Wow! All of the great writers of antenna software "woke" up. Thanks for all
of your work guys. At age 85 I'm not building a contest station, but trying to
optimize for fun. Maybe 6 years ago I went to Iron Mound here in Kansas
where my 4 el SteppIR is. Mid-morning heard some southern African stn working
a stream of central Eu. Listened a bit and while the linear was warming up
gave him a call with 70 watts. Right back. Then after a pause: Where are
you? Kansas. How much power? 70w. Another pause and he said OK and went back
to EU. I was off the side of his beam!Same about that time in a SSB contest on
20. Heard an Alaska calling CQ. Gave a call. Right back. The a comment: I
didn't think the band was open to down there! Priceless moments for a S&P
guy.Brian: If you get time to get your software up to current Windows use, let
me know.Thanks to all for your work,N0UU
On Tuesday, January 14, 2025 at 09:01:53 PM CST,
towertalk-request@contesting.com <towertalk-request@contesting.com> wrote:
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Today's Topics:
1. Verticals on sloping ground (Lawrence Stoskopf)
2. Re: Verticals on sloping ground (Jim Brown)
3. Re: Verticals on sloping ground (Jim Brown)
4. 160 meter vertical on sloping ground (Brian Beezley)
5. Re: Verticals on sloping ground (David Gilbert)
6. Apparent choke balun blown, now what (N4IJ)
7. Re: 160 meter vertical on sloping ground (RONDALL SPENCER)
8. Re: Apparent choke balun blown, now what (Jim Brown)
9. Re: Verticals on sloping ground (Dan Maguire)
10. W7RN for sale (Gary Johnson)
----------------------------------------------------------------------
Message: 1
Date: Tue, 14 Jan 2025 17:10:05 +0000 (UTC)
From: Lawrence Stoskopf <lstoskopf@cox.net>
To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: [TowerTalk] Verticals on sloping ground
Message-ID: <1058298110.734303.1736874605328@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
I'm not an antenna expert but been around reading for a long time.? We have
good software for horizontal polarization antennas over sloping ground.? My
SteppIR is at the edge of a 35 degree slope of about 400 ft drop right to EU.?
I'll match any antenna!
But the info I have on doing that with vertical polarization isn't really that
helpful (to me).? And I don't play up on the isolated hill at night!!!
N0UU
------------------------------
Message: 2
Date: Tue, 14 Jan 2025 10:45:46 -0800
From: Jim Brown <jim@audiosystemsgroup.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Verticals on sloping ground
Message-ID:
<fce9c7a9-0af2-412d-a102-5cbe4bd7a3ee@audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 1/14/2025 9:10 AM, Lawrence Stoskopf wrote:
> I'm not an antenna expert but been around reading for a long time.? We have
> good software for horizontal polarization antennas over sloping ground.? My
> SteppIR is at the edge of a 35 degree slope of about 400 ft drop right to
> EU.? I'll match any antenna!
> But the info I have on doing that with vertical polarization isn't really
> that helpful (to me).? And I don't play up on the isolated hill at night!!!
Dean Straw, N6BV, who edited the ARRL Handbook and Antenna Book at the
time, wrote that software. Many of us out here in the western mountains
use it extensively, and have found it's predictive accuracy to be quite
good. I got to know Dean after moving here, and asked if he could do
something similar for vertically polarized antennas. He replied that the
math was more complex, that data was less easy to come by, and that
since he'd been diagnosed with Parkinson's, he no longer felt able to do
it.
73, Jim K9YC
------------------------------
Message: 3
Date: Tue, 14 Jan 2025 12:42:19 -0800
From: Jim Brown <jim@audiosystemsgroup.com>
To: David Gilbert <ab7echo@gmail.com>
Cc: towertalk reflector <towertalk@contesting.com>
Subject: Re: [TowerTalk] Verticals on sloping ground
Message-ID:
<7d3fcce6-8ad1-4b4e-a48d-422bdedc112c@audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 1/14/2025 12:12 PM, David Gilbert wrote:
> I suspect that professional modeling software like FEKO can do the job,
> although I've never tried to learn it.? It does have a free version for
> individual use.
Yes and no. Dean told me that in our mountains, we should have data out
as far as practical (don't remember the distance he suggested). In my
experience, the result is as good as the accuracy of the model.
Vertically polarized antenna performance is quite dependent on soil
characteristics, whereas horizontally polarized antennas are not. Having
good data for soil would be an additional factor limiting accuracy.
That doesn't mean it isn't worth trying. :)
N6BT took his test antenna to a mesa, set it up at various locations,
and probed the pattern using a drone. Then setting up a rig (probably
QRP) feeding the antenna close to the edge of the mesa, he worked
stations only in the direction of the drop-off, repeating for multiple
directions, and none in the center.
------------------------------
Message: 4
Date: Tue, 14 Jan 2025 12:53:24 -0800
From: Brian Beezley <k6sti@att.net>
To: towertalk@contesting.com
Subject: [TowerTalk] 160 meter vertical on sloping ground
Message-ID: <145dc4f8-1762-4dea-948c-abaece87e285@att.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
"A good way to think about this kind of 'antenna on the side of a hill'
is to rotate the pattern for flat ground to the angle of the hill."
