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

[Jeff Liebermann]

On Tue, 20 Oct 2020 14:27:45 +0300, Tauno Voipio
<tauno.voipio@notused.fi.invalid> wrote:

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.

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

Oops. You\'re right. A G5RV is symmetrical. I was thinking of a
different OCF (off center fed) antenna, possibly a Windom.
<https://www.google.com/search?q=ocf+antenna>

<Excuse> I don\'t do much with HF antennas. Mostly, I do VHF and up.
<http://www.learnbydestroying.com/jeffl/antennas/>
I\'ve never built, used, measured, or repaired a G5RV antenna.
</Excuse>


--
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 Tue, 20 Oct 2020 18:43:24 -0700, Joerg <news@analogconsultants.com>
wrote:

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

If you run a balanced HF antenna system, you don\'t need a ground.
Yeah, I know this is heresy:
<https://www.electronics-notes.com/articles/antennas-propagation/grounding-earthing/how-to-ground-earth-antenna-aerial.php>
Some types of antenna are unbalanced and are designed
to operate with a ground connection to enable them to
operate correctly. Balanced antennas like dipoles do
not need an RF ground for their correct operation as
long as common-mode currents are kept off the feeder.
However, even with a balanced antenna system, you might need a ground
to deal with lightning hits, electrical safety, and
building/electrical code requirements. If your station is full of RF
(everything you touch is RF hot), you did something wrong.

If you have a septic tank, cram some wire down the cleanout for a
ground. Fiberglass tanks don\'t work too well but there\'s enough
capacitance between the sewage and the ground to get some kind of
ground. Concrete tanks are better because the concrete is about 50%
water. Note that ground conductivity is sometimes used to detect a
leaking septic system. If your HF grounding results are too good to
be true, your tank is probably leaking or your leach field is flooded.
Also, you can get good results if your buried water lines are
galvanized steel.

Anyway, think of using symmetrical antennas, avoid asymmetrical or
monopole antennas, and don\'t worry (much) about grounding.

--
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 10/20/20 7:45 PM, Clifford Heath wrote:

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. ...

Only if the coax isn\'t parallel to mains wiring a lot. In Germany that
was the case, here not so much and the noise sources have greatly
multiplied because almost every power supply is switch-mode now. Plus
all those CFL and LED lights.

... As I said, you get better noise performance if the unun
is away from the house wiring (unlike mine).

Of course. Mine will be right at the feed point of ground plane and 40m
dipole. They\'ll be tied together except the \"hot\" leg of the 40m dipole
will have a 21MHz trap in series, so it won\'t resonate there and steal
energy from the ground plane. I am hoping a 1\" diameter #6 iron powder
core will suffice for the trap inductor because that\'s the biggest I
have and can fit inside the balun box.

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 would be very tough here. However, there is a copper water pipe to
the pool pump house that starts off about 10ft from where all the coaxes
enter the house. This is also where the coaxes are all bonded together.

When they built that pool and some of the trenches around 1970 that work
was started before the house (any any other house nearby) because they
needed dynamite.

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.

I still need to get a pole for the 2m/70cm stuff. Not my wind load, just
a Diamond X50A vertical and a folded 2m dipole horizontal. I was
planning on EMT conduit. Unfortunately they only sell 10ft sections,
20ft are nearly unobtanium here. So I\'ll have to join two, in a way that
it won\'t shake loose so I don\'t need guy wires. This concoction will ba
supported about 6ft up from the ground via connection to a balcony rail.

The flag poles they sell around here are expensive and often tapered.
And they often come with a flag

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 10/20/20 10:50 PM, Jan Panteltje wrote:

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.

Out here most people do. 40m is probably more practical for the terrain
and distances.

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.

Cool. Like the big repeater in the sky.

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

Blocked? Their web site shows up here. I am using news.individual.de in
Berlin, Germany. It\'s only 10 Euros per year, a very small price for a
reliable service. No binaries but most other folks don\'t have access to
those anyhow so sharing schematics that way is no longer practical.

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

Until one fine day when that network quits. I\'ve experienced it numerous
times and then ham radio can become a lifeline. For example, when a
neighbor has a stroke and nobody else can call an ambulance because
everyone ditched their landlines.

Same on mountain trails which is one reasons why we have the KA6GWY-R
High Sierra repeater. One of its purposes is to provide emergency
communications when somebody messed up big time on the Rubicon trail (no
cell coverage).

