Tower base concrete should not be in series between the tower and
ground. There should not be a voltage gradient across the concrete
base. All ground paths should be strapped around the concrete base.
73
Rob
K5UJ
_
Searchable Archives: http://www.contesting.com/_topband -
Hi Gene,
I do not know why you would try to insulate the radials from the pad.
The tower is grounded (I hope), the tower base is in the concrete, and the
concrete base is a big huge UFER ground. It makes no difference if the radials
are insulated from the base, since they are already very much
Gents:
When I constructed my Trylon tower in 2001, I also installed a
shunt-feed wire up the side for 160M. My RF radial system consisted of
about 11 #18 insulated wires in the dirt surrounding the tower base. I
recently purchased additional wire to augment those initial few and
hopefully
I have an 80' Rohn 45 tower that I shunt feed. At 85' there is a SteppIR
MonstIR. I set it on 7020 when I want to transit on 160M. The setting of the
antenna has a dramatic effect on 160M with SWR.
I have side mounted antennas at 45' and 50'.
The shunt feed is a set of three parallel #16
Dale,
What are you using as your capacitor in your gamma match?
Like some of the others, this is what I would initially suspect also.
(btdthtts)
Mike VE9AA
Mike, Coreen & Corey
Keswick Ridge, NB
_
Searchable Archives: http://www.contesting.com/_topband -
lems.
> >
> > 73
> >
> > Lloyd - N9LB
> >
> >
> > -Original Message-
> > From: Topband [mailto:topband-bounces+lloydberg=tds@contesting.com]
> On
> > Behalf Of Dale Drake
> > Sent: Thursday, August 27, 2020 12:06 PM
> > To: topb
t.
Changed to Vacuum Caps, no more problems.
73
Lloyd - N9LB
-Original Message-
From: Topband [mailto:topband-bounces+lloydberg=tds@contesting.com] On
Behalf Of Dale Drake
Sent: Thursday, August 27, 2020 12:06 PM
To: topband@contesting.com
Subject: Topband: Shunt Fed Tower SWR Trouble
s.
73
Lloyd - N9LB
-Original Message-
From: Topband [mailto:topband-bounces+lloydberg=tds@contesting.com] On
Behalf Of Dale Drake
Sent: Thursday, August 27, 2020 12:06 PM
To: topband@contesting.com
Subject: Topband: Shunt Fed Tower SWR Troubles
Here's my problem. I'm experiencing SWR problems
While air variables certainly do flash over, the effect is sudden, and has
no "ramping up" effect.
From Dale's original post: "The problem I having is that when transmitting
the SWR goes up with power
and if I key-down for very long the SWR rises rapidly and takes off."
He can observe the SWR
I experienced wide spaced air variables flash over at moderate to high power in
my shunt feed omega match. I changed to vac variables. That solved the problem
with the additional benefit of easier tuning via the vac cap's verniers.
GL - Steve WB6RSE
> On Aug 27, 2020, at 10:58 AM, John Harden,
I am wondering if the air variable is flashing over. I am willing to bet that a
vacuum variable would correct the problem. I use two (2) Vacuum variables in an
Omega match.
73,
John, W4NU
Sent from my iPhone
> On Aug 27, 2020, at 1:38 PM, Guy Olinger K2AV wrote:
>
> Hi Dale,
>
> The
Hi Dale,
The RF voltage is always looking at the far end (stuff on the end away from
the tower base) to jump onto.
*** Provide a deliberate, designed, long-term weather survivable metallic
path to the boom of the highest yagi and provide a low R path from the
boom to BOTH sides of at least one
The balun heating hypothesis could be tested by disconnecting the balun.
Dave, KH6AQ
On Thu, Aug 27, 2020 at 7:06 AM Dale Drake wrote:
> Here's my problem. I'm experiencing SWR problems
> with 160M shunt feed on my tower. Using a gamma
> match with HV air variable caps I am able adjust
>
Here's my problem. I'm experiencing SWR problems
with 160M shunt feed on my tower. Using a gamma
match with HV air variable caps I am able adjust
the tap point to get a very nice SWR curve using
my AA-35 Zoom analyzer. The problem I having is
that when transmitting the SWR goes up with power
and
Hey,
does one of you use a BP60 Versatower or Westtower (18m)
as shunt fed for 160m?I have some questions about tuning
73 Andy DL8LAS
www.dl8las.com
www.swing-company-bigband.de/
www.uni-big-band-kiel.de/
_
Searchable Archives: http://www.contesting.com/_topband -
I have my tower on Cayman Brac Shunt fed for both 160 and 80 using separate
coaxes, capacitors and shunt feed wires. Works great, except that I don't like
the way it behaves. It appears to me that when I am on 160 for an extended
length of time that something may be going on with the 80m
Thanks for the direct replies.
