Cecil, was it you that mention a "windom balun?"
 

lu6etj wrote in
:

....
For monoband applications we can get more Z from a coaxial choke
making the winding for autorresonance. K1TTT have a good data table.

Time ago I want test differents antenna to lift with a kite and I
found =
http://www.io.com/~n5fc/rfd.htm, the idea seems to me interesting
enough to make some test that are descibed here =

http://www.solred.com.ar/lu6etj/tecn...ga_revisada-en
.htm

from here I think of another use of de "coaxial trap" to get more Z
from coaxial winding specially in monoband antennas, I named de
critter "The Trap balun" =

http://www.solred.com.ar/lu6etj/tecn...a_balun-en.htm

4NEC2 simulations and real field test show me both approachs works
fine :)

How did you arrive at the value of Q (=100) used in the modelling. Was it
measured, or guessed?

Based on some experimental work, I expect that the effective RF
resistance of a closed space solenoidal coil of braided coax is much
higher than the same straight length a copper cylinder.

BTW, if you want to make a more compact self resonant trap on the lower
HF bands, wind the coil in two layers. The article at
http://vk1od.net/antenna/7MDipole/7MDipole.htm shows a pic of a two layer
7MHz self resonant balun made with IIRC about 6 turns per layer of RG6.

Owen

Cecil, was it you that mention a "windom balun?"
 

On Sep 14, 3:02*pm, lu6etj wrote:
For monoband applications we can get more Z from a coaxial choke
making the winding for autorresonance. K1TTT have a good data table.

Good idea. Choose your favorite band for your Carolina Windom and wind
an "ugly balun" choke just below the isolator. An "ugly balun" choke
is capable of forcing a common-mode standing-wave current node
(minimum) on the outside of a coax braid just like a trap is capable
of such on a trapped dipole.
--
73, Cecil, w5dxp.com

Cecil, was it you that mention a "windom balun?"
 

On 9/14/2010 3:37 PM, Cecil Moore wrote:
On Sep 14, 3:02 pm, wrote:
For monoband applications we can get more Z from a coaxial choke
making the winding for autorresonance. K1TTT have a good data table.

Good idea. Choose your favorite band for your Carolina Windom and wind
an "ugly balun" choke just below the isolator. An "ugly balun" choke
is capable of forcing a common-mode standing-wave current node
(minimum) on the outside of a coax braid just like a trap is capable
of such on a trapped dipole.
--
73, Cecil, w5dxp.com

OK, I'll ask, "I am correct in thinking that most are using a 'voltage
balun' (ruthroff 1:4) as the 'Low Loss Matching Transformer' and a
'current balun' (guanella 1:1) as the 'Special-High Isolation Line
Isolator?'"

I mean, logic dictates this to be the best combination ... however, one
is best to ask ...

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

"John Smith" wrote in message
...
OK, I'll ask, "I am correct in thinking that most are using a 'voltage
balun' (ruthroff 1:4) as the 'Low Loss Matching Transformer' and a
'current balun' (guanella 1:1) as the 'Special-High Isolation Line
Isolator?'"

I mean, logic dictates this to be the best combination ... however, one is
best to ask ...

Regards,
JS


That is what I am using on a home built version. Using a 4:1 voltage balun
at the feedpoint and the ferrite bead type about 20 feet down from the
feedpoint.

The ferrite choke is doing something as it gets warm while running around
about 1 KW to the antenna. Doesn't heat up when going into a dummy load.

My 'Windom' usually works beter than an 80 meter dipole on 80 meters plus
gives me the option to operate several other bands.

Cecil, was it you that mention a "windom balun?"
 

On 9/14/2010 4:11 PM, Ralph Mowery wrote:

...
That is what I am using on a home built version. Using a 4:1 voltage balun
at the feedpoint and the ferrite bead type about 20 feet down from the
feedpoint.

The ferrite choke is doing something as it gets warm while running around
about 1 KW to the antenna. Doesn't heat up when going into a dummy load.

My 'Windom' usually works beter than an 80 meter dipole on 80 meters plus
gives me the option to operate several other bands.



Sounds like you must be using A LOT of beads for 80m. Why not a couple
#43 toroids, stacked? Or, a t300-X or t400-X?

