Which ferrite material for 3-30MHz balun?...

[Joerg]

On 10/18/20 11:34 PM, Clifford Heath wrote:

On 19/10/20 2:43 pm, Joerg wrote:
On 10/18/20 4:03 PM, Clifford Heath wrote:
On 19/10/20 9:33 am, Joerg wrote:
Attention, this is a non-political post, for a change

Getting back into ham radio after a decades-long hiatus I need to
make a balun for 3-30MHz. Essentially just a glorified common-mode
choke and preferably without an extra 3rd magnetizing winding.
Realistically I won\'t use more than 200W but it would be nice if it
can take more. There are a bunch of new materials that showed up
which I can\'t remember from the 80\'s. From some research on the web
it seems 61-material is a really good contender when it comes to low
core loss yet acceptable permeability. So I was thinking of getting
an FT240-61 core. What do thee think?

Main reason I ask is that I remember having blown up a few baluns
back in the days and I don\'t want this thing to cause a meltdown
here in bone-dry California.

The EFHW antenna enthusiasts on the Facebook group seem to use type
43 material. Two FT240-43 toroids handle over 100W, and three, up to
1kW (not sure about duty cycles, probably SSB ham chatter). Type 52
is another option, lower loss but lower power handling.


43 is also my goto material but for EMI cases. For this application it
has too much resistive losses.


You might find more in this article (which I haven\'t read in depth):
https://lookaside.fbsbx.com/file/EFHW%20German%20Article.pdf


\"Arcticle isn\'t available\". I guess only for Facebook members. Only
over my dead body


Ahh, sorry I don\'t know about that. The article seems to have been
removed since I posted it. My downloaded copy is now here:
https://www.dropbox.com/s/lze82hwbbhhxcen/EFHW%20German%20Article.pdf?dl=0

Thanks. On page 12 he talks about his \"sheath current lock\" or
Mantelwellensperre in German (common-mode choke) but not which core he
used. It looks fat but small in diameter. Also, he spread te wires a bit
far, it\'s usually better to use a bifilar winding technique.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 10/18/20 11:35 PM, Michael Terrell wrote:

On Sunday, October 18, 2020 at 6:33:23 PM UTC-4, Joerg wrote:
Attention, this is a non-political post, for a change

Getting back into ham radio after a decades-long hiatus I need to make a
balun for 3-30MHz. Essentially just a glorified common-mode choke and
preferably without an extra 3rd magnetizing winding. Realistically I
won\'t use more than 200W but it would be nice if it can take more. There
are a bunch of new materials that showed up which I can\'t remember from
the 80\'s. From some research on the web it seems 61-material is a really
good contender when it comes to low core loss yet acceptable
permeability. So I was thinking of getting an FT240-61 core. What do
thee think?

Main reason I ask is that I remember having blown up a few baluns back
in the days and I don\'t want this thing to cause a meltdown here in
bone-dry California.

Fair-Rite made Amidon toroids.
Amidon used to print a nice databook that sold for about $15. All I find now is the datasheet that the always sent with an order. <http://www.amidoncorp.com/product_images/Amidon-Tech-Data-Flyer-v19.pdf> This indicates that #2 is the only material covering the desired range, but it was created in 2001. The Amidon cores are available up to 5.2\" OD and a 3.08\" ID. <http://www.amidoncorp.com/2-material-iron-powder-toroids/

https://people.zeelandnet.nl/wgeeraert/ferrietUK.htm> has a lot of materials that might help.

Thanks. That article would make the 61 material the clear winner at
least up to 10MHz. Unfortunately he didn\'t compare against 31 material.
This one has both

https://palomar-engineers.com/Downloads/Fair-Rite%20Material%20Specifications.pdf

and it makes 61 the winner. Unfortunately at much lower permeability. Of
course, at 10MHz 31 is also down to around 150 but that is still more
than 125.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 10/18/20 11:58 PM, Jeff Liebermann wrote:

On Sun, 18 Oct 2020 15:33:15 -0700, Joerg <news@analogconsultants.com
wrote:

Attention, this is a non-political post, for a change

I take it that you and your house survived the fires. Congrats. Same
here except the fire came within 1400 feet of my back door.

We had a brush fire flare up yesterday about 3mi from here. Looked
serious but an air tanker arrived soon. Vegetation management is a major
problem in California. As a mountain biker I see classic examples on
nearly every ride.

Getting back into ham radio after a decades-long hiatus I need to make a
balun for 3-30MHz.

1:1 Balun or something else like a 4:1 ??

Just a large current mode choke. I want to suppress coax shield currents
as much as possible. The antenna will be a multi-band ground plane
(10-15-20m) plus a 40m dipole in parallel. Later maybe an 80m dipole as
well.

The main reason is receive noise. If you do not suppress shield currents
well enough the coax becomes a small part of the antenna and picks up
all sorts of man-made noise from switch mode supplies.

Essentially just a glorified common-mode choke and
preferably without an extra 3rd magnetizing winding. Realistically I
won\'t use more than 200W

200W CW or PEP? The average power is different.
Duty cycle?

CW. There could also be digital modes in the future.

but it would be nice if it can take more.

How much more power? For how long? Duty cycle?

Well, the legal limit is 1500W but I won\'t likely go there because then
the neighbor\'s electronics will likely keel over.

There
are a bunch of new materials that showed up which I can\'t remember from
the 80\'s.
From some research on the web it seems 61-material is a really
good contender when it comes to low core loss yet acceptable
permeability. So I was thinking of getting an FT240-61 core. What do
thee think?

