[Hammarlund] Re: [R-390] Tube shields? We don’t need any stinking tube shields!

[Les Locklear]

I should have noted that immediately after shooting the tube shield 
temperature, the shield was removed and the tube temperature was shot.

Les
----- Original Message ----- 
From: "Les Locklear" <leslocklear at cableone.net>
To: <r-390 at mailman.qth.net>; <Hammarlund at mailman.qth.net>
Sent: Monday, December 03, 2007 4:09 PM
Subject: [R-390] Tube shields? We don’t need any stinking tube shields!


> Groups,
>
>
>
> This test was done using a Raytek laser digital thermometer. Temperatures 
> were taken from a 6BZ6 1st RF amp tube on a John R. Leary SP-600JX no 
> suffix number, serial number 1262. Ambient room temperature was 75°F. I’m 
> not a scientist nor should this be misconstrued as a scientific test. I 
> have always been curious as to whether the IERC tube shields “actually” 
> prolong tube life. As noted there were several different tube shields used 
> in this “test.” Also note there are several different types of inserts 
> inside these tube shields.
>
>
>
> The “Real McCoy” IERC Tube Shields have a finger grip type of insert that 
> acts as a heat sink and the test results show that the temperature 
> difference between the shield and the tube itself is little. That should 
> tell us that that type of shield is the “Standard.” For your information, 
> I don’t use tube shields and my tubes seem to last a long time.
>
>
>
> Take this information as it’s meant to be, strictly informational.
>
>
>
>
>
>
>
>  1.. Shiny metal Eby tube shield no insert. 94°, bare tube 124°F.
>
>
>  2.. Shiny metal Eby tube shield with seven-sided black aluminum insert. 
> 96°F, bare tube 127°F.
>
>
>  3.. Dull metal Elco tube shield no insert.108°F, bare tube 135°F.
>
>
>  4.. Black heat resistant painted Eby tube shield no insert. 104°F, 126°F 
> bare tube.
>
>
>  5.. Black anodized Eby tube shield with “waveform, nine ridges” aluminum 
> black heat shield insert. 107°F, bare tube 127°F.
>
>
>  6.. Collins black anodized tube shield with “waveform, nine ridges” 
> aluminum black heat shield. 100°F, bare tube 122°F.
>
>
>  7.. W.P.M. tube shield with five-sided aluminum insert. 106°F, bare tube 
> 118°F.
>
>
>  8.. IERC tube shield with “finger grip” type beryllium insert. “The 
> Standard.” 102°F, bare tube 104°F. ( has to be the insert)
>
>
>  9.. Bare tube, no shield. 6BZ6 114°F.
>   YMMV
>
>
> Les Locklear
> Gulfport, Ms.
> DX'ing Since '57
> http://www.hammarlund.info/
>
>
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