave bridge rectifier and
> >capacitors you would get about 1,000 volts and 0.5 amps under load (500
> >watts), or feed it into a voltage doubler circuit, like that in the
> >SB-201, and you get about 2,000 vdc at 0.5 amps under load (1,000
> >watts)...
> >
> >I'm confused... What am I missing???
>
> ? Duty-cycle considerations. For SSB, a 600W-CCS rated transformer will
> make c. 1500w pep RF-output.
>
> ------------------------------
>
> Date: Wed, 27 Aug 2003 11:34:05 -0500
> From: "Thomas Hix" <w4th@hotmail.com>
> To: amps@contesting.com
> Subject: [Amps] None
> Message-ID: <Law10-F743Bma4RCIlW00003c6c@hotmail.com>
> Content-Type: text/plain; format=flowed
> MIME-Version: 1.0
> Precedence: list
> Message: 2
>
>
> Hello fellow Hams;
> I posted a question yesterday asking if any of you had ever been contacted
> by a "procurement company" from overseas in reference to an amp you had
> listed for sale on the ham classified sites.
> I did some more investigating and found out that such offers are
definitely
> a scam.
> The way it works is this.....they send you a counterfeit cashiers check
that
> even your bank will tell you is a good check.....you think you have a good
> cashiers check so you release your item to the thief's shipper.....then in
a
> week or two after your item is long gone you find out the check has been
> returned and you are left holding the proverbial bag as it were.
> Thanks to all those of you how sent me mail on this.
> 73
> Tom....w4th
>
> Tom's Tubes: Specializing in Amateur Radio Amplifier Tubes, Sockets, &
G3SEK
> Triode/Tetrode Boards and Kits. http://www.tomstubes.com
>
> _________________________________________________________________
> Get MSN 8 and enjoy automatic e-mail virus protection.
> http://join.msn.com/?page=features/virus
>
> ------------------------------
>
> Date: Wed, 27 Aug 2003 10:11:17 -0600
> From: "Tommy/Barb Taylor" <windrift@mindspring.com>
> To: "Thomas Hix" <w4th@hotmail.com>, <amps@contesting.com>
> Subject: Re: [Amps] anyone else been contacted?
> Message-ID: <007001c36cb5$d994e4c0$90044bab@mshome.net>
> References: <Law10-F26dRPC8aITMW0005d1b3@hotmail.com>
> Content-Type: text/plain;
> charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 3
>
> Tom,
>
> If it sounds too good to be true, then it usually is.
>
> 73/Tommy W7RV
> ----- Original Message -----
> From: "Thomas Hix" <w4th@hotmail.com>
> To: <amps@contesting.com>
> Sent: Tuesday, August 26, 2003 2:53 PM
> Subject: [Amps] anyone else been contacted?
>
>
> > Hello fellow hams.
> > I recently posted my Ameritron ALS 600 solid state amp for sale on
several
> > of the amateur radio classified sites.....I had the amp listed for
$800.00
> > plus shipping.....I received the email below today offering me $1000.00
> and
> > no shipping cost because the buyer would arrange for pickup....I would
not
> > have thought much about this except I remembered another similar offer I
> had
> > received when I listed my Emtron DX-2 SP amp for sale several months
> > back.....That time I was also offered a good deal more in payment than I
> had
> > the amp listed for, and they also would have their shipper come buy and
> pick
> > up the amp.....in that case the procurement company said they were in
some
> > African country.....in this latest case the procurement company is in
the
> > UK.
> >
> > My question is this....Have any of the rest of you ever been contacted
by
> > one of the procurement companies when you had listed items for sale on
any
> > of the ham classifieds? If so were they legit? My concern is that these
> > companies are operating some kind of a scam operation.....I may be
> entirely
> > wrong, but I just have that old feeling in my gut that something is
wrong
> > here....why would these people offer MORE for the item than it's listed
> > price?.....Maybe I am just paranoid....I dont know....what do you think?
