Hf Antenna Question - so what's the conclusion?
 

Ian White GM3SEK wrote:
Sorry, maybe there's language barrier here. Imagine coiling a rope in
your hand like a cowboy, then laying the coil on the ground. I meant a
"flat" coil in that sense, as opposed to the other way of winding these
chokes on a cylindrical former.

A lot of arguments are over semantics. Again, there are
three ways of winding the chokes; helical, flat spiral,
and bunched like a cowboy rope. The flat spiral is also
known as a "pancake" choke or coil.
--
73, Cecil http://www.w5dxp.com

Hf Antenna Question - so what's the conclusion?
 

Richard Clark wrote:
Ian White GM3SEK wrote:
that the ARRL was overly optimistic when
they asserted that a coiled coax choke can cover
all three octaves of HF.

Agreed.

Really? 3 to 30 MHz is more than three octaves:
3 - 6 - 12 - 24 + 1/3 octave more

3 is not in the ham bands. 3.6 - 7.2 - 14.4 - 28.8
There's the three octaves the ARRL was talking about.
--
73, Cecil http://www.w5dxp.com

Hf Antenna Question - so what's the conclusion?
 

Dave wrote:
Christopher Cox wrote:

SNIPPED


You have recognized a GREAT TRUTH about this group. There NEVER is a
conclusion! Oh, there are subthreads, red herring threads, three
month continuous running threads, insulting threads, I am better than
you are threads, even threads that remain close to the original subject.

But, there is NEVER a concluding post to a thread.


/s/ DD ... I wrote the above



Actually there was enough information to conclude if you want an all
hf band 1:1 balun, abandoning the coiled coax and using ferrite may be
the way to go.

Wow, what a run on sentence!


Which sentence? Mine is totally grammatically correct.

A real run on sentence will be found if you study the serious works of
some Jesuit Priests. When I was in seminary I had to read/study some
Jesuit theology texts. The first sentence took three pages. One chapter
took an 8 hour flight from Boston to LA. And, I still didn't finish :-(

But, they were grammatically correct ... Does that mean your sentence is
too short? :-)

Now, hopefully to conclude this thread [well maybe] I agree that a
broadband ferrite balun is the way to go for typical HF.

/s/ DD


Hi Dave,

I am notorious for my poor grammar and run on sentence creation. It was
a knee jerk reaction of mine to point out my poor grammar before someone
else does.

But three pages! Wow that beats any sentence I could come up with.

Regards,

Chris

Hf Antenna Question - so what's the conclusion?
 

Dave wrote:
wrote:

Ian White (GM3SEK), Cecil Moore (W5DXP), and probably others have
discused HF chokes made from flat vs. bunched coils of coaxial cable,
but I must have missed some posting(s), for I haven't recognized
anything that looks like a CONCLUSION.

* Is "bunched" or "flat" better?
* Are they basically single-band or wide-band or somewhere in-between?
* Are there "rules of thumb" to make them for hams with
* No test equipment?
* A grid-dip meter?
* A noise bridge?
* An antenna analyzer?


Conclusions! You want WHAT??

You have recognized a GREAT TRUTH about this group. There NEVER is a
conclusion! Oh, there are subthreads, red herring threads, three month
continuous running threads, insulting threads, I am better than you are
threads, even threads that remain close to the original subject.

But, there is NEVER a concluding post to a thread.

You need to do some reading. Try "Conclusions for Dummies", along with
Feynman's "Special Relativity and the Dipole" and possibly also "String
Theory and Its Applications to Near Field Anomalies". After that, you
have my permission to post in this NG.
:)

Hf Antenna Question - so what's the conclusion?
 

wrote:

* Is "bunched" or "flat" better?
* Are they basically single-band or wide-band or somewhere in-between?
* Are there "rules of thumb" to make them for hams with
* No test equipment?
* A grid-dip meter?
* A noise bridge?
* An antenna analyzer?

