Re: Topband: Beverage over Inverted L

[Mike Waters]

Back-to-back diodes and series lamps help, too.

73, Mike
www.w0btu.com
_
Topband Reflector

Re: Topband: Beverage over Inverted L

[Jose Orellana]

http://www.ok1rr.com/index.php/technical-topics/39-yet-another-front-end-saver

> Date: Sun, 11 Aug 2013 17:15:47 -0400
> From: a...@aol.com
> To: topband@contesting.com
> Subject: Topband: Beverage over Inverted L
> 
> All,
> 
> I have 160m inverted L and the only way I can get a 500' plus beverage 
> out to the NE/SW is over top of the radials that are on the ground.  In 
> my research it looks like I'm inviting RF to be induced into the L's 
> feedline and back into my ICOM 756 PROIII.Not good.  Does anyone 
> know of a TR switch or some black box to shield the PRO III?
> 
> Randy,  AA8R
> _
> Topband Reflector
  
_
Topband Reflector

Re: Topband: Lightning QRN season?

[Mike Waters]

Tonight was a perfect example of that. N2RK called CQ DX for the longest
time, and he had a great S/N ratio from multiple stations on the RBN,
including GW8IZR. I spotted him on the cluster, and so did HK1MW ("Good
copy northen Colombia"). He was two or three S-units above the lightning
QRN here, but perfectly Q5. *But no answers from anyone.*

Frankly, I think many hams are just too lazy (maybe disinclined is a better
word) to try and copy weak signals buried in the noise. To me, that's
what's the most fun about this hobby. That's why I loved working 144.2 MHz,
the challenge. And I managed to work 30 states there from a section of
Toledo, Ohio that had prolific power line noise.

All I can think of is, "what a bunch of wimps". Sorry if that offended
anyone, but what else can we say? :-)

73, Mike
www.w0btu.com

On Wed, Jul 24, 2013 at 11:44 AM, Guy Olinger K2AV wrote:

> The persistence of easily more than half a year of loud QRN in the
> evenings on 160, perhaps 3/4 of the year, has generated the *expectation*
> that no one is on.  The expectation of activity is what generates activity.
>  The band is clearly open to some degree at various times any night, even
> in July.  A lot of people will get on for the summer Stew Perry, and
> various summer contests will get contestants on 160 for multipliers.  There
> is an expectation of activity at certain times known to many contestants.
>  The summer 160 starved can get on 160 for the NCCC Thursday night tests,
> but will have to take the time to know when the participants come down to
> 160 for a few minutes of a very short contest.
>
> An unexpectedly quiet summer night on 160 with no expectation of activity,
> will be just that -- a quiet night.
>
_
Topband Reflector

Topband: Beverage over Inverted L

[AA8R]

All,

I have 160m inverted L and the only way I can get a 500' plus beverage 
out to the NE/SW is over top of the radials that are on the ground.  In 
my research it looks like I'm inviting RF to be induced into the L's 
feedline and back into my ICOM 756 PROIII.Not good.  Does anyone 
know of a TR switch or some black box to shield the PRO III?


Randy,  AA8R
_
Topband Reflector

Re: Topband: Vertical vs inverted L question/opinions

[Goldtr8 (KD8NNU)]

Thanks everyone for all the replies.

I guess that I will work on several things now for the next winter season.

First is the standby length of wire to use as an inverted L which I used as 
a fan vertical last winter.


Second I will also play with the coil loading on the 80m vertical and do 
some reverse beacon testing to see what happens with the belief that it will 
not be as good as the L


Third I will study my options with the trees to see if I can figure out an 
inverted T arraignment as this may be the best of all.   Now I have to study 
on how to calculate the length of such an antenna.


Also when the lawn mowing season is done I will add some more radial wires 
to the radial field.


Thanks for all the comments, now I have more options to play with and may I 
work you all on the air this year.



~73
Don
KD8NNU
-.- -.. ---.. -. -. ..-
-Original Message- 
From: Chortek, Robert L

Sent: Saturday, August 10, 2013 5:38 PM
To: Goldtr8 (KD8NNU)
Cc: topband
Subject: Re: Topband: Vertical vs inverted L question/opinions

Don,

Others are far more knowledgable than I, but top loading has less loss than 
base loading so the L should perform better, all else being equal.


That said, I have been using a 60' base loaded vertical with 8 elevated 
radials and have 136 countries from a 1/4 acre city lot in the black hole of 
California,  I suspect the total would be a lot better with an L!


Good luck,

Bob

AA6VB

Sent from my iPhone

On Aug 10, 2013, at 11:10 AM, "Goldtr8 (KD8NNU)"  
wrote:


I am requesting opinions on what would work best for 160m based on a 
bottom loaded vertical or inverted L.


I have in the past used and inverted L for 160m using a common feed with 
my 80m vertical.   The 80m vertical has parallel wires for 40m and 20m 
also and it works real well with 38 radials laid down in the grass.  I 
like to compare it to a fan dipole but only the vertical section is the 
multi wire part as the radials are buried.


Anyway I am starting to plan for the winter season and I am wondering if a 
loading coil on the bottom of the vertical would yield better results than 
the inverted L.   The L is limited to at best 50ft vertical section and 
the rest on trees.My thoughts are if I use the 80m vertical section I 
will have 68 ft of height which may be better than the L.The vertical 
is not structurally strong enough to add a wire or a cap hat to the top of 
it.


Clearly I have the ability to try both and play around but I have time to 
make alternate plans so I am fishing for opinions and or suggestions.



~73
Don
KD8NNU
-.- -.. ---.. -. -. ..-
_
Topband Reflector




_
Topband Reflector

Re: Topband: Vertical vs inverted L question/opinions

[Carl]

Seldom mentioned and worth repeating. The L has a bit of high angle 
radiation which can be useful at times. The T cancels it.


Carl
KM1H

- Original Message - 
From: "Mike Waters" 

To: "topband" 
Sent: Saturday, August 10, 2013 5:48 PM
Subject: Re: Topband: Vertical vs inverted L question/opinions



That's exactly what I was thinking. Top load it and forget about a loading
coil at the base.

73, Mike
www.w0btu.com

On Sat, Aug 10, 2013 at 4:38 PM, Chortek, Robert L <
robert.chor...@berliner.com> wrote:


 top loading has less loss than base loading ...


_
Topband Reflector


-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1432 / Virus Database: 3211/6066 - Release Date: 08/10/13



_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Mike Waters]

Maybe I'm too easily entertained, but I think it would be fun to try 1500W+
through it on 160 sometime. Years ago, I did that with RG-58C/U on 10
meters. Just because I could. :-)

Not that I plan on using CAT5 cable for anything except my LAN here, but it
might actually surprise us. I've ran over 1500w solid carrier through an F
junction on 160 --F-6, two F plugs, and a double-female connector-- until I
could smell the dummy load oil under the bench. I could not discern any
temperature rise in the connectors or cable whatsoever.


