[AMRadio] Tubing

Stevan A. White w5saw at pathwayz.com
Mon Jul 9 23:04:44 EDT 2007

Good guess, use copper tubing from your favorite home center store!  
What you see in the transmitter is more likely than not silver plated 
copper tubing.

When I was the chief engineer at an AM station with a 5 tower AM 
directional array several years ago and we rebuilt the phasing and 
tuning circuits used plain old copper tubing from Lowe's.  I mashed the 
ends flat with lineman's pliers, nipped off the sharp corners using the 
cutter part of the same pliers then dunked it in a solder pot to tin the 
ends well.  Silver solder like plumbers use is the best but regular 
resin core solder will work too, you just have to clean the sticky gunk 
off after it cools.  Clean the ends well with emory cloth before you 
shape it and use a punch to cut your holes before you tin it or a drill 
afterwards if you don't have a punch.  Whatever you do, don't use acid 
core solder!  If you don't own a solder pot, try an old (small) saucepan 
or maybe a food can on a camp stove.  Be sure to use something that will 
take the heat because silver solder has a higher melting point than 
resin core solder.

You've already mentioned that you need 1/4" diameter tubing so you 
should be OK using the cheap copper swamp cooler tubing from Wally 
World.  We used 1/2" for our 10 kW system so you ought to be good for 
several thousand watts.

Stevan A. White, W5SAW
SW Commercial Electronics
928 South Crockett Street
Amarillo, Texas 79102
Phone 806-681-7228
w5saw at pathwayz.com

"Our five senses are incomplete without the sixth -- a sense of humor." 
-- Source Unknown

Bill Smith wrote:
> Automobile air conditioning line?  Or perhaps tubing from a refrigerator?
> Bill
> ----- Original Message ----- 
> From: "Rick Brashear" <rickbras at airmail.net>
> To: "'Discussion of AM Radio in the Amateur Service'"
> <amradio at mailman.qth.net>
> Sent: Monday, July 09, 2007 6:51 PM
> Subject: [AMRadio] Tubing
> I need to make a couple of RF connections using 1/4" O.D. tubing.  The stuff
> that is already in the transmitter appears to be soft steel of some kind.
> It's not aluminum and could possibly be coated copper.  Any ideas of what
> this is?  I checked McMaster-Carr and they have some annealed steel aircraft
> tubing that appears to be similar, but I'm not sure.  I only need a couple
> of feet, so I hate to buy $30.00 to get it.
> Thanks for any help or advice...
> Rick/K5IAR

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