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WONRP, The current charts are on a new factory ended 100ft length of RG8X now.

I also think they must be something wrong with the balun as well since there is not much
that could be wrong with the wires on it, although i wonder if it could also be the fact that
there is extra wire on the spools which according to windcamp does not effect it.

I just received 2 - T130-2 cores today just need to find a schematic to wire up an new balun
with them at 1:1 to test it again before i see if i can open the factory balun on it. I think i need
150 watts for the kenwood.

I decided to test the Balun itself maybe someone can help me read these plots.

I have one plot with the ant lead of balun open, shorted and with 2 100ohm resistors in parallel that read 49.9 ohms on my digital meter.

From the plot with 50 Ohm resistor you can see, that the balun is good (VSWR < 1.5) from 3 MHz to 30 MHz. The other plots are unimportant.

But remember that an antenna with bad VSWR will also give that bad VSWR through your balun to the transceiver.

73, Günter, DK5DN

Am 05.11.2020 um 21:10 schrieb deadman1966@...:

so if the balun is good how can the wires themselves be bad?

I would have expected this ant to be usable across the band windcamp advertised it to work at 5-50Mhz but it seems in most cases my Kenwood would likely not even auto tune it so i can transmit.

Can anyone suggest another ant that is worth buying I am tried of wasting money on this.

No.....NO.....N O.....!! Something is wrong, here. Look at just the
Smith Chart! Open shows lots of loss. Short shows very high Z. 50-ohm
termination shows high Z and totally inductive. All show extremely bad
return loss. Read from the Smith Chart markers (values given in the
numerical data to the left of the chart):
SWR Open: 30 MHz: 109:1 1.5 MHz: 1.9:1
SWR Short: 30 MHz: 196:1 1.5 MHz: 3.9:1
SWR Terminated: 30 MHz: 94:1 1.5 MHz: 62:1
I would conclude this balun is trash!!!!!! The previous commenter is not
familiar with what the return loss plot represents. Low numbers, which are
shown in these plots for all three configurations of the balun (open,
shourt, and properly terminated) are small which indicate much of the
source energy is reflected back to the input port. Large numbers of return
loss indicate low SWR while small numbers of return loss indicate high
SWR.

Again, based on the well executed measurements, that balun is trash.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Thanks for the detailed explanation of the graphs I could certainly follow it on the graphs.

I have 2 of the T130-2 cores but the only mag wire i have measures 1.90mm across
which is way too heavy to get 18 turns of 3 wires.

I do have a ton of coated 14awg gauge stranded wire or 14/2 electrical wire as well.

Can either of those be used in a balun at 100-150 watts?

Since the gypsy balun is trash and its sealed in a way the is not open able i would
like to get a balun wired on the core and perhaps at least use the connectors from
the trashed one, lol after likely having to saw it in half in the middle.

I got two cores i also want to make a 9:1 for playing with end feed wires as well.

For the doublet which consists of two roughly equal lengths of wire each
side of the center insulator, just wind yourself a common mode choke. It
will serve very well as a balun as it will discourage common mode currents,
and, therefore, current on the outside of the coaxial feedline (the
function of a balun). I use AWG #14 Davis RF superflex wire (finely
stranded and coated) , but I have 3" OD cores. With your smaller core,
smaller wire would be advised. You'd do far better to use #18 or #20
stranded (it forms easier) and coated wire for your size cores. Wind in a
bifilar manner, two parallel conductors through the red core. Do not twist
the wires. Without overlapping bifilar windings, try to get 12 to 15 turns
of wire on your core. It choke is bipolar, so one side of the pair
connects to the coax while the other side of the pair connects at the
center insulator to your two wires. That will work well to isolate current
on the outside of the coaxial cable from becoming part of the antenna and
is good for 100 to 150-watts. It will not function much as an impedance
transformer, which you do not want using an antenna matching network,
a.k.a., an antenna 'tuner'. I'll attach a picture of two of my common
mode chokes wound on two stacked 3" cores (to assure adequate magnetic
current capability within the magnetics at legal limit). I have
measurements of these chokes made with the HP 8753C VNA somewhere on the
hard drive.