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

On Tue, 14 Sep 2010 19:11:43 -0400, "Ralph Mowery"
wrote:

That is what I am using on a home built version. Using a 4:1 voltage balun
at the feedpoint

This is like using a lighter to find a gas leak in the basement.

and the ferrite bead type about 20 feet down from the
feedpoint.

The ferrite choke is doing something as it gets warm while running around
about 1 KW to the antenna. Doesn't heat up when going into a dummy load.

Hi Ralph,

Through the 4:1? Probably not, or you would have said so (and
unlikely you have gone to the trouble to build a 4:1 dummy load).

As the dummy load is most likely enclosed and shielded, then that
suppresses common mode currents due to your test transmission.

And, yes, when your ferrite choke (AKA 1:1 BalUn) heats up that is due
to common mode currents that were not snubbed by the voltage balun (by
design - so why choose it?).

Add a second ferrite choke (AKA 1:1 BalUn) at the feedpoint -before
feeding the voltage balun.

My 'Windom' usually works beter than an 80 meter dipole on 80 meters plus
gives me the option to operate several other bands.

Better in what sense?

73's
Richard Clark, KB7QHC

Cecil, was it you that mention a "windom balun?"
 

"Ralph Mowery" wrote in
m:

....
That is what I am using on a home built version. Using a 4:1 voltage
balun at the feedpoint and the ferrite bead type about 20 feet down
from the feedpoint.

The ferrite choke is doing something as it gets warm while running
around about 1 KW to the antenna. Doesn't heat up when going into a
dummy load.

I am not surprised at your results with a dummy load. If it is a well
screened unbalanced dummy load, you should expect zero dissipation in the
balun cores.

The fact the balun cores are heating in the antenna scenario indicates
there is some common mode current. You probably have no idea of the
current.

Something to keep in mind is that the average power of uncomressed voice
SSB is about 3% of PEP, so if your 1kW was uncompressed voice SSB, the
average transmitter power might be more like 30W, or half that in a 50:50
over scenario over the long term.

Another thing is the ferrite toroids heat and cool very slowly, so the
operating temperature might still be rising half an hour after the
transmitter is applied (so long as you haven't exceeded their Curie
temperature).

It would not surprise me if the common mode choke consumes a significant
portion of transmitter power on some bands, the portion will depend a lot
on your own scenario.

Owen

Cecil, was it you that mention a "windom balun?"
 

"Richard Clark" wrote in message
...
On Tue, 14 Sep 2010 19:11:43 -0400, "Ralph Mowery"
wrote:

That is what I am using on a home built version. Using a 4:1 voltage
balun
at the feedpoint

This is like using a lighter to find a gas leak in the basement.

and the ferrite bead type about 20 feet down from the
feedpoint.

The ferrite choke is doing something as it gets warm while running around
about 1 KW to the antenna. Doesn't heat up when going into a dummy load.

Hi Ralph,

Through the 4:1? Probably not, or you would have said so (and
unlikely you have gone to the trouble to build a 4:1 dummy load).

As the dummy load is most likely enclosed and shielded, then that
suppresses common mode currents due to your test transmission.

And, yes, when your ferrite choke (AKA 1:1 BalUn) heats up that is due
to common mode currents that were not snubbed by the voltage balun (by
design - so why choose it?).

Add a second ferrite choke (AKA 1:1 BalUn) at the feedpoint -before
feeding the voltage balun.

My 'Windom' usually works beter than an 80 meter dipole on 80 meters plus
gives me the option to operate several other bands.

Better in what sense?

73's
Richard Clark, KB7QHC

I tested the bead choke just by going from the amplifier to the dummy load.
I did not have the 4:1 balun in the line with the dummy load. The dummy
load was 50 ohms. I just ran this test to make sure the beads were heating
up and not the coax. It is a comercial bead choke and the coax was about
the size of rg-58. Suspose to be some kind of higher power rated coax good
for over 1 KW. I just wanted to make sure it was power on the outside of
the coax and not inside the coax. If inside the coax, then it would have
heated up while going into the dummy load as has been mentioned by this
thread.

