[TowerTalk] 40M Loading Coils

[W7TMT - Patrick]

I've no source for premade but several links that might help you roll your own. 

I used AD5X's technique to make loading coils for a shortened 40/15M dipole I use on my sailboat. The elements are supported on two Jackite telescoping fiberglass poles joined end-to-end in the middle. While the poles would easily support a full sized 40M antenna I don't have the room due to other vessel masts on either side along the dock. Happy to send you a picture of a coils I made if you want. Note that I used his method of spacing the windings but didn't need the support structure he describes for his vertical application.

AD5X's article is here: http://www.ad5x.com/images/Articles/CoilRevB.pdf

There is another one that may be of interest here:
"Homebrew Your Own Inductors," by Robert H. Johns, W3JIP, QST, Aug 1997, p 35

I used W8WWV's method for winding a single large coil for my 80' high 160M vertical over saltwater.  I used 1/8" refrigeration tubing for that one. 
His article is here: http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/HiQCoil.htm

K7MEM has some nice on-line calculators that might be helpful here: http://www.k7mem.com/Site_Map.html#HF%20Wire

Patrick, W7TMT

-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Frank VO1HP
Sent: Monday, March 15, 2021 16:50
To: towertalk at contesting.com
Subject: [TowerTalk] 40M Loading Coils

Does anyone know of a  source of  High Q 40M load coils and one could use for a DIY Rotary Dipole?
73
Frank VO1HP