[image: image.png]

The SO-239 connects to the coaxial cable. The banana plugs connect to my
open wire feeders. Left choke is wound with #12 insulated stranded house
wire (PVC coating) while the right-hand choke is wound with the DavisRF
superflex stranded insulated #14 wire.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Attached are the measured data sets for the CM chokes I illustrated in the
previous email plus a couple of others

Dave - W?LEV

On Thu, Nov 5, 2020 at 11:40 PM David Eckhardt <davearea51a@...>
wrote:

For the doublet which consists of two roughly equal lengths of wire each
side of the center insulator, just wind yourself a common mode choke. It
will serve very well as a balun as it will discourage common mode currents,
and, therefore, current on the outside of the coaxial feedline (the
function of a balun). I use AWG #14 Davis RF superflex wire (finely
stranded and coated) , but I have 3" OD cores. With your smaller core,
smaller wire would be advised. You'd do far better to use #18 or #20
stranded (it forms easier) and coated wire for your size cores. Wind in a
bifilar manner, two parallel conductors through the red core. Do not twist
the wires. Without overlapping bifilar windings, try to get 12 to 15 turns
of wire on your core. It choke is bipolar, so one side of the pair
connects to the coax while the other side of the pair connects at the
center insulator to your two wires. That will work well to isolate current
on the outside of the coaxial cable from becoming part of the antenna and
is good for 100 to 150-watts. It will not function much as an impedance
transformer, which you do not want using an antenna matching network,
a.k.a., an antenna 'tuner'. I'll attach a picture of two of my common
mode chokes wound on two stacked 3" cores (to assure adequate magnetic
current capability within the magnetics at legal limit). I have
measurements of these chokes made with the HP 8753C VNA somewhere on the
hard drive.

[image: image.png]

The SO-239 connects to the coaxial cable. The banana plugs connect to my
open wire feeders. Left choke is wound with #12 insulated stranded house
wire (PVC coating) while the right-hand choke is wound with the DavisRF
superflex stranded insulated #14 wire.

Dave - W?LEV


On Thu, Nov 5, 2020 at 11:06 PM <deadman1966@...> wrote:

Thanks for the detailed explanation of the graphs I could certainly
follow it on the graphs.

I have 2 of the T130-2 cores but the only mag wire i have measures
1.90mm across
which is way too heavy to get 18 turns of 3 wires.

I do have a ton of coated 14awg gauge stranded wire or 14/2 electrical
wire as well.

Can either of those be used in a balun at 100-150 watts?

Since the gypsy balun is trash and its sealed in a way the is not open
able i would
like to get a balun wired on the core and perhaps at least use the
connectors from
the trashed one, lol after likely having to saw it in half in the middle.

I got two cores i also want to make a 9:1 for playing with end feed wires
as well.

--
*Dave - W?LEV*
*Just Let Darwin Work*

--
*Dave - W?LEV*
*Just Let Darwin Work*

In the write-up, the last 'subject' was professionally done. Notice it
consists of 16 turns of AWG #14 solid copper wire wound in a bifilar
manner. This one measured the best and is the size of the cores you have.
So,........ try to duplicate that choke. Again, the last one shown in the
write-up attached to the last 'reply'.

Dave - W?LEV

On Thu, Nov 5, 2020 at 11:51 PM David Eckhardt via groups.io <davearea51a=
[email protected]> wrote:

Attached are the measured data sets for the CM chokes I illustrated in the
previous email plus a couple of others

Dave - W?LEV

On Thu, Nov 5, 2020 at 11:40 PM David Eckhardt <davearea51a@...>
wrote:

For the doublet which consists of two roughly equal lengths of wire each
side of the center insulator, just wind yourself a common mode choke. It
will serve very well as a balun as it will discourage common mode

currents,

and, therefore, current on the outside of the coaxial feedline (the
function of a balun). I use AWG #14 Davis RF superflex wire (finely
stranded and coated) , but I have 3" OD cores. With your smaller core,
smaller wire would be advised. You'd do far better to use #18 or #20
stranded (it forms easier) and coated wire for your size cores. Wind in

a

bifilar manner, two parallel conductors through the red core. Do not

twist

the wires. Without overlapping bifilar windings, try to get 12 to 15

turns

of wire on your core. It choke is bipolar, so one side of the pair
connects to the coax while the other side of the pair connects at the
center insulator to your two wires. That will work well to isolate

current

on the outside of the coaxial cable from becoming part of the antenna and
is good for 100 to 150-watts. It will not function much as an impedance
transformer, which you do not want using an antenna matching network,
a.k.a., an antenna 'tuner'. I'll attach a picture of two of my common
mode chokes wound on two stacked 3" cores (to assure adequate magnetic
current capability within the magnetics at legal limit). I have
measurements of these chokes made with the HP 8753C VNA somewhere on the
hard drive.

