[TowerTalk] SRTM Fill Data

[Paul Christensen]

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 at 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