> >
> > Thanks for your time and 73
> >
> > Tom.....W4TH
> >
> >
> >
> >
> > >From : george masela <albertrings2003@yahoo.co.uk>
> >
> > To : w4th@hotmail.com
> > Subject : ALS 600 Ameritron ( INTERNATIONAL ORDER)
> > Date : Tue, 26 Aug 2003 21:02:12 +0100 (BST)
> >
> >
> > Hi ,
> > We are a procurement concern and we specialise in
> > purchasing preowned goods on behalf of our
> > clients worldwide. We however have and order for the
> > above ALS 600 Ameritron and our client is offering to buy these for the
> sum
> > of $1000.00
> > Please can We will arrange to remit payment for purchase to you . a
> > prepaid shipper will come to your home for pickup.
> > Best Regards,
> > GEORGE....
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
> --------------------------------------------------------------------------
> ------
> > Yahoo! Plus - For a better Internet experience
> >
> >
> >
> >
> >
> > Tom's Tubes: Specializing in Amateur Radio Amplifier Tubes, Sockets, &
> G3SEK
> > Triode/Tetrode Boards and Kits. http://www.tomstubes.com
> >
> > _________________________________________________________________
> > Get MSN 8 and enjoy automatic e-mail virus protection.
> > http://join.msn.com/?page=features/virus
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
> ------------------------------
>
> Date: Wed, 27 Aug 2003 13:41:31 -0700 (PDT)
> From: Dan Evans <n9rla@yahoo.com>
> To: w4th@hotmail.com, amps@contesting.com
> Subject: Re: [Amps] anyone else been contacted?
> Message-ID: <20030827204131.31205.qmail@web20606.mail.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
> MIME-Version: 1.0
> Precedence: list
> Message: 4
>
> I don't know, but if a deal seems to good to be true,
> then it probably is.
>
> By all means, be sure the amp doesn't leave your
> house, until you have cash in your hands:-)
>
> 73
> Dan
> Dan Evans K9ZF
> Scottsburg, IN 47170
> {EM78}
> K9ZF /R no budget Rover
> ex-N9RLA
> Check out the Rover Resource Page at:
> http://www.qsl.net/n9rla
> QRP-l #1269
> Central States VHF Society
> IN-Ham list administrator
>
>
> ----- Original Message -----
> From: "Thomas Hix" <w4th@hotmail.com>
> To: <amps@contesting.com>
> Sent: Tuesday, August 26, 2003 3:53 PM
> Subject: [Amps] anyone else been contacted?
> If so were they legit? My concern is that these
> > companies are operating some kind of a scam
> operation.....I may be entirely
> > wrong, but I just have that old feeling in my gut
> that something is wrong
> > here....why would these people offer MORE for the
> item than it's listed
> > price?.....Maybe I am just paranoid....I dont
> know....what do you think?
> >
> > Thanks for your time and 73
> >
> > Tom.....W4TH
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! SiteBuilder - Free, easy-to-use web site design software
> http://sitebuilder.yahoo.com
> ------------------------------
>
> Date: Wed, 27 Aug 2003 18:27:43 -0400
> From: wb8jkr@juno.com
> To: w8ron@stratos.net
> Cc: Amps@contesting.com
> Subject: Re: [Amps] PS Theory ?
> Message-ID: <20030827.182743.-255329.0.wb8jkr@juno.com>
> Content-Type: text/plain
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 5
>
> Actually in doubler service I think the transformer peak current
> is about four times the DC output current in a capacitor input filter.
> A transformer should be designed for doubler service.
>
> 73, Mark WB8JKR
>
>
> On Tue, 26 Aug 2003 11:38:31 -0400 Ron <w8ron@stratos.net> writes:
> > When you feed it to a doubler , the current is not .5 A but .25A.
> >
> > THe remainder may be due to CCS and ICAS duty.
> > ---
> > Ron
> >
> >
> > Mike, K8LH wrote:
> >
> > >Please excuse the dumb question... I'm trying to figure out how to
> > >determine the power handling capability of transformers (I did take
> > a
> > >quick look through the ARRL Handbook last night)...
