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
> 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
> 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
> -----Original Message-----
> From: firstname.lastname@example.org [mailto:email@example.com]
> On Behalf Of Neal Laugman
> Sent: Friday, January 14, 2011 7:44 PM
> To: firstname.lastname@example.org
> 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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