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Re: Topband: Usable size of Flag antenna and FSM

To: topband@contesting.com
Subject: Re: Topband: Usable size of Flag antenna and FSM
From: Eric NO3M <no3m@no3m.net>
Reply-to: no3m@no3m.net
Date: Fri, 26 Feb 2021 18:44:07 -0500
List-post: <mailto:topband@contesting.com>
Anti-phased double loops are also a good way to approach an RDF of 10dB on 2200m (137kHz).  1/2lambda is nearly 3600ft.... so broadside arrays and beverages are usually a non-starter... close spaced end-fire vertical arrays get very touchy (amplitude/phase).  A DHDL style system spanning about 350ft works well here (quiet rural QTH):

http://no3m.net/2020/09/2200m-double-loop-receive-antenna/

The one I use is aimed west and hears VK4YB (and recently VK2AN) on 2200m most mornings starting a couple of hours prior to sunrise (and at times has gone an hour or more past sunrise).

- Eric NO3M


On 2/26/21 12:57 PM, n4is@comcast.net wrote:
I would like to share some of my experience with small flags'.

The directivity is the same for a large chance in frequency but the gain 
increase with size.

So a small loop is not thermal noise limited on 160m, and works very well on

80, 60 40 and 30m.

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