Topband: Air Wound Coil

[Jim Thomson]

Date: Thu, 30 Aug 2018 07:44:04 +0100 (IST)
From: MR TREVOR DUNNE <ei2glb at eircom.net>
To: ''''''topband List' <topband at contesting.com>
Subject: Topband: Air Wound Coil

<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


###  That mfj coil is listed as a whopping  79 uh  !    I cant  see having to use anywhere near that  value  for a simple   160m  T  ant. 
I calculated the  value for a buddy a few yrs back, for his  160m  T  vertical, and it was no where near  79 uh...just a few uh.    It was easy to wind by hand.
The ant was resonated a bit on the high side, so the  Xc  of the ant + the coil  formed a step up  L network.  No different than using a 
beta match or hairpin on any mono band yagi.   Think we used 8 gauge wire..  which is  .128  copper.   It was freestanding, after being removed from the
form used to initially wind it on.   Coil was oriented  vertically..and placed  right across the feed point.  Then the vert is also DC grounded.

Jim  VE7RF