And FWIW, the RG58C/U (rated for 600w at 30 MHz) DID get warm indoors on
10m, yes. It actually became a lot more flexible.

73, Mike
www.w0btu.com

On Mon, Aug 12, 2013 at 12:33 PM, Jim Brown wrote:

>
> As to power handling and loss -- at these frequencies, its all copper
> loss, and CAT5 is pretty small cable. We don't care about modest losses in
> RX antennas, but it's a different story for TX.
>
_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[James Rodenkirch]

When asked, these days, how my day is going, Charlie, I respond with, "Going 
great 'cuz I am on the green side of the grass"!

> From: charlie-cunning...@nc.rr.com
> To: rodenkirch_...@msn.com; n...@comcast.net; j...@audiosystemsgroup.com; 
> topband@contesting.com
> Date: Mon, 12 Aug 2013 18:18:28 -0400
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> Well, we're mostly all " 'ol farts", Jim, but the alternative is GRIM!
> 
> 73,
> Charlie. K4OTV
> 
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James
> Rodenkirch
> Sent: Monday, August 12, 2013 6:08 PM
> To: JC N4IS; j...@audiosystemsgroup.com; topband@contesting.com
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> Well, I have the wiring scheme all written out and plan on labeling each
> connection and checking twice and three times b4 soldering up the connection
> boxes and then connecting to the loop itself.great dialogue, fellas.
> Thank you ALL so much!!!
>  
> Great learning experience, trust me -- especially for being an 'ol fart!
>  
> 72, Jim Rodenkirch K9JWV
>  
> 
> 
> 
> > From: n...@comcast.net
> > To: rodenkirch_...@msn.com; j...@audiosystemsgroup.com;
> topband@contesting.com
> > Date: Mon, 12 Aug 2013 17:10:18 -0400
> > Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> > 
> > Well, Jim, here is what N4IS stated (bolded words my emphasis) - 
> > > > looks like he found the twisted pair to reduce the noise
> > > Yes, but there's a bit more to it. Twisted pair, by its nature, 
> > > minimizes noise pickup.  That rejection is maximized if the 
> > > terminations at both ends of the line are balanced -- that is, each 
> > > side of the line has equal impedance to ground -- and if there is 
> > > minimal common mode coupling at each end
> > 
> > 
> > Hi guys
> > 
> > Jim is 100% right, balancing both ends is a MUST. But there is more. I
> would
> > like to share what happened few month ago with a WF project. Peter N8PR
> > built a beautiful WF with a polarization rotator. Peter can turn his WF
> > horizontal or vertical. Very nice project. We decided to check the phase
> > when the WF was about to go up. I measured the phase using a oscilloscope
> > driving the feed line input with 5W to measure the phase at the loops.
> First
> > at the 9:1 BALUN that feed the loops, the phase was correct and near 180
> > degree, but the amplitude was not the same between the two loops, let's
> say
> > 10% different from each other. Then when I measured the phase at the
> > resistors, the phase was very different between them, near 50 degree and
> the
> > amplitude way off, like 50% difference. It was hard to understand why such
> > difference between the two loops and even harder to understand the phase
> > difference between the transformer  and the resistor in the same loop.
> After
> > removing all BALUNS and measuring them at the bench with a VNA we found
> one
> > isolation BALUN inverted. Peter was feeding his WF with 75 ohm, and the
> > BALUN had 4 turns on the 50ohms side and 5 turns on 75 ohms, and it was
> > connected backward, 4 turns to the 75 ohms and 5 turns to the 50 ohm
> point,
> > where the two 100 ohms line are connected 180 degree. After connecting the
> > BALUN the way it should be, the phase measured at the transformer and the
> > resistor become equal in both loops, and the amplitude also was equal as
> > expected, the difference in phase or amplitude was not detectable anymore.
> > 
> > It was the first time I faced this situation. The FLAG antenna, or EWE,
> K9AY
> > , pennant and WF are actually a loaded loop. Adding one resistor inside
> the
> > loop the gain drops but you  get a cardioid pattern, good front back and
> > good RDF. The signal when reach the first vertical wire is reflected to
> the
> > second wire, and the signal when reach the second wire the signal is
> > reflected to the first wire. When the signal reach the resistor it is
> > dissipated, and when the second signal reach the transformer it goes to
> the
> > feed line. The combination of these two currents give us the cardioid
> > pattern. In the WF there is a combination of two cardioids to get side
> nulls
> > and higher RDF. All this work fine "IF" there is no mismatch when the
> signal
> > current reach the resistor and the BALUN, any mismatch impedance inside
> the
> > loop will change the phase, and as a result, a deterioration in
> directivity.
> > The value of the resistor should be very close to the impedance at the
> > transformer, Example, for a FLAG feed with100 ohm line and 9:1 BALUM
> giving
> > 900 ohms impedance,  the resistor should be near 900 ohms to avoid SWR
> > inside the loops. This is necessary to keep the right phase to form a
> > cardioid pattern. The FLAG is no resonant an can be used from 1Mhz to 10
> > MHz, BUT it is very sensitive to impedance mismatch.
> > 
> > Before correcting the 50/75 BALUN the SWR measured with a MFJ was near
>

Re: Topband: Zo of an individual CAT5 twisted pair

[William Schneider]

Sent via BlackBerry by AT&T

-Original Message-
From: "Bruce" 
Sender: "Topband" 
Date: Mon, 12 Aug 2013 13:42:17 
To: 
Subject: Topband: Zo of an individual CAT5 twisted pair




I am using a twisted  pair, with shield,  that is near  55 ohm impedance for
 my receiving delta loop. The cable is designed for audio,  but looks good 
up
 to 10 MHZ. The KB-5 antenna end transformer has an isolated output. At the
 shack end I wound a transformer with a balanced center tapped winding to an
 unbalanced winding for  my transceiver.  The center tap is for the shield.
 The center tap is floating at the antenna end. It is working well so far. 
See Pennant notes for more
 info.   www.qsl.net/k1fz/pennantnotes.html

73
Bruce-K1FZ



 - Original Message - 
> From: 
> To: 
> Sent: Monday, August 12, 2013 10:11 AM
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
>
>
>
> you fellers dont know what to use CAT5 for, out here in the west we use
> it to tie down our pickup loads.easy to tie, bends well and
> is almost indestructible.
>
> mike w7dra  still using an NC183 on topband

_
Topband Reflector
_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Charlie Cunningham]

Well, we're mostly all " 'ol farts", Jim, but the alternative is GRIM!

73,
Charlie. K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James
Rodenkirch
Sent: Monday, August 12, 2013 6:08 PM
To: JC N4IS; j...@audiosystemsgroup.com; topband@contesting.com
Subject: Re: Topband: Zo of an individual CAT5 twisted pair

Well, I have the wiring scheme all written out and plan on labeling each
connection and checking twice and three times b4 soldering up the connection
boxes and then connecting to the loop itself.great dialogue, fellas.
Thank you ALL so much!!!
 