These might help:
http://k9yc.com/FerriteDataHF.pdf
http://k9yc.com/Toroid61Data-2.pdf
http://k9yc.com/RFI-Ham.pdf
http://k9yc.com/2018Cookbook.pdf> (He uses #31 here).
Might be more buried on his web pile:
http://k9yc.com/publish.htm

I have four FT240-31 toroids that I was going to use in an HF antenna
project which was interrupted by ummm... everything.
https://www.fair-rite.com/31-material-data-sheet/
https://www.fair-rite.com/61-material-data-sheet/
http://www.amidoncorp.com/ft-240-31/

Thanks, that has interesting info in there that I hadn\'t pondered yet.
Resonance with the line, that could really mess things up. So I guess 31
material is better in the end and that is also what he uses.

No, you can\'t have them. I\'m not sure what to recommend for your
antenna project.

Looking at the Far-Right data sheets,
https://www.fair-rite.com/materials/
I would guess(tm) that #31 is better than #61 because of the much
higher initial permeability. That translates into needing few turns
of wire for the same inductance. Getting a sufficiently large number
of wire turns, or more likely coax cable turns, through the toroid
hole might be a problem.

It doesn\'t help that the loss tangent is specified at 100 KHz for #31
and at 10 MHz for #61. Just to make things weird, #31 includes this
cryptic statement:
This material does not have the dimensional resonance
limitations associated with conventional MZn ferrite
materials.
What\'s a \"dimensional resonance limitation\"?

That only applies if you use a tricorder

Since power dissipation might be a problem, #61 Curie Temp is >300C,
while #31 is >150C. If you\'re planning on running the balun hot, this
might be a consideration making #61 the better material.

I can\'t go too high. I assume that is what made at least one of my
baluns fail in Germany. One went with a muffle POOF. The other went
silently. Suddenly I heard a thwock sound and that was my wire antenna
smacking to the groud. Luckily there wasn\'t any car parked underneath
when that happened. The balun enclosed had melted, stretched, stretched
some more, wanted to become spaghetti and then it was over.

Send Jim (K9YC) an email and maybe he can help. Note that he just
recently returned from a rather protracted fire evacuation and might
be rather busy.

Ouch, that is tough. I better not bother him for now and just trust his
judgment that 31 material is the ticket.

Full disclosure: I bought the four T240-31 toroids from Jim at a
discounted price in a group buy through the local radio club.

Main reason I ask is that I remember having blown up a few baluns back
in the days and I don\'t want this thing to cause a meltdown here in
bone-dry California.

Hang a galvanized steel bucket under the balun to catch any flaming
material selection errors. Or, perhaps consider the possibilities of
QRP.

I am not a QRP guy but my wild days of full legal power are nearly over.
If I can\'t use 1500W it\'ll be ok. At least for now. I\'ll jsut go with a
single FT-240-31 and if I ever need more power I\'ll stack two or three.

Thanks for the great input here.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 10/19/20 8:31 AM, bitrex wrote:

On 10/19/2020 5:34 AM, Jan Panteltje wrote:
On a sunny day (Sun, 18 Oct 2020 15:33:15 -0700) it happened Joerg
news@analogconsultants.com> wrote in <hv3u5cF49h2U1@mid.individual.net>:

Attention, this is a non-political post, for a change

I recently found
  uk.radio.amateur.moderated
    may be worth asking there.
Still active and no noise!


As to antenna matching, antenna tuners can match any piece of wire...
I have a small QRP one... kit from ebay...
  http://panteltje.com/pub/ebay_QRP_antenna_tuner_IXIMG_0552.JPG
search ebay for  \"QRP MANUAL DAYS ANTENNA TUNER TUNE DIY KIT 1 - 30 MHZ\"
100W would set it on fire.
  But think if you look for higher power they will have it, else
alieexpress:
   https://www.aliexpress.com/w/wholesale-automatic-antenna-tuner.html

why bother with single cores...


Bought some
  Micrometals Amidon T80-2 Iron Powder Toroidal
for experiments long time ago:
   https://toroids.info/T80-2.php

There are a lot of Usenet amateur radio groups:
  http://www.panteltje.com/pub/usenet_amateur_radio_groups_IXIMG_0550.JPG
   the green ones are dead (no longer in active list on nntp.aioe.org),
   the red one is new,
   and the blue one is the one I am subscribed to ATM,
   have not checked the other ones for activity.


For the 10m band I have a GPA, no balun needed, ...

If your house is EMI-quiet that may be true. I found that any kind of
imbalance in the coax (meaning common mode curents) causes pickup from
stuff near the cable ... bzzz ... rat-tat-tat .. phssss. Wood frame
building construction doesn\'t help either.

150 W PEP, Ranger
RCI2970DX.
Not much used these days.
Nothing for lower frequencies than that.


The #2 carbonyl iron material is a nice all-rounder material for just
regular inductors in the low MHz range, for inductors that need to store
energy. The only bummer is its pretty low Al value.

Yes, it\'s more suitable for a voltage mode transformer than a CM choke.

The #8 material is similar but with a nice boost to the Al value and a
little lower transition frequency, it\'s about 4 times the price though.

Commmon mode chokes don\'t need to store energy so a hard ferrite is more
appropriate, you can have Al values of like a thousand rather than say, 25.

Until things get hot

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Jeff Liebermann]

On Mon, 19 Oct 2020 09:41:38 +0100, Piglet <erichpwagner@hotmail.com>
wrote:

On 19/10/2020 07:58, Jeff Liebermann wrote:
It doesn\'t help that the loss tangent is specified at 100 KHz for #31
and at 10 MHz for #61. Just to make things weird, #31 includes this
cryptic statement:
This material does not have the dimensional resonance
limitations associated with conventional MZn ferrite
materials.
What\'s a \"dimensional resonance limitation\"?

I guess they mean magneto-striction induced mechanical resonance causing
cracking? I once used some small square-loop material toroids where the
datasheet said to avoid some frequencies to avoid cracking - these were
small cores and the frequencies to avoid were in the low hundreds kHz.