That's how I think of it, too, Jim. It's a good first approximation, but
there's more to it. In the simplest case, the far field includes a
direct ray, one from sloping ground, one from flat ground after the
slope quits, and diffraction from the bottom of the slope. There might
also be a secondary bounce from sloping to flat. Although sloping ground
can certainly concentrate power at low angles, you never get power right
at the horizon due to the inevitable phase cancellations. W6NL has an
old photo me of explaining this very geometry to W7EL by drawing rays in
the dirt with a stick at his hilltop QTH!
My TA program will calculate the resulting pattern for a vertical
antenna at the edge of a slope, including all possible reflections and
diffractions. But I don't have a working copy.
One thing to note about these ray-tracing programs is that they all do a
one-dimensional analysis along a given bearing. For mountainous terrain,
this is often inadequate. Power can easily reflect or diffract from
terrain to the right or left and wind up on the bearing of interest. The
magnitude of these off-bearing paths can be quite large. This really
restricts terrain for which results are accurate.
I've been thinking of resurrecting TA for Windows. If I do, it will only
be for a full 2D analysis. That should be possible in a reasonable
amount of time with modern computers, especially with multiple
processors gnawing away at all of the potential paths. But the main
problem is getting reliable data to check the calculations. What I used
for TA was the original WA3FET IEEE article. I had to extract data by
hand from the curves. But as I recall, the helicopter that took the data
flew directly over a hill with the RF source so it is not a good test of
2D terrain. I would not write a 2D program without having reliable data
to check it with. There are just too many ways to make ray-tracing errors.
Brian
------------------------------
Message: 5
Date: Tue, 14 Jan 2025 14:38:58 -0700
From: David Gilbert <ab7echo@gmail.com>
To: jim@audiosystemsgroup.com
Cc: towertalk reflector <towertalk@contesting.com>
Subject: Re: [TowerTalk] Verticals on sloping ground
Message-ID: <9de3607d-aefd-456f-a7b2-86db1591d231@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
That's a very good point.? The soil even on my own four acre lot is
HIGHLY variable, and I know that for a fact because there is a deep
ravine running across a portion of it. The variation in the composition
(soil versus rock formations of all kinds) is pretty amazing.
I have also compared HFTA plots for various distances from my home.?
There is a mountain range about 15 miles east of me and the HFTA results
vary significantly whether I include that range or not in the terrain file.
So yeah, since there is a river in between I doubt whether it would be
possible to ever get accurate soil data for that kind of range.
By the way, I have also used my drone to plot an antenna pattern, albeit
it was for a 5 element wire log periodic antenna tilted upward at a
steep angle for radio astronomy purposes.? It's not difficult to put a
small transmitter on the drone with a short antenna, and the GPS
position reporting capability of a decent modern drone lets you know
where it is accurately enough to get worthwhile data.
Dave?? AB7E
On 1/14/2025 1:42 PM, Jim Brown wrote:
> On 1/14/2025 12:12 PM, David Gilbert wrote:
>> I suspect that professional modeling software like FEKO can do the
>> job, although I've never tried to learn it.? It does have a free
>> version for individual use.
>
> Yes and no. Dean told me that in our mountains, we should have data
> out as far as practical (don't remember the distance he suggested). In
> my experience, the result is as good as the accuracy of the model.
> Vertically polarized antenna performance is quite dependent on soil
> characteristics, whereas horizontally polarized antennas are not.
> Having good data for soil would be an additional factor limiting
> accuracy.
>
> That doesn't mean it isn't worth trying. :)
>
> N6BT took his test antenna to a mesa, set it up at various locations,
> and probed the pattern using a drone. Then setting up a rig (probably
> QRP) feeding the antenna close to the edge of the mesa, he worked
> stations only in the direction of the drop-off, repeating for multiple
> directions, and none in the center.
------------------------------
Message: 6
Date: Tue, 14 Jan 2025 16:57:50 -0500
From: N4IJ <dougn4ij@gmail.com>
To: towertalk <towertalk@contesting.com>
Subject: [TowerTalk] Apparent choke balun blown, now what
Message-ID:
<CA+Ht2hO7JpDEciKdMyXiQvTDwoiM5DAOdKZutLLMF8aNDrfjLQ@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Took down a choke balun today to inspect ot since it
has been sitting on a wooden post with no antenna connected. Homemade with
balanced output I used with
a fullsize vertical GP for 80m. Anyway it looks like it either got really
hot or maybe lightening, not sure. Attached pic of apparent hot spots.
This is a pair of FT240 toroids glued together with teflon wire pairs etc.
Balun choke, not unun.
Is there really a way to determine if the cores are good or not? If it
weren't visible by several of the brown fiber tape that holds the wire
pairs together I wouldn't know any better. I hate to toss it....
