I don't have the latest ON4UN book, but I have an end-fire array of two K9AY
loops pointed NE, phased 180 degrees and spaced 130 feet. I'm just starting to
evaluate it in the real world. I chose 180 because it is absurdly easy to set
the phasing at that value just by transposing one winding of the matching
transformer, and because 180-degree phasing is least affected by any mismatch
between the antennas and the transmission line. It yields a pattern that is a
little different, but the overall RDF is pretty decent.
73, Pete N4ZR
At 06:16 PM 12/18/2005, Guy Olinger, K2AV wrote:
>If you are using EZNEC and have the wire structure for the flags,
>setting phase is easy.
>1) model each flag with a source record (the two sources will be
>assumed to be fed in parallel).
>2) on the Sources window set the offset flag to "160" under "Phase".
>This will allow you to check out the model and get your understanding
>of the phasing confirmed.
>Since these two antennas are lossy, the interaction will be very
>slight, and assuming attention is paid to equal construction and
>getting a 50 ohm feed, the usual two to one devices will work, with
>160 degrees more 50 ohm coax to the flag doing the lagging.
>----- Original Message -----
>From: "David Gould" <firstname.lastname@example.org>
>Sent: Sunday, December 18, 2005 5:05 PM
>Subject: [Antennaware] Help with modelling phased Flags
>> My antenna modelling with EZNEC has been limited to simple antennas.
>> I no longer have access to the land I used to use for beverages so
>> would like to try a pair of end-fire flag antennas as described by
>> ON4UN in his latest edition (4) of his "Low Band Dxing" (Fig 7.137,
>> Page 7.95). I can model the basic wire structure, but do not know
>> how to go about modelling the feed arrangement where the phasing
>> angle needs to be 160degs.
>> I would like to ask if anyone would volunteer to act as a "mentor"
>> give me some help to get started on this project, any offers of
>> would be much appreciated.
>> Dave, G3UEG
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