In comparison it is an expensive hobby, ham radio.

I do not find it epensive but I built a lot of stuff myself and except
for a litte Baofeng UV-5R I never bought any gear new. All used or even
worse, defective and then I repaired it.

But experimenting is fun:
http://panteltje.com/panteltje/raspberry_pi_dvb-s_transmitter/

Hey, the usual solder spatters on the schematics are missing

digital.

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

I have an old HW100 for \"post-EMP communications\". Regarding digital
modes I am a rookie and may remain that for a while. CW has been more
fun so far.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 10/20/20 11:35 PM, Jeff Liebermann wrote:

On Tue, 20 Oct 2020 18:43:24 -0700, Joerg <news@analogconsultants.com
wrote:

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

If you run a balanced HF antenna system, you don\'t need a ground.
Yeah, I know this is heresy:
https://www.electronics-notes.com/articles/antennas-propagation/grounding-earthing/how-to-ground-earth-antenna-aerial.php
Some types of antenna are unbalanced and are designed
to operate with a ground connection to enable them to
operate correctly. Balanced antennas like dipoles do
not need an RF ground for their correct operation as
long as common-mode currents are kept off the feeder.
However, even with a balanced antenna system, you might need a ground
to deal with lightning hits, ...

Bingo.

... electrical safety, and
building/electrical code requirements. If your station is full of RF
(everything you touch is RF hot), you did something wrong.

One big scare when I was a teenager: My arm happened to be near the coax
and I was blasting away at around a kilowatt on IIRC 20m. Suddenly the
lower right arm experienced a sharp pain. When I touched it with my
other hand it was at a high temperature ...

If you have a septic tank, cram some wire down the cleanout for a
ground. Fiberglass tanks don\'t work too well but there\'s enough
capacitance between the sewage and the ground to get some kind of
ground. Concrete tanks are better because the concrete is about 50%
water. Note that ground conductivity is sometimes used to detect a
leaking septic system. If your HF grounding results are too good to
be true, your tank is probably leaking or your leach field is flooded.

Yuck!

Also, you can get good results if your buried water lines are
galvanized steel.

Not the kind of pipe I saw lately. Totally rusted and crudded.
Galvanization after 50 years is usually ... gone.

However, we have a buried copper pipe going to a pool pump house and
that is only 10ft from my coax feed-through into the house.

Anyway, think of using symmetrical antennas, avoid asymmetrical or
monopole antennas, and don\'t worry (much) about grounding.

For 20m and up a ground plane is usually beneficial and given that there
isn\'t space for a ton of radials this will never be symmetrical. So that
has to go through the balun just to make sure the coax jacket doesn\'t
become part of the antenna and pick up noise from the house.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Jan Panteltje]

On a sunny day (Wed, 21 Oct 2020 08:05:31 -0700) it happened Joerg
<news@analogconsultants.com> wrote in <hvb11rFj69mU1@mid.individual.net>:

On 10/20/20 10:50 PM, Jan Panteltje wrote:
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.


Out here most people do. 40m is probably more practical for the terrain
and distances.

My current place will be rebuild for \'gas free\', the idea is that I will move house
around the end of this year to a different castle just a few miles from here.
That one has a very large garden, even wine grapes grow there, tasted them!
Is being carpeted now for me.
The idea came up to put a large dish for QO100 in the back of that garden so it can just beam
over the house.
But it involves also getting power there etc....

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.


Cool. Like the big repeater in the sky.

It covers Africa too.
There is a lot of German chat on SSB on it, French, English, even Dutch.

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


Blocked? Their web site shows up here. I am using news.individual.de in
Berlin, Germany. It\'s only 10 Euros per year, a very small price for a
reliable service. No binaries but most other folks don\'t have access to
those anyhow so sharing schematics that way is no longer practical.

OK, well why pay if you can get it for free.,,,
I have a website and put everything I want to publish on it, is more expensive but gives full control,
and no ads.

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


Until one fine day when that network quits. I\'ve experienced it numerous
times and then ham radio can become a lifeline. For example, when a
neighbor has a stroke and nobody else can call an ambulance because
everyone ditched their landlines.

Yes, I keep my Ranger stuff for that.

