[TopBand: Inv-L proper matching]

[Eric Gustafson]

Mystery solved.  Scott never got my previous messages beacuse our mailer
can't deal with all the "."s in the username field of his address.  So, I
guess I'll have to use reflector bandwidth for this.  Sorry again folks.

Scott,

Do you have a login account name to use instead of scott.a.long?  If so,
please send it to me or better yet, set your mailer up to put the real
e-mail address to you in the "Reply-to:" field of the header.  Most mailers
will use the Reply-to field preferrentially.

Anyhow, here is what I sent you monday. Please reply direct.  No need to
fill up the reflector with the chit-chat about the antenna specifics until
there are really results to talk about.

Eric


>From: "long, scott a." <scott.a.long@owenscorning.com>
>Date: Mon, 11 Nov 1996 13:01:54 -0500
>
>I am using an Inv-L, it is 85 ft vertical and approximately 52 ft
>horizontal.  I am limited to space so this is as long as I could
>go horizontally.  With total length of wire I find the swr is
>around 3.1.  It has 10 radials on it, four of them are 100 ft
>long, the others are various lengths, min. 80 ft. I am feeding it
>direct with RG-213.  At the present time I am using my big
>Dentron tuner (the one with the roller inductor) to tune this
>antenna.
>
>Can someone please tell what gadgets and parts I need to do the
>above and use this antenna without the tuner?  How much bandwidth
>should I expect?  Keep in mind I am using 700 watts.  Please let
>me know where to find whatever parts that I'll need.
>
>Tks for taking the time to read this.
>
>Scott  K8SM
>

Scott,

This antenna is simple enough that I could probably model it with
sufficient accuracy that I could tell you what you want to know
about matching it to a 50 ohm system without a tuner.  However,
there are a few details that I will need in order to do this.

1.  Are the radials relatively evenly distributed around the
    base?

2.  Are the radials on the ground or elevated?

3.  What is the diameter of the horizontal section?

4.  Are both ends of the horizontal section at the same height
    (85 ft)?

5.  What is the nature (and diameter) of the 85 ft long vertical
    radiator conductor?  If it is not itself a tower, what
    supports it?


6.  What is the apparent resonant frequency of the antenna?

7.  You say you are feeding it "direct".  Is that at the base of
    the vertical or farther up?

8.  If you can go 100 foot horizontally for some radials, why
    can't you go more than 52 feet horizontally for the
    horizontal top section?


73,  Eric

-- 
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Eric Gustafson  N7CL                  | The mountains are high and the Emperor
6730 S. Old Spanish Trail             | is far away.
Tucson, AZ 85747                      |
			              | You can't work 'em
INTERNET: n7cl@mmsi.com		      | if you can't hear 'em.
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