Confused over coax and windom - newbie
 

On older models of Carolina Windoms, the line isolator was simply a
piece of RG-8x coax, with one end wrapped around a ferrite rod (and
housed inside a piece of PVC).

If you do away with the line isolator and hook your coax directly to
the balun (I think they use a 4:1), you should receive signals just
like any other dipole. If you do not, I'd say the balun is bad. If
you do, then the line isolator is bad.

If this is a new antenna from Radio Works, they will probably make it
good. If it's a used antenna you can try to fix it yourself. Take a
hacksaw to the PVC and get it apart. You may find a broken or
unsoldered wire. You will need some new PVC caps, pipe, glue and such
to make new housings, but that shouldn't be difficult.

Kingfish


On Sun, 27 May 2007 13:40:06 +0100, "Andre C" wrote:

I am very new at ham radio and find myself confused over an installation of a Carolina windom 80 special.

I attatched a 20m run of coax to the line isolator. When I switch on the rig I get nothing, even on strong BC stations.
I assumed it was a coax prob and striped my plugs down etc. I then
discovered that if the shielding was not touching the socket on the
rig I got a very good signal. So I assumed there was a short in the
coax. I checked the plugs and they seem fine but I note that even when
I have just the co-ax plugged in (ie no windom) I get a good signal
unless the shielding is connected. (I guess that would make sense
though I thought the shielding stopped the centre core picking up a
signal.

So where is my problem? Is it the antenna? Is it the ine isolator. (There is no indicator which way round it goes so
I presume it is universal.) I have no tset equipment as yet so an
easy solution would be valuable.

Confused over coax and windom - newbie
 

wrote in message
...
On older models of Carolina Windoms, the line isolator was simply a
piece of RG-8x coax, with one end wrapped around a ferrite rod (and
housed inside a piece of PVC).

If you do away with the line isolator and hook your coax directly to
the balun (I think they use a 4:1), you should receive signals just
like any other dipole. If you do not, I'd say the balun is bad. If
you do, then the line isolator is bad.

If this is a new antenna from Radio Works, they will probably make it
good. If it's a used antenna you can try to fix it yourself. Take a
hacksaw to the PVC and get it apart. You may find a broken or
unsoldered wire. You will need some new PVC caps, pipe, glue and such
to make new housings, but that shouldn't be difficult.

Kingfish


On Sun, 27 May 2007 13:40:06 +0100, "Andre C" wrote:

I am very new at ham radio and find myself confused over an installation
of a Carolina windom 80 special.

I attatched a 20m run of coax to the line isolator. When I switch on the
rig I get nothing, even on strong BC stations.
I assumed it was a coax prob and striped my plugs down etc. I then
discovered that if the shielding was not touching the socket on the
rig I got a very good signal. So I assumed there was a short in the
coax. I checked the plugs and they seem fine but I note that even when
I have just the co-ax plugged in (ie no windom) I get a good signal
unless the shielding is connected. (I guess that would make sense
though I thought the shielding stopped the centre core picking up a
signal.

So where is my problem? Is it the antenna? Is it the ine isolator. (There
is no indicator which way round it goes so
I presume it is universal.) I have no tset equipment as yet so an
easy solution would be valuable.


I never could really figure out a windom except that the origional was just
a flat top that was tuner friendly on all the ham bands.



Jimmie

Confused over coax and windom - newbie
 

In article ,
Jimmie D wrote:

I never could really figure out a windom except that the origional was just
a flat top that was tuner friendly on all the ham bands.

As I understand it, the original Windom is essentially a vertical
radiator, with an asymmetrical capacitive "top-hat" (which will
probably radiate at least a bit because of its asymmetry), bottom-fed,
working against the station's RF ground. It's simply a form of
Marconi antenna.

The "Carolina Windom" is a very different sort of antenna... AIUI it's
a off-center-fed doublet which (by design) also has some
vertically-polarized radiation from the upper portion of its coaxial
feedline.

Although the two have a superficial resemblance, I believe that the
two types have very different distributions of RF current, feedpoint
impedances, and (probably) radiation patterns and polarization
distributions.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Confused over coax and windom - newbie
 

Dave Platt wrote:
In article ,
Jimmie D wrote:

I never could really figure out a windom except that the origional was just
a flat top that was tuner friendly on all the ham bands.

As I understand it, the original Windom is essentially a vertical
radiator, with an asymmetrical capacitive "top-hat" (which will
probably radiate at least a bit because of its asymmetry), bottom-fed,
working against the station's RF ground. It's simply a form of
Marconi antenna.

The "Carolina Windom" is a very different sort of antenna... AIUI it's
a off-center-fed doublet which (by design) also has some
vertically-polarized radiation from the upper portion of its coaxial
feedline.

Although the two have a superficial resemblance, I believe that the
two types have very different distributions of RF current, feedpoint
impedances, and (probably) radiation patterns and polarization
distributions.

Yes, my 1957 ARRL Handbook makes the distinction between
the single-wire feed of the Windom vs the transmission
line feed of an Off-Center Fed (OCF) dipole. The currents
at the vertical wire to horizontal wire junction in a Windom
are flowing in opposite directions in the horizontal wire.
The currents at the Carolina Windom's coax to horizontal
wire interface are flowing in the same direction, more like
an OCF dipole than a Windom. It was probably a marketing
ploy to call it a "Windom" when it was not. "Carolina OCF"
doesn't have much of a ring to it.
--
73, Cecil http://www.w5dxp.com

Confused over coax and windom - newbie
 

"Dave Platt" wrote in message
...
In article ,
Jimmie D wrote:

I never could really figure out a windom except that the origional was
just
a flat top that was tuner friendly on all the ham bands.

As I understand it, the original Windom is essentially a vertical
radiator, with an asymmetrical capacitive "top-hat" (which will
probably radiate at least a bit because of its asymmetry), bottom-fed,
working against the station's RF ground. It's simply a form of
Marconi antenna.

The "Carolina Windom" is a very different sort of antenna... AIUI it's
a off-center-fed doublet which (by design) also has some
vertically-polarized radiation from the upper portion of its coaxial
feedline.

Although the two have a superficial resemblance, I believe that the
two types have very different distributions of RF current, feedpoint
impedances, and (probably) radiation patterns and polarization
distributions.

I tried to do an analysis on the antenna several years ago having an LCR
bridge at my disposal and basically I found an antenna built for the ham
bands to be non resonant on any of the ham bands, Had an input impdance of a
few hundred ohms on all the hf bands and the reactive portion of the
impedance could be handled by most tuners. The relatively high feedpoint
impedance probably made it radiate reasonably efficently with even a
mediocre ground system.

I think the top hat may have been eithr capacitive or inductive depending on
which band you were on and/or which leg of the top hat you were talking
about. As I remember an antenna 10 M tall by 10M wide would tune up easily
on all the bands 10 thru 80 but I am curious to what the radition patterns
would look like. I would think they may not be so good on some of the bands.

Jimmie