The 80 meter dipole and the 'Windom' are at right angles to each other
suported on the ends at 50 to 60 feet. In almost all cases the signals are
usually much beter on the Windom. It seems the only time the dipole is
beter is when the stations are almost off the end of the Windom. Stations
around 45 deg to both antennas still give the windom a beter signal.

Cecil, was it you that mention a "windom balun?"
 

"Owen Duffy" wrote in message
...
"Ralph Mowery" wrote in
m:
..

Something to keep in mind is that the average power of uncomressed voice
SSB is about 3% of PEP, so if your 1kW was uncompressed voice SSB, the
average transmitter power might be more like 30W, or half that in a 50:50
over scenario over the long term.

Another thing is the ferrite toroids heat and cool very slowly, so the
operating temperature might still be rising half an hour after the
transmitter is applied (so long as you haven't exceeded their Curie
temperature).

It would not surprise me if the common mode choke consumes a significant
portion of transmitter power on some bands, the portion will depend a lot
on your own scenario.

Owen

I was running the amp around 1 KW with a carrier so the power was a constant
KW.
I only felt the choke while testing on 80 meters. It got warm, but not hot
after about 5 minuits of applied power while hooked to the antenna. Never
got even warm just going into the dummy load.

While I don't know what the choke actually does to the outgoing signal, my
reasoning was to try and keep the unradiated power from comming back in the
the shack and causing problems.

Cecil, was it you that mention a "windom balun?"
 

On 9/14/2010 4:32 PM, Richard Clark wrote:

...
Add a second ferrite choke (AKA 1:1 BalUn) at the feedpoint -before
feeding the voltage balun.


Yeah, screw up the windom pattern and see how you like it then! Why
heat the 1:1 so far away, heat it at the antenna, 30ft up, then you
won't be tempted to check the temp! ROFLOL

...
73's
Richard Clark, KB7QHC

Cecil, was it you that mention a "windom balun?"
 

On 9/14/2010 5:09 PM, Owen Duffy wrote:

...
It would not surprise me if the common mode choke consumes a significant
portion of transmitter power on some bands, the portion will depend a lot
on your own scenario.

Owen

Yep, why I don't like windoms ... unless he has discovered a zero point
energy source, his RF IS heating those beads ...

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

On Sep 14, 5:51*pm, John Smith wrote:
OK, I'll ask, "I am correct in thinking that most are using a 'voltage
balun' (ruthroff 1:4) as the 'Low Loss Matching Transformer' and a
'current balun' (guanella 1:1) as the 'Special-High Isolation Line
Isolator?'"

That's the theory behind the Carolina Windom. Whether it actually
performs up to expectations is questionable. The marketing hype
acknowledges that the 4:1 voltage balun will cause common-mode current
on the coax which is expected for off-center-fed dipoles. They seem to
assume that the "Isolator" located 20 feet from the dipole feedpoint
is an ideal device with an infinite choking impedance. If it were
that, the antenna would work exactly as advertised. Unfortunately,
there's no such thing as an ideal isolator so we are zeroing in on
what is possible in reality and what must remain as marketing hype.
From my modeling, it appears that the isolator works well for any
frequency where the length of the coax from the feedpoint to the
isolator is approximately an odd multiple of 1/4WL. That occurs on 20m
and 10m. Unfortunately, my modeling indicates that RF-in-the-shack may
be a problem on 40m and I would be tempted to add an ugly balun.
--
73, Cecil, w5dxp.com

Cecil, was it you that mention a "windom balun?"
 

On 14 sep, 17:34, Owen Duffy wrote:
lu6etj wrote :

...





For monoband applications we can get more Z from a coaxial choke
making the winding for autorresonance. K1TTT have a good data table.

Time ago I want test differents antenna to lift with a kite and I
found =
http://www.io.com/~n5fc/rfd.htm, the idea seems to me interesting
enough to make some test that are descibed here =

http://www.solred.com.ar/lu6etj/tecn...ga_revisada-en
.htm

from here I think of another use of de "coaxial trap" to get more Z
from coaxial winding specially in monoband antennas, I named de
critter "The Trap balun" *=

http://www.solred.com.ar/lu6etj/tecn...a_balun-en.htm

4NEC2 simulations and real field test show me both approachs works
fine :)

How did you arrive at the value of Q (=100) used in the modelling. Was it
measured, or guessed?

