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Re: [TenTec] ant

To: tentec@contesting.com
Subject: Re: [TenTec] ant
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Reply-to: geraldj@weather.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 14 Jan 2011 19:52:21 -0600
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
In Germany that coil tubing was probably 6 or 8 mm diameter. Practically 
1/4 or 5/16" diameter. I just checked a couple banana plugs and jacks. I 
get 0.145" as the smallest rigid diameter of the plug and about 0.151" 
as the ID of the banana jack which is close to 4mm (0.1575") and 
measuring with a dial caliper in that small a hole is subject to error. 
I'm sure a vendor of banana jacks like Keystone Electronics will be more 
specific about that diameter.

http://en.wikipedia.org/wiki/Banana_connector says the banana plug and 
jack is a German invention and IS 4mm diameter.

Checking two handy vintage meters with drill bit shanks. The B&K DVM 
jacks take a 0.159, won't take a 0.161. Must be about 0.160 like some 
Pomona jacks I found dimensioned on line. My older Simpson 260 series 5 
takes 0.157 snugly, not 0.159 in a jack that's rarely been used. 
Fortunately the banana plug has a large range of sizes it will fit, part 
of its fundamental design if its a true banana. There have been more 
solid plugs that are split four ways that aren't as tolerant of jack 

73, Jerry, K0CQ

On 1/14/2011 7:08 PM, Rick - NJ0IP / DJ0IP wrote:
> Well guys, Jerry probably touched on the most important factor here.
> The doggone manufacturers somehow assumed we wanted everything smaller and
> smaller and so they compromised performance for size.
> In Germany about 30 years ago a very good OM put forth a scheme for doing it
> right.
> He is an SK now.
> Arno (DL9AH) suggested making a very large coil out of thick copper tubing,
> about 1/4 inch thick.
> It was a monster.
> Ok, this is overkill, but he did it for another reason.
> He then drilled holes (I'll pick a number) "3mm" in diameter into every
> winding.
> A typical banana plug would fit snugly into these holes.
> Thus you were able to tap anywhere you wanted, just as Jerry suggested,
> using clips.
> These things had about as close to zero loss as you could have.
> Would make a lot of sense using a circuit based on the K1JJ design.
> Measure the correct diameter of the banana plug.  My "3mm" was just an
> example.
> 73
> Rick
> -----Original Message-----
> From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
> On Behalf Of Neal Laugman
> Sent: Friday, January 14, 2011 7:44 PM
> To: tentec@contesting.com
> Subject: Re: [TenTec] ant
> My bad - I did mean polystyrene, but I was under the impression
> the Airdux coil had a denser plastic.
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