Yep, magnetostriction or magneto-elastic resonance:
<https://www.google.com/search?q=magnetoelastic+resonance+toroid+core>

<http://www.pa3fwm.nl/technotes/tn11a.html>
...an FT50-43 has a mean circumference of 32.04 mm; for
a soundwave to travel that distance 190,000 times per
second (resonance at 190 kHz), then the speed must be
6088 m/s. And sound speeds of about 6 km/s are indeed
normal for such materials, according to literature.

>Shouldn\'t be a problem at OPs 3-30MHz.

Agreed. #31 was apparently formulated for low frequency RFI
suppression as evident by the loss tangent being specified at 100KHz.
Mechanical resonance would likely be a problem at those frequencies.

>piglet

Thanks for the relevant terms.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[bitrex]

On 10/19/2020 1:28 PM, Joerg wrote:

On 10/19/20 8:31 AM, bitrex wrote:
On 10/19/2020 5:34 AM, Jan Panteltje wrote:
On a sunny day (Sun, 18 Oct 2020 15:33:15 -0700) it happened Joerg
news@analogconsultants.com> wrote in
hv3u5cF49h2U1@mid.individual.net>:

Attention, this is a non-political post, for a change

I recently found
  uk.radio.amateur.moderated
    may be worth asking there.
Still active and no noise!


As to antenna matching, antenna tuners can match any piece of wire...
I have a small QRP one... kit from ebay...
  http://panteltje.com/pub/ebay_QRP_antenna_tuner_IXIMG_0552.JPG
search ebay for  \"QRP MANUAL DAYS ANTENNA TUNER TUNE DIY KIT 1 - 30 MHZ\"
100W would set it on fire.
  But think if you look for higher power they will have it, else
alieexpress:
   https://www.aliexpress.com/w/wholesale-automatic-antenna-tuner.html

why bother with single cores...


Bought some
  Micrometals Amidon T80-2 Iron Powder Toroidal
for experiments long time ago:
   https://toroids.info/T80-2.php

There are a lot of Usenet amateur radio groups:

http://www.panteltje.com/pub/usenet_amateur_radio_groups_IXIMG_0550.JPG
   the green ones are dead (no longer in active list on nntp.aioe.org),
   the red one is new,
   and the blue one is the one I am subscribed to ATM,
   have not checked the other ones for activity.


For the 10m band I have a GPA, no balun needed, ...


If your house is EMI-quiet that may be true. I found that any kind of
imbalance in the coax (meaning common mode curents) causes pickup from
stuff near the cable ... bzzz ... rat-tat-tat .. phssss. Wood frame
building construction doesn\'t help either.


150 W PEP, Ranger RCI2970DX.
Not much used these days.
Nothing for lower frequencies than that.


The #2 carbonyl iron material is a nice all-rounder material for just
regular inductors in the low MHz range, for inductors that need to
store energy. The only bummer is its pretty low Al value.


Yes, it\'s more suitable for a voltage mode transformer than a CM choke.


The #8 material is similar but with a nice boost to the Al value and a
little lower transition frequency, it\'s about 4 times the price though.

Commmon mode chokes don\'t need to store energy so a hard ferrite is
more appropriate, you can have Al values of like a thousand rather
than say, 25.


Until things get hot

Yeah I don\'t think I\'ve used a core bigger than a T50 in my own work,
I\'ll leave the high-power stuff to hams and professionals!

 

[Jeff Liebermann]

On Mon, 19 Oct 2020 10:24:53 -0700, Joerg <news@analogconsultants.com>
wrote:

Just a large current mode choke. I want to suppress coax shield currents
as much as possible. The antenna will be a multi-band ground plane
(10-15-20m) plus a 40m dipole in parallel. Later maybe an 80m dipole as
well.

Probably a Guanella type balun. Plenty of construction articles
available online. Also see articles by Walter Maxwell (W2DU), Owen
Duffy (VK1OD), and others. For example:
<https://owenduffy.net/balun/W2DU/index.htm>

All About the 1:1 Current/Choke Balun
<https://www.balundesigns.com/reference/all-about-the-11-currentchoke-balun/>

For symmetrical antennas, such as 1/2 wave dipoles and yagi antennas,
you don\'t really need a balun if you feed it with symmetrical ladder
line or twin-lead. As long as the currents through each wires is
equal and symmetrical, the feed line will not radiate. However, if
you follow my mistake, and install your antenna on a hillside, where
one half the dipole is closer to the ground than the other half,
you\'ll have some radiation from even the best ladder line. Therefore,
it\'s probably best to install a balun, even if the antenna design
appears to not need it.

Note: In my never humble opinion, asymmetrical antennas, such a the
G5RV are abominations that should be avoided.

The main reason is receive noise. If you do not suppress shield currents
well enough the coax becomes a small part of the antenna and picks up
all sorts of man-made noise from switch mode supplies.

I have a different theory about HF receive noise. Most of what the
receiver is hearing as noise is the product of mixes between multiple
noise sources in the bandpass of the antenna system (which includes
any balun, transmission lines, antenna tuner, and RF power meter).
Once the noise gets into the system, no amount of filtering will
remove mixes that land on the receive frequency. By my warped logic,
the only way to reduce the noise is to narrowband the antenna system
so that it doesn\'t pickup any out of band junk. That\'s opposite of
conventional wisdom which favors broadband systems. The usual result
is overloading (and mixing in) the first RF amplifier. The most
common fix is to improve the IP3 point of the receive RF amplifier
resulting in some rather high power dissipation in the receive RF
amplifier and first mixer. If the antenna and front end were not
trying to amplify the entire 2-30MHz HF band in one gulp, none of this
would be necessary. A really high Q and a very narrow antenna receive
bandwidth is how a small magnetic loop antenna works.