Great learning experience, trust me -- especially for being an 'ol fart!
 
72, Jim Rodenkirch K9JWV
 



> From: n...@comcast.net
> To: rodenkirch_...@msn.com; j...@audiosystemsgroup.com;
topband@contesting.com
> Date: Mon, 12 Aug 2013 17:10:18 -0400
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> Well, Jim, here is what N4IS stated (bolded words my emphasis) - 
> > > looks like he found the twisted pair to reduce the noise
> > Yes, but there's a bit more to it. Twisted pair, by its nature, 
> > minimizes noise pickup.  That rejection is maximized if the 
> > terminations at both ends of the line are balanced -- that is, each 
> > side of the line has equal impedance to ground -- and if there is 
> > minimal common mode coupling at each end
> 
> 
> Hi guys
> 
> Jim is 100% right, balancing both ends is a MUST. But there is more. I
would
> like to share what happened few month ago with a WF project. Peter N8PR
> built a beautiful WF with a polarization rotator. Peter can turn his WF
> horizontal or vertical. Very nice project. We decided to check the phase
> when the WF was about to go up. I measured the phase using a oscilloscope
> driving the feed line input with 5W to measure the phase at the loops.
First
> at the 9:1 BALUN that feed the loops, the phase was correct and near 180
> degree, but the amplitude was not the same between the two loops, let's
say
> 10% different from each other. Then when I measured the phase at the
> resistors, the phase was very different between them, near 50 degree and
the
> amplitude way off, like 50% difference. It was hard to understand why such
> difference between the two loops and even harder to understand the phase
> difference between the transformer  and the resistor in the same loop.
After
> removing all BALUNS and measuring them at the bench with a VNA we found
one
> isolation BALUN inverted. Peter was feeding his WF with 75 ohm, and the
> BALUN had 4 turns on the 50ohms side and 5 turns on 75 ohms, and it was
> connected backward, 4 turns to the 75 ohms and 5 turns to the 50 ohm
point,
> where the two 100 ohms line are connected 180 degree. After connecting the
> BALUN the way it should be, the phase measured at the transformer and the
> resistor become equal in both loops, and the amplitude also was equal as
> expected, the difference in phase or amplitude was not detectable anymore.
> 
> It was the first time I faced this situation. The FLAG antenna, or EWE,
K9AY
> , pennant and WF are actually a loaded loop. Adding one resistor inside
the
> loop the gain drops but you  get a cardioid pattern, good front back and
> good RDF. The signal when reach the first vertical wire is reflected to
the
> second wire, and the signal when reach the second wire the signal is
> reflected to the first wire. When the signal reach the resistor it is
> dissipated, and when the second signal reach the transformer it goes to
the
> feed line. The combination of these two currents give us the cardioid
> pattern. In the WF there is a combination of two cardioids to get side
nulls
> and higher RDF. All this work fine "IF" there is no mismatch when the
signal
> current reach the resistor and the BALUN, any mismatch impedance inside
the
> loop will change the phase, and as a result, a deterioration in
directivity.
> The value of the resistor should be very close to the impedance at the
> transformer, Example, for a FLAG feed with100 ohm line and 9:1 BALUM
giving
> 900 ohms impedance,  the resistor should be near 900 ohms to avoid SWR
> inside the loops. This is necessary to keep the right phase to form a
> cardioid pattern. The FLAG is no resonant an can be used from 1Mhz to 10
> MHz, BUT it is very sensitive to impedance mismatch.
> 
> Before correcting the 50/75 BALUN the SWR measured with a MFJ was near
> 1;1,8. After correcting the BALUN it was 1:1,5. Measuring only the SWR
does
> not tell much about the antenna. The FLAG wants to work, like Luis once
> said. However if there is a mismatch anywhere the results won't be good.
It
> is complicated to measure impedance on 160m, near AM signals around.
> 
> The FLAG or dual FLAG like the WF require a perfect match to provide the
> expected performance, and any common mode current can compromise the RDF
and
> the overall performance. 
> 
> Do It right at the first time, don't change anything in the project! Use
> what 

Re: Topband: CAT5 twisted pair

[Charlie Cunningham]

J

 

From: James Rodenkirch [mailto:rodenkirch_...@msn.com] 
Sent: Monday, August 12, 2013 6:04 PM
To: Charlie Cunningham; j...@audiosystemsgroup.com; topband@contesting.com
Subject: RE: Topband: CAT5 twisted pair

 

OH...okee dokee on not needing the 2:1 xfmr 

 

> From: charlie-cunning...@nc.rr.com
> To: j...@audiosystemsgroup.com; topband@contesting.com
> Date: Mon, 12 Aug 2013 17:12:59 -0400
> Subject: Re: Topband: CAT5 twisted pair
> 
> Jim,
> 
> I completely agree with Jim Brown! I noted those 2:1 transformers the
other
> day and meant to send you a note to say that I wouldn't bother! That
> little bit of mismatch loss won't make any difference!
> 
> 73,
> Charlie, K4OTV
> 
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim
Brown
> Sent: Monday, August 12, 2013 5:03 PM
> To: topband@contesting.com
> Subject: Re: Topband: CAT5 twisted pair
> 
> On 8/12/2013 1:50 PM, James Rodenkirch wrote:
> > as well as a 2:1 transformer just prior to the input to the shack.
> 
> While there's nothing wrong with attempting to match the termination Z, 
> don't assume that it will do much. The input Z of the RX may not be 50 
> ohms (although the doc may say it is), a small mismatch won't contribute 
> enough loss to matter, and it does not affect noise rejection. What 
> matters is balance and twisting.
> 
> 73, Jim K9YC
> _
> Topband Reflector
> 
> _
> Topband Reflector

_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[James Rodenkirch]

Well, I have the wiring scheme all written out and plan on labeling each 
connection and checking twice and three times b4 soldering up the connection 
boxes and then connecting to the loop itself.great dialogue, fellas.  Thank 
you ALL so much!!!
 
Great learning experience, trust me -- especially for being an 'ol fart!
 
