On Wed, 29 Mar 2006 17:01:51 GMT, rocky wrote:

To sort of sum things up, then what should I use for a choke balun on
75 meters, 77, 73 or 43 mix? More the better? I read the W2DU article
and he used 73, but I thought 77 may be better?

Hi OM,

More is better? What do you seek to achieve that is not already
answered by Walt's article? Didn't he specify which type?

#64 material is going to offer about 3 Ohms per bead;
#43 material is going to offer about 8 Ohms per bead;
#73 & 77 material is going to offer about 18 Ohms per bead;
#75 material is going to show offer 28 Ohms per bead.

If you are running power into a matched load, you may want more of the
lower resistance beads. If you are running barefoot, fewer more
resistive beads will work.

Or you could do it the old-fashion way by looping your coax at the
drive point.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
(snip)
#64 material is going to offer about 3 Ohms per bead;
#43 material is going to offer about 8 Ohms per bead;
#73 & 77 material is going to offer about 18 Ohms per bead;
#75 material is going to show offer 28 Ohms per bead.
(snip)

What dimension cores produce these impedances at 75 meters?

On Wed, 29 Mar 2006 17:30:54 -0500, John Popelish
wrote:

Richard Clark wrote:
(snip)
#64 material is going to offer about 3 Ohms per bead;
#43 material is going to offer about 8 Ohms per bead;
#73 & 77 material is going to offer about 18 Ohms per bead;
#75 material is going to show offer 28 Ohms per bead.
(snip)

What dimension cores produce these impedances at 75 meters?

Hi John,

It is called a 101 sized bead:
.138" OD
.051" ID
.128" high

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Wed, 29 Mar 2006 17:30:54 -0500, John Popelish
wrote:


Richard Clark wrote:
(snip)

#64 material is going to offer about 3 Ohms per bead;
#43 material is going to offer about 8 Ohms per bead;
#73 & 77 material is going to offer about 18 Ohms per bead;
#75 material is going to show offer 28 Ohms per bead.

(snip)

What dimension cores produce these impedances at 75 meters?


Hi John,

It is called a 101 sized bead:
.138" OD
.051" ID
.128" high

Are these what you recommend as coax choke balun beads? That is some
fine coax.

On Wed, 29 Mar 2006 17:50:28 -0500, John Popelish
wrote:

Richard Clark wrote:
On Wed, 29 Mar 2006 17:30:54 -0500, John Popelish
wrote:


Richard Clark wrote:
(snip)

#64 material is going to offer about 3 Ohms per bead;
#43 material is going to offer about 8 Ohms per bead;
#73 & 77 material is going to offer about 18 Ohms per bead;
#75 material is going to show offer 28 Ohms per bead.

(snip)

What dimension cores produce these impedances at 75 meters?


Hi John,

It is called a 101 sized bead:
.138" OD
.051" ID
.128" high

Are these what you recommend as coax choke balun beads? That is some
fine coax.

Hi John,

I do use some small stuff, like RG-174 and precision hard line, but
you are right, this is not for RG-58 which I commonly use. The 101
size is Amidon's reference for a multiplier for other forms.

73's
Richard Clark, KB7QHC

Richard Clark wrote:

I do use some small stuff, like RG-174 and precision hard line, but
you are right, this is not for RG-58 which I commonly use. The 101
size is Amidon's reference for a multiplier for other forms.

I wind about 10 turns of RG-174 type coax on a core having an OD of a
bit more than an inch. Works fine up to at least 300 watts with a
reasonably matched antenna.

Roy Lewallen, W7EL