[TowerTalk] disassemble traps, cleaning aluminum

[Chris Adams]

I've got a few antenna projects going on that have brought up some
questions....

The first item I'm doing is converting an old Hy-Gain DB-1015 (duo band
10/15m, 3 element trapped beam) into a 15m 3 element monobander.

During my investigations, using YA (from ARRL Ant Book, 18th edition,
and "scale"), I've become aware of just how much tapering can change
dimensions.  Which leads me to the aluminum from this antenna....

I suppose due to the weight of the traps, I have the following taper
schedule for each element:


section 1:  	1 1/4"
section 2: 	1 1/8"  tapered to 7/8"
section 3:	3/4"  tapered to 1/2"  (unfortunately this section includes
the trap)
section 4:	7/16"

The problem section is #3 with the trap.  Since I don't know where to
buy aluminum sections that are tapered like Hy-Gain's, I'm either left
with much larger diameter elements, adding weight and some wind
resistance, or I can do some fancy tapering with short pieces of
aluminum to make a sleeve or I could take apart the trap.

My take on the above ideas after some deliberation is....

1.  Would prefer not to add any more weight and wind resistance then I
have too.

2.  Fancy tapering schemes seem increase the odds of having some type of
quality problem. 


3.   I would like to use 7/16" end pieces of at all possible (well maybe
not, if present pieces aren't long enough, Texas Towers does not sell
7/16" tubing).


This means I need to take the trap apart.  Any suggestions on how to
disassemble a trap?

Any other ideas on how to taper down to small diameter aluminum tubing?

------------

Another question:

I have been cleaning the outside of the aluminum tubing where two pieces
meet with a circular wire sander attachment for my drill.  However, that
does NOT clean the inside of the larger telescoping tubing.  There is
definitely some type of gunk/paste, not sure if it is aluminum oxide or
the remains of some type of conducting paste, etc.  Any suggestions of
cleaning the inside of aluminum elements?

I have other questions, but they escape me at the moment.

73's

chris, n4vi

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