Some added info.
Radials are 8 feet above the ground.
There are no antennae on top of the tower.
A small VHF yagi at 45 feet on the opposite side of the tower; face is 5
1/2 feet at this point of the tower.
I have done these tests with a couple of different
Ok not sure where to start.
I decided to redo my vertical.
I have a 89 degree tall tower. (125 feet self support).
It is shunt fed (#6 copper) 55 feet above the elevated radials three
feet from the tower.
There are 5 radials, 130 feet long.
There is a 1 to 1 transformer I wound and a number of
Jut watched this video. It's given me added incentive to re-install my
gamma wire again! It fell down last winter. so, that's another project,
after re-ropi g my tower.
Very impressed with the presentation Steve.
Many thanks for making it.
I am the Prog Sec for the Norfolk ARC and wonder if
After posting my video on shunt-feeding a tower, I have received a few emails
asking about the “omega match”.
Here is the link to a short 3 min video I made explaining the method of using
the omega match, how it can transform the resistive component of the complex
impedance of a shunt feed,
Great Job Steve (VE6WZ) on the shunt fed tower video. It's nice to see
some quality technical chat on the reflector. yours is a great model for
the new guys!
73
Bob, W7RH
--
W7RH DM35os
"It has become appallingly obvious that our technology has exceeded our
humanity." - Albert Einstein
Steve,
This is an excellent tutorial. Thanks for not only sharing but taking
the time to produce it as well.
73 Joel W5ZN
On 2019-04-24 20:03, VE6WZ_Steve wrote:
This week I added a second gamma-wire to my shunt fed tower for 160m
in order to lower the reactance and therefore lower the
Steve,
That's an excellent video.
Both in the technique of shunt feeding and the overall video
presentation which sets the bar.
Most impressive.
73
John G3XRJ
This week I added a second gamma-wire to my shunt fed tower for 160m in order
to lower the reactance and therefore lower the
This week I added a second gamma-wire to my shunt fed tower for 160m in order
to lower the reactance and therefore lower the voltage across my matching
network. This winter I was having some flash-over problems.
While doing this work I decided to make a video that explains the method for
This week I added a second gamma-wire to my shunt fed tower for 160m in order
to lower the reactance and therefore lower the voltage across my matching
network. This winter I was having some flash-over problems.
While doing this work I decided to make a video that explains the method for
Herbert Schoenbohm
Thu, Aug 2, 10:04 AM (5 days ago)
to TopBand
I recently installed a 2 element 40-meter beam and a 4 element 20-meter
beam on top of a 90-foot tower which I use for TX on Topband. The tower is
cage fed with a 3-wire cage spaced24 inches around the tower, I am able to
get 1.2
I would not use any inductance unless the tower naturally resonates above
1800 kHz. If I were going to use a cage for the gamma connection, I would
make a small cage that would only be on one side of the tower. I find that
the shield of old coax spaced a couple of feet from the tower works fine. I
I recently installed a 2 element 40-meter beam and a 4 element 20-meter
beam on top of a 90-foot tower which I use for TX on Topband. The tower is
cage fed with a 3-wire cage spaced24 inches around the tower, I am able to
get 1.2 to 1 on 1845 by putting about 1200 pf and a 500 pf fixed HV cap to
I have a 90' shunt fed stick of 45G that works well on Topband with about
20 quarter wave radials.
I just obtained another 90' of 45G with a BCB tower base insulator which
I'd like to put up at the proper distance for a phased array on both 160
and 80.
I'm assuming the 1/4 wave on 160 would be
-Ursprungligt meddelande-
Från: Topband [mailto:topband-boun...@contesting.com] För Paul Staupe
Skickat: den 30 maj 2013 15:30
Till: topband
Ämne: Topband: Shunt fed tower plus Marconi vertical phasing on 160 and80?
I have a 90' shunt fed stick of 45G that works well on Topband with about 20
quarter wave
I'm assuming the 1/4 wave on 160 would be about 130' which would be a half
wave on 80 and that they would have to be fed via different networks.
Has anybody done this? Does the shunt fed tower work in a phased array
situation, or would I be better off just using the insulated tower as a
Marconi
...and reasonable instrumentation and a good understanding of what is
actually going on. Difficult or hard is a judgment call from one's own
particular expertise and experience perspective. Antennas are a wonderful
interest area of amateur and professional radio. Experiment and enjoy.
