We'll soon see if it works ok/better
I need to work on the transformer a bit and have had some more pointers from
Jim M so that's a project for tomorrow
See you on WSPR
With best regards
Jim
Dr. James Cowburn
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of John P-G
Sent: 17 September 2009 20:32
To: [email protected]
Subject: Re: LF: G7NKS back on WSPR with new Umbrella ant
James Cowburn wrote:
> Dear LF
>
>
>
> G7NKS is back on tonight with a new umbrella antenna under test.
>
>
>
> 10m vertical element with 4x8m capacity wires sloping down at 45degrees.
> Not ideal but a little better than the old "L".
James,
This is much the same antenna as I've used on 500kHz. I started with 12m
height, but Shetland weather saw to that.... I then used 8m, with
sloping capacity wires of approx 6m, acting as guys (insulators at the
lower ends ends and nylon rope for the last section to the guying points.)
I tuned it with a variety of fixed and tapped inductors and matched to
50 ohms with a tapped ferrite transformer, all in a plastic bin at the
feed point. A run of 50 ohm feeder back to the shack.
I've had reports and QSOs (in-band and cross-band) from at least the
follwing: G/GW/GM/GI/EI/LA/SM/DL/OH/F/PA/ON and probably others. I've
had QSOs with powers as low as 100mW TX power and up to 200W TX power.
My estimate of the ERP for 100W TX power is 4-500mW on a good day (very
dependant on ground losses which affect the antenna current and hence
the radiated power).
Hope you have success with it.
John
GM4SLV
--
http://gm4slv.blogspot.com
Clousta, Shetland
IP90gg
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