Bill,
Saw your excellent material from a few years ago. Last night, I ran the
numbers for 17m and 15m using a hypothetical 3L monoband Yagi on the same
Wincharger tower. Between 1-3 degrees elevation on the 355 degree radial into
Asia, the effective gain is between 17 and 19 dBi. To JA and Asia especially,
a single Mosley TA-33 on his 70 ft. tower would have outperformed many stacks
today that operate over flat terrain.
Switching to 40m, the 355 degree radial has a peak gain of almost 17 dBi. Into
Asia, a simple 3L Yagi on that 70 ft. tower would likely blow away any modern
stack today over flat land, even those with the top stack at 200+ ft. The only
viable way to get that kind of gain down to 1 degree of elevation is to elevate
a top stack 400+ feet above flat terrain – or use phased verticals over salt
water. I know little about the performance of Sterba/USIA curtains, but on
40m, this would probably be in that league for low angles. The big performance
he obtained was mostly over a 180 degree arc from SW to NE only. My guess is
he was just fine not having similar performance to the rest of the world.
Paul, W9AC
From: Bill Tippett
Sent: Sunday, June 22, 2014 8:45 PM
To: towertalk@contesting.com ; Paul Christensen
Subject: Re: [TowerTalk] SRTM Fill Data
W9AC:
Been trying to model the legendary W3CRA site using HFTA.
I did that about 10 years ago. The following includes some interesting
anecdotes and photos as well as HFTA:
http://users.vnet.net/btippett/w3cra.htm
73, Bill W4ZV
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