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Re: [Amps] GU-84b Cooling

To: amps@contesting.com
Subject: Re: [Amps] GU-84b Cooling
From: "Will Matney" <craxd@engineer.com>
Date: Wed, 20 Jul 2005 07:51:08 -0500
List-post: <mailto:amps@contesting.com>
Tom,

Doing a Google search, I found several pages refering to the GU-84B as a 
GU84B/4CX1600 just then, and then also seen some refering to it as a 4CX2500. 
The very first hits I list below;

http://www.nd2x.net/OH3AWW.html
GU-84b/4CX1600b PA design
144MHz 1.5KW GU-84b Linear Amplifier Matti Vilppula, OH3AWW, 2003. During the 
summer 1997 I completed my new GU-84b tetrode power amplifier. ...
www.nd2x.net/OH3AWW.html - 29k - Cached - Similar pages
[ More results from www.nd2x.net ]


and;

http://oh3tr.ele.tut.fi/~oh3aww/pa_gu84b/pa_gu84b.htm
OH3AWW:n GU-84b/4CX1600b 144 MHz lineaarinen
144 MHz 1.5 kW GU-84b lineaarinen. Kesällä 1997 sain venäläisellä tetrodilla 
GU-84b tekemäni vahvistimen valmiiksi. Niin tai ainakin toimintakuntoon ...
oh3tr.ele.tut.fi/~oh3aww/pa_gu84b/pa_gu84b.htm



Then for calling it a 4CX2500A;

http://www.classifiedbuyers.com/1036deItemDetail.asp?AdID=33347&BuySell=2&id=
ClassifiedBuyers - FREE Classified Ads - No Fraud, No Upfront Fees ...
GU-84B/4CX2500A Svetlana. Brand New! The Sockets are sale also. ... The GU-84B 
is a ceramic-metal forced-air cooled tetrode intended for use in power ...
www.classifiedbuyers.com/1036deItemDetail. asp?AdID=33347&BuySell=2&id=

and;

http://xoomer.virgilio.it/atpaolo/4cx2500.htm
CX2500 - [ Translate this page ]
Tubo utilizzato, n°1 4CX2500 / GU-84B. Commutazione, relays sotto vuoto alta 
velocità. Alimentazione, 220 / 240 volt - 3 kw. Dimensioni sezione RF (in mm) 
...
xoomer.virgilio.it/atpaolo/4cx2500.htm


So, which one is it? Emtron says it's has a 2500 watt dissapation but does not 
call it a 4CX2500. It sounds like some wants to call it one thing and others 
something else.

