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Re: Topband: Air Wound Coil

To: topband@contesting.com
Subject: Re: Topband: Air Wound Coil
From: Brian Pease <bpease2@myfairpoint.net>
Date: Thu, 30 Aug 2018 08:54:25 -0400
List-post: <mailto:topband@contesting.com>
I used #10 plastic insulated solid "house wire" salvaged from 2-conductor + ground cable for the small 5 inch dia coil on my 630m inverted-L.  The insulation automatically provides a spacing of about 1 wire diameter and measured Q was 300 at 475kHz.

On 8/30/2018 8:31 AM, David Cutter via Topband wrote:
If you don't have plastic pipe, select a plastic beaker from the kitchen
cupboard.
David G3UNA-G6CP

-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Don Kirk
Sent: 30 August 2018 12:53
To: Tim Shoppa
Cc: Trevor; topband
Subject: Re: Topband: Air Wound Coil

To follow up on what Tim said, I often just use PVC pipe for my coil forms
and wind my coils using enamel coated wire (16 or 14 gauge enamel coated
wire), and to keep things simple I often just use close wound turns (no
space between turns).  With no space between turns the coil loss will not be
minimized, but compared with most stations ground systems the additional
coil loss is typically just a small additional loss.

Don (wd8dsb)

On Thu, Aug 30, 2018 at 7:27 AM Tim Shoppa <tshoppa@gmail.com> wrote:

That is a very nice transmitter tank coil for a kilowatt amplifier.
But if you have already calculated or measured the inductance you
need, you can just wrap reasonable gauge insulated wire around any
cardboard or plastic form you find. I used magnet wire around a
cardboard tube. You can see a picture of the coil I wound for my 160M
antenna match here, along with some other more complicated link
coupled tuners:  http://n3qe.org/tuners.html

Tim N3QE

On Aug 30, 2018, at 2:44 AM, MR TREVOR DUNNE <ei2glb@eircom.net> wrote:

Hi All

I'm looking for an Air wondering coil like in this link,

http://www.mfjenterprises.com/Product.php?productid=404-0669

I've had one on order from MFJ via a UK company for 4 months now and
no
sign of it, I want to build a at matching network for my 160m inverted
T using it or something similar,
Can anyone tell me where I can get one of these or similar that is
in
stock today,
I don't have access to the tools/parts to wind one my self,

Thanks
Trevor
EI2GLB
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