Topband
[Top] [All Lists]

Re: Topband: T loaded vertical

To: Tod - Idaho <tao@skypoint.com>
Subject: Re: Topband: T loaded vertical
From: Herb Schoenbohm <herbs@vitelcom.net>
Date: Tue, 23 Sep 2003 10:41:23 -0300
List-post: <mailto:topband@contesting.com>
Tod, I should have been more specific. Top loading with a T type marconi with a short vertical 60 foot down lead can be peaked to reasonable performance with a 75 foot (each side of center) flat top with the method I described. (If I recall the modeling done on this a longer flat top has a slightly lower take off angle and off course a higher feed point impedance.) Yes Earl is right about the current maximum always appearing 1/4 wave from each end. Yet I have found that a shorter flat top can be a terrific performer on top band as long as care is taken to match the feed point at the base. (W8UVZ and K8GG worked JA's from my QTH with only this type of antenna during the CQ 160 meter Contest a few years ago.)

The marconi T is a superb DX limited space antenna for 160 meters especially in restricted space circumstances. It is also a relatively efficient antenna as long as radials (in the ground or above the ground) are employed.

73

Herb, KV4FZ

Tod - Idaho wrote:

Jeez, I am just reacting to the thought of 260 feet of top loading on a
vertical. It almost seems as though one is using a single wire feed line to
feed an horizontal antenna.


Herb, what is the reasoning behind the statement, ""Try to get the current
loop to appear at the connection to the flat top
T.  This can be done by modeling or in the old days we would just tape a
small 6 volt bulb on a loop at the T."









_______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband

<Prev in Thread] Current Thread [Next in Thread>