Subject: GLOWBUGS digest 108

From: [email-masked]
Date: Sat, 17 Feb 1996 16:03:04 -0600 (CST)

GLOWBUGS Digest 108

Topics covered in this issue include:

  1) Plug-in coils -- latest version
	by [email-masked] (michael silva)

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Date: Sat, 17 Feb 1996 14:01:17 -0800
From: [email-masked] (michael silva)
To: [email-masked]
Subject: Plug-in coils -- latest version
Message-ID: <[email-masked]>

Thought I'd let everybody in on my latest attempts to come up with a 
good plug-in coil.  I had been fooling around with 1" i.d. PVC and some 
octal bases from AES, but that required removing about half the 
diameter of the PVC for a quarter-inch so it would slip into the base 
-- too much work and not very pretty to boot.  So yesterday I got some 
1.25" i.d. PVC, which slips over the base with a bit to spare.  I 
wedged the base into the PVC with flat toothpicks, snipped them off and 
pumped as much hot glue as I could into the space (oh yeah, first I 
roughed up the pipe and the base).  At first I was going to use epoxy 
but I couldn't imagine any way to get it into the small space without 
making a mess of everything.  The hot glue seems to be holding fine, 
and I'm going to shove some more slivers of it into the spaces from the 
top and heat-gun them until they all melt.

So now I've got a nice-sized (1.75" o.d.) coil form for about a buck.  
Then I decided to get a little hi-tech fancy and wrote a quick Windows 
program to print out a winding template.  Enter in the diameter, length 
of the winding area and number of turns and it prints out a strip of 
slightly diagonal lines which is taped onto the form.  Finally I used 
my Dremel to make a little notch for each line, every 120 degrees 
around the form.  Pull off the template and it's ready for winding.

One nice thing about using octal bases is that you can use the extra 
pins for jumpering in extra capacitance if you need it on the lower 
bands.  One thing I need to do is try to figure out which pins are most 
commonly left off of octal tubes and not use those, so I'll be more 
likely to be able to use the bases off of any dead tubes that turn up.

Well, that's the report for today.  Hope somebody finds it useful.

73,
Mike, KK6GM

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End of GLOWBUGS Digest 108
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