Based on some experimental work, I expect that the effective RF
resistance of a closed space solenoidal coil of braided coax is much
higher than the same straight length a copper cylinder.

BTW, if you want to make a more compact self resonant trap on the lower
HF bands, wind the coil in two layers. The article athttp://vk1od.net/antenna/7MDipole/7MDipole.htmshows a pic of a two layer
7MHz self resonant balun made with IIRC about 6 turns per layer of RG6.

Owen- Ocultar texto de la cita -

- Mostrar texto de la cita -

I do not remember Owen, I believe Q 100 was a number for the text
example, calculated Q on 7 MHz for ideal coil was about 400 and
measured real coaxial made coil with a GR-1606 A near 200. at that
time I did not think to use RG6, It is more light than RG58, isn't it?
Seven turns of RG 58 on 63 mm diameter with parallel condenser it was
very light, enough for the purpose, Rokkaku lifted 40 m "syringe"
antenna flied very well.

R, to two layers choke. Well... frankly to me common mode radiation it
is not something I lose sleep, I have not troubles in my shack and I
was not very lucky in all attempts to reduce nasty modern suburban
noise with baluns + chokes + grounded points, so many noisy companies
and neighbors cables around :( antenna height showed much better
results.

73

Miguel LU6ETJ

Cecil, was it you that mention a "windom balun?"
 

On Tue, 14 Sep 2010 21:18:00 -0400, "Ralph Mowery"
wrote:

It got warm, but not hot
after about 5 minuits of applied power while hooked to the antenna.

Hi Ralph,

Then the loss is trivial. On 80M the Z should be sufficiently high
enough to prevent a large current to develop a node at that point on
the line - it remains to be seen if you need another one further down
to suppress induced current that would then slide into your shack (you
would be complaining of it by now, however).

73's
Richard Clark, KB7QHC

Cecil, was it you that mention a "windom balun?"
 

On 9/14/2010 5:09 PM, Owen Duffy wrote:
"Ralph wrote in
m:

...
That is what I am using on a home built version. Using a 4:1 voltage
balun at the feedpoint and the ferrite bead type about 20 feet down
from the feedpoint.

The ferrite choke is doing something as it gets warm while running
around about 1 KW to the antenna. Doesn't heat up when going into a
dummy load.

I am not surprised at your results with a dummy load. If it is a well
screened unbalanced dummy load, you should expect zero dissipation in the
balun cores.

The fact the balun cores are heating in the antenna scenario indicates
there is some common mode current. You probably have no idea of the
current.

Something to keep in mind is that the average power of uncomressed voice
SSB is about 3% of PEP, so if your 1kW was uncompressed voice SSB, the
average transmitter power might be more like 30W, or half that in a 50:50
over scenario over the long term.

Another thing is the ferrite toroids heat and cool very slowly, so the
operating temperature might still be rising half an hour after the
transmitter is applied (so long as you haven't exceeded their Curie
temperature).

It would not surprise me if the common mode choke consumes a significant
portion of transmitter power on some bands, the portion will depend a lot
on your own scenario.

Owen

Even worse than that! A lot will only consider the loss in the
transmitted signal of such an antenna, perhaps even call it "trivial."
However, the received signal will suffer from exactly the same losses
.... while even losing 500 watts of a 1KW signal can be considered
"trivial", losing 50% of ones received signal is NOT!

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

Even worse than that! A lot will only consider the loss in the
transmitted signal of such an antenna, perhaps even call it "trivial."
However, the received signal will suffer from exactly the same losses
... while even losing 500 watts of a 1KW signal can be considered
"trivial", losing 50% of ones received signal is NOT!

Regards,
JS


3dB is still only 3dB regardless of where it happens in the link budget!!

Jeff

Cecil, was it you that mention a "windom balun?"
 

On Sep 15, 6:18*am, John Smith wrote:
... while even losing 500 watts of a 1KW signal can be considered
"trivial", losing 50% of ones received signal is NOT!