Possibly this has been posted previously...but just in case:

http://www.bcdxc.org/balun_information.htm#Ed,%20WA2SRQ

Measurements of practical baluns of various types using an HP Vector
Impedance Meter. It should answer most of your questions above.

73, Bill W4ZV

Hf Antenna Question - so what's the conclusion?
 

wrote:
Possibly this has been posted previously...but just in case:
http://www.bcdxc.org/balun_information.htm#Ed,%20WA2SRQ

Thanks for the URL. There are a couple of points to make.

When I suggested that 40 turns might be required for 75m,
I was chastised for my statement. Note that the above URL
contains data on a 38 turn choke on a 4.5" coil form for
75m operation. The choking impedance is 1300 ohms on 75m.
Parallel self-resonance on 75m would require more turns
than 38.

Much of the "Ugly Balun" information should be ignored. It
is not possible for an ugly balun to be "effective" from
1.8 MHz to 30 MHz. Note there are no impedance measurements
to back up the ugly balun's claim of being "effective" over
that frequency range.
--
73, Cecil, http://www.qsl.net/w5dxp

Hf Antenna Question - so what's the conclusion?
 

Ian White GM3SEK wrote:
The 854 that I reviewed for Radcom was the same. We both got one that
had the core assembled upside-down, so instead of showing you how to
snap the plastic catch open, the instruction manual shows you how to
break it.

I'm trying to figure out how I can make more effective
measurements on coiled coax chokes with the equipment
that I presently have. I can measure the impedance with
my MFJ-259B if it is less than 650 ohms.

I also have a GDO. If I get an open circuit dip, would
that be the parallel resonant frequency? If I get a
short circuit dip, would that be the series resonant
frequency?

I also have a dual-trace 100 MHz Leader o'scope. I
should be able to find the resonant frequencies
by watching the voltage drop across a series resistor.
I also have the X-Y feature so I could look at the
source voltage, voltage across the choke, and voltage
across the resistor as the frequency is changed.

What do you think?
--
73, Cecil, http://www.qsl.net/w5dxp

Hf Antenna Question - so what's the conclusion?
 

Cecil Moore wrote:a couple of points to make.

When I suggested that 40 turns might be required for 75m,
I was chastised for my statement. Note that the above URL
contains data on a 38 turn choke on a 4.5" coil form for
75m operation. The choking impedance is 1300 ohms on 75m.
Parallel self-resonance on 75m would require more turns
than 38.

8 turns loose wound in a 6.625" diameter bundle looks like an effective
single band balun for 80m (approx 500 ohms). W6TC's voltage balun (Feb
1980 Ham Radio) uses 6 turns loose wound on ~5" diameter (8' total
length) but adds a compensating winding in the opposite direction. It
has nice characteristics for 40-160m but can only be used with balanced
antennas (e.g. dipoles, inverted-Vs, etc). I've used a W6TC balun for
many years on a trapped 80/160 inverte-V.

73, Bill W4ZV

Hf Antenna Question - so what's the conclusion?
 

wrote:
8 turns loose wound in a 6.625" diameter bundle looks like an effective
single band balun for 80m (approx 500 ohms).

A ladder-line fed dipole might present an impedance of
8000 ohms to the choke. A 500 ohm choke would have
very little effect. However, a self-resonant choke
might have 40K ohms of choking impedance and it
would need to have a lot more turns than 8.
--
73, Cecil, http://www.qsl.net/w5dxp

Hf Antenna Question - so what's the conclusion?
 

Cecil Moore wrote:
wrote:
8 turns loose wound in a 6.625" diameter bundle looks like an effective
single band balun for 80m (approx 500 ohms).

This would only be true for a resonant coax-fed 1/2WL
dipole. What about all the other possible configurations?

A ladder-line fed dipole might present an impedance of
8000 ohms to the choke. A 500 ohm choke would have
very little effect. However, a self-resonant choke
might have 40K ohms of choking impedance and it
would need to have a lot more turns than 8.
--
73, Cecil, http://www.qsl.net/w5dxp