Hi Jim
How well did you do on FieldDay? How well did the 2 element vertical array
perform?
--
Jim K9TF
_
Topband Reflector
Right. There's some discussion of this in the ON4UN book, where I found
the Christman matching. As published there, it's 84 degrees of 50 ohm
line in each element, plus 71 degrees of 50 ohm line in the element
facing the desired forward direction,change directions by switching the
71 degree secti
Jim Sounds like you have a great 40M antenna for filed Day. QRP sounds
like fun. All you need now is brats and beer and something to keep you warm
at night.
Right. There's some discussion of this in the ON4UN book, where I found
the Christman matching. As published there, it's 84
On 6/12/2013 3:34 PM, Tom W8JI wrote:
I can't think of a reason to pick 90 degrees as a target value, unless it
is a system designed to protect something on groundwave that happens to
be straight in line with the elements.
I agree. For me, the primary design objectives are maximizing forwar
I agree. For me, the primary design objectives are maximizing forward
gain, beamwidth, and gain bandwidth. I don't care about F/B.
Null depth is maximum when radiation is equal from the two elements, and
that occurs with equal effective ampere-feet in the antennas. Equal
construction antennas
On 6/12/2013 3:34 PM, Tom W8JI wrote:
I can't think of a reason to pick 90 degrees as a target value, unless
it is a system designed to protect something on groundwave that
happens to be straight in line with the elements.
I agree. For me, the primary design objectives are maximizing forward
Right. There's some discussion of this in the ON4UN book, where I found
the Christman matching. As published there, it's 84 degrees of 50 ohm line
in each element, plus 71 degrees of 50 ohm line in the element facing the
desired forward direction,change directions by switching the 71 degree
se
On 6/12/2013 10:10 AM, Jim GM wrote:
What kind of gain readings are you getting now?
We didn't measure gain, but we did measure F/B. Gain is rather
difficult to pin down. Even F/B is tricky -- there was at least 6dB of
QSB on the rear setup (with the 71 degree line traded to the other
elem
On 6/12/2013 10:18 AM, Jim GM wrote:
Sounds like your gearing up for Field Day. If so where are you going to
set up?
With the K6MI "Chews Ridge Gang," about 50 miles E of Monterey, CA. We
do QRP battery.
73, Jim K9YC
All good topband ops know how to put up a beverage at night.
___
I guess 90 degree phase shift might result in a cardioid pattern?
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI
Sent: Wednesday, June 12, 2013 2:58 PM
To: topband
Subject: Re: Topband: My Turn For a Brain Pick - Sanity Check
On 6/12/2013 11:58 AM, Tom W8JI wrote:
Christman phasing is at 71 degrees? I was thinking 90 degree phasing.
Whats the reasoning for this?
Optimum phasing of two verticals 1/4 wave apart is never 90 degrees,
unless the user for some reason wants a single-point zero-angle null
and less than
Christman phasing is at 71 degrees? I was thinking 90 degree phasing.
Whats the reasoning for this?
Optimum phasing of two verticals 1/4 wave apart is never 90 degrees, unless
the user for some reason wants a single-point zero-angle null and less than
maximum gain. Optimum element current d
Read and envy: http://shakespeare-military.com/masts.asp
They take Visa and Mastercard!
Tim N3QE
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim GM
Sent: Wednesday, June 12, 2013 1:19 PM
To: topband
Subject: Re: Topband: My Turn For a Brain Pick
I have seen some thing like those military surplus mast sections. I
believe the ones I saw were made by Shakespear. I think this is the same
company that made those good trout fishing rods and reels like the one I
have.
Sounds like your gearing up for Field Day. If so where are you going to
set
Very fine Jim.
What kind of gain readings are you getting now?
Christman phasing is at 71 degrees? I was thinking 90 degree phasing.
Whats the reasoning for this?
--
Jim K9TF
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
On 6/11/2013 9:24 AM, Jim GM wrote:
So Jim, what are your final conclusions?
I was convinced by K2AV that the Yagi idea (passive reflector) was a bad
idea because it is too sensitive to ground characteristics. I went to
the Christman phasing method and it plays nicely.
Another mistake I mad
So Jim, what are your final conclusions?
--
Jim K9TF
All good topband ops know how to put up a beverage at night.
_
Topband Reflector
[mailto:topband-boun...@contesting.com] On Behalf Of Jim GM
Sent: Saturday, June 08, 2013 4:14 AM
To: topband
Subject: Re: Topband: My Turn For a Brain Pick - Sanity Check
I think your too close to tell, or just coupling into every thing around
there. Knowing you I am sure you have done every thing
y, June 07, 2013 4:05 PM
To: 'Jim GM'; 'topband'; Tom W8JI
Subject: Re: Topband: My Turn For a Brain Pick - Sanity Check
Hi, Jim
I'm most suspicious regarding your radial systems:
* Are your radials resonant? For the purposes that you are attempting,
they need to
* Are your radials resonant? For the purposes that you are attempting,
they need to be, in order to maintain the phase relationship between the
driven element and the parasite.
Actually there are three cases that work:
1.) Where a limited size system has radials are exactly resonant
2.) Where
made to play pretty well! If you are 5m from the array, I
would think that your measurements are pretty good except for elevation
effects.
Best regards,
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim GM
Sent: Friday, June 07
I think your too close to tell, or just coupling into every thing around
there.
I get good F/B on arrays I test, even within a wavelength or two. As long as
the elements are reasonable length (under 1/2 wave) and spacing reasonable,
the pattern should be formed up almost totally by somewhere a
I think your too close to tell, or just coupling into every thing around
there. Knowing you I am sure you have done every thing right. Try calling
CQ during day light hours and see what signal strengths the Reverse beacons
give you. http://www.reversebeacon.net/main.php
Problem with doing this i
Jim,
Equipment wise, is this reciprocal if you use the array for your receive
measurements?
Jim, KR9U
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown
Sent: Thursday, June 06, 2013 5:29 PM
To: 'TopBand'
Subject: Topband: My Turn F
Hi Jim,
Have you tried measuring the current in the parasitic when connected?
73, Greg, ZL3IX
On 2013-06-07 09:29 a.m., Jim Brown wrote:
I'm building a simple 2-el vertical array for 40M, with one element
driven against radials, and a passive reflector with an equal number
of radials. NEC pr
I'm building a simple 2-el vertical array for 40M, with one element
driven against radials, and a passive reflector with an equal number of
radials. NEC predicts 2.7 dBi over lousy ground at 15 degrees, with
peak gain of 3.6 dBi at 25 degrees elevation, and F/B of about 8 dB.
We've got this s
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