View Single Post
  #13   Report Post  
Old April 16th 08, 03:40 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default 80m inductor kit or a pair of 80m traps?

On Wed, 16 Apr 2008 14:39:27 +0100, "Barrett"
wrote:

When I put the homebrew HF traps in my wire Ariel how do I calculate the
length of wire before and after each trap for each band?


Hi Barrett,

1. You either copy an existing design and follow their specifications
for this explicitly;

2. You model the design and plan to trim length, and/or adjust turns;

3. You throw something together and (again) plan to trim length,
and/or adjust turns.

The placement of the coil along the radiator by actual distance and
proportion, seriously changes its requirements for any application.
That is to say, a 50 turn coil, with turns every 3mm, and a 4cm
diameter will work for one frequency at one position for one length of
wire ONLY. And even height above ground may upset this too; but
perhaps not as much as the first set of variables.

73's
Richard Clark, KB7QHC