72, Jim Rodenkirch K9JWV
 



> From: n...@comcast.net
> To: rodenkirch_...@msn.com; j...@audiosystemsgroup.com; topband@contesting.com
> Date: Mon, 12 Aug 2013 17:10:18 -0400
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> Well, Jim, here is what N4IS stated (bolded words my emphasis) - 
> > > looks like he found the twisted pair to reduce the noise
> > Yes, but there's a bit more to it. Twisted pair, by its nature, 
> > minimizes noise pickup.  That rejection is maximized if the 
> > terminations at both ends of the line are balanced -- that is, each 
> > side of the line has equal impedance to ground -- and if there is 
> > minimal common mode coupling at each end
> 
> 
> Hi guys
> 
> Jim is 100% right, balancing both ends is a MUST. But there is more. I would
> like to share what happened few month ago with a WF project. Peter N8PR
> built a beautiful WF with a polarization rotator. Peter can turn his WF
> horizontal or vertical. Very nice project. We decided to check the phase
> when the WF was about to go up. I measured the phase using a oscilloscope
> driving the feed line input with 5W to measure the phase at the loops. First
> at the 9:1 BALUN that feed the loops, the phase was correct and near 180
> degree, but the amplitude was not the same between the two loops, let's say
> 10% different from each other. Then when I measured the phase at the
> resistors, the phase was very different between them, near 50 degree and the
> amplitude way off, like 50% difference. It was hard to understand why such
> difference between the two loops and even harder to understand the phase
> difference between the transformer  and the resistor in the same loop. After
> removing all BALUNS and measuring them at the bench with a VNA we found one
> isolation BALUN inverted. Peter was feeding his WF with 75 ohm, and the
> BALUN had 4 turns on the 50ohms side and 5 turns on 75 ohms, and it was
> connected backward, 4 turns to the 75 ohms and 5 turns to the 50 ohm point,
> where the two 100 ohms line are connected 180 degree. After connecting the
> BALUN the way it should be, the phase measured at the transformer and the
> resistor become equal in both loops, and the amplitude also was equal as
> expected, the difference in phase or amplitude was not detectable anymore.
> 
> It was the first time I faced this situation. The FLAG antenna, or EWE, K9AY
> , pennant and WF are actually a loaded loop. Adding one resistor inside the
> loop the gain drops but you  get a cardioid pattern, good front back and
> good RDF. The signal when reach the first vertical wire is reflected to the
> second wire, and the signal when reach the second wire the signal is
> reflected to the first wire. When the signal reach the resistor it is
> dissipated, and when the second signal reach the transformer it goes to the
> feed line. The combination of these two currents give us the cardioid
> pattern. In the WF there is a combination of two cardioids to get side nulls
> and higher RDF. All this work fine "IF" there is no mismatch when the signal
> current reach the resistor and the BALUN, any mismatch impedance inside the
> loop will change the phase, and as a result, a deterioration in directivity.
> The value of the resistor should be very close to the impedance at the
> transformer, Example, for a FLAG feed with100 ohm line and 9:1 BALUM giving
> 900 ohms impedance,  the resistor should be near 900 ohms to avoid SWR
> inside the loops. This is necessary to keep the right phase to form a
> cardioid pattern. The FLAG is no resonant an can be used from 1Mhz to 10
> MHz, BUT it is very sensitive to impedance mismatch.
> 
> Before correcting the 50/75 BALUN the SWR measured with a MFJ was near
> 1;1,8. After correcting the BALUN it was 1:1,5. Measuring only the SWR does
> not tell much about the antenna. The FLAG wants to work, like Luis once
> said. However if there is a mismatch anywhere the results won't be good. It
> is complicated to measure impedance on 160m, near AM signals around.
> 
> The FLAG or dual FLAG like the WF require a perfect match to provide the
> expected performance, and any common mode current can compromise the RDF and
> the overall performance. 
> 
> Do It right at the first time, don't change anything in the project! Use
> what was recommended.
> 
> Regards
> JCarlos
> N4IS
> 
> _
> Topband Reflector
  
_
Topband Reflector

Re: Topband: CAT5 twisted pair

[James Rodenkirch]

OH...okee dokee on not needing the 2:1 xfmr 
 
> From: charlie-cunning...@nc.rr.com
> To: j...@audiosystemsgroup.com; topband@contesting.com
> Date: Mon, 12 Aug 2013 17:12:59 -0400
> Subject: Re: Topband: CAT5 twisted pair
> 
> Jim,
> 
> I completely agree with Jim Brown!  I noted those 2:1 transformers the other
> day and  meant to send you a note to say that I wouldn't bother!  That
> little bit of mismatch loss won't make any difference!
> 
> 73,
> Charlie, K4OTV
> 
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown
> Sent: Monday, August 12, 2013 5:03 PM
> To: topband@contesting.com
> Subject: Re: Topband: CAT5 twisted pair
> 
> On 8/12/2013 1:50 PM, James Rodenkirch wrote:
> > as well as a 2:1 transformer just prior to the input to the shack.
> 
> While there's nothing wrong with attempting to match the termination Z, 
> don't assume that it will do much. The input Z of the RX may not be 50 
> ohms (although the doc may say it is), a small mismatch won't contribute 
> enough loss to matter, and it does not affect noise rejection. What 
> matters is balance and twisting.
> 
> 73, Jim K9YC
> _
> Topband Reflector
> 
> _
> Topband Reflector
  
_
Topband Reflector

Re: Topband: CAT5 twisted pair

[Charlie Cunningham]

Jim,

I completely agree with Jim Brown!  I noted those 2:1 transformers the other
day and  meant to send you a note to say that I wouldn't bother!  That
little bit of mismatch loss won't make any difference!

73,
Charlie, K4OTV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown
Sent: Monday, August 12, 2013 5:03 PM
To: topband@contesting.com
Subject: Re: Topband: CAT5 twisted pair

On 8/12/2013 1:50 PM, James Rodenkirch wrote:
> as well as a 2:1 transformer just prior to the input to the shack.

While there's nothing wrong with attempting to match the termination Z, 
don't assume that it will do much. The input Z of the RX may not be 50 
ohms (although the doc may say it is), a small mismatch won't contribute 
enough loss to matter, and it does not affect noise rejection. What 
matters is balance and twisting.

73, Jim K9YC
_
Topband Reflector

_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[JC N4IS]

Well, Jim, here is what N4IS stated (bolded words my emphasis) - 
> > looks like he found the twisted pair to reduce the noise
> Yes, but there's a bit more to it. Twisted pair, by its nature, 
> minimizes noise pickup.  That rejection is maximized if the 
> terminations at both ends of the line are balanced -- that is, each 
> side of the line has equal impedance to ground -- and if there is 
> minimal common mode coupling at each end


Hi guys

Jim is 100% right, balancing both ends is a MUST. But there is more. I would
like to share what happened few month ago with a WF project. Peter N8PR
built a beautiful WF with a polarization rotator. Peter can turn his WF
horizontal or vertical. Very nice project. We decided to check the phase
when the WF was about to go up. I measured the phase using a oscilloscope
driving the feed line input with 5W to measure the phase at the loops. First
at the 9:1 BALUN that feed the loops, the phase was correct and near 180
degree, but the amplitude was not the same between the two loops, let's say
10% different from each other. Then when I measured the phase at the
resistors, the phase was very different between them, near 50 degree and the
amplitude way off, like 50% difference. It was hard to understand why such
difference between the two loops and even harder to understand the phase
difference between the transformer  and the resistor in the same loop. After
removing all BALUNS and measuring them at the bench with a VNA we found one
isolation BALUN inverted. Peter was feeding his WF with 75 ohm, and the
BALUN had 4 turns on the 50ohms side and 5 turns on 75 ohms, and it was
connected backward, 4 turns to the 75 ohms and 5 turns to the 50 ohm point,
where the two 100 ohms line are connected 180 degree. After connecting the
BALUN the way it should be, the phase measured at the transformer and the
resistor become equal in both loops, and the amplitude also was equal as
expected, the difference in phase or amplitude was not detectable anymore.