Another approach is to simply reduce the antenna gain. That reduces
the receive signal by some amount, but also reduces the noise by the
same amount. Eventually, the signal levels are small enough so that a
fairly simple RF amplifier can handle whatever the tiny antenna picks
up. See the various PA0RDT mini-whip variations:
<http://dl1dbc.net/SAQ/miniwhip.html>
<https://owenduffy.net/antenna/PA0RDT-MiniWhip/>
There\'s nothing in the \"rules\" that require you to use the same
antenna for transmit and receive.

Well, the legal limit is 1500W but I won\'t likely go there because then
the neighbor\'s electronics will likely keel over.

True, but the real problem is the antenna, any antenna. No sooner do
you install a big ugly antenna farm on your roof or tower, all manner
of electronic failure at the neighbors will be instantly attributed to
your activities. When I first moved into my house, I installed a 3ft
white fiberglass marine antenna on my roof. Within a week, I was
being blamed for poor TV and FM reception at two different neighbors
houses. This problem is partly responsible for the trend toward
smaller HF antennas.

Observation: The uglier the antenna, the better it works.

Thanks, that has interesting info in there that I hadn\'t pondered yet.
Resonance with the line, that could really mess things up. So I guess 31
material is better in the end and that is also what he uses.

Notice that most of Jim\'s assertions are backed by measurements and
experimental testing.

Send Jim (K9YC) an email and maybe he can help. Note that he just
recently returned from a rather protracted fire evacuation and might
be rather busy.

Ouch, that is tough. I better not bother him for now and just trust his
judgment that 31 material is the ticket.

Just send him an email at @arrl.net. If he\'s busy, he\'ll let you
know. I don\'t think it will be a bother. Just don\'t remind him that
I still have his Mirage VHF power amplifier that I\'m suppose to be
repairing.

I am not a QRP guy but my wild days of full legal power are nearly over.
If I can\'t use 1500W it\'ll be ok.

Plug: We have a local company that manufactures excellent ham radio
equipment:
<https://elecraft.com/products/kpa1500-amplifier>
Not involved with Elecraft in any manner.

You might become involved with QRP by using WSPR for testing your
transmit antenna system and checking propagation. See:
<http://wsprnet.org/drupal/node/6523>

At least for now. I\'ll jsut go with a
single FT-240-31 and if I ever need more power I\'ll stack two or three.

A bit more on which material to use:
<http://www.m0pzt.com/baluns/>
Notice the frequency range graph. If you want to go down to 3MHz, I
think you\'re stuck with #31. Also, notice the effect of more or less
turns of coax through the core.

>Thanks for the great input here.

Y\'er welcome.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Mon, 19 Oct 2020 12:04:56 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

I think this will help with the material selection:

\"High Performance Common Mode Chokes\"
<https://gm3sek.files.wordpress.com/2019/01/G3TXQ-RC.pdf>
See Fig 10. The author prefers stacking 2 or 3 FT240-xx toroids.
There\'s no ideal material or number of turns that will operate over
the entire 3-30MHz. It looks 10 small FB-31-1020 ferrite beads strung
over RG213 is the best overall. See the black horizontal line on the
graph for the optimum frequency range for each combination.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Joerg]

On 10/19/20 12:04 PM, Jeff Liebermann wrote:

On Mon, 19 Oct 2020 10:24:53 -0700, Joerg <news@analogconsultants.com
wrote:

Just a large current mode choke. I want to suppress coax shield currents
as much as possible. The antenna will be a multi-band ground plane
(10-15-20m) plus a 40m dipole in parallel. Later maybe an 80m dipole as
well.

Probably a Guanella type balun. Plenty of construction articles
available online. Also see articles by Walter Maxwell (W2DU), Owen
Duffy (VK1OD), and others. For example:
https://owenduffy.net/balun/W2DU/index.htm

All About the 1:1 Current/Choke Balun
https://www.balundesigns.com/reference/all-about-the-11-currentchoke-balun/

For symmetrical antennas, such as 1/2 wave dipoles and yagi antennas,
you don\'t really need a balun if you feed it with symmetrical ladder
line or twin-lead. As long as the currents through each wires is
equal and symmetrical, the feed line will not radiate. However, if
you follow my mistake, and install your antenna on a hillside, where
one half the dipole is closer to the ground than the other half,
you\'ll have some radiation from even the best ladder line.

Welcome to reality

We live in very hilly terrain and even the ground conductivity is
grossly different from 20ft down the yard.

... Therefore,
it\'s probably best to install a balun, even if the antenna design
appears to not need it.

The easiest test is to tune into a noise from a switcher or similar. If
you clamp a 43 clip-on ferrite around the coax and the amplitude drops
then you know there\'s shield current on the coax.

Note: In my never humble opinion, asymmetrical antennas, such a the
G5RV are abominations that should be avoided.

But they look so cool ...

The main reason is receive noise. If you do not suppress shield currents
well enough the coax becomes a small part of the antenna and picks up
all sorts of man-made noise from switch mode supplies.

I have a different theory about HF receive noise. Most of what the
receiver is hearing as noise is the product of mixes between multiple
noise sources in the bandpass of the antenna system (which includes
any balun, transmission lines, antenna tuner, and RF power meter).

If stuff mixes then either the receiver is lousy or there are corroded
contacts in the line and maybe nearby.

Once the noise gets into the system, no amount of filtering will
remove mixes that land on the receive frequency. By my warped logic,
the only way to reduce the noise is to narrowband the antenna system
so that it doesn\'t pickup any out of band junk. That\'s opposite of
conventional wisdom which favors broadband systems. The usual result
is overloading (and mixing in) the first RF amplifier. The most
common fix is to improve the IP3 point of the receive RF amplifier
resulting in some rather high power dissipation in the receive RF
amplifier and first mixer. If the antenna and front end were not
trying to amplify the entire 2-30MHz HF band in one gulp, none of this
would be necessary. A really high Q and a very narrow antenna receive
bandwidth is how a small magnetic loop antenna works.

