[TenTec] The OCFD Mystique
k8mp at aol.com
k8mp at aol.com
Wed Sep 23 05:55:08 EDT 2015
Neat story Tony. Herb's Windom worked well also. I think he mainly used it on 80 cw cuz he did a lot of traffic handling and I assume he covered all of FL with a good signal. It was his only low band antenna. (He had a tribander for the upper bands)
I only got to meet him a few times when we visited my grandmother in Winter Haven but thinking back now, I guess I have to count Herb as one if my Elmers because he taught me a lot.
Later, Joe, K8MP
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-----Original Message-----
From: Tony Lelieveld <va3dwi at gmail.com>
To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Sent: Wed, Sep 23, 2015 02:00 AM
Subject: Re: [TenTec] The OCFD Mystique
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<pre style="font-size: 9pt;"><tt>Hi Joe,
In 1989 I used that kind of antenna for about a year (before I put up a
tower with a tribander) and it was quite useful on 20 mtr. I had a regular
schedule with my brother in New Zealand, ZL1BVE now a SK, on Friday evenings
on 20 mtr. Whenever I worked him on the beam I switched to the Windom
antenna and it worked very well. Obviously signals were down compared to
the beam but it worked. I ran the wire from a hydro pole at the curb at the
street side to a tree in the back yard. It passed over the peak of the
house and at the back of the house I soldered a wire to the horizontal part,
about 1/3 away from the end. This wire dropped straight down, entered the
house through a hole in the window sill and was attached to the "wire"
terminal on an MFJ tuner.
For the ground, on the tuner, I had a wire go
through the same window sill
and connected to a 15 foot long 2 inch wide strip
of Copper, buried about a
foot down in the soil. I don't even know how long
the horizontal part of
the antenna was, I guess maybe 120 some feet, but it
worked fine on 80 and
40 mtr. Had to be cautious at times while tuning for
not to get too much RF
in the shack though. Now we live in the country and my
wire antenna is a
double extended Zep up 50 feet and fed with ladder line
directly to a
Ten-Tec 238 tuner. Works wonderful on all bands.
73, Tony
VE3DWI.
----- Original Message -----
From: "Joe Papworth via TenTec"
<<a href="mailto:tentec at contesting.com">tentec at contesting.com</a>>
To: <<a href="mailto:k3ndm at comcast.net">k3ndm at comcast.net</a>>; <<a href="mailto:tentec at contesting.com">tentec at contesting.com</a>>;
<<a href="mailto:tvman1954 at gmail.com">tvman1954 at gmail.com</a>>
Cc: <<a href="mailto:k8mp at aol.com">k8mp at aol.com</a>>
Sent: Tuesday, September 22, 2015
7:13 PM
Subject: Re: [TenTec] The OCFD Mystique
>I can't believe this
discussion is still going on.
> But, since someone mentioned Mr. Windom I have
to ask if anyone has ever
> used or seen what I call the "Classic" Windom,
which I believe was the
> original Windom design.
> I have only ever seen one
in use and it was at K4DNX's QTH in Winter
> Haven, FL, way back in 1964.
>
The antenna was an 80 meter half-wave. It was a continuous hunk of wire
> (no
insulators 'cept for the end ones. The feed line was a single wire and
> it
was attached to the antenna
> 33% in from one end.
> I believe OM Herb told me
the antenna had an impedance around 300 ohms.
> Fifty-plus years later, I'm
still waiting to run across another antenna
> like that.
> Later,
Joe
>
>
>
> Sent from AOL Mobile Mail
>
>
> -----Original Message-----
>
From: Barry LaZar <<a href="mailto:k3ndm at comcast.net">k3ndm at comcast.net</a>>
> To: Wade Staggs <<a href="mailto:tvman1954 at gmail.com">tvman1954 at gmail.com</a>>;
Discussion of Ten-Tec Equipment
> <<a href="mailto:tentec at contesting.com">tentec at contesting.com</a>>
> Sent: Tue, Sep
22, 2015 06:09 PM
> Subject: Re: [TenTec] The OCFD Mystique
>
>
>
> <div
id="AOLMsgPart_1_fd93b1c5-79f2-4110-9345-35cd1354b404" style="margin:
>
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>
> <pre style="font-size: 9pt;"><tt>Wade,
>
The Windom was invented when tube transmitters were around. The
>
> output
stage of most, not all, could handle a fair difference in
> impedance,
> but
most could not handle the very high impedances reflected
> by feeding in a
>
voltage loop. So Windom said I have the answer. I'll
> feed the antenna at a
>
point that would reflect a reasonable impedance
> regardless of band. THERE
>
NEVER was a consideration for SWR. The SWR
> issue ONLY came up after coax
cable
> began to be used widely.