Best,

Will



> 
> I read this today on the amps reflector.
> 
> "On a webpage somewhere, I cant remember now where, I read about
> the GU-84B (4CX1600) having an undersized radiator"
> 
> The GU-84B tube is NOT the same tube as the 4cx1600 tube.......they are
> entirely different in size, and power output.
> 
> There was a tube called the GU-91B that is almost identical to the 4cx1600b
> tube......the only difference being the GU-91B does have a slightly smaller
> radiator than the 4cx1600b tube.......The GU-91B WILL WORK IN PLACE OF THE
> 4CX1600B TUBE.....The only thing you need to watch out for is that if you do
> a lot of continious duty type modes like RTTY or SSTV ect, the GU-91B could
> overheat unless you are careful........but for normal SSB useage, the GU91B
> will work just fine.
> 
> I hope I have not confused the issues here, (my mind is still a little foggy
> after my hospital stay) but if I have got things mixed up please excuse my
> mistake.
> 
> 73
> 
> Tom.....w4th......Tom's Tubes
> 
> 
> 
> 
> 
> 
> Tom's Tubes: Amateur Radio Amp Tubes & Sockets, CTHRD Hand Made CW Keys,
> K4POZ Screwdriver Antennas & G3SEK Triode/Tetrode Boards & Kits.
> http://www.tomstubes.com
> 
> 
> 
> 
> ----Original Message Follows----
> From: amps-request@contesting.com
> Reply-To: amps@contesting.com
> To: amps@contesting.com
> Subject: Amps Digest, Vol 31, Issue 35
> Date: Wed, 20 Jul 2005 07:47:12 -0400
> 
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> Today's Topics:
> 
> 1. Re: Amps Digest, Vol 31, Issue 34 (K3vw@aol.com)
> 2. GU-84B Cooling (Will Matney)
> 3. Re: GU-84B Cooling (Dan K9ZF)
> 4. Fw: GU-84B Cooling (PA3DUV)
> 5. Re: GU-84B Cooling (gdaught6@stanford.edu)
> 6. Re: GU-84B Cooling (Will Matney)
> 7. Re: GU-84B Cooling (R.Measures)
> 8. Re: GU-84B Cooling (R.Measures)
> 9. Re: GU-84B Cooling (pa3duv@planet.nl)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 19 Jul 2005 13:35:41 EDT
> From: K3vw@aol.com
> Subject: Re: [Amps] Amps Digest, Vol 31, Issue 34
> To: amps@contesting.com
> Message-ID: <42.6d6427b6.300e93ed@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
> Did he run it grounded grid? What is filament voltage/ current of a GU-84B ?
> Did he have to build a socket or can you buy them. What is plate disapation
> of the 84B ? I think 2500 watts. Willy
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 19 Jul 2005 14:53:19 -0500
> From: "Will Matney" <craxd@engineer.com>
> Subject: [Amps] GU-84B Cooling
> To: amps@contesting.com
> Message-ID: <20050719195320.5FB054BEAD@ws1-1.us4.outblaze.com>
> Content-Type: text/plain
> 
> On a webpage somewhere, I cant remember now where, I read about the GU-84B
> (4CX1600) having an undersized radiator. I think it was on a Russian amateur
> website. What I had read was this tube was actually designed for running in
> a missle by the Russians, and was designed for a 1 time use. So, they
> undersized the radiator a good bit because of space limitations. They were
> making the comparison to a 4CX1500's radiator size being larger in the
> discussion. However the guts of the GU-84B supposed to be really good. So
> this brings the delima of how to cool it so one would get a long life out of
> it. One way would be add some sort of extra aluminum heat fins, or some made
> of brass, with fins sticking out to catch more air, thus increasing the
> overall surface area. The only other way would be to increase the amount of
> air flow and volume over the fins that's there. When doing this though, the
> noise goes up from the blower. However, if one is going to dealve into using
> the GU-84B, I'd s
> uggest looking into this and compare the sizes between its radiator and the
> one for the 4CX1500. Even though the tube is cheaper than some others, it's
> still expensive if you have to re-tube all the time. If I can remember where
> I seen this, I'll post the link.
> 
> Best,
> 
> Will
> 
> --
> ___________________________________________________________
> Sign-up for Ads Free at Mail.com
> http://promo.mail.com/adsfreejump.htm
> 
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Tue, 19 Jul 2005 15:15:14 -0500
> From: Dan K9ZF <n9rla@yahoo.com>
> Subject: Re: [Amps] GU-84B Cooling
> To: Will Matney <craxd@engineer.com>
> Cc: amps@contesting.com
> Message-ID: <42DD5F52.7030806@yahoo.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Will Matney wrote:
> 
> > So this brings the delima of how to cool it so one would get a 
> > long life out of it. One way would be add some sort of extra 
> > aluminum heat fins, or some made of brass, with fins sticking out 
> > to catch more air, thus increasing the overall surface area. The 
> > only other way would be to increase the amount of air flow and 