I\'ve got good receivers with high IP3. The main one is a JRC NRD-515.
The transceiver is a JRC JST-100, also high IP3.

That transceiver has me worried after a hint from a friend. It is
controlled by an 8085 MCU (anyone remember those?) which gets its brain
contents from a 2732 EPROM. That EPROM is now almost 40 years old. I do
not have a programmer and modern TL866-based ones can\'t program those
anyhow. Might have to roach in a 27128. Disappointingly, the
manufacturer quit ham radio and could not even send me the code that\'s
in this EPROM.

Another approach is to simply reduce the antenna gain. That reduces
the receive signal by some amount, but also reduces the noise by the
same amount. Eventually, the signal levels are small enough so that a
fairly simple RF amplifier can handle whatever the tiny antenna picks
up. See the various PA0RDT mini-whip variations:
http://dl1dbc.net/SAQ/miniwhip.html
https://owenduffy.net/antenna/PA0RDT-MiniWhip/
There\'s nothing in the \"rules\" that require you to use the same
antenna for transmit and receive.

One day I am going to build myself a magnetic field receive antenna. Not
a priority though because the receiver can handle just about anything.

Well, the legal limit is 1500W but I won\'t likely go there because then
the neighbor\'s electronics will likely keel over.

True, but the real problem is the antenna, any antenna. No sooner do
you install a big ugly antenna farm on your roof or tower, all manner
of electronic failure at the neighbors will be instantly attributed to
your activities. When I first moved into my house, I installed a 3ft
white fiberglass marine antenna on my roof. Within a week, I was
being blamed for poor TV and FM reception at two different neighbors
houses. This problem is partly responsible for the trend toward
smaller HF antennas.

Or they might blame your equipment interference for making their
candidate losing in Dancing with the Stars

One of the reasons why keeping an electronic log might be a good idea.

Observation: The uglier the antenna, the better it works.

But ... I am married.

Thanks, that has interesting info in there that I hadn\'t pondered yet.
Resonance with the line, that could really mess things up. So I guess 31
material is better in the end and that is also what he uses.

Notice that most of Jim\'s assertions are backed by measurements and
experimental testing.

Yes, I noted that and promptly ordered a FT-240-31.

[...]

I am not a QRP guy but my wild days of full legal power are nearly over.
If I can\'t use 1500W it\'ll be ok.

Plug: We have a local company that manufactures excellent ham radio
equipment:
https://elecraft.com/products/kpa1500-amplifier
Not involved with Elecraft in any manner.

A friend in Germany is a fan of their stuff.

You might become involved with QRP by using WSPR for testing your
transmit antenna system and checking propagation. See:
http://wsprnet.org/drupal/node/6523

Yeah, all those digital modes did not exist when I was a ham in Germany
(DK9JK) and now I had to learn all that for the US exams (now it\'s
AJ6QL). Might as well try using some of it one day.

At least for now. I\'ll jsut go with a
single FT-240-31 and if I ever need more power I\'ll stack two or three.

A bit more on which material to use:
http://www.m0pzt.com/baluns/
Notice the frequency range graph. If you want to go down to 3MHz, I
think you\'re stuck with #31. Also, notice the effect of more or less
turns of coax through the core.

Yup. One of the reasons I decided to order a 31 core. Not sure if I ever
do 1.8MHz, first I\'ll have to find out if there is anything interesting
going on down there. In this area 7MHz seems to be the main band.

To my utter surprise 440MHz is also quite busy so I bought a Diamond
X50A dual-band vertical.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 10/19/20 11:32 AM, bitrex wrote:

On 10/19/2020 1:28 PM, Joerg wrote:
On 10/19/20 8:31 AM, bitrex wrote:

[...]

The #8 material is similar but with a nice boost to the Al value and
a little lower transition frequency, it\'s about 4 times the price
though.

Commmon mode chokes don\'t need to store energy so a hard ferrite is
more appropriate, you can have Al values of like a thousand rather
than say, 25.


Until things get hot


Yeah I don\'t think I\'ve used a core bigger than a T50 in my own work,
I\'ll leave the high-power stuff to hams and professionals!

It\'s not just hams. I used a lot of this stuff in medical ultrasound
designs. However, those all had to be voltage mode baluns in order to
provide a 5kV-rated defibrillator-proof isolation barrier.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[amdx]

On 10/18/2020 11:00 PM, Joerg wrote:

On 10/18/20 5:22 PM, amdx wrote:
On 10/18/2020 5:33 PM, Joerg wrote:
Attention, this is a non-political post, for a change

Getting back into ham radio after a decades-long hiatus I need to
make a balun for 3-30MHz. Essentially just a glorified common-mode
choke and preferably without an extra 3rd magnetizing winding.
Realistically I won\'t use more than 200W but it would be nice if it
can take more. There are a bunch of new materials that showed up
which I can\'t remember from the 80\'s. From some research on the web
it seems 61-material is a really good contender when it comes to low
core loss yet acceptable permeability. So I was thinking of getting
an FT240-61 core. What do thee think?

Main reason I ask is that I remember having blown up a few baluns
back in the days and I don\'t want this thing to cause a meltdown
here in bone-dry California.

   From all my reading of other peoples work, I have not seen where
anyone uses

material 61 for a multiband ham antenna.  From one of W8ji balun
pages, one criteria he uses is

curie temperature. He uses 75 for receiving antennas, but because of
it\'s lower curie temperature,


He actually recommends, among other things, 61:

http://www.w8ji.com/core_selection.htm

Quote \"At higher power levels, it is necessary to move to lower loss
tangent and higher curie temperature materials like 65, 61, or (in
extreme cases) 43 materials.”

Not sure why he recommend 43 though because that\'s lossy. Gets hot.



  not for power baluns. Sorry in my 10 minutes searching, I couldn\'t
find what material he does use.