>
> Next, a Windom type antenna, dipole,
and OCFD
> are the exact same
> thing. The only difference is the feed. A 132'
wire will
> have generally
> the same gain regardless of how you feed it.
However, the
> pattern will
> be skewed a bit showing a bit more gain in one
direction feeding
> it off
> center. Most Windoms, OCFDs are designed for a
300 Ohm feed point
> making
> it necessary to use a 6:1 balun transformer. And
if you have RF in the
>
> shack, you are not using a good balun or have
coupled energy from the
>
> antenna to the transmission line, not an uncommon
issue if you do not
> come
> away from the antenna at a right angles.
>
>
I do not intend to flame you so
> take off the fire retardant clothes.
>
However, I will say you have fallen
> victim to a lack of understanding of
>
antennas. I really don't mean to
> criticize, but more than half of the
> hams
today really don't understand the
> very basics of antenna design.
>
>
Now having gone through all of that, let
> me say, A very good antenna
> is a
center fed 1/2 wave on 80 meters fed with
> open wire, if you have a
> fair
run. Where you enter the house/shack, you
> transition to something
> like
LMR-400 using a good 4:1 current balun. This
> antenna will work all
> of the
bands 80-10 with a tuner. The losses will be very
> low, even on 10
> meter.
You are correct about losses, keep'em down.
>
> So,
> why do I use a
Carolina Windom type antenna. Because I bought
> into having the
> ability to
do some fill in at the lower angles on the
> lower bands. The center
> fed
dipole would have been a bit simpler, but I
> felt at the time this would be
>
better; mine is a modified Carolina
> Windon that I built using EZNEC
modeling.
> I have a really good choke 15
> feet below the feed, so I have no
problems with
> RF in the shack. My
> tuners seem to have no problem with
tuning on 40-10; I do
> have a little
> trouble on 80 as my antenna is only
66' vice 132' long.
>
>
>
> My advice is to just pick a design and put it up
as high as you can.
> Let your
> tuner do all of the worrying for you. Feed
the antenna with the
> least loss
> transmission line you can find or afford
that fits your
> chosen design, and
> then use the heck out of it. Most of
this makes
> little difference from a
> practical perspective, yet it's more
than a
> semester for the engineering
> student. Just remember the ionosphere
will
> mess with your signal in the 10s of
> dbs while antennas may only
amount
> to a
> few.
>
> 73,
> Barry
> K3NDM
>
>
>
> ------ Original
Message ------
> From: "Wade
> Staggs" <<a
href="<a href="mailto:tvman1954 at gmail.com">tvman1954 at gmail.com</a?">mailto:tvman1954 at gmail.com">tvman1954 at gmail.com</a</a>>>
> To: "Barry LaZar"
<<a
> href="<a href="mailto:k3ndm at comcast.net">k3ndm at comcast.net</a?">mailto:k3ndm at comcast.net">k3ndm at comcast.net</a</a>>>;
> "Discussion
of Ten-Tec Equipment"
> <<a
href="<a href="mailto:tentec at contesting.com">tentec at contesting.com</a?">mailto:tentec at contesting.com">tentec at contesting.com</a</a>>>
> Sent:
9/22/2015
> 4:49:14 PM
> Subject: Re: [TenTec] The OCFD Mystique
>
>>Once
again I walk
> forward with my Asbestos Suit on hi .. hi .. In the
>>QST
Article linked below,
> modeled on a 66 foot dipole. The SWR and
Loss
>>Figures comparing Ladder Line (
> Windowed Line ) and Coax is
Drastically
>>Different. I know that the Antennas
> are different Beasts in
many ways.
>>And also that the SWR Figures should be
> lower on an OCF
Antenna. We are
>>also very aware that Ladder Line can't be
> used on an OCF
Antenna
>>because it is an Unbalanced Antenna. But .... if you
> are going to
need
>>a Tuner anyway to cover the Full Bands? Why do folks even
> bother
with
>>OCF Antennas? Just take a quick look at the Gain an 130 foot
> dipole
has
>>on 20 Meters using Ladder Line. Sure there are lots of Major and
>
Minor
>>Lobes, but the gain in the Major Lobes is Outstanding. Plus you can
run
>
>>QRO without having enough RF in the Shack to cause major problems.