That depends on the signal to noise ratio. If the signal to noise
ratio remains the same while 50% of one's signal is lost, the dynamic
range of a low-noise HF receiver usually makes up for it. Witness the
Beverage antenna where 99% receive power loss is tolerated: (from
Wikipedia)

"While Beverage antennas have excellent directivity, because they are
close to lossy earth they do not produce absolute gain (typically -20
to -10 dBi). This is rarely a problem, because the antenna is used at
frequencies where there are high levels of atmospheric radio noise."
--
73, Cecil, w5dxp.com

Cecil, was it you that mention a "windom balun?"
 

On 9/15/2010 4:51 AM, Cecil Moore wrote:

...
That depends on the signal to noise ratio. If the signal to noise
ratio remains the same while 50% of one's signal is lost, the dynamic
range of a low-noise HF receiver usually makes up for it. Witness the
Beverage antenna where 99% receive power loss is tolerated: (from
Wikipedia)

"While Beverage antennas have excellent directivity, because they are
close to lossy earth they do not produce absolute gain (typically -20
to -10 dBi). This is rarely a problem, because the antenna is used at
frequencies where there are high levels of atmospheric radio noise."
--
73, Cecil, w5dxp.com

Cecil,

If a mere loss of 10% drops you too close to the sensitivity threshold
of your receiver, your ability to pull out a weak signal just suffered
the kiss of death ... 100w on a kw might not even be noticed on the
other end ...

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

In message , John Smith
writes
On 9/15/2010 4:51 AM, Cecil Moore wrote:

...
That depends on the signal to noise ratio. If the signal to noise
ratio remains the same while 50% of one's signal is lost, the dynamic
range of a low-noise HF receiver usually makes up for it. Witness the
Beverage antenna where 99% receive power loss is tolerated: (from
Wikipedia)

"While Beverage antennas have excellent directivity, because they are
close to lossy earth they do not produce absolute gain (typically -20
to -10 dBi). This is rarely a problem, because the antenna is used at
frequencies where there are high levels of atmospheric radio noise."
--
73, Cecil, w5dxp.com

Cecil,

If a mere loss of 10% drops you too close to the sensitivity threshold
of your receiver, your ability to pull out a weak signal just suffered
the kiss of death ... 100w on a kw might not even be noticed on the
other end ...

As a Windom is only likely to be used on the HF bands (and probably
mainly on the lower HF bands), I would have thought that a few dB of
attenuation would have negligible effect on the SNR.
--
Ian

Cecil, was it you that mention a "windom balun?"
 

On 9/15/2010 5:30 AM, Ian Jackson wrote:

...
As a Windom is only likely to be used on the HF bands (and probably
mainly on the lower HF bands), I would have thought that a few dB of
attenuation would have negligible effect on the SNR.

There are "Windom only baluns?" I thought that was something they just
told the newbies!

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

Ian Jackson wrote in
:

....
As a Windom is only likely to be used on the HF bands (and probably
mainly on the lower HF bands), I would have thought that a few dB of
attenuation would have negligible effect on the SNR.

Ian,

Ah, the statements in support of mediocrity about.

Yes, there is an element of truth in what you say... but looking at it a
little further....

On any bands where the external noise is very much greater than the
receiver internal noise, small extra antenna loss will not markedly
degrade S/N ratio on receive.

One of the issues when the feedline participates as an antenna condcutor
is that its proximity to noise sources (eg the power wiring of a
building) may lead to higher receive noise without increasing signal
strength, so feedline participation can degrade S/N by that mechanism.
You won't see that called out in Carolina Windom adds which claim
feedline participation as an advantage.

On the tx side, loss in the antenna system reduces EIRP, and so directly
degrades S/N at the other end. So, even on those bands where external
noise is very much greater than receiver internal noise, pay attention to
antenna efficiency to achieve optimal radiated power to be heard at best
S/N.

One of the bogus arguments often trotted out is that efficiency is less
important with QRP since there is less power to damage a lossy component.
Another view is that if you start out with a transmitter that is 10dB or
so behind the average transmitter power being used, then why exacerbate
the situation when an even lossier antenna system.

For a once technically based hobby, we do think up some phony rationale.

