for all of the 160M operator
Nuradi YB0UNC
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of JC
Sent: Saturday, August 15, 2015 8:55 PM
To: 'John Davies'; topband@contesting.com
Subject: Re: Topband: Best wire antenna for roof top location.
All of us
All of us have tried separate small loop receive antennas, both passive
and active, with only marginal improvements. Noise cancelling antennas don't
work due to the myriad of noise sources in built-up areas. Short Beverages
are a waste of time as well.
Bottom line is it is hardly worth bothering.
Subject: Topband: Best wire antenna for roof top location.
From: coupe...@hotmail.com
To: topband@contesting.com
Subject: Re: Best wire antenna for roof top location.
Date: Thu, 13 Aug 2015 23:55:30 +
9V operations are similar to Jakarta, with huge noise problems in an urban
environment.
Over
antenna for roof top location.
From: coupe...@hotmail.com
To: topband@contesting.com
Subject: Re: Best wire antenna for roof top location.
Date: Thu, 13 Aug 2015 23:55:30 +
9V operations are similar to Jakarta, with huge noise problems in an urban
environment.
Over the past 15 years
wire antenna for roof top location.
From: coupe...@hotmail.com
To: topband@contesting.com
Subject: Re: Best wire antenna for roof top location.
Date: Thu, 13 Aug 2015 23:55:30 +
9V operations are similar to Jakarta, with huge noise problems in an urban
environment.
Over the past 15 years
From: coupe...@hotmail.com
To: topband@contesting.com
Subject: Re: Best wire antenna for roof top location.
Date: Thu, 13 Aug 2015 23:55:30 +
9V operations are similar to Jakarta, with huge noise problems in an urban
environment.
Over the past 15 years there have only been three or four
Guy and jim,
No, I'm not missing anything -- did you miss my words first
approximation in my description of the model? That model was a
feasibility study, not intended or accepted (by me, at least) as a
predictor of actual performance of an antenna on a building that we
known nothing more
Okay guys - when email starts getting this specific and personal - the rest
of the list is really not interested in it.
Please take this debate off the list.
Thanks.
Tree
On Wed, Aug 12, 2015 at 8:16 AM, Jim Brown j...@audiosystemsgroup.com
wrote:
Guy and jim,
No, I'm not missing anything
Ah, perfection. Sadly, EZNEC does not provide that set of options. If I
could build that model, I would. But I can't. I will take this first
approximation, understanding its limitations. Brown's 99th law -- never
let perfect be the enemy of good. We don't know the nature of that
roof, so
Hi Jim,
I must respectfully disagree. And warn any reader that using NEC ground
media to simulate a conductive roof is a very troubled procedure with
significant issues.
Using the first media to simulate an elevated conductive plane for any
purpose is a problem. Using it to simulate radials is
I hope Nuradi's rooftop antenna installation doesn't proceed like this:
https://www.youtube.com/watch?v=IU7eSAw3IZs
73
Frank
W3LPL
_
Topband Reflector Archives - http://www.contesting.com/_topband
I'm still laughing !!
Ollie did try a safety idea when he tied a rope around his waist in case he
fell.
Who would have thought the brick chimney would come crashing down ?HIHIHI
thanks Frank !
Bob
K6UJ
On Aug 10, 2015, at 9:31 AM, donov...@starpower.net wrote:
I hope Nuradi's
It might be fun to drive around Culver City for a while and find some of those
old buildings. The houses are a lot closer together now, but most of the
originals are probably still there.
'JK
On Monday, August 10, 2015 9:31 AM, donov...@starpower.net
donov...@starpower.net wrote:
Hi Bud,
Thanks for comments.
I used sea water in the model to correspond to your copper plate
example. I also tried other less conductive mediums for the roof as a
sanity check. What changes is the strength of the high angle stuff.
No surprise that a dipole 5 ft above a conductive surface
On Mon,8/10/2015 5:53 AM, Tom W8JI wrote:
A dipole on a real tall building roof is worth a try (because it is so
simple and easy), but it is not a simple predictable system.
Tom,
I agree with this post on all counts. What's actually there can be
difficult to predict or even know, so
, YB0UNC/KU2B
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
donov...@starpower.net
Sent: Monday, August 10, 2015 11:32 PM
To: topband@contesting.com
Subject: Re: Topband: Best wire antenna for roof top location
I hope Nuradi's rooftop antenna installation
Actually, what he says is not use the high level media to model a RADIAL
system.
While playing with this model, I changed the characteristics of the
higher level media to have far less conductivity. The result suggested
that my model was good for what I was trying to understand -- that is,
There is a rather stern W7EL caution in the EZNEC doc about using two
ground media. He particularly nixes using the inner media as sea water
to mimic a high conductive surface.
(EZNEC doc)---
Using Two Ground Media
The ground may be broken into two media, each having its own
Hmmm! Let's remind ourselves of Nuradi's situation. The roof is 110m
high, 45m x 33 m. Corner to corner is less than a wavelength on 80M, more
than a wavelength on 40M, but the distance to a corner from a wire strong
between the two corners is less than a quarter wave on 80M, less than a
half
Jim — I’m not sure you’re “missing” anything from a theoretical standpoint.
Some comments from a practical standpoint, however:
1. In my dormitory roof example, our objective was to work W/VE — most of
whom were very close to us, hence very high angle. We might well have had a
great DXing
On Sat,8/8/2015 10:36 AM, W2RU - Bud Hippisley wrote:
but, with the usual wire sag, the feedpoint was about 5 feet above the gravel.
We weren’t worried, because the roof was at least 70 feet above the surrounding
terrain.
Hmmm! Let's remind ourselves of Nuradi's situation. The roof is 110m
On Aug 8, 2015, at 10:58 22AM, Tom W8JI w...@w8ji.com wrote:
Large buildings are not towers or poles. Buildings have a significant amount
of large conductive metallic things and noise generating junk inside.
If the building has wiring and large connected metallic things under the
Nuradi, how about halfwave sloping dipoles hung digonally from the top of
the building? Some 30 years ago at YU1EXY we had contest shack at top of
60m tall building with student's dormitory. In spite the building was in
the middle of city noise, sloping dipoles played extremely well. Later we
hace que uno se olvide de comer,
de dormir, de todo. - Nikola Tesla
- Original Message -
From: Mirko S57AD miroslav.sibi...@amis.net
To: Nuradi yb0...@gmail.com
Cc: topband@contesting.com
Sent: Saturday, August 08, 2015 3:03 PM
Subject: Re: Topband: Best wire antenna for roof top location
Dear all,
In preparation of this coming WW big contest, I plan to install wire antenna
on a roof top of a 33rd storey building (about 110metres above the ground)
for operating on the 160M, 80M and 40M band.
The building roof top rectangular size about 45 metres long (from
NWtoN-326.8
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