> > volume over the fins that's there. When doing this though, the 
> > noise goes up from the blower.
> >
> > Best,
> >
> > Will
> >
> >
> >
> 
> Water cool it?
> 
> 73
> Dan
> 
> --
> K9ZF /R no budget Rover ***QRP-l #1269
> Check out the Rover Resource Page at: <http://www.qsl.net/n9rla>
> List Administrator for: InHam+grid-loc+ham-books
> 
> 
> 
> 
> ------------------------------
> 
> Message: 4
> Date: Tue, 19 Jul 2005 23:19:26 +0200
> From: PA3DUV <pa3duv@planet.nl>
> Subject: [Amps] Fw: GU-84B Cooling
> To: amps@contesting.com
> Message-ID: <025101c58ca7$8afbc4f0$6c9a390a@TVLT001>
> Content-Type: text/plain; format=flowed; charset=iso-8859-1;
> reply-type=response
> 
> 
> Will,
> In my twin tube GU84B amp one fan is used to pressurize the subchassis and
> two axial fans to draw the air out.
> With a B+ of 2900 VDC, from the 3 phase PSU the two GU84B tubes generate an
> easy 6 kW of output. During normal (6 dB compressed) SSB transmissions the
> exaust air stays below 55 degrees celcius.
> Cheers, Dick Knol
> PA3DUV
> 
> 
> 
> > ----- Original Message -----
> > From: "Will Matney" <craxd@engineer.com>
> > To: <amps@contesting.com>
> > Sent: Tuesday, July 19, 2005 9:53 PM
> > Subject: [Amps] GU-84B Cooling
> >
> >
> >> On a webpage somewhere, I cant remember now where, I read about the
> >> GU-84B (4CX1600) having an undersized radiator. I think it was on a
> >> Russian amateur website. What I had read was this tube was actually
> >> designed for running in a missle by the Russians, and was designed for a
> >> 1 time use. So, they undersized the radiator a good bit because of space
> >> limitations. They were making the comparison to a 4CX1500's radiator size
> >> being larger in the discussion. However the guts of the GU-84B supposed
> >> to be really good. So this brings the delima of how to cool it so one
> >> would get a long life out of it. One way would be add some sort of extra
> >> aluminum heat fins, or some made of brass, with fins sticking out to
> >> catch more air, thus increasing the overall surface area. The only other
> >> way would be to increase the amount of air flow and volume over the fins
> >> that's there. When doing this though, the noise goes up from the blower.
> >> However, if one is going to dealve into using the GU-84B, I'd s
> >> uggest looking into this and compare the sizes between its radiator and
> >> the one for the 4CX1500. Even though the tube is cheaper than some
> >> others, it's still expensive if you have to re-tube all the time. If I
> >> can remember where I seen this, I'll post the link.
> >>
> >> Best,
> >>
> >> Will
> >>
> >> --
> >> ___________________________________________________________
> >> Sign-up for Ads Free at Mail.com
> >> http://promo.mail.com/adsfreejump.htm
> >>
> >> _______________________________________________
> >> Amps mailing list
> >> Amps@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/amps
> >
> 
> 
> 
> ------------------------------
> 
> Message: 5
> Date: Tue, 19 Jul 2005 15:47:47 -0700
> From: gdaught6@stanford.edu
> Subject: Re: [Amps] GU-84B Cooling
> To: amps@contesting.com
> Message-ID: <42DD20A3.19877.1A01FDD@localhost>
> Content-Type: text/plain; charset=US-ASCII
> 
> On 19 Jul 2005 at 14:53, Will Matney wrote:
> 
> > On a webpage somewhere, I cant remember now where, I read about the
> > GU-84B (4CX1600) having an undersized radiator. I think it was on a
> > Russian amateur website. What I had read was this tube was actually
> > designed for running in a missle by the Russians, and was designed for
> > a 1 time use. So, they undersized the radiator a good bit because of
> > space limitations. They were making the comparison to a 4CX1500's
> > radiator size being larger in the discussion. However the guts of the
> > GU-84B supposed to be really good. So this brings the delima of how to
> > cool it so one would get a long life out of it. One way would be add
> > some sort of extra aluminum heat fins, or some made of brass, with
> > fins sticking out to catch more air, thus increasing the overall
> > surface area. The only other way would be to increase the amount of
> > air flow and volume over the fins that's there. When doing this
> > though, the noise goes up from the blower.
> 
> The radiator is comparatively small. But why not take to heart what
> Rich, AG6K, says? "The only time there's too much cooling air is
> when it blows the tube out of the socket!" (or something like that.)
> 
> If the blower is too loud, wear headphones. I wear them all the
> time.
> 
> 73,
> 
> George T. Daughters, K6GT
> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 6
> Date: Wed, 20 Jul 2005 03:12:04 -0500
> From: "Will Matney" <craxd@engineer.com>