It was the first time I faced this situation. The FLAG antenna, or EWE, K9AY
, pennant and WF are actually a loaded loop. Adding one resistor inside the
loop the gain drops but you  get a cardioid pattern, good front back and
good RDF. The signal when reach the first vertical wire is reflected to the
second wire, and the signal when reach the second wire the signal is
reflected to the first wire. When the signal reach the resistor it is
dissipated, and when the second signal reach the transformer it goes to the
feed line. The combination of these two currents give us the cardioid
pattern. In the WF there is a combination of two cardioids to get side nulls
and higher RDF. All this work fine "IF" there is no mismatch when the signal
current reach the resistor and the BALUN, any mismatch impedance inside the
loop will change the phase, and as a result, a deterioration in directivity.
The value of the resistor should be very close to the impedance at the
transformer, Example, for a FLAG feed with100 ohm line and 9:1 BALUM giving
900 ohms impedance,  the resistor should be near 900 ohms to avoid SWR
inside the loops. This is necessary to keep the right phase to form a
cardioid pattern. The FLAG is no resonant an can be used from 1Mhz to 10
MHz, BUT it is very sensitive to impedance mismatch.

Before correcting the 50/75 BALUN the SWR measured with a MFJ was near
1;1,8. After correcting the BALUN it was 1:1,5. Measuring only the SWR does
not tell much about the antenna. The FLAG wants to work, like Luis once
said. However if there is a mismatch anywhere the results won't be good. It
is complicated to measure impedance on 160m, near AM signals around.

The FLAG or dual FLAG like the WF require a perfect match to provide the
expected performance, and any common mode current can compromise the RDF and
the overall performance. 

Do It right at the first time, don't change anything in the project! Use
what was recommended.

Regards
JCarlos
N4IS

_
Topband Reflector

Re: Topband: CAT5 twisted pair

[Jim Brown]

On 8/12/2013 1:50 PM, James Rodenkirch wrote:

as well as a 2:1 transformer just prior to the input to the shack.


While there's nothing wrong with attempting to match the termination Z, 
don't assume that it will do much. The input Z of the RX may not be 50 
ohms (although the doc may say it is), a small mismatch won't contribute 
enough loss to matter, and it does not affect noise rejection. What 
matters is balance and twisting.


73, Jim K9YC
_
Topband Reflector

Re: Topband: CAT5 twisted pair

[James Rodenkirch]

 Bruce and Jim: I will have 9:1 transformers at both ends of the antenna (going 
to make it "switchable" for east and west directivity) as well as a 2:1 
transformer just prior to the input to the shack.
 
Won't bury the cable - run it "above the rocks" at 2 to 3 feet above the lousy 
ground we have around here in s/w Utah.
 
Appreciate the insight !!!  72, Jim Rodenkirch K9JWV
 


 
> From: k...@myfairpoint.net
> To: topband@contesting.com
> Date: Mon, 12 Aug 2013 15:00:32 -0700
> Subject: Topband:  CAT5 twisted pair
> 
> It is working well, and possibly because it is buried except a short 
> distance at both ends.  I was avoiding burying a non shielded, twisted pair 
> with possible varying losses due to
> changing ground conditions.
> 
> 73
> Bruce-K1FZ
> 
> 
> 
>  On 8/12/2013 1:42 PM, Bruce wrote:
>  I am using a twisted  pair, with shield,  that is near  55 ohm
>  impedance for
>  my receiving delta loop. The cable is designed for audio,
> 
>  Depending on the nature of that cable, you're probably better off
>  without the shield if both ends are transformer-isolated as I described.
>  There are two potential problems. First, the shield provides a lovely
>  path for common mode current, which can couple noise via Pin One
>  Problems to a rig. Second, if the cable shield is foil plus drain wire
>  ("rack wire" like Belden 8451), shield current will be STRONGLY coupled
>  to the twisted pair by a mechanism that Neil Muncy named
>  "shield-current-induced noise" (SCIN). The mechanism is that the drain
>  wire has the same lay as the signal pair, and is manufactured so that it
>  is much closer to one conductor the pair than the other. This results in
>  more inductive coupling to the closer conductor, converting the common
>  mode current to a differential voltage.
> 
>  73, Jim K9YC
> > _
> > Topband Reflector
> > 
> 
> _
> Topband Reflector
  
_
Topband Reflector

Topband: CAT5 twisted pair

[Bruce]

It is working well, and possibly because it is buried except a short 
distance at both ends.  I was avoiding burying a non shielded, twisted pair 
with possible varying losses due to

changing ground conditions.

73
Bruce-K1FZ



On 8/12/2013 1:42 PM, Bruce wrote:
I am using a twisted  pair, with shield,  that is near  55 ohm
impedance for
my receiving delta loop. The cable is designed for audio,

Depending on the nature of that cable, you're probably better off
without the shield if both ends are transformer-isolated as I described.
There are two potential problems. First, the shield provides a lovely
path for common mode current, which can couple noise via Pin One
Problems to a rig. Second, if the cable shield is foil plus drain wire
("rack wire" like Belden 8451), shield current will be STRONGLY coupled
to the twisted pair by a mechanism that Neil Muncy named
"shield-current-induced noise" (SCIN). The mechanism is that the drain
wire has the same lay as the signal pair, and is manufactured so that it
is much closer to one conductor the pair than the other. This results in
more inductive coupling to the closer conductor, converting the common
mode current to a differential voltage.

73, Jim K9YC

_
Topband Reflector



_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Jim Garland]

When I did my test, I didn't use a balun - I just attached a coax connector
to the CAT5e to get a rough check on the VSWR.  The noise pickup was
probably a result of not having a balanced feed. I made this test to see if
CAT5 would be a suitable feedline for portable QRP operation, and it
actually worked quite well. Running 100W into a dummy load, with about 50 ft
of CAT5, showed no perceptable VSWR. 