Mikek

If that\'s the case you might try  a cross referenced part,
Phillips\\Ferroxcube 4C6 or 4C65. Unless you want  to use a rod.

I think it takes a lot of turns though, maybe that\'s why the end up with 43.

                                    Mikek



--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

[Joerg]

On 10/19/20 2:50 PM, amdx wrote:

On 10/18/2020 11:00 PM, Joerg wrote:
On 10/18/20 5:22 PM, amdx wrote:
On 10/18/2020 5:33 PM, Joerg wrote:
Attention, this is a non-political post, for a change

Getting back into ham radio after a decades-long hiatus I need to
make a balun for 3-30MHz. Essentially just a glorified common-mode
choke and preferably without an extra 3rd magnetizing winding.
Realistically I won\'t use more than 200W but it would be nice if it
can take more. There are a bunch of new materials that showed up
which I can\'t remember from the 80\'s. From some research on the web
it seems 61-material is a really good contender when it comes to low
core loss yet acceptable permeability. So I was thinking of getting
an FT240-61 core. What do thee think?

Main reason I ask is that I remember having blown up a few baluns
back in the days and I don\'t want this thing to cause a meltdown
here in bone-dry California.

   From all my reading of other peoples work, I have not seen where
anyone uses

material 61 for a multiband ham antenna.  From one of W8ji balun
pages, one criteria he uses is

curie temperature. He uses 75 for receiving antennas, but because of
it\'s lower curie temperature,


He actually recommends, among other things, 61:

http://www.w8ji.com/core_selection.htm

Quote \"At higher power levels, it is necessary to move to lower loss
tangent and higher curie temperature materials like 65, 61, or (in
extreme cases) 43 materials.”

Not sure why he recommend 43 though because that\'s lossy. Gets hot.



  not for power baluns. Sorry in my 10 minutes searching, I couldn\'t
find what material he does use.

Mikek





If that\'s the case you might try  a cross referenced part,
Phillips\\Ferroxcube 4C6 or 4C65. Unless you want  to use a rod.

I think it takes a lot of turns though, maybe that\'s why the end up with
43.

I ordered an FT-240-31 core this morning. It\'s probably a good
compromise between Al value (low number of turns) and core losses. Long
term I likely have to cover 3.5MHz as well and maybe even 1.8MHz. We\'ll
see. If it becomes too hot I can buy another and stack them. That was my
mistake as a teenager. I only had the funds for one core, wasn\'t enough
.... poof. Well, to be honest, I had the funds for two but half was
invested in a crate of beer. Plus we could only buy 2\" cores back then,
2-1/2\" might have survived.

For receive it would be easy because there\'d be no risk of a meltdown or
kablouie.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Jeff Liebermann]

On Mon, 19 Oct 2020 12:36:42 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Mon, 19 Oct 2020 12:04:56 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

I think this will help with the material selection:

\"High Performance Common Mode Chokes\"
https://gm3sek.files.wordpress.com/2019/01/G3TXQ-RC.pdf
See Fig 10. The author prefers stacking 2 or 3 FT240-xx toroids.
There\'s no ideal material or number of turns that will operate over
the entire 3-30MHz. It looks 10 small FB-31-1020 ferrite beads strung
over RG213 is the best overall. See the black horizontal line on the
graph for the optimum frequency range for each combination.

Oops. Looks like the author does NOT like the 10 beads over RG213
coax. Quoting:
G3TXQ Choke Chart. The chart in Fig 10 shows my
recommendations for a range of high-performance
ferrite chokes, between them covering all the HF
amateur bands. Be warned that the last three are
examples that you should not follow!
Sorry. I missed that during my first reading.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Clifford Heath]

On 20/10/20 2:34 am, Joerg wrote:

On 10/18/20 11:34 PM, Clifford Heath wrote:
On 19/10/20 2:43 pm, Joerg wrote:
On 10/18/20 4:03 PM, Clifford Heath wrote:
On 19/10/20 9:33 am, Joerg wrote:
Attention, this is a non-political post, for a change

Getting back into ham radio after a decades-long hiatus I need to
make a balun for 3-30MHz. Essentially just a glorified common-mode
choke and preferably without an extra 3rd magnetizing winding.
Realistically I won\'t use more than 200W but it would be nice if it
can take more. There are a bunch of new materials that showed up
which I can\'t remember from the 80\'s. From some research on the web
it seems 61-material is a really good contender when it comes to
low core loss yet acceptable permeability. So I was thinking of
getting an FT240-61 core. What do thee think?

Main reason I ask is that I remember having blown up a few baluns
back in the days and I don\'t want this thing to cause a meltdown
here in bone-dry California.

The EFHW antenna enthusiasts on the Facebook group seem to use type
43 material. Two FT240-43 toroids handle over 100W, and three, up to
1kW (not sure about duty cycles, probably SSB ham chatter). Type 52
is another option, lower loss but lower power handling.


43 is also my goto material but for EMI cases. For this application
it has too much resistive losses.


You might find more in this article (which I haven\'t read in depth):
https://lookaside.fbsbx.com/file/EFHW%20German%20Article.pdf


\"Arcticle isn\'t available\". I guess only for Facebook members. Only
over my dead body


Ahh, sorry I don\'t know about that. The article seems to have been
removed since I posted it. My downloaded copy is now here:
https://www.dropbox.com/s/lze82hwbbhhxcen/EFHW%20German%20Article.pdf?dl=0


Thanks. On page 12 he talks about his \"sheath current lock\" or
Mantelwellensperre in German (common-mode choke) but not which core he
used. It looks fat but small in diameter. Also, he spread te wires a bit
far, it\'s usually better to use a bifilar winding technique.