> > >
> > >Questions:
> > >
> > >How can you determine the power handling capability of a
> > transformer???
> > >
> > >For example, the secondary on the transformer in my Heath SB-201 is
> > >rated at 800 VAC at 0.5 amps... I would think this transformer
> > would
> > >only be good for about 400 watts of power (800 x 0.5) but it seems
> > that
> > >if you feed this secondary into a full-wave bridge rectifier and
> > >capacitors you would get about 1,000 volts and 0.5 amps under load
> > (500
> > >watts), or feed it into a voltage doubler circuit, like that in the
> > >SB-201, and you get about 2,000 vdc at 0.5 amps under load (1,000
> > >watts)...
> > >
> > >I'm confused... What am I missing??? Thanks...
> > >_______________________________________________
> > >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
> >
>
>
> ________________________________________________________________
> The best thing to hit the internet in years - Juno SpeedBand!
> Surf the web up to FIVE TIMES FASTER!
> Only $14.95/ month - visit www.juno.com to sign up today!
> ------------------------------
>
> Date: Wed, 27 Aug 2003 15:48:22 -0700
> From: Bill Turner <wrt@dslextreme.com>
> To: "Mike, K8LH" <k8lh@kramerairtool.com>
> Cc: Amps@contesting.com
> Subject: Re: [Amps] PS Theory ?
> Message-ID: <aecqkv0an7onla50j6nvcb16nd9bq2utqm@4ax.com>
> In-Reply-To: <3F4C86AC.4E22F78D@kramerairtool.com>
> References: <LFEPLDMBNIJEBNALEDFDGEHLCDAA.fgrisafi@tin.it>
> <3F4C86AC.4E22F78D@kramerairtool.com>
> Content-Type: text/plain; charset=us-ascii
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Precedence: list
> Reply-To: wrt@dslextreme.com
> Message: 6
>
> On Wed, 27 Aug 2003 06:23:40 -0400, "Mike, K8LH"
> <k8lh@kramerairtool.com> wrote:
>
> >How can you determine the power handling capability of a transformer???
>
> _________________________________________________________
>
> The power handling capability of a transformer in a steady-state
> condition is determined mainly by it's internal temperature.
> Excessive heat buildup reduces the breakdown voltage of insulation,
> both of the wires and the insulation between windings.
>
> If you know nothing at all about the transformer, I'd recommend
> letting it get no hotter than about 140 degrees F - slightly hotter
> than your hand can stand to touch it. Transformers with ordinary
> insulation should handle that ok. If you want to be conservative, run
> it even cooler and it will last even longer.
>
> For test purposes, a string of 120 volt light bulbs of the appropriate
> wattage can be used as a dummy load. They have the advantage of
> increasing resistance with increasing current, so they have a sort of
> built-in regulation. I'd recommend using a variac to bring the
> transformer up to full power to avoid the initial surge when the lamps
> are cold. I have done this with transformers in the few hundred watt
> range, but never at the kilowatt level. Be careful!
>
> --
> 73, Bill W7TI
>
> ------------------------------
>
> Date: Wed, 27 Aug 2003 21:45:49 -0400 (EDT)
> From: "ad5gb" <ad5gb@myway.com>
> To: amps@contesting.com
> Cc:
> Subject: [Amps] 4CX350A for VHF?
> Message-ID: <20030828014549.666AA3975@xmxpita.myway.com>
> Content-Type: text/plain; charset="us-ascii"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Reply-To: ad5gb@myway.com
> Message: 7
>
>
> Greetings all,
>
> I was just given a shiny new pair of 4CX350As. I thought of trying to
make a little desktop amp for 2M out of them but a quick look at Eimac's web
page at the specs make me wonder if this this might be a bad idea. Further,
web searches produce a mixed bag of success/failure stories.
>
> Anyone on this reflector ever use these on 2M?
>
> Many thanks!
>
> --
> Randall D. DuCharme (Radio AD5GB)
>
> Powered by FreeBSD!
