Topband: Vertical vs inverted L question/opinions

Herb Schoenbohm herbs at vitelcom.net
Sun Aug 11 18:15:49 EDT 2013


Why is an inverted "L" apparently so popular on 160 when it wastes so 
much RF as a cloud warmer?  It is so easy converting an inverted "L" 
into a Marconi T.  The flat top can be 130 feet fed exactly in the 
center  by a single drop wire to the ground with the appropriate 
network.  A 65 foot drop wire comes very close to 50 ohms and any 
reactance can be removed with a series capacitor. Apart for the 
cancellation of high angle radiation this configuration is some distance 
away from support structures.  So many try to configure an inverted L by 
using their metal towers as supports for the fed end.  This sometimes 
means you are just shock exciting the metal tower and your feed 
impedance results may be all over the ball park.

I challenge anyone to find a situation where an Inverted "L"  will 
outperform a properly configured Marconi "T" with an ample ground system 
on either.



Herb Schoenbohm, KV4FZ



On 8/11/2013 5:48 PM, Don Johnson wrote:
> I have not seen a length mentioned for the inverted L, so thought I would note that by making the inverted L longer than a quarter wave moves the high current portion up the vertical. I had good luck with an inverted L about 3/8 wave long. By good luck I mean DXCC plus some on 160. I still am trying to improve. In any event feeding the inverted L with a series capacitor made tuning a breeze. By going longer than a quarter wave made the feed point inductive and raised the R value closer to 50.
> 73,
> Don
> N4DJ
>
> Sent from my iPhone
> _________________
> Topband Reflector



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