[TowerTalk] loading coils

[Jim Thomson]

Date: Tue, 22 Jun 2010 12:54:46 -0700
From: "Dino Darling" <dino at kx6d.com>
Subject: Re: [TowerTalk] Have we been wasting our money?


Roger, stop stirring the pot!  That CB antenna works perfect for what it
was designed for.  The design was stolen from a guy named Kale who
builds the "Penetrator 10K" antenna.  I know you are not so naive to
think that there isn't a huge outlaw CB market.

## anybody notice that the center loading coils in a cushcraft  402CD
[and probably the new version XM-240]  have puny coils , wound with really small
ga magnet wire ??   Those coils have aprx  8.5 ohms  RF resistance each !
The Un loaded Q of those coils  is a joke. 

## feed point Z =   rad resistance +  series losses.  32 + 8.5 + 8.5 =  49 ohms.  
Sure, you end up with a low swr.. and that's  about it.  The ant is very effective
however.  They shoulda used  way bigger coils.. and also big capacity hats  [f-12 calls em
T-bars] .. then you end up with a more eff ant.   IMO, capacity hats are the closest thing to
a free lunch you can get.   F-12 opted for center loading on their sigma series loaded yagi's
on 80 + 40m.... and used   3/8"  OD  AL tubing...[ and big T bars]    Big diff  between puny small ga
magnet wire  [close wound to make the UN loaded Q even worse].. and  3/8"  tubing coils. 

## and folks are bashing 11m ops for using 3/4"  wide bar stock for a coil.. and corrona balls ? 

later... Jim   VE7RF 




Dino - KX6D