> Subject: Re: [Amps] GU-84B Cooling
> To: Amps@contesting.com
> Message-ID: <20050720081204.3E61C4BEAD@ws1-1.us4.outblaze.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Dick,
> 
> I'm not saying it's a bad tube, and dont want none to think that. I just
> dont want anyone to undercool the tube so it will last. Who knows, the
> 4CX1500 may have an over-sized radiator too! About the only way to tell
> about the temp would be to use a thermocouple connected to the anode. Then
> the temp read under contesting conditions both under SSB and AM using the
> air flow they recommend. AM/CW creates a good bit more load on one as does
> SSB transmissions. Then if the temp stays down where it should, one would
> know it would be ok. I'm like Rich, and what George mentioned, use the
> largest blower possible. Another thing too is maybe mount and external
> blower and duct it to the amp. You can set one of these in another room to
> help kill the sound down if it's a concern. On yours, you may have the right
> combination by using enough fans both pushing and pulling. Have you measured
> what the air flow and pressure is on your amp? If so, let us know so we all
> have a starting point.
> 
> Best,
> 
> Will
> 
> ----- Original Message -----
> From: PA3DUV <pa3duv@planet.nl>
> To: "Will Matney" <craxd@engineer.com>
> Subject: Re: [Amps] GU-84B Cooling
> Date: Tue, 19 Jul 2005 22:45:03 +0200
> 
> >
> > Will,
> > In my twin tube GU84B amp one fan is used to pressurize the
> > subchassis and two axial fans to draw the air out.
> > With a B+ of 2900 VDC, from the 3 phase PSU the two GU84B tubes
> > generate an easy 6 kW of output. During normal (6 dB compressed)
> > SSB transmissions the exaust air stays below 55 degrees celcius.
> > Cheers, Dick Knol
> > PA3DUV
> >
> >
> >
> > ----- Original Message ----- From: "Will Matney" <craxd@engineer.com>
> > To: <amps@contesting.com>
> > Sent: Tuesday, July 19, 2005 9:53 PM
> > Subject: [Amps] GU-84B Cooling
> >
> >
> > > On a webpage somewhere, I cant remember now where, I read about
> > > the GU-84B (4CX1600) having an undersized radiator. I think it
> > > was on a Russian amateur website. What I had read was this tube
> > > was actually designed for running in a missle by the Russians,
> > > and was designed for a 1 time use. So, they undersized the
> > > radiator a good bit because of space limitations. They were
> > > making the comparison to a 4CX1500's radiator size being larger
> > > in the discussion. However the guts of the GU-84B supposed to be
> > > really good. So this brings the delima of how to cool it so one
> > > would get a long life out of it. One way would be add some sort
> > > of extra aluminum heat fins, or some made of brass, with fins
> > > sticking out to catch more air, thus increasing the overall
> > > surface area. The only other way would be to increase the amount
> > > of air flow and volume over the fins that's there. When doing
> > > this though, the noise goes up from the blower. However, if one
> > > is going to dealve into using the GU-84B, I'd s
> > > uggest looking into this and compare the sizes between its
> > > radiator and the one for the 4CX1500. Even though the tube is
> > > cheaper than some others, it's still expensive if you have to
> > > re-tube all the time. If I can remember where I seen this, I'll
> > > post the link.
> > >
> > > Best,
> > >
> > > Will
> > >
> > > -- ___________________________________________________________
> > > Sign-up for Ads Free at Mail.com
> > > http://promo.mail.com/adsfreejump.htm
> > >
> > > _______________________________________________
> > > Amps mailing list
> > > Amps@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/amps
> 
> 
> --
> ___________________________________________________________
> Sign-up for Ads Free at Mail.com
> http://promo.mail.com/adsfreejump.htm
> 
> 
> 
> ------------------------------
> 
> Message: 7
> Date: Wed, 20 Jul 2005 04:02:10 -0700
> From: R.Measures <r@somis.org>
> Subject: Re: [Amps] GU-84B Cooling
> To: "Will Matney" <craxd@engineer.com>
> Cc: Amps@contesting.com
> Message-ID: <0695c7b77d5d4292cc35d734e726c82b@somis.org>
> Content-Type: text/plain; charset=US-ASCII; format=flowed
> 
> 
> On Jul 20, 2005, at 1:12 AM, Will Matney wrote:
> 
> > Dick,
> >
> > I'm not saying it's a bad tube, and dont want none to think that. I
> > just dont want anyone to undercool the tube so it will last. Who
> > knows, the 4CX1500 may have an over-sized radiator too! About the only
> > way to tell about the temp would be to use a thermocouple connected to
> > the anode.
> 
> An IR thermometer would work.
> 
> > ...
> >
> > ----- Original Message -----
> > From: PA3DUV <pa3duv@planet.nl>
> > To: "Will Matney" <craxd@engineer.com>