73 Doug N4IJ
------------------------------
Message: 7
Date: Tue, 14 Jan 2025 17:07:12 -0500
From: RONDALL SPENCER <n4vos@bellsouth.net>
To: Brian Beezley <k6sti@att.net>
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] 160 meter vertical on sloping ground
Message-ID: <ED9735DA-A28C-4B7B-88EA-503FF94112FB@bellsouth.net>
Content-Type: text/plain; charset=utf-8
As I read this I now wonder about TA distance from vertical base. Im kinda on a
knob but then about 2000 feet the hill's in all directions are back at the same
level as vertical. So ai guess the question is whats the area that one should
be concered about if any at all.
Ron
Sent from my iPhone
> On Jan 14, 2025, at 4:34?PM, Brian Beezley <k6sti@att.net> wrote:
>
> ?"A good way to think about this kind of 'antenna on the side of a hill' is
> to rotate the pattern for flat ground to the angle of the hill."
>
> That's how I think of it, too, Jim. It's a good first approximation, but
> there's more to it. In the simplest case, the far field includes a direct
> ray, one from sloping ground, one from flat ground after the slope quits, and
> diffraction from the bottom of the slope. There might also be a secondary
> bounce from sloping to flat. Although sloping ground can certainly
> concentrate power at low angles, you never get power right at the horizon due
> to the inevitable phase cancellations. W6NL has an old photo me of explaining
> this very geometry to W7EL by drawing rays in the dirt with a stick at his
> hilltop QTH!
>
> My TA program will calculate the resulting pattern for a vertical antenna at
> the edge of a slope, including all possible reflections and diffractions. But
> I don't have a working copy.
>
> One thing to note about these ray-tracing programs is that they all do a
> one-dimensional analysis along a given bearing. For mountainous terrain, this
> is often inadequate. Power can easily reflect or diffract from terrain to the
> right or left and wind up on the bearing of interest. The magnitude of these
> off-bearing paths can be quite large. This really restricts terrain for which
> results are accurate.
>
> I've been thinking of resurrecting TA for Windows. If I do, it will only be
> for a full 2D analysis. That should be possible in a reasonable amount of
> time with modern computers, especially with multiple processors gnawing away
> at all of the potential paths. But the main problem is getting reliable data
> to check the calculations. What I used for TA was the original WA3FET IEEE
> article. I had to extract data by hand from the curves. But as I recall, the
> helicopter that took the data flew directly over a hill with the RF source so
> it is not a good test of 2D terrain. I would not write a 2D program without
> having reliable data to check it with. There are just too many ways to make
> ray-tracing errors.
>
> Brian
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 8
Date: Tue, 14 Jan 2025 15:20:42 -0800
From: Jim Brown <jim@audiosystemsgroup.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Apparent choke balun blown, now what
Message-ID:
<87c3a51a-03f1-4360-bfe4-e5a6bcad3d4a@audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 1/14/2025 1:57 PM, N4IJ wrote:
> Anyway it looks like it either got really
> hot or maybe lightening, not sure. Attached pic of apparent hot spots.
> This is a pair of FT240 toroids glued together with teflon wire pairs etc.
> Balun choke, not unun.
No attachments on this reflector. Describe the visual evidence that it
got hot. What core -- that is, what material? The only material I know
of that's useful on HF is Fair-Rite #31. Is the core cracked? What is
the transmission line used to wind it? Coax? Exactly what coax? Two-wire
line made from two insulated conductors? Magnet wires? Do you see any
evidence of arcing, or insulation overheating?
73, Jim K9YC
------------------------------
Message: 9
Date: Tue, 14 Jan 2025 16:10:51 -0800
From: Dan Maguire <danac6la@gmail.com>
To: towertalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] Verticals on sloping ground
Message-ID:
<CAOnXRMsFnqJZDUFMrPBPw4oL+D-6L3tvG5nK2dGa8Nj_4PLSGw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Dave @AB7E wrote:
>>> I have also compared HFTA plots for various distances from my home. There
is a mountain range about 15 miles east of me and the HFTA results vary
significantly whether I include that range or not in the terrain file.
This qrz.com thread from a year ago might be of interest:
https://forums.qrz.com/index.php?threads/simple-dx-gain-measure-for-antenna-comparisons-using-autoez.899027/
Post #23 of that thread refers to another thread where the N6BV HFTA app is
discussed:
https://forums.qrz.com/index.php?threads/seeing-the-effects-of-local-terrain-on-radiation-patterns.733041/
Dan, AC6LA
------------------------------
Message: 10
Date: Tue, 14 Jan 2025 19:01:13 -0800
From: Gary Johnson <gwj@me.com>
To: towertalk@contesting.com
Subject: [TowerTalk] W7RN for sale
Message-ID: <15F14936-466D-405A-A85B-24F7363563C7@me.com>
Content-Type: text/plain; charset=utf-8
This was inevitable for the usual reasons. Hopefully someone or some
organization can take over, otherwise it?s the end of one of the very finest
contest stations.
http://www.w7rn.com/w7rn-for-sale/
Gary NA6O
------------------------------
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