Hey
>
>>guys, just asking here. There are many people here that are
Much
>>smarter
> than me. You never learn unless you ask the
questions....
>>Someday when we can
> afford a Faraday Cage.... I would like
to play with
>>OCF Antennas again .. hi
> ... hi ..
>>
>
>><a
>>href="<a href="http://www.arrl.org/files/file/Technology/tis/info/pdf/QST_Dec_1993_p70-71.pdf" target="_blank">http://www.arrl.org/files/file/Technology/tis/info/pdf/QST_Dec_1993_p70-71.pdf</a>"
>>target="_blank"><a href="http://www.arrl.org/files/file/Technology/tis/info/pdf/QST_Dec_1993_p70-71.pdf</a" target="_blank">http://www.arrl.org/files/file/Technology/tis/info/pdf/QST_Dec_1993_p70-71.pdf</a</a>>
>>
>
So ... we sit here with the 1% Silvadene Cream and Asbestos
>>Underwear on.
>
Please, be kind fellas This is an honest question because
>>I want to learn
>
something.
>> 73 from Wade/KJ4WS
>>
>>On Tue,
Sep
> 22, 2015 at 12:35 PM, Barry LaZar <<a
>
href="<a href="mailto:k3ndm at comcast.net">k3ndm at comcast.net</a?">mailto:k3ndm at comcast.net">k3ndm at comcast.net</a</a>>>
>>wrote:
>>>Fellas,
>>>
>
There is nothing magic about an OCFD. It just a variant of the
>>>Windom
that
> was invented, I believe, in the 1920's. It's nothing more
>>>than a
dipole fed
> off center so that when you use it on even multiples
>>>of a 1/2
wave the
> impedance is either 50 Ohms or in the region of what
>>>your tuner
can handle.
> If you can get it up 35 or more feet, it does
>>>make for a
pretty good all
> around antenna. I have a variant called a
>>>Carolina
Windom. It's up about 40
> feet and I've worked DXCC, mixed CW,
>>>and phone.
I've also gotten my WAS
> using it and 100 Watts.
>>>
>>> The issue of
SWR is a red herring. So long
> as you can tune the
>>>"system" such that your
rig can accept what the tuner
> gives it, that
>>>is really all that matters.
Yes, there are losses associated
> with high
>>>SWR, but if you use low loss
transmission line, the additional
> loss
>>>due to high SWR can be pretty
trivial, a 1db or so, depending on SWR
>
>>>and band being worked. On 10
meters my system losses total around 2 db
>
>>>which includes everything
behind the tuner.
>>>
>>> One thing that must
> be remembered is that the
transmission line
>>>from the antenna to the station
> can be an impedance
transformer if the
>>>SWR is greater than 1:1. What this
> means is that what
you measure at
>>>the station may not be reflective of what
> the antenna is
reflecting.
>>>So, some of the comments about this antenna works
> well over
all but
>>>this band or another may not be accurate unless the
> effects of
the
>>>length of the transmission line is included.
>>>
>>>
>>>
> Bottom
line from here is put up 66' or 132' of wire. Feed it ~ 1/3
>>>of the
> way
from an end. Use a 4:1 current balun if you don't want the
>>>feed line to
>
radiate or voltage balun if you do. And, if you force the
>>>feed line to
>
radiate, put a good RF choke about 15 or so feet down
>>>from the antenna
feed
> point point, load it up, and start working the
>>>world. Just remember
to use a
> good low loss coax like Belden 9913 or
>>>Times Wire
>
LMR-400.
>>>
>>>
>>>73,
>>>Barry
>>>K3NDM
>>>_______________________________________________
>>>TenTec
>
mailing
> list
>>><a
href="<a href="mailto:TenTec at contesting.com">TenTec at contesting.com</a?">mailto:TenTec at contesting.com">TenTec at contesting.com</a</a>>
>>><a
href="<a href="http://lists.contesting.com/mailman/listinfo/tentec" target="_blank">http://lists.contesting.com/mailman/listinfo/tentec</a>"
>>>target="_blank"><a href="http://lists.contesting.com/mailman/listinfo/tentec</a" target="_blank">http://lists.contesting.com/mailman/listinfo/tentec</a</a>>
>>
>>
>>
>>--
>>Living
>
one day at a time with Jesus as my Savior. But, still having
>
>>Fun.
>
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