> The Power to Serve ( http://www.freebsd.org )
>
>
>
> _______________________________________________
> No banners. No pop-ups. No kidding.
> Introducing My Way - http://www.myway.com
> ------------------------------
>
> Date: Wed, 27 Aug 2003 19:33:23 -0700
> From: skipp isaham <nospam4me@juno.com>
> To: amps@contesting.com
> Subject: Fw: Re: [Amps] anyone else been contacted?
> Message-ID: <20030827.193325.-409125.0.nospam4me@juno.com>
> Content-Type: text/plain
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 8
>
>
> It's a scam,
>
> They will pay you with a bank check or money order and
> arrange to pick up the equipment before the check has
> bounced back.
>
> They rely on the long delay between your deposit and
> the relatively long time before you receive notice that
> the payment paper is bad.
>
> One additional hook is the account may be real with
> almost no funds on hand. A calling bank will only
> receive notice that the account is valid and current.
>
> Very common scam, don't fall for it.
>
> cheers
> skipp
>
>
> [paste]
> >Hello fellow hams.
> >I recently posted my Ameritron ALS 600 solid state amp for sale on
> several
> >of the amateur radio classified sites.....I had the amp listed for
> $800.00
> >plus shipping.....I received the email below today offering me $1000.00
> and
> >no shipping cost because the buyer would arrange for pickup....I would
> not
> >have thought much about this except I remembered another similar offer I
> had
> >received when I listed my Emtron DX-2 SP amp for sale several months
> >back.....That time I was also offered a good deal more in payment than I
> had
> >the amp listed for, and they also would have their shipper come buy and
> pick
> >up the amp.....in that case the procurement company said they were in
> some
> >African country.....in this latest case the procurement company is in
> the
> >UK.
> >
>
> ________________________________________________________________
> The best thing to hit the internet in years - Juno SpeedBand!
> Surf the web up to FIVE TIMES FASTER!
> Only $14.95/ month - visit www.juno.com to sign up today!
> ------------------------------
>
> Date: Thu, 28 Aug 2003 04:45:46 -0400
> From: wb8jkr@juno.com
> To: w8ron@stratos.net, k8lh@kramerairtool.com, Amps@contesting.com
> Subject: Re: [Amps] PS Theory ?
> Message-ID: <20030828.044547.-168955.0.wb8jkr@juno.com>
> Content-Type: text/plain
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 9
>
>
> Oops, I meant to say the transformer secondary current is
> three times (2.828) the DC output of the supply in doubler service.
>
> 73, Mark WB8JKR
>
>
> On Wed, 27 Aug 2003 18:27:43 -0400 wb8jkr@juno.com writes:
>
> > Actually in doubler service I think the transformer peak current
> > is about four times the DC output current in a capacitor input
> > filter.
> > A transformer should be designed for doubler service.
> >
> > 73, Mark WB8JKR
> >
> >
> > On Tue, 26 Aug 2003 11:38:31 -0400 Ron <w8ron@stratos.net> writes:
> > > When you feed it to a doubler , the current is not .5 A but .25A.
> > >
> > > THe remainder may be due to CCS and ICAS duty.
> > > ---
> > > Ron
> > >
> > >
> > > Mike, K8LH wrote:
> > >
> > > >Please excuse the dumb question... I'm trying to figure out how
> > to
> > > >determine the power handling capability of transformers (I did
> > take
> > > a
> > > >quick look through the ARRL Handbook last night)...
> > > >
> > > >Questions:
> > > >
> > > >How can you determine the power handling capability of a
> > > transformer???
> > > >
> > > >For example, the secondary on the transformer in my Heath SB-201
> > is
> > > >rated at 800 VAC at 0.5 amps... I would think this transformer
> > > would
> > > >only be good for about 400 watts of power (800 x 0.5) but it
> > seems
> > > that
> > > >if you feed this secondary into a full-wave bridge rectifier and
> > > >capacitors you would get about 1,000 volts and 0.5 amps under
> > load
> > > (500
> > > >watts), or feed it into a voltage doubler circuit, like that in
> > the
> > > >SB-201, and you get about 2,000 vdc at 0.5 amps under load (1,000
> > > >watts)...