73,

Jim W8ZR

 

  _  

From: James Rodenkirch [mailto:rodenkirch_...@msn.com] 
Sent: Monday, August 12, 2013 10:47 AM
To: Jim Garland; topband@contesting.com
Subject: RE: Topband: Zo of an individual CAT5 twisted pair

 

Well, Jim, here is what N4IS stated (bolded words my emphasis) - looks like
he found the twisted pair to reduce the noise OR am I reading it
incorrectly?  Or are there two different noises being discussed???
 
 
  www.t6lg.com 
 
The noise level was unbearable for low bands, Ilian was not able to hear
even the strong European station but Ilian had a good signal on low bands. I
worked him on 80m back in October and start chatting with him on skype. I
proposed a flag antenna to improve his RX capabilities. The problem with
most field station is lack of good ground, this issue makes a very
complicated situation with common mode noise everywhere, from the coax cable
feeding the inverted V to the AC wire system and power generators, and other
antenna cables. There is not a simple way to ground the receiver, every wire
connected to the radio became part of the antenna system. The solution was a
system , not only a simple flag antenna. Ilian radio is a FT897 that does
not have a separated RX port. I send him a DX Engineering RTR-1 Receive
Antenna Interfaces RTR-1, that switch was necessary to keep high isolation
between the RX antenna and the TX antenna. The flag antenna has low gain and
I sent Ilian a preamp made by Gary KD9SV, a FET follower design with high
IP3. 
 
The parts for the antenna was very simple, a 9"1 balun and a 910 ohms
resistor, and a 100 to 75 ohms BALUN to feed the preamp. The key component
here was the CAT 5 single twisted pair to feed the flag antenna without any
common mode noise pickup (it is necessary to strip the CAT5 and separate
each of the 4 pairs), a coax cable won't work in high noise environment,
even with a killer choke the ground does not help to stop the common node
noise. That was not the first time a twisted pair saved the day, two years
ago I suggested Rolf PY1RO a similar antenna fed with twisted pair that
worked very well, bringing the noise to zero in a s9+20 noise environment.  

 

> From: 4cx2...@miamioh.edu
> To: rodenkirch_...@msn.com; topband@contesting.com
> Date: Mon, 12 Aug 2013 10:38:57 -0600
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> I believe that if you parallel two twisted pairs of a CAT5 cable, you'll
> have a 50 ohm transmission line.(Each twisted pair is 100 ohms). I've
tried
> this with CAT5e cable and find it works well, even for transmitting, up to
> about 100W. The VSWR match was very close to 50 ohms. The problem is that
> there is very poor noise rejection. When I used it as transmission line
for
> a receive antenna I picked up all the computer hash, fluorescent lights,
> etc. in the area. I quickly abandoned the experiment and went back to coax
> cable.
> 73,
> Jim W8ZR
> 
> > -Original Message-
> > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James
> > Rodenkirch
> > Sent: Monday, August 12, 2013 10:32 AM
> > To: topband@contesting.com
> > Subject: Topband: Zo of an individual CAT5 twisted pair
> > Importance: High
> > 
> > In an earlier post to this reflector, Carlos, N4IS, mentions using one
> pair of twisted wires
> > out of a CAT5 cable to feed the delta loop antenna used by T6LJ.
> > 
> > I am assembling the pieces/components needed to put an "FO0AAA style"
> delta loop
> > receive antenna up and want to use the twisted pair cable as well.,
> > 
> > My question is:
> > 
> > Does it matter which twisted pair of wires I use?
> > 
> > Thanks, in advance, for any thoughts72, Jim Rodenkirch K9JWV
> > 
> > _
> > Topband Reflector
> 
> _
> Topband Reflector

_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[James Rodenkirch]

AhSo!  Unnerstud'!!

> Date: Mon, 12 Aug 2013 10:33:09 -0700
> From: j...@audiosystemsgroup.com
> To: topband@contesting.com
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> On 8/12/2013 9:46 AM, James Rodenkirch wrote:
> > Well, Jim, here is what N4IS stated (bolded words my emphasis) - looks like 
> > he found the twisted pair to reduce the noise
> Yes, but there's a bit more to it. Twisted pair, by its nature, 
> minimizes noise pickup.  That rejection is maximized if the terminations 
> at both ends of the line are balanced -- that is, each side of the line 
> has equal impedance to ground -- and if there is minimal common mode 
> coupling at each end. This would be achieved by connecting the twisted 
> pair to the low-Z side of the RX antenna transformer, and to a 1:1 
> transformer in the shack. Both transformers should be wound to minimize 
> capacitive coupling between windings, which is what mimizes the common 
> mode coupling (by maximizing the common mode Z).  That's the same thing 
> we're doing when we wind a lot of turns of any cable through a ferrite 
> core to form a high-Z common mode choke.
> 
> On 8/12/2013 9:38 AM, Jim Garland wrote:
> > I believe that if you parallel two twisted pairs of a CAT5 cable, you'll
> > have a 50 ohm transmission line.(Each twisted pair is 100 ohms).  I've tried
> > this with CAT5e cable and find it works well, even for transmitting, up to
> > about 100W.
> Yes. But to clarify (to others, not you) we must be placing two 
> transmission lines in parallel by using the solid color conductors as 
> one side of the line, and the corresponding "color/white" conductors as 
> the other side of the line. If we did the opposite -- use both sides of 
> a pair as one side of the line and both side of another pair as the 
> other side, we would have a parallel wire line of unknown Zo and with 
> lousy noise rejection properties.
> 
> As to power handling and loss -- at these frequencies, its all copper 
> loss, and CAT5 is pretty small cable. We don't care about modest losses 
> in RX antennas, but it's a different story for TX.
> 
> 73, Jim K9YC
> _
> Topband Reflector
  
_
Topband Reflector

Re: Topband: Vertical vs inverted L question/opinions

[Henry Pollock - K4TMC]

Dale,

I thing someone has already beat you.  Have you noticed all of those
self-supporting tapered tubular galvanized steel cell phone towers
sprouting over the country?  And they have short limbs at the top for
attachments.

I would think some enterprising 160M buff would consider parking an RV near
the base of one of them and shoot a line over the top, then pull up a wire
cage gamma rod for feeding the tower. (K4TMC idea patent pending). :-)

73,
Henry - K4TMC



On Sun, Aug 11, 2013 at 10:41 PM, DALE LONG  wrote:

>
>
> Tom, that gives me an idea..
>
> An artificial tree (metallic) about 130 feet tall.  Wonder how many of
> them I could sell.
>
> Where's the nearest patent office?
>
> 73,
>
> Dale - N3BNA
>
>
>
> 
>  From: Tom W8JI 
> To: topband@contesting.com
> Sent: Sunday, August 11, 2013 10:21 PM
> Subject: Re: Topband: Vertical vs inverted L question/opinions
>
>
> > Why is an inverted "L" apparently so popular on 160 when it wastes so
> much RF as a cloud warmer?
>
> "Wastes so much RF" is sort of subjective.
>
> Comparing an L to a T, both 65 feet high and resonant over 50 radials, the
> T has almost exactly the same average ground wave signal. There is only a
> tiny fraction of a dB difference. In some directions the L is a tiny bit
> stronger, and in some directions the T is a tiny bit stronger, but it all
> amounts to a fraction of a dB.
>
> The only real major issue is the L has about 0.4 dB front-to-back.
>
> They aren't that much different in impedance, either.
>
> I'm not sure anyone would see any difference, except perhaps the L fills
> in the deep vertical null a little bit.
>
> This changes if the L and T are not self-resonant. Even so, unless the L
> is made so long the current maximum moves out of the vertical section,
> there isn't really what most would consider a significant difference.
>
> In my opinion, the choice is mostly a matter of what best fits the
> supports. Unless you try to use Tree for an antenna, then you might be 20
> dB down.
>
> 73 Tom
> _
> Topband Reflector
> _
> Topband Reflector
>
_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Jim Brown]