[image: image.png]

The SO-239 connects to the coaxial cable. The banana plugs connect to my
open wire feeders. Left choke is wound with #12 insulated stranded house
wire (PVC coating) while the right-hand choke is wound with the DavisRF
superflex stranded insulated #14 wire.

Dave - W?LEV


On Thu, Nov 5, 2020 at 11:06 PM <deadman1966@...> wrote:

Thanks for the detailed explanation of the graphs I could certainly
follow it on the graphs.

I have 2 of the T130-2 cores but the only mag wire i have measures
1.90mm across
which is way too heavy to get 18 turns of 3 wires.

I do have a ton of coated 14awg gauge stranded wire or 14/2 electrical
wire as well.

Can either of those be used in a balun at 100-150 watts?

Since the gypsy balun is trash and its sealed in a way the is not open
able i would
like to get a balun wired on the core and perhaps at least use the
connectors from
the trashed one, lol after likely having to saw it in half in the

middle.

I got two cores i also want to make a 9:1 for playing with end feed

wires

as well.

--
*Dave - W?LEV*
*Just Let Darwin Work*

--
*Dave - W?LEV*
*Just Let Darwin Work*

--
*Dave - W?LEV*
*Just Let Darwin Work*

Is this the antenna which is 6 feet (1.8m) above the ground we are complaining about?

What can one expect with such a large capacitor to ground. Let's get back to basics. Pre VNAs.

The most important component of an airial is the air. They need to be up there as high as possible which is a good start.

If it's not a balanced antenna then it also needs a good ground.

This idea has served me well since I built my first twin triode Regen Receiver in 1959.

73 Bob




--
No good deed goes unpunished.

Bob, I do understand the antenna is low to the ground to go any higher i only have one option and that is to slope the wire from the 2nd floor of house so around 25 to 30 feet down to the back fence line which is 6.5 to 7 feet at the post but i would have to but i would have to feed it from the high end.

With that in mind are you saying the actual readings i posted for the balun itself connected to calibrated cables on the vna with a 50 ohm termination reflect no issues with the balun itself?

Dave,

I had some 18awg coated solid copper wire i stripped form a piece of thermostat wire and managed to get 16 loops onto the core. I am 3d printing a centre insulator for the two wires form the windcamp since their balun serves that purpose as soon as i get that done i will get this unit on it and do some readings.

In the interim i have installed a 50ohm resistor to one end and connected the other end to the nanovna and tooks some readings that are attached If i read them right it looks like I did something right. It seems to me these are the sort of readings i should have gotten form the 1:1 balun that came with the antenna.

One thing I am not sure of is how much power i can transmit through the unit with 18awg instead of 14. I did order some of the wire you mentioned could you perhaps let me know what cores you use so i can order the larger ones.

I want to thank all those the have responded to this thread i have a much better understanding now on how measure and read results on the nanovna as a result of all the help.

Dave,

Thank you for those clear photo's and measurements.
From the Smith charts I think we me conclude that the windings (forming a 2 wire transmissionline) have a Z0 of about 100 ohms. The enameled wires on the red core seem close to a 50 ohm transmission line.

New inspiration because of your contribution. Off to the shack this weekend to measure some of my own chokes. :-)

73 all,

Arie PA3A

Op 6-11-2020 om 00:49 schreef David Eckhardt:

Part of the problem could be that you seem to be using a Red type 2 low permeability iron powder core.

This will not provide a high enough value of choking impedance for the purpose you wish to use it for.

Some suggestions for starting points for choke baluns can be derived from the chart in this article.



If you wish to examine the common mode impedance of chokes like this, connect the VNA across the windings between both wires of the Balun connected together at the input and output of the choke.

You can either measure the S11 impedance or S21 insertion loss in order to obtain an estimate of the chokes likely effectiveness, but remember that the common mode impedance that will be found on an antenna system will not be 50 Ohms, it could be anything between a few Ohms and several thousand, depending upon the standing wave current at the point the choke is connected. So if you measure S21 of say 20dB (in a 50 Ohm system) that will not equate to 20dB of choking impedance in 'real life'.
--
Regards,

Martin - G8JNJ

Yes, many use 31 material for this purpose. I've wound many like CM chokes
using red cores, 31, and 43 material. Problem is with the higher ?r
materials, I end up with a virtual tesla coil at the transition of my open
wire feeders and the output of the matching network. Too much inductance.
The red cores I use once wound as the CM chokes measure in the vicinity of
+j1000 or greater, even at 1.8 MHz. The red cores are the correct cores to
use for this purpose. These are also the same core material Amidon offers
in their kits.