Not for this type of unun. The 1:64 impedance ratio (more commonly 1:49
or 1:56 is used) is made with a 2 turn primary twisted onto the first
two turns of 14, 15 or 16 turns. This creates a very high output
impedance suitable for driving very near the end of a dipole. The
windings are best when they\'re spaced close initially, then further and
further apart, with a cross-over in the middle. If you crunch them up
you get too much distributed capacitance for the >2400 ohm output
impedance. It also needs 100pF across the primary to work well on the
higher bands.

What\'s really nice about this type of antenna is when you hang and cut
the wire right to resonate on 40m (or 80m), it also resonates in higher
modes on 20&10m (or 40&20m with reduced performance on 10m) and that
means you can operate three bands without using an antenna tuner. The
lowest band chosen tends to resonate a little low (depending on wire
height in the middle vs the ends) which some folk fix by adding 50uH
about 2m away from the unun.

This is very different from a 9:1 (3:1 turns ratio) antenna, which has a
much lower feedpoint impedance and will not resonate on multiple bands;
it needs a tuner.

The unun should be grounded with a short path, and far away from E-field
noise sources (often away from the shack). Any residual RF current on
the coax is rejected with a CMC.

That\'s my setup anyhow, and a lot of other folk find it works really
well, low SWR and great efficiency without needing a tuner.

Clifford Heath.

 

[Tauno Voipio]

On 19.10.20 22.04, Jeff Liebermann wrote:

On Mon, 19 Oct 2020 10:24:53 -0700, Joerg <news@analogconsultants.com
wrote:


Note: In my never humble opinion, asymmetrical antennas, such a the
G5RV are abominations that should be avoided.

Jeff,

A G5RV is a symmetrical dipole with impedance-stepped feed.
You may be thinking of Windoms.

--

-Tauno Voipio (OH2UG)

 

[Don]

Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> wrote:

<snip>

There are a lot of Usenet amateur radio groups:
http://www.panteltje.com/pub/usenet_amateur_radio_groups_IXIMG_0550.JPG
the green ones are dead (no longer in active list on nntp.aioe.org),
the red one is new,
and the blue one is the one I am subscribed to ATM,
have not checked the other ones for activity.

The signal-to-noise ratio on most groups looks high thanks to moderators
who muzzle churls and blarney spewers.

Danke,

--
Don, KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Don]

Jeff Liebermann <jeffl@cruzio.com> wrote:

<snip>

Plug: We have a local company that manufactures excellent ham radio
equipment:
https://elecraft.com/products/kpa1500-amplifier
Not involved with Elecraft in any manner.

A brand spanking new Elecraft K-3 kit was acquired after my decades old
Kenwood TS-440S broke down once too often. (The Kenwood-TS440S groups.io
mail list is an invaluable resource for TS440S DIY repairs.)
The K-3 uses innovative construction techniques to allow assembly of
a \"top shelf\" radio from small pieces of sheet metal:
https://cdn.shopify.com/s/files/1/2029/4979/products/k3s-silo-product_530x@2x.jpg
It\'s a joy to operate. It features an RS-232 interface to allow
operators to use software to remotely control about a hundred parameters
instead of fiddling with its front panel.

Danke,

--
Don, KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Joerg]

On 10/19/20 5:58 PM, Clifford Heath wrote:

On 20/10/20 2:34 am, Joerg wrote:
On 10/18/20 11:34 PM, Clifford Heath wrote:
On 19/10/20 2:43 pm, Joerg wrote:
On 10/18/20 4:03 PM, Clifford Heath wrote:
On 19/10/20 9:33 am, Joerg wrote:
Attention, this is a non-political post, for a change

Getting back into ham radio after a decades-long hiatus I need to
make a balun for 3-30MHz. Essentially just a glorified common-mode
choke and preferably without an extra 3rd magnetizing winding.
Realistically I won\'t use more than 200W but it would be nice if
it can take more. There are a bunch of new materials that showed
up which I can\'t remember from the 80\'s. From some research on the
web it seems 61-material is a really good contender when it comes
to low core loss yet acceptable permeability. So I was thinking of
getting an FT240-61 core. What do thee think?

Main reason I ask is that I remember having blown up a few baluns
back in the days and I don\'t want this thing to cause a meltdown
here in bone-dry California.

The EFHW antenna enthusiasts on the Facebook group seem to use type
43 material. Two FT240-43 toroids handle over 100W, and three, up
to 1kW (not sure about duty cycles, probably SSB ham chatter). Type
52 is another option, lower loss but lower power handling.


43 is also my goto material but for EMI cases. For this application
it has too much resistive losses.


You might find more in this article (which I haven\'t read in depth):
https://lookaside.fbsbx.com/file/EFHW%20German%20Article.pdf


\"Arcticle isn\'t available\". I guess only for Facebook members. Only
over my dead body


Ahh, sorry I don\'t know about that. The article seems to have been
removed since I posted it. My downloaded copy is now here:
https://www.dropbox.com/s/lze82hwbbhhxcen/EFHW%20German%20Article.pdf?dl=0


Thanks. On page 12 he talks about his \"sheath current lock\" or
Mantelwellensperre in German (common-mode choke) but not which core he
used. It looks fat but small in diameter. Also, he spread te wires a
bit far, it\'s usually better to use a bifilar winding technique.

Not for this type of unun. The 1:64 impedance ratio (more commonly 1:49
or 1:56 is used) is made with a 2 turn primary twisted onto the first
two turns of 14, 15 or 16 turns. This creates a very high output
impedance suitable for driving very near the end of a dipole. The
windings are best when they\'re spaced close initially, then further and
further apart, with a cross-over in the middle. If you crunch them up
you get too much distributed capacitance for the >2400 ohm output
impedance. It also needs 100pF across the primary to work well on the
higher bands.

He has a CM choke in there (says Mantelwellensperre on the lid) but it\'s
not the big white round toroid, it is the black slot core up top.
Surprisingly small.