> > Subject: Re: [Amps] GU-84B Cooling
> > Date: Tue, 19 Jul 2005 22:45:03 +0200
> >
> >>
> >> Will,
> >> In my twin tube GU84B amp one fan is used to pressurize the
> >> subchassis and two axial fans to draw the air out.
> >> With a B+ of 2900 VDC, from the 3 phase PSU the two GU84B tubes
> >> generate an easy 6 kW of output. During normal (6 dB compressed)
> >> SSB transmissions the exaust air stays below 55 degrees celcius.
> >> Cheers, Dick Knol
> >> PA3DUV
> >>
> >>
> >>
> >> ----- Original Message ----- From: "Will Matney" <craxd@engineer.com>
> >> To: <amps@contesting.com>
> >> Sent: Tuesday, July 19, 2005 9:53 PM
> >> Subject: [Amps] GU-84B Cooling
> >>
> >>
> >>> On a webpage somewhere, I cant remember now where, I read about
> >>> the GU-84B (4CX1600) having an undersized radiator. I think it
> >>> was on a Russian amateur website. What I had read was this tube
> >>> was actually designed for running in a missle by the Russians,
> >>> and was designed for a 1 time use. So, they undersized the
> >>> radiator a good bit because of space limitations. They were
> >>> making the comparison to a 4CX1500's radiator size being larger
> >>> in the discussion. However the guts of the GU-84B supposed to be
> >>> really good. So this brings the delima of how to cool it so one
> >>> would get a long life out of it. One way would be add some sort
> >>> of extra aluminum heat fins, or some made of brass, with fins
> >>> sticking out to catch more air, thus increasing the overall
> >>> surface area. The only other way would be to increase the amount
> >>> of air flow and volume over the fins that's there. When doing
> >>> this though, the noise goes up from the blower. However, if one
> >>> is going to dealve into using the GU-84B, I'd s
> >>> uggest looking into this and compare the sizes between its
> >>> radiator and the one for the 4CX1500. Even though the tube is
> >>> cheaper than some others, it's still expensive if you have to
> >>> re-tube all the time. If I can remember where I seen this, I'll
> >>> post the link.
> >>>
> >>> Best,
> >>>
> >>> Will
> >>>
> >>> -- ___________________________________________________________
> >>> Sign-up for Ads Free at Mail.com
> >>> http://promo.mail.com/adsfreejump.htm
> >>>
> >>> _______________________________________________
> >>> Amps mailing list
> >>> Amps@contesting.com
> >>> http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> > --
> > ___________________________________________________________
> > Sign-up for Ads Free at Mail.com
> > http://promo.mail.com/adsfreejump.htm
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> 
> Richard L. Measures, AG6K, 805.386.3734. www.somis.org
> 
> 
> 
> ------------------------------
> 
> Message: 8
> Date: Wed, 20 Jul 2005 04:07:27 -0700
> From: R.Measures <r@somis.org>
> Subject: Re: [Amps] GU-84B Cooling
> To: Dan K9ZF <n9rla@yahoo.com>
> Cc: amps@contesting.com
> Message-ID: <fffd55ee21291825e84cf7ea3237c09a@somis.org>
> Content-Type: text/plain; charset=US-ASCII; format=flowed
> 
> 
> On Jul 19, 2005, at 1:15 PM, Dan K9ZF wrote:
> 
> > Will Matney wrote:
> >
> >> So this brings the delima of how to cool it so one would get a long
> >> life out of it. One way would be add some sort of extra aluminum heat
> >> fins, or some made of brass, with fins sticking out to catch more
> >> air, thus increasing the overall surface area. The only other way
> >> would be to increase the amount of air flow and volume over the fins
> >> that's there. When doing this though, the noise goes up from the
> >> blower.
> >>
> >> Best,
> >>
> >> Will
> >>
> >>
> >>
> >
> > Water cool it?
> 
> Large electric generators are cooled with hydrogen gas, which removes
> heat c. 5-times more efficiently than air-cooling.
> >
> > 73
> > Dan
> >
> > --
> > K9ZF /R no budget Rover ***QRP-l #1269
> > Check out the Rover Resource Page at: <http://www.qsl.net/n9rla>
> > List Administrator for: InHam+grid-loc+ham-books
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> 
> Richard L. Measures, AG6K, 805.386.3734. www.somis.org
> 
> 
> 
> ------------------------------
> 
> Message: 9
> Date: Wed, 20 Jul 2005 13:47:04 +0200
> From: pa3duv@planet.nl
> Subject: Re: [Amps] GU-84B Cooling
> To: amps@contesting.com
> Message-ID: <18c76a518ce2e4.18ce2e418c76a5@planet.nl>
> Content-Type: text/plain; charset=us-ascii
> 
> Van pa3duv@planet.nl
> Verstuurd op woensdag, juli 20, 2005 11:49 am
> Aan Will Matney <craxd@engineer.com>
> Cc
> Bcc
> Onderwerp Re: [Amps] GU-84B Cooling
> Will,
> 
> Perhaps I could measure the anode cooler temperature with a UV
> thermometer.
> "Contesting conditions" is a rather vague performance indicator, I
> could run the amplifier flat out full carrier for a defined period of
