[Collins] IERC Tube Shields in the S-line

[Jerry Seligman]

On the subjects of tube shields and tube envelope heat reduction,
I believe I have better method than IERC shields. At flea markets I
have purchased tube shields with fins. The shields fit tightly over the
tubes touching the complete envelope. Then I have quiet muffin fans
set directly over the hottest tube pulling hot air out over the fins of
the shields. I have the fans on the receiver, transmitter, and power
supply. Right at this minute, we have  been contesting in the IARU
contest for 12 hours and all three units are at ambient room
temperature as measured with an industrial thermometer. I've been
told these finned shield were used in tube type audio equipment.
I use these shields on all tubes, whether or not they required
shields originally or not. I had to realign everything due to the
presence of the shields on previously unshielded tubes.
W7BUN