Hi Jim,
It was nearly midnight last night when I read the entire presentation.
I sure wish I could have heard the audio that accompanied it.
Yes indeed, I overlooked the "vertical rules on 160m". Missed that point.
That's it in a nutshell! That pretty much nails it!
Total waste of time to even fool with horizontal antennas on 160m unless you
just want to rag chew with the local yuks. It took me many years to arrive
at this conclusion. What a difference it made to my contest scores once I
switched to verticals!
I haven't gotten any further yet with your material.
My XYL had surgery today and I spent the entire day in the clinic.
As I wrote earlier, there is so much meat in your paper, it will take a
couple of days to go through all of this.
While hanging out in the clinic today, I wished I had had the time to print
your stuff out and take it with me, but it was just too late last night.
The reading material in the waiting room wasn't exactly my flavor.
Also, as a result of reading your paper, it reminded me that I hadn't
uploaded my own folded radial vertical to my web yet, so I did that this
evening, including the EZNEC model of the antenna. It is a simple,
effective 40 DX antenna requiring very little floor space.
Mine had only one bend in the radial (copied from a Moxon design in RadCom).
>From your link to K2VA I saw it still works good with multiple bends which
make 80 and 160m more feasible.
Tnx for the tip. Hadn't ever heard of that before. I have lots of reading
to do!
Here's a link to my vertical with the single folded radial:
http://www.dj0ip.de/vertical-antennas/40m-low-space/
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Tuesday, August 19, 2014 7:14 PM
To: tentec@contesting.com
Subject: Re: [TenTec] 160 Meter Problem
On Mon,8/18/2014 10:16 PM, Rick - DJ0IP / NJ0IP wrote:
> Jim, I didn't understand the point on slides 4 and 5.
> I concur with everything you wrote.
> Perhaps you mean where you wrote 130 ft. height for a horizontal
> antenna is "low" on 160m.
Well, remember that these slides accompany my talk, and also this talk was
to the Pacificon Antenna Forum, which draws folks a somewhat above average
knowledge of antennas. Ya hadda be there. :)
The fundamental principle at work is that a horizontal antenna that is low
as a fraction of a wavelength is an inefficient antenna, both because of
ground losses and because all the energy goes more or less straight up. I'd
call any horizontal antenna lower than a quarter wavelength low. Most of us
are stuck with low antennas for 40M and below.
But what is is about the line "Verticals RULE on 160M" that you don't
understand? To me, that says don't even consider a horizontal antenna.
Further, the fact that the rest of the talk covers only vertical antennas
(with various forms of counterpoise) should tell you SOMETHING. :)
> Well my main point is, we have good dB numbers shown for different
> vertical solutions, but there are no dB numbers shown comparing a low
> dipole at a typical height one would have in a city - say 50 ft. max,
> to anything vertical.
You're right -- I almost never see that sort of comparison, which is what I
did in the other link I gave. It compares vertical and horizontal antennas
at various heights on 80, 40, and 20. The 80M plots are easily scaled for
160M. Simply double the heights shown on the horizontal axis.
So a resonant horizontal dipole at 80ft on 160 would behave like a resonant
80M dipole at 40 ft on 80M.
Also, both of those presentations are 1 hour talks, and especially with the
160M talk, I had to have my roller skates on to get through it in that time.
:)
> There the difference is larger (in dB) than the difference between a
> good vertical and a great vertical.
Yes. And the primary difference between a mediocre vertical and a great one
is the counterpoise/radial system.
Another tutorial you might find interesting is this one.
http://k9yc.com/VerticalHeight.pdf It doesn't address 160M, but it clearly
shows the effects of the quality of the soil on a vertical antenna, and also
the value of mounting vertical antennas higher.
73, Jim K9YC
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