On 8/12/2013 1:42 PM, Bruce wrote:
I am using a twisted  pair, with shield,  that is near  55 ohm 
impedance for

my receiving delta loop. The cable is designed for audio,


Depending on the nature of that cable, you're probably better off 
without the shield if both ends are transformer-isolated as I described. 
There are two potential problems. First, the shield provides a lovely 
path for common mode current, which can couple noise via Pin One 
Problems to a rig. Second, if the cable shield is foil plus drain wire 
("rack wire" like Belden 8451), shield current will be STRONGLY coupled 
to the twisted pair by a mechanism that Neil Muncy named 
"shield-current-induced noise" (SCIN). The mechanism is that the drain 
wire has the same lay as the signal pair, and is manufactured so that it 
is much closer to one conductor the pair than the other. This results in 
more inductive coupling to the closer conductor, converting the common 
mode current to a differential voltage.


SCIN is a strong component of RFI to audio systems when the equipment it 
feeds lacks adequate low-pass filtering. Until about ten years ago, Greg 
Mackie built all of his mixers with DC-to-daylight frequency response in 
a misguided attempt to avoid phase shift at higher audio frequencies. He 
also built them with massive Pin One Problems. They were otherwise very 
nice mixers, great bang for the buck, but if you used one anywhere close 
to a TX on the high end of the AM broadcast band you were almost certain 
to hear it. And the problem was made worse because the mic cables 
running through the walls of a wood frame church had foil/drain shields.


And, of course, the Behringer mixers of that period, which were perfect, 
but poorly built copies of the Mackies, complete with mistakes on the PC 
boards,  had the same problems.


73, Jim K9YC
_
Topband Reflector

Topband: Zo of an individual CAT5 twisted pair

[Bruce]

I am using a twisted  pair, with shield,  that is near  55 ohm impedance for
my receiving delta loop. The cable is designed for audio,  but looks good 
up

to 10 MHZ. The KB-5 antenna end transformer has an isolated output. At the
shack end I wound a transformer with a balanced center tapped winding to an
unbalanced winding for  my transceiver.  The center tap is for the shield.
The center tap is floating at the antenna end. It is working well so far. 
See Pennant notes for more

info.   www.qsl.net/k1fz/pennantnotes.html

73
Bruce-K1FZ



- Original Message - 

From: 
To: 
Sent: Monday, August 12, 2013 10:11 AM
Subject: Re: Topband: Zo of an individual CAT5 twisted pair



you fellers dont know what to use CAT5 for, out here in the west we use
it to tie down our pickup loads.easy to tie, bends well and
is almost indestructible.

mike w7dra  still using an NC183 on topband


_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Jim Brown]

On 8/12/2013 9:46 AM, James Rodenkirch wrote:

Well, Jim, here is what N4IS stated (bolded words my emphasis) - looks like he 
found the twisted pair to reduce the noise
Yes, but there's a bit more to it. Twisted pair, by its nature, 
minimizes noise pickup.  That rejection is maximized if the terminations 
at both ends of the line are balanced -- that is, each side of the line 
has equal impedance to ground -- and if there is minimal common mode 
coupling at each end. This would be achieved by connecting the twisted 
pair to the low-Z side of the RX antenna transformer, and to a 1:1 
transformer in the shack. Both transformers should be wound to minimize 
capacitive coupling between windings, which is what mimizes the common 
mode coupling (by maximizing the common mode Z).  That's the same thing 
we're doing when we wind a lot of turns of any cable through a ferrite 
core to form a high-Z common mode choke.


On 8/12/2013 9:38 AM, Jim Garland wrote:

I believe that if you parallel two twisted pairs of a CAT5 cable, you'll
have a 50 ohm transmission line.(Each twisted pair is 100 ohms).  I've tried
this with CAT5e cable and find it works well, even for transmitting, up to
about 100W.
Yes. But to clarify (to others, not you) we must be placing two 
transmission lines in parallel by using the solid color conductors as 
one side of the line, and the corresponding "color/white" conductors as 
the other side of the line. If we did the opposite -- use both sides of 
a pair as one side of the line and both side of another pair as the 
other side, we would have a parallel wire line of unknown Zo and with 
lousy noise rejection properties.


As to power handling and loss -- at these frequencies, its all copper 
loss, and CAT5 is pretty small cable. We don't care about modest losses 
in RX antennas, but it's a different story for TX.


73, Jim K9YC
_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[w7dra]

you fellers dont know what to use CAT5 for, out here in the west we use
it to tie down our pickup loads.easy to tie, bends well and
is almost indestructible.

mike w7dra  still using an NC183 on topband


30-second trick for a flat belly
This daily 30-second trick BOOSTS your body's #1 fat-burning hormone
http://thirdpartyoffers.juno.com/TGL3141/5209177dcf761177d5b84st03vuc
_
Topband Reflector

Re: Topband: CQ160 Contest results now available

[j...@verizon.net]

Hi Andy 
Would like to see the CW report.

73
.Jon AA1K

Sent via the HTC Vivid™, an AT&T 4G LTE smartphone

- Reply message -
From: "Andy Blank" 
To: "CQ-Contest Reflector" 
Cc: 
Subject: Topband: CQ160 Contest results now available
Date: Mon, Aug 12, 2013 09:19


The results for  the 2013 CQ 160 Meter Contest are now posted on the web
site.

http://www.cq160.com/results.htm

If anyone would like to see their Log Checking Report, send me a request to
direc...@cq160.com
Please make sure to include your contest call sign, and the mode operated.

73, Andy N2NT

Director CQ160 Meter Contest
_
Topband Reflector
_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[James Rodenkirch]

Well, Jim, here is what N4IS stated (bolded words my emphasis) - looks like he 
found the twisted pair to reduce the noise OR am I reading it incorrectly?  Or 
are there two different noises being discussed???
 
 

www.t6lg.com


 
The noise level was unbearable for low bands, Ilian was not able to hear
even the strong European station but Ilian had a good signal on low bands. I
worked him on 80m back in October and start chatting with him on skype. I
proposed a flag antenna to improve his RX capabilities.

The problem with most field station is lack of good ground, this issue makes
a very complicated situation with common mode noise everywhere, from the
coax cable feeding the inverted V to the AC wire system and power
generators, and other antenna cables. There is not a simple way to ground
the receiver, every wire connected to the radio became  part of the antenna
system.

