[TowerTalk] loading coils

[Roger (K8RI)]

On 6/23/2010 6:01 AM, Jim Thomson wrote:
> 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.
>    
Which brings up the question:  which is better, the old WARC-7 with 
linear loading, or the new ones using what they call the Sigma series 30 
for the two 30 meter elements.  It drops the required spacing from 16' 
to a minimun of 4'. And that begs the question, can the old WARC-7 be 
converted to the New WARC-7?

73

Roger (K8RI)
> ## and folks are bashing 11m ops for using 3/4"  wide bar stock for a coil.. and corrona balls ?
>
> later... Jim   VE7RF
>
>
>
>
> Dino - KX6D
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