> time and then measure the cooler temperature afterwards.
> I will set up a measurement session, measuring the pressure in the sub
> chassis in mm-H2O and the temperature in degrees Celcius. It is very
> difficult to measure the actual airflow without proper anemometers and
> a measurement-tube.
> 
> The B+ current is approx. 3.5 amps @ 6000 watt output. The power gain
> is approx 20 dB and the output power is adequate. The 3-phase B+
> transformer is switched in a delta configuration, AC voltage between
> the phases is approx 390 VAC @ 50 Hz. The airflow noise is of no
> concern to me since I always use a headset. I'll get back with some
> more detailed measurements later on.
> 
> Cheers, Dick Knol
> PA3DUV
> 
> 
> 
> ----- Oorspronkelijk bericht -----
> Van: Will Matney <craxd@engineer.com>
> Datum: woensdag, juli 20, 2005 10:12 am
> Onderwerp: Re: [Amps] GU-84B Cooling
> 
> > Dick,
> >
> > I'm not saying it's a bad tube, and dont want none to think that.
> > I just dont want anyone to undercool the tube so it will last. Who
> > knows, the 4CX1500 may have an over-sized radiator too! About the
> > only way to tell about the temp would be to use a thermocouple
> > connected to the anode. Then the temp read under contesting
> > conditions both under SSB and AM using the air flow they
> > recommend. AM/CW creates a good bit more load on one as does SSB
> > transmissions. Then if the temp stays down where it should, one
> > would know it would be ok. I'm like Rich, and what George
> > mentioned, use the largest blower possible. Another thing too is
> > maybe mount and external blower and duct it to the amp. You can
> > set one of these in another room to help kill the sound down if
> > it's a concern. On yours, you may have the right combination by
> > using enough fans both pushing and pulling. Have you measured what
> > the air flow and pressure is on your amp? If so, let us know so we
> > all have a starting point.
> >
> > Best,
> >
> > Will
> >
> > ----- Original Message -----
> > From: PA3DUV <pa3duv@planet.nl>
> > To: "Will Matney" <craxd@engineer.com>
> > Subject: Re: [Amps] GU-84B Cooling
> > Date: Tue, 19 Jul 2005 22:45:03 +0200
> >
> > >
> > > Will,
> > > In my twin tube GU84B amp one fan is used to pressurize the
> > > subchassis and two axial fans to draw the air out.
> > > With a B+ of 2900 VDC, from the 3 phase PSU the two GU84B tubes
> > > generate an easy 6 kW of output. During normal (6 dB compressed)
> > > SSB transmissions the exaust air stays below 55 degrees celcius.
> > > Cheers, Dick Knol
> > > PA3DUV
> > >
> > >
> > >
> > > ----- Original Message ----- From: "Will Matney"
> > <craxd@engineer.com>> To: <amps@contesting.com>
> > > Sent: Tuesday, July 19, 2005 9:53 PM
> > > Subject: [Amps] GU-84B Cooling
> > >
> > >
> > > > On a webpage somewhere, I cant remember now where, I read
> > about
> > > > the GU-84B (4CX1600) having an undersized radiator. I think it
> > > > was on a Russian amateur website. What I had read was this
> > tube
> > > > was actually designed for running in a missle by the Russians,
> > > > and was designed for a 1 time use. So, they undersized the
> > > > radiator a good bit because of space limitations. They were
> > > > making the comparison to a 4CX1500's radiator size being
> > larger
> > > > in the discussion. However the guts of the GU-84B supposed to
> > be
> > > > really good. So this brings the delima of how to cool it so
> > one
> > > > would get a long life out of it. One way would be add some
> > sort
> > > > of extra aluminum heat fins, or some made of brass, with fins
> > > > sticking out to catch more air, thus increasing the overall
> > > > surface area. The only other way would be to increase the
> > amount
> > > > of air flow and volume over the fins that's there. When doing
> > > > this though, the noise goes up from the blower. However, if
> > one
> > > > is going to dealve into using the GU-84B, I'd s
> > > > uggest looking into this and compare the sizes between its
> > > > radiator and the one for the 4CX1500. Even though the tube is
> > > > cheaper than some others, it's still expensive if you have to
> > > > re-tube all the time. If I can remember where I seen this,
> > I'll
> > > > post the link.
> > > >
> > > > Best,
> > > >
> > > > Will
> > > >
> > > > -- ___________________________________________________________
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> >
> >
> > --
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> >
> 
> 
> 
> 
> 
> 
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> 
> End of Amps Digest, Vol 31, Issue 35
> ************************************
> 
> 
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