It is a personal judgement about whether 3dB (mentioned by one poster) or
any other number is acceptable in the compromise that is made with all
practical antenna systems.

Owen

Cecil, was it you that mention a "windom balun?"
 

On Sep 15, 7:24*am, John Smith wrote:
If a mere loss of 10% drops you too close to the sensitivity threshold
of your receiver, your ability to pull out a weak signal just suffered
the kiss of death ...

John, when are you going to give up on this crystal receiver set of
yours and get a decent receiver?

http://crystalradiosupply.com/conten...%20edition.jpg

For me, receiving at anywhere near the 0.13 uV receiver threshold is
just too much work. I think they should outlaw any received signal
below 1 uV.
--
73, Cecil, w5dxp.com

Cecil, was it you that mention a "windom balun?"
 

On 9/15/2010 12:55 PM, Cecil Moore wrote:
On Sep 15, 7:24 am, John wrote:
If a mere loss of 10% drops you too close to the sensitivity threshold
of your receiver, your ability to pull out a weak signal just suffered
the kiss of death ...

John, when are you going to give up on this crystal receiver set of
yours and get a decent receiver?

http://crystalradiosupply.com/conten...%20edition.jpg

For me, receiving at anywhere near the 0.13 uV receiver threshold is
just too much work. I think they should outlaw any received signal
below 1 uV.
--
73, Cecil, w5dxp.com

Darn Cecil, quite peeking!

From the crystal silicon in the semiconductors, to the crystaline
structure of the metals ... I just can't get away from the darn crystal
radios! And, alas, I am afraid, these days, the sensitivity of my
receivers front end far exceeds my hearing ... I was just bragging. You
caught me!

But, I can still remember those days when I could pull out a gnats
whisper above ... but then, as I remember, there was far less noise then.

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

On 9/15/2010 12:55 PM, Cecil Moore wrote:

...
--
73, Cecil, w5dxp.com

quite = quit ... another bad habit in the making.

Regards,
JS

Cecil, was it you that mention a "windom balun?"
 

In message , Owen Duffy
writes
Ian Jackson wrote in
:

...
As a Windom is only likely to be used on the HF bands (and probably
mainly on the lower HF bands), I would have thought that a few dB of
attenuation would have negligible effect on the SNR.

Ian,

Ah, the statements in support of mediocrity about.

Yes, there is an element of truth in what you say... but looking at it a
little further....

On any bands where the external noise is very much greater than the
receiver internal noise, small extra antenna loss will not markedly
degrade S/N ratio on receive.

One of the issues when the feedline participates as an antenna condcutor
is that its proximity to noise sources (eg the power wiring of a
building) may lead to higher receive noise without increasing signal
strength, so feedline participation can degrade S/N by that mechanism.
You won't see that called out in Carolina Windom adds which claim
feedline participation as an advantage.

On the tx side, loss in the antenna system reduces EIRP, and so directly
degrades S/N at the other end. So, even on those bands where external
noise is very much greater than receiver internal noise, pay attention to
antenna efficiency to achieve optimal radiated power to be heard at best
S/N.

One of the bogus arguments often trotted out is that efficiency is less
important with QRP since there is less power to damage a lossy component.
Another view is that if you start out with a transmitter that is 10dB or
so behind the average transmitter power being used, then why exacerbate
the situation when an even lossier antenna system.

For a once technically based hobby, we do think up some phony rationale.

It is a personal judgement about whether 3dB (mentioned by one poster) or
any other number is acceptable in the compromise that is made with all
practical antenna systems.

Owen

I can't disagree with anything you say. I'm no advocate of the Carolina
Windom, and have no plans to use one.

From the point of view of receiving (and causing) interference, allowing
the feeder to contribute to the antenna radiation is certainly something
which one should be circumspect about. The various comments and
explanations (here and elsewhere) indicate that can be a bit of an art
to ensure that the radiating common-mode feeder currents are restricted
to where they ought to be.

And while, on receive, a bit of 'unnecessary' loss is usually of little
consequence on the lower frequencies, losing transmitter power is not
something you want to do, on any frequency (if you can avoid it). But,
as always, it is often a balance between performance, convenience, and
what you are really trying to achieve with your amateur radio station.
--
Ian