What\'s really nice about this type of antenna is when you hang and cut
the wire right to resonate on 40m (or 80m), it also resonates in higher
modes on 20&10m (or 40&20m with reduced performance on 10m) and that
means you can operate three bands without using an antenna tuner. The
lowest band chosen tends to resonate a little low (depending on wire
height in the middle vs the ends) which some folk fix by adding 50uH
about 2m away from the unun.

This is very different from a 9:1 (3:1 turns ratio) antenna, which has a
much lower feedpoint impedance and will not resonate on multiple bands;
it needs a tuner.

I mounted five coax connections in the feedthrough box plus there will
be 16 control wires for relays and such. That leaves me lots of room for
antenna experiments.

The unun should be grounded with a short path, and far away from E-field
noise sources (often away from the shack). Any residual RF current on
the coax is rejected with a CMC.

Grounding is a major challenge here. Huge rocks everywhere and low soil
conductivity.

That\'s my setup anyhow, and a lot of other folk find it works really
well, low SWR and great efficiency without needing a tuner.

No tuner is what I like as well. Never had one and not planning on one
now. I am ok not having all bands. 15m and 40m will probably be my main
roaming places, later maybe 20m and, hoping the sun spots will become
more favorable, 10m.

In Europe most local traffic happened on 80m but here on the US West
Coast 40m seems busier and more interesting. An 80m dipole will likely
follow some day but that requires a small pole on the other side of the
driveway and there are ... huge rocks in the ground.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Clifford Heath]

On 21/10/20 12:43 pm, Joerg wrote:

On 10/19/20 5:58 PM, Clifford Heath wrote:
On 20/10/20 2:34 am, Joerg wrote:
On 10/18/20 11:34 PM, Clifford Heath wrote:
https://www.dropbox.com/s/lze82hwbbhhxcen/EFHW%20German%20Article.pdf?dl=0
Thanks. On page 12 he talks about his \"sheath current lock\" or
Mantelwellensperre in German (common-mode choke) but not which core
he used. It looks fat but small in diameter. Also, he spread te wires
a bit far, it\'s usually better to use a bifilar winding technique.

Not for this type of unun. The 1:64 impedance ratio (more commonly
1:49 or 1:56 is used) is made with a 2 turn primary twisted onto the
first two turns of 14, 15 or 16 turns.
He has a CM choke in there (says Mantelwellensperre on the lid) but it\'s
not the big white round toroid, it is the black slot core up top.
Surprisingly small.

If you run a long enough co-ax to your feedpoint you can probably do
without a CMC. As I said, you get better noise performance if the unun
is away from the house wiring (unlike mine).

What\'s really nice about this type of antenna is when you hang and cut
the wire right to resonate on 40m (or 80m), it also resonates in
higher modes on 20&10m (or 40&20m with reduced performance on 10m) and
that means you can operate three bands without using an antenna tuner.
The lowest band chosen tends to resonate a little low (depending on
wire height in the middle vs the ends) which some folk fix by adding
50uH about 2m away from the unun.

This is very different from a 9:1 (3:1 turns ratio) antenna, which has
a much lower feedpoint impedance and will not resonate on multiple
bands; it needs a tuner.
I mounted five coax connections in the feedthrough box plus there will
be 16 control wires for relays and such. That leaves me lots of room for
antenna experiments.

The unun should be grounded with a short path, and far away from
E-field noise sources (often away from the shack). Any residual RF
current on the coax is rejected with a CMC.
Grounding is a major challenge here. Huge rocks everywhere and low soil
conductivity.

The average soil depth here is perhaps 20cm. The rest is Sydney
sandstone. I ran coax through our metal roof (ca 200m^2) and call that
\"RF ground\".

You might need to splay out a dozen ground wires, if possible.

That\'s my setup anyhow, and a lot of other folk find it works really
well, low SWR and great efficiency without needing a tuner.
In Europe most local traffic happened on 80m but here on the US West
Coast 40m seems busier and more interesting. An 80m dipole will likely
follow some day but that requires a small pole on the other side of the
driveway and there are ... huge rocks in the ground.

It is as common here to own a jack-hammer as it is to own a shovel.
But the alternative is to get a fence-builder in with a core drill and
make a nice hole in the rock. I plan to get a \"flagpole\" aka antenna
mast mounted that way, to avoid the need for guy wires.

CH

 

[Jan Panteltje]

On a sunny day (Tue, 20 Oct 2020 18:43:24 -0700) it happened Joerg
<news@analogconsultants.com> wrote in <hv9i1sF9o69U1@mid.individual.net>:

No tuner is what I like as well. Never had one and not planning on one
now. I am ok not having all bands. 15m and 40m will probably be my main
roaming places, later maybe 20m and, hoping the sun spots will become
more favorable, 10m.

The issue is that not everyone has space for long antennas.


>In Europe most local traffic happened on 80m

Most local traffic is on 70 cm here in the Netherlands, via repeaters.

And now we have access to the QO100 stationary satellite for audio an video SSB and DVB-S2.
2.4 GHz uplink, ~10 GHz downlink, small dish will do for SSB, websdr:
https://eshail.batc.org.uk/nb/
covers most of Europe and part of South America.

Finally I think you perhaps blocked nntp.aioe.org ?
the only free Usenet server that is still usable!

As to problems with GPA antennas, last place I lived almost everybody had one for CB...
When the across the road neighbor was transmitting I could light a LED with my antenna.

Here I can see an other one from here...
But CB is very quiet these days.

With one Baofeng on 70cm I cover the north east of the country via the repeaters.

Of course cellphones work even better, worldwide

In comparison it is an expensive hobby, ham radio.
But experimenting is fun:
http://panteltje.com/panteltje/raspberry_pi_dvb-s_transmitter/

digital.

When next WW happens maybe Morse an tubes again...