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Re: [Amps] GU-84B Cooling

To: "'Gary Smith'" <wa6fgi@sbcglobal.net>, PA3DUV <pa3duv@planet.nl>,amps@contesting.com
Subject: Re: [Amps] GU-84B Cooling
From: "Carcia, Francis A HS" <francis.carcia@hs.utc.com>
Date: Wed, 20 Jul 2005 13:06:34 -0400
List-post: <mailto:amps@contesting.com>
all you need is some thermal couple wire and a DVM Calibrate it in frozen
water
and boiling water and make a graph,

-----Original Message-----
From: Gary Smith [mailto:wa6fgi@sbcglobal.net]
Sent: Wednesday, July 20, 2005 10:30 AM
To: PA3DUV; amps@contesting.com
Subject: Re: [Amps] GU-84B Cooling


To the list: 
In this thread is the mention of IR thermometers.  As I fly r/c airplanes,
such thermometers for reading cylinder head temps have found their way into
my hobby.  Raytek is one brand name, it sells for $70.00 or so.  Go to
www.towerehobbies.com and search for temperature gauge, found one that read
+- 2% from -27 to 428 Fahrenheit.  Price is $24.95, comes with many features
including a "temp hold." 
A price such as this beats the dickens of having to pay for a lab grade
instrument.
73 to all,
Gary... wa6fgi  
  ----- Original Message ----- 
  From: PA3DUV 
  To: amps@contesting.com 
  Sent: Wednesday, July 20, 2005 4:56 AM
  Subject: Re: [Amps] GU-84B Cooling


  oops.. UV should read IR...
  Thanks Rich.

  ----- Original Message ----- 
  From: <pa3duv@planet.nl>
  To: <amps@contesting.com>
  Sent: Wednesday, July 20, 2005 1:47 PM
  Subject: Re: [Amps] GU-84B Cooling


  > 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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