Same on mountain trails which is one reasons why we have the KA6GWY-R
High Sierra repeater. One of its purposes is to provide emergency
communications when somebody messed up big time on the Rubicon trail (no
cell coverage).

Yes distances are much less here, next doctor is one street away,

In comparison it is an expensive hobby, ham radio.


I do not find it epensive but I built a lot of stuff myself and except
for a litte Baofeng UV-5R I never bought any gear new. All used or even
worse, defective and then I repaired it.

In my school days I build a 250 W what was it 7 MHz linear as exam piece,
school had a license.
PE1-100 tube, man that was in the sixties!

Not much of a QSO maker, once it works I move to the next thing it seems.
But yes I have build all that stuff.
Also had some army stuff, 31 set... 40-48MHz, FM:
https://www.pa3esy.nl/military/gb/army/ws-31-AFV/html/ws-31-afv_set.html
As kid I bought that in the army surplus, got it working in one afternoon, called on some frequency
got the army asking me who I was, switched it off
You do not mess with them

But experimenting is fun:
http://panteltje.com/panteltje/raspberry_pi_dvb-s_transmitter/


Hey, the usual solder spatters on the schematics are missing


digital.

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


I have an old HW100 for \"post-EMP communications\". Regarding digital
modes I am a rookie and may remain that for a while. CW has been more
fun so far.

In highschool I once build a spark transmitter.. not even tubes,,,
RF is easy to make.

The big problem with the lower frequency bands the days is the interference from all the switchmode wallwarts etc etc..

On the 10 meter band it is already much better, worked South America S9 on that, all you need
is a bit decent conditions, and then the GPA works very well.
A wire dipole has directivity, different up-beam angle.
https://www.electronicdesign.com/technologies/wireless/article/21799716/whats-the-difference-between-a-dipole-and-a-ground-plane-antenna
?
<ducks>

 

[Clifford Heath]

On 22/10/20 1:48 am, Joerg wrote:

On 10/20/20 7:45 PM, Clifford Heath wrote:
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. ...
Only if the coax isn\'t parallel to mains wiring a lot.

Of course. The main reason for running a long co-ax is to get the feed
point away from the house.

In Germany that
was the case, here not so much and the noise sources have greatly
multiplied because almost every power supply is switch-mode now. Plus
all those CFL and LED lights.

And solar power inverters. A lot of installations here use the Israeli
SolarEdge systems, which use a \"power optimiser\" aka DC-DC converter on
every panel, with signalling superimposed on the DC feed. It means they
can handle situations where some panels in a string get shaded, but they
do make quite a bit of noise. I installed passive strings with a Fronius
inverter (and extra ferrites on that) and using a 15cm sniffer loop, the
spectrum analyser can\'t hear anything from more than 1m away.

The unun should be grounded with a short path,
You might need to splay out a dozen ground wires, if possible.
That would be very tough here.

The local ground isn\'t essential because there isn\'t much return current
(c.f. the high feed impedance) and you can ground that inside the shack
or elsewhere if you need to. It just means that your coax acts as a
partial counterpoise and changes the tuned length.

When they built that pool and some of the trenches around 1970 that work
was started before the house (any any other house nearby) because they
needed dynamite.

Hydraulic rock splitters (inserted into core-drilled 50mm holes) and
large diamond saws (like 1.5-2m diameter) are seeing a lot of use here
in Sydney.

> I still need to get a pole for the 2m/70cm stuff.

I bolted a pole through the metal roof onto the top of a wall and into
the crossing point of two rafters. It was a rather painful job, but it
supports a decent pole with the Ringo (2m/70cm) on top (and other antennas).

I drilled access holes 40cm from the top of the through pipe, stuffed
wadding above that so I could seal it with silicone (leaving the top
section for the Ringo to slide into) so the antenna cables come up
inside the pole rather than through a separate roof penetration. The
perforations are covered by a sliding PVC \"umbrella\" I made by shrinking
a piece of PVC pipe onto the pole. You can shrink PVC to fit rightly
using a hot air gun and hose clamps. Duct tape provides the final seal.

> The flag poles they sell around here are expensive and often tapered.

I picked up a used sailboat mast for a flagpole. I just need to set a
base into the rock to support it. Some folk use fiberglass squid poles,
which are telescopic and available above 10m. Perhaps not so long-lived
but good for portable ops.

CH