Dave - W?LEV

On Fri, Nov 6, 2020 at 1:35 PM Martin via groups.io <martin_ehrenfried=
[email protected]> wrote:

Part of the problem could be that you seem to be using a Red type 2 low
permeability iron powder core.

This will not provide a high enough value of choking impedance for the
purpose you wish to use it for.

Some suggestions for starting points for choke baluns can be derived from
the chart in this article.



If you wish to examine the common mode impedance of chokes like this,
connect the VNA across the windings between both wires of the Balun
connected together at the input and output of the choke.

You can either measure the S11 impedance or S21 insertion loss in order to
obtain an estimate of the chokes likely effectiveness, but remember that
the common mode impedance that will be found on an antenna system will not
be 50 Ohms, it could be anything between a few Ohms and several thousand,
depending upon the standing wave current at the point the choke is
connected. So if you measure S21 of say 20dB (in a 50 Ohm system) that will
not equate to 20dB of choking impedance in 'real life'.
--
Regards,

Martin - G8JNJ

--
*Dave - W?LEV*
*Just Let Darwin Work*

The #14 wire and the large cores which I use address the requirement of
operating at full power of 1.5 kW. Not that I use that much, but on
occasion on 75 and 160, it is required. There's no doubt your choke will
introduce a bit more loss than my large units, but you should be OK with
100-watts. Key down in CW at 100-watts for a few minutes with the output
of the choke connected to a dummy load and see how much heating occurs. If
minimal, you're fine. If too much heat, yes, larger core and wiremay be
required, but I would venture a guess that you're fine.

Your plots look just as I would expect. Now you have a 'real' balun / CM
choke. Give yourself a pat on the back, just for me......?? And, you've
learned a whole bunch on the way. Good work!

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Martin:

Re:
If you wish to examine the common mode impedance of chokes like this, connect the VNA across the windings between both wires of the Balun connected together at the input and output of the choke.

Could be a bit more specific about the connections,? Can’t quite figure out your suggested wiring.

Thanks.

Ed McCann
AG6CX

To measure the total inductance, or more importantly, the +jX of the
windings: Short both conductors together at both ends so the choke forming
a single conductor consisting of two paralleled conductors on the core.
This is for test purposes, only. Then connect one end to the S11 center
pin and the other to the S11 backshell. Then, on the Smith Chart using the
cursors, you can measure the total inductance and +jX of the windings on
the core. To provide adequate choking, the total +jX should be at least 5
times the system impedance (some state 10X). For a 50-ohm system
impedance, this, of course would be +j250, ideally at the lowest frequency
of interest. If you don't want 160-meters, that requirement becomes much
easier to reach.

With my doublet fed with open wire transmission line, I measure (from 1.8
through 29.5 MHz) : real: 25 to 5 ohms ±jX: -200 to +80
So I have read data to address with my choke designs. You might make the
same measurements of your antenna to properly design your CM choke as I
have. No single solution fits all applications. Fortunately, with the
advent of the NANOVNA's, we now have the tools to measure and to design to
what we have installed as an antenna.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

I have the antenna spooled out to exactly the 7Mhz silver markers on the wire here is the readings on the antenna with my homemade choke on it. Not sure what other improvements i can make yet. Based on the readings are there frequencies i should not transmit on I really don't know how the AT unit works in the kenwood and how much range it has to correct SWR.

You're certainly looking good at 40 and 15 meters. Also at 36 MHz where we
don't have an allocation. Looks very good!

Now, you might zero in on both 40 and 15 meters and do a measurement of
those bands to assure you are less than 3:1 over the whole band. Set up to
scan 7.000 to 7.300 MHz (40-meters) and 21.000 to 21.350 MHz (15-metes).
That will tell you whether the internal tuner in the Kenwood will correct
for SWR. I have the TS-2000X and its internal tuner will properly match up
to and including 3"1 SWR, but not much more. Most of the internal tuners
stop at 3:1.

On your return loss plot, only these two amateur bands show less than 6 dB
which is an SWR of 3:1. So, you are limited to those bands.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*