[AMRadio] Need advice on storing RF power tubes

[Todd Bigelow - PS]

Mark Foltarz wrote:

> Some stuff will be fine in sub zero weather  to come in the next couple
>months. But every once in a while I hear that storing power tubes in a cold
>climate somehow degrades them or renders them useless.
>
>  What's the score on tube storage?  I don't want to screw this up.
>

Mark -

I live in northern New England and have stored the bulk of my tubes in 
boxes for years outside in unheated garages, barns, etc. I have yet to 
have a problem that could be (in my opinion) related to the cold, unless 
dropping and breaking one because of cold fingers counts. I certainly 
wouldn't take an ice cold tube and throw it into a full power situation 
a few seconds later, although I have seen military and commercial 
manuals which give temperature guidelines for use of the equipment. Many 
of these include sub-zero temperature ratings, occassionally with 
cautions on different matters. Perhaps some of the ex-military types 
with arctic experiences will add to this. Personally I am not aware of 
cold storage being harmful to tubes, but then I still have a bit to 
learn. From my experience, it is not.

However, be VERY careful with equipment and condensation. When you get 
large temperature variations in the same day it can wreak havoc on gear, 
even if it's wrapped, boxed, or otherwise 'protected'. Your storage 
space may seem dry, but the humidity in the air is your actual enemy. I 
suspect this is why they store all of those aircraft out in the desert 
for long-term storage. Don't move your gear from a nice, toasty house to 
an ice box garage - try to make the move gradual, and try to do it 
during a time of no precipitation (think 'rainy days') or other times 
when the humidity is high. If the gear is small (table-top sized), 
consider getting some silica gel pacs and stashing them inside. Bake the 
pacs in the oven at a low temperature (150 maybe?) to remove moisture, 
then seal them inside the piece of gear. It might sound extreme, but it 
sure can't hurt.

BTW, where in 4-land are you where it gets below zero?  I thought you 
folks had it easy down there compared to those in the great white north? 
 (o:

73 de Todd/'Boomer'  KA1KAQ