[TowerTalk] Inverted L..........

AD5VJ Bob rtnmi at sbcglobal.net
Tue Dec 25 13:19:11 EST 2007

 Problem here is there are *no trees* much less tall ones in the yard.
The ground is almost solid rock on this hill here also, so radials are a must.

This is Texas the tallest trees we have around North Texas are 30 feet and they are usually old timers or are dieing at bottoms.

I guess I am going to be forced to save and buy more tower sections.

I have two 10 footers of ROHN25 with an 8 footer top section right now, but dont have it installed yet.

Looks like I am going to need 4 more sections of ten feet before its all over.

73 frm AD5VJ
 Merry Christmas to All EVERYWHERE !!
Because whether you know Jesus The Christ
or whether you dont, He knows and Loves YOU.

Happy New year as well.

> -----Original Message-----
> From: towertalk-bounces at contesting.com 
> [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Brown
> Sent: Tuesday, December 25, 2007 11:30 AM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Inverted L..........
> On Mon, 24 Dec 2007 14:48:58 -0600, John wrote:
> >Although I have worked 78 entities in a very short period of
> time, 
> >it just doesn't seem like this thing is playing very well.  The 
> >vertical portion is about 3' to 4' from the pine tree.
> You've worked 78 entities on 160M in a short time and you're 
> complaining? I've worked 61 in a year and a half and I'm thrilled!  
> You guys on the east coast have all the fun with DXCC, with 
> all those entities in EU and Central America. :) 
> There are four things that can make it play better for DX, 
> but they may not be practical at your QTH. 1) Make the 
> vertical section taller. 2) Move the vertical section further 
> from the tree (loss in the tree MIGHT be a small issue on 
> 160, but I've seen no science on this). 3) Add more radials. 
> 4) Turn the horizontal section into a Tee so that there's 
> less high angle radiation. 
> All of these are "a dB here and a dB there" sort of improvements. 
> As to your impedance measurements -- you should really try to 
> measure at the base of the antenna with a decent bridge. I'd 
> bet that the Z is a lot lower than you think it is. If you 
> measure in the shack, you've got to translate complex R + jX 
> measurements to the other end of the feedline to get it 
> right, and to do that, you've got to know the ELECTRICAL 
> length of the feedline to fairly good accuracy. 
> 73,
> Jim Brown K9YC
> Santa Cruz, CA
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