Read good
...and reasonable instrumentation and a good understanding of what is
actually going on. Difficult or hard is a judgment call from one's
own
particular expertise and experience perspective. Antennas are a wonderful
interest area of amateur and professional radio. Experiment and enjoy.
Read
It is more cookie cutter to use series fed quarter wave elements with
current feed (95% of people still do that wrong), but if you have a little
patience and don't mind experimentation, you could certainly make it work.
I phased dissimilar elements many times over the years, with the grossest
I’d like to try shunt-feeding my 60-foot freestanding tower on 160M and
80M. how can this be done? If you’ve done it successfully I’d be grateful
for the specifics, or maybe a reference to the construction article you used.
73 and Happy Holidays, Jerry K3BZ
06, 2012 3:55 PM
Subject: Topband: Shunt Fed Tower
I’d like to try shunt-feeding my 60-foot freestanding tower on 160M and
80M. how can this be done? If you’ve done it successfully I’d be
grateful for the specifics, or maybe a reference to the construction article
you used.
73 and Happy
I've been reading all of the posts about the 160 shunt feeds...
I have a 100 foot 45G tower festooned with monobanders from 80 - 10
meters. Because of the monobanders my 4-wire cage is only 30 feet high.
The series capacitor is a 1000 pfd vacuum variable and the shunt
capacitor is 2000 pfd
Many shunt-fed, loaded towers on 160 exhibit narrow bandwidth and are difficult
to match with a single series capacitor for one simple reason:
The gamma rod (shunt wire) is TOO CLOSE to the tower.
A few years ago, after struggling with Omega matches in conjunction with MANY
trips up my tower,
Vertical antennas have been shunt fed for over 70 years. There is no
magic involved. Very few MW verticals are ever resonant and resonance is
irrelevant. The only important thing is to match the TX so it is happy.
The easiest way to deal with matching is to first model on EZNEC which
will
Joe, W4TV,
Thanks for the info on the insulators. !I just ordered some myself.
These are great for making a fat gamma rod as you indicated.
(They are a little pricey though, a whopping 35 cents apiece! hihihi)
Here is the webpage on RL for these insulators if anybody wants to check it
out.
in 87 or
88.
Carl
KM1H
- Original Message -
From: W2RU - Bud Hippisley w...@frontiernet.net
To: John Harden jh...@bellsouth.net
Cc: topband@contesting.com
Sent: Thursday, December 15, 2011 7:27 AM
Subject: Re: Topband: Shunt fed tower
Many shunt-fed, loaded towers on 160 exhibit narrow
, DJ7WW
-Original Message-
From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com]
On Behalf Of Price Smith
Sent: Donnerstag, 15. Dezember 2011 19:17
To: 'W2RU - Bud Hippisley'; 'John Harden'
Cc: topband@contesting.com
Subject: Re: Topband: Shunt fed tower
Construction
approximation that would
give reasonable results as a place to start on the tower. Suggestions?
73, Larry W6NWS
- Original Message -
From: W2XJ w...@nyc.rr.com
To: topband@contesting.com
Sent: Thursday, December 15, 2011 10:34 AM
Subject: Re: Topband: Shunt fed tower
Vertical antennas have
reasonable results as a place to start on the tower. Suggestions?
73, Larry W6NWS
- Original Message -
From: W2XJw...@nyc.rr.com
To:topband@contesting.com
Sent: Thursday, December 15, 2011 10:34 AM
Subject: Re: Topband: Shunt fed tower
Vertical antennas have been shunt fed for over 70
: Thursday, December 15, 2011 4:28 PM
Subject: Re: Topband: Shunt fed tower
For most of us a precise model is not possible. EZNEC will give you an
approximation. The tower is represented as a cylinder equal to the cross
section of the real tower. You could measure the existing R and J
, December 15, 2011 5:49 PM
Subject: Re: Topband: Shunt fed tower
Larry,
Because of the complexity of modeling without going crazy, although in
simple situations it will get you in the ball park, I would highly
recommend a 3 or 4 wire cage space at least 24 inches from the area near
the rotor
@contesting.com
Sent: Thursday, December 15, 2011 5:49 PM
Subject: Re: Topband: Shunt fed tower
Larry,
Because of the complexity of modeling without going crazy, although in
simple situations it will get you in the ball park, I would highly
recommend a 3 or 4 wire cage space at least 24 inches
as a place to start on the tower. Suggestions?
73, Larry W6NWS
- Original Message -
From: W2XJ w...@nyc.rr.com
To: topband@contesting.com
Sent: Thursday, December 15, 2011 10:34 AM
Subject: Re: Topband: Shunt fed tower
Vertical antennas have been shunt fed for over 70 years
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