The solution was a system , not only a simple flag antenna. Ilian radio is a
FT897 that does not have a separated RX port. I send him a DX Engineering
RTR-1 Receive Antenna Interfaces RTR-1, that switch was necessary to keep
high isolation between the RX antenna and the TX antenna. The flag antenna
has low gain and I sent Ilian a preamp made by Gary KD9SV, a FET follower
design with high IP3.


 
The parts for the antenna was very simple, a 9"1 balun and a 910 ohms
resistor, and a 100 to 75 ohms BALUN to feed the preamp. The key component
here was the CAT 5 single twisted pair to feed the flag antenna without any
common mode noise pickup (it is necessary to strip the CAT5 and separate
each of the 4 pairs), a coax cable won't work in high noise environment,
even with a killer choke the ground does not help to stop the common node
noise. That was not the first time a twisted pair saved the day, two years
ago  I suggested Rolf PY1RO a similar antenna fed with twisted pair that
worked very well, bringing the noise to zero in a s9+20 noise environment.

 
 
> From: 4cx2...@miamioh.edu
> To: rodenkirch_...@msn.com; topband@contesting.com
> Date: Mon, 12 Aug 2013 10:38:57 -0600
> Subject: Re: Topband: Zo of an individual CAT5 twisted pair
> 
> I believe that if you parallel two twisted pairs of a CAT5 cable, you'll
> have a 50 ohm transmission line.(Each twisted pair is 100 ohms).  I've tried
> this with CAT5e cable and find it works well, even for transmitting, up to
> about 100W.  The VSWR match was very close to 50 ohms. The problem is that
> there is very poor noise rejection. When I used it as transmission line for
> a receive antenna I picked up all the computer hash, fluorescent lights,
> etc. in the area. I quickly abandoned the experiment and went back to coax
> cable.
> 73,
> Jim W8ZR
> 
> > -Original Message-
> > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James
> > Rodenkirch
> > Sent: Monday, August 12, 2013 10:32 AM
> > To: topband@contesting.com
> > Subject: Topband: Zo of an individual CAT5 twisted pair
> > Importance: High
> > 
> > In an earlier post to this reflector, Carlos, N4IS, mentions using one
> pair of twisted wires
> > out of a CAT5 cable to feed the delta loop antenna used by T6LJ.
> > 
> > I am assembling the pieces/components needed to put an "FO0AAA style"
> delta loop
> > receive antenna up and want to use the twisted pair cable as well.,
> > 
> > My question is:
> > 
> >  Does it matter which twisted pair of wires I use?
> > 
> > Thanks, in advance, for any thoughts72, Jim Rodenkirch K9JWV
> > 
> > _
> > Topband Reflector
> 
> _
> Topband Reflector
  
_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Jim Garland]

I believe that if you parallel two twisted pairs of a CAT5 cable, you'll
have a 50 ohm transmission line.(Each twisted pair is 100 ohms).  I've tried
this with CAT5e cable and find it works well, even for transmitting, up to
about 100W.  The VSWR match was very close to 50 ohms. The problem is that
there is very poor noise rejection. When I used it as transmission line for
a receive antenna I picked up all the computer hash, fluorescent lights,
etc. in the area. I quickly abandoned the experiment and went back to coax
cable.
73,
Jim W8ZR

> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James
> Rodenkirch
> Sent: Monday, August 12, 2013 10:32 AM
> To: topband@contesting.com
> Subject: Topband: Zo of an individual CAT5 twisted pair
> Importance: High
> 
> In an earlier post to this reflector, Carlos, N4IS, mentions using one
pair of twisted wires
> out of a CAT5 cable to feed the delta loop antenna used by T6LJ.
> 
> I am assembling the pieces/components needed to put an "FO0AAA style"
delta loop
> receive antenna up and want to use the twisted pair cable as well.,
> 
> My question is:
> 
>  Does it matter which twisted pair of wires I use?
> 
> Thanks, in advance, for any thoughts72, Jim Rodenkirch K9JWV
> 
> _
> Topband Reflector

_
Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[Jim Brown]

On 8/12/2013 9:32 AM, James Rodenkirch wrote:

Does it matter which twisted pair of wires I use?


The Zo of all pairs is the same, to manufacturing tolerances, but each 
pair has a different twist ratio (called the "lay"). This is done to 
minimize crosstalk between pairs. A higher twist ratio (more turns per 
inch) improves interference rejection of the line, so the one with the 
greatest number of turns per inch would be the one to use. I don't 
remember which one that is, but it's sort of obvious when you open up 
the cable.


BTW -- Belden CAT5/6/7 cables have pairs with each pair molded together, 
so they tend to be better transmission lines (more uniform over their 
length). Not a big deal for loss on 160M, but uniformity does minimize 
interference rejection.


73, Jim K9YC
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Topband Reflector

Re: Topband: Zo of an individual CAT5 twisted pair

[James Rodenkirch]

To embellish the below some, the twisted pairs in a CAT5 cable have different 
twists, e.g., 
 
Pair color[cm] per turnTurns per 
[m]Green1.5365.2Blue1.5464.8Orange1.7856.2Brown1.9451.7 
So, one would assume the Zo for each pair is differentI suspect the 
difference isn't that much butthought I'd "axe around" 

 
> From: rodenkirch_...@msn.com
> To: topband@contesting.com
> Date: Mon, 12 Aug 2013 10:32:20 -0600
> Subject: Topband: Zo of an individual CAT5 twisted pair
> 
> In an earlier post to this reflector, Carlos, N4IS, mentions using one pair 
> of twisted wires out of a CAT5 cable to feed the delta loop antenna used by 
> T6LJ.
>  
> I am assembling the pieces/components needed to put an "FO0AAA style" delta 
> loop receive antenna up and want to use the twisted pair cable as well.,
>  
> My question is: 
>  
>  Does it matter which twisted pair of wires I use?
>  
> Thanks, in advance, for any thoughts72, Jim Rodenkirch K9JWV
>   
>   
> _
> Topband Reflector
  
_
Topband Reflector

Topband: Zo of an individual CAT5 twisted pair

[James Rodenkirch]

In an earlier post to this reflector, Carlos, N4IS, mentions using one pair of 
twisted wires out of a CAT5 cable to feed the delta loop antenna used by T6LJ.
 
I am assembling the pieces/components needed to put an "FO0AAA style" delta 
loop receive antenna up and want to use the twisted pair cable as well.,
 
My question is: 
 
 Does it matter which twisted pair of wires I use?
 
Thanks, in advance, for any thoughts72, Jim Rodenkirch K9JWV

  
_
Topband Reflector

Topband: CQ160 Contest results now available

[Andy Blank]

The results for  the 2013 CQ 160 Meter Contest are now posted on the web
site.

http://www.cq160.com/results.htm

If anyone would like to see their Log Checking Report, send me a request to
direc...@cq160.com
Please make sure to include your contest call sign, and the mode operated.

73, Andy N2NT

Director CQ160 Meter Contest
_
Topband Reflector