Topband: 160m inv vee questions

[Chuck Dietz]

There was a QEX article in 2016 that examined ground mounted verticals. 
http://www.arrl.org/files/file/QEX_Next_Issue/2016/March-April2016/Zavrel.pdf

According to the plots in the article, over average ground the signal is still pretty strong at an arrival angle of 80 degrees above the horizon (5db down from 0 deg). I’m thinking the occasional large enhancement for the low dipoles may be at least partially due to the signals being predominantly horizontally polarized at those times.

Chuck W5PR

Sent from Mail for Windows 10

From: Bill Tippett
Sent: Monday, April 2, 2018 6:35 AM
To: topband
Subject: Re: Topband: 160m inv vee questions

This plot shows my low inv-V (30m apex is only 0.19 wavelengths) compared
to my 3 element parasitic vertical.  Study the relative gain vs TOA plots
carefully:

Ooops...bad link.  Use this one:

http://users.vnet.net/btippett/new_page_10.htm

On Mon, Apr 2, 2018 at 7:10 AM, Bill Tippett <btippett at alum.mit.edu> wrote:

> FYI in response to two recent threads:
>
> http://lists.contesting.com/archives//html/Topband/2018-03/msg00139.html
> http://lists.contesting.com/archives//html/Topband/2018-04/msg00043.html
>
> This plot shows my low inv-V (30m apex is only 0.19 wavelengths) compared
> to my 3 element parasitic vertical.  Study the relative gain vs TOA plots
> carefully:
>
> http://lists.contesting.com/archives//html/Topband/2018-03/msg00139.html
>
> My observations over the past 14 years comparing both:
>
> 1.  The vertical array is best 99% of the time.  Usually by ~10 dB to the
> NE (e.g. EU/W1 from here).  From the plots you can see this equates to TOAs
> (<20 degrees).
>
> 2.  The inv-V (wires running NNW/SSE) is occasionally (1%of the time) much
> better to EU or other directions at my local sunset or sunrise.  This is
> striking when it happens and is easy to detect since the inv-V is also
> better for RX than either Beverages or an RX4SQ.  This is clearly some sort
> of high angle mode around SR/SS and it usually lasts for <30 minutes.
>
> 3.  The inv-V BW is much broader than the vertical array which is very
> narrow (~30 kHz).
>
> 4.  TX antennas are separated by about 100m on different towers and the
> 30m inv-V height is near optimum for maximum radiation straight up
> (intentionally).
>
> 5.  The inv-V also works well to the SE (Caribbean/SA) even without SR/SS
> enhancement.  I have no idea whether how it would behave if rotated 90
> degrees since my site doesn't allow for that.
>
> Just FYI,
>
> Bill  W4ZV
>
>
>
>
>
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