> > > >
> > > >I'm confused... What am I missing??? Thanks...
> > > >_______________________________________________
> > > >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
> > >
>
>
> ________________________________________________________________
> The best thing to hit the internet in years - Juno SpeedBand!
> Surf the web up to FIVE TIMES FASTER!
> Only $14.95/ month - visit www.juno.com to sign up today!
> ------------------------------
>
> Date: Thu, 28 Aug 2003 04:01:40 -0700
> From: rlm <r@somis.org>
> To: "Dr. William J. Schmidt, II" <bill@wjschmidt.com>,
> "AMPS" <amps@contesting.com>
> Subject: Re: [Amps] PS Theory ?
> Message-ID: <200308281051.h7SApXgq020013@contesting.com>
> Content-Type: text/plain; charset="iso-8859-1"
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> Precedence: list
> Message: 10
>
> ? Cashier's cheques can be forged.
>
> >Cashier's check only.....
> >
> >Sincerely,
> >
> >Dr. William J. Schmidt, II K9HZ
> >
> >"Collector of Edison Wind-up Phonographs... Do you have one for me?"
> >Email: bill@wjschmidt.com
> >Alternate Email: wmschmidt@charter.net
> >WebPage: www.wjschmidt.com
> >
> >
> >
> >----- Original Message -----
> >From: "rlm" <r@somis.org>
> >To: "Mike, K8LH" <k8lh@kramerairtool.com>; "AMPS" <Amps@contesting.com>
> >Sent: Wednesday, August 27, 2003 11:01 AM
> >Subject: Re: [Amps] PS Theory ?
> >
> >
> >>
> >>
> >> >
> >> >Please excuse the dumb question... I'm trying to figure out how to
> >> >determine the power handling capability of transformers (I did take a
> >> >quick look through the ARRL Handbook last night)...
> >> >
> >> >Questions:
> >> >
> >> >How can you determine the power handling capability of a
transformer???
> >> >
> >> ? primarily by measuring the resistance of the secondary winding.
> >> Look in "Amplifiers" on my Web site for some rule of thumb formulas.
> >>
> >> >For example, the secondary on the transformer in my Heath SB-201 is
> >> >rated at 800 VAC at 0.5 amps... I would think this transformer would
> >> >only be good for about 400 watts of power (800 x 0.5) but it seems
that
> >> >if you feed this secondary into a full-wave bridge rectifier and
> >> >capacitors you would get about 1,000 volts and 0.5 amps under load
(500
> >> >watts), or feed it into a voltage doubler circuit, like that in the
> >> >SB-201, and you get about 2,000 vdc at 0.5 amps under load (1,000
> >> >watts)...
> >> >
> >> >I'm confused... What am I missing???
> >>
> >> ? Duty-cycle considerations. For SSB, a 600W-CCS rated transformer
will
> >> make c. 1500w pep RF-output.
> >>
> >> _______________________________________________
> >> Amps mailing list
> >> Amps@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/amps
> >
> >
>
> ------------------------------
>
> Date: Thu, 28 Aug 2003 08:34:46 -0400
> From: tongaloa <tongaloa@alltel.net>
> To: paule@sfu.ca
> Cc: amps@contesting.com
> Cc: w4th@hotmail.com
> Subject: Re: [Amps] anyone else been contacted?
> Message-ID: <3F4DF6E6.9000904@alltel.net>
> References: <200308271527.h7RFRGag026947@rm-rstar.sfu.ca>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Precedence: list
> Message: 11
>
> paule@sfu.ca wrote:
>
> >I understand that, but you are also locatable other ways
> >via the internet. Having a findable website adds to your
> >percieved credability,
> >
> "On the Internet, Nobody Knows You're a Dog "
>
> http://www.unc.edu/depts/jomc/academics/dri/idog.html
>
>
>
> ------------------------------
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> End of Amps Digest, Vol 8, Issue 30
> ***********************************
>
>
>
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