Coax Choke For Receiving Antenna ?
 

Wouldn't a ferrite work better?

I think ferrite is a good choice too, but based on some other posts
I've seen here, you apparently need a whole bunch of them to work
really well (like, dozens or more). Maybe a combination of both
methods would be workable for some. For me, and considering that it
didn't really need additional weatherproofing, the coax coil worked out
as a good solution for 11 MHz and up. Cost a bit less too.

Bruce Jensen

Coax Choke For Receiving Antenna ?
 

"bpnjensen" wrote in message
oups.com...
Wouldn't a ferrite work better?

I think ferrite is a good choice too, but based on some other posts
I've seen here, you apparently need a whole bunch of them to work
really well (like, dozens or more). Maybe a combination of both
methods would be workable for some. For me, and considering that it
didn't really need additional weatherproofing, the coax coil worked out
as a good solution for 11 MHz and up. Cost a bit less too.

Bruce Jensen

Hi Bruce,
The coax loop is a good solution for HF- particularly if you have G.D.O. and
can select the number of turns that achieves self resonance in the middle
of the freq of interest.

And remember on the ferrites- if they are big enough, you can make multiple
passes through them- the reactance goes up as the square of the number of
turns- saves on ferrites.

Dale W4OP

Coax Choke For Receiving Antenna ?
 

And remember on the ferrites- if they are big enough, you can make multiple
passes through them- the reactance goes up as the square of the number
of
turns- saves on ferrites.

Dale W4OP

Hi Dale - I've done this with standard electrical cords (like zipcord),
but that's much smaller stuff and works OK with little snap-on types of
ferrites. Your comment suggests that one would benefit from one of
those great big toroids about 4 to 6 inches across, threading the coax
through it many times - is that right? If so, is it best to wind it
tightly, or does that risk messing up the construction of the coax?

Thanks,
Bruce Jensen

Coax Choke For Receiving Antenna ?
 

On 2 Feb 2006 07:05:31 -0800, "bpnjensen" wrote:

And remember on the ferrites- if they are big enough, you can make multiple
passes through them- the reactance goes up as the square of the number
of
turns- saves on ferrites.

Dale W4OP

Hi Dale - I've done this with standard electrical cords (like zipcord),
but that's much smaller stuff and works OK with little snap-on types of
ferrites. Your comment suggests that one would benefit from one of
those great big toroids about 4 to 6 inches across, threading the coax
through it many times - is that right? If so, is it best to wind it
tightly, or does that risk messing up the construction of the coax?

Thanks,
Bruce Jensen

There's no electrical reason to use anything thicker than RG-58/U for
HF receiving. You can get 6 loops through your standard Radio Shack
ferrite.
http://www.wr6wr.com/newSite/article...ndyou0598.html

http://www.radioshack.com/product/in...tId=2103979&cp

Coax Choke For Receiving Antenna ?
 

"bpnjensen" wrote in message
oups.com...
And remember on the ferrites- if they are big enough, you can make
multiple
passes through them- the reactance goes up as the square of the number
of
turns- saves on ferrites.

Dale W4OP

Hi Dale - I've done this with standard electrical cords (like zipcord),
but that's much smaller stuff and works OK with little snap-on types of
ferrites. Your comment suggests that one would benefit from one of
those great big toroids about 4 to 6 inches across, threading the coax
through it many times - is that right? If so, is it best to wind it
tightly, or does that risk messing up the construction of the coax?

Thanks,
Bruce Jensen

Scarmble winding will be as good as a neat winiding.

Dale W4OP

Coax Choke For Receiving Antenna ?
 

David wrote:
There's no electrical reason to use anything thicker than RG-58/U for
HF receiving.

I'll agree with that for short runs, but RG-8X is only slightly larger in
diameter and less than half the loss per foot.

--
If John McCain gets the 2008 Republican Presidential nomination,
my vote for President will be a write-in for Jiang Zemin.

Coax Choke For Receiving Antenna ?
 

On Sun, 05 Feb 2006 01:03:44 -0600, clifto wrote:

David wrote:
There's no electrical reason to use anything thicker than RG-58/U for
HF receiving.

I'll agree with that for short runs, but RG-8X is only slightly larger in
diameter and less than half the loss per foot.
That's flat out factually inaccurate.

http://users.erols.com/rfc/attenrat.htm#RG8MINIX

Coax Choke For Receiving Antenna ?
 

I'll agree with that for short runs, but RG-8X is only slightly larger in
diameter and less than half the loss per foot.

That's flat out factually inaccurate.

http://users.erols.com/rfc/attenrat.htm#RG8MINIX

The latter seems correct - this table indicates that the difference in
loss between the two at 10 MHz is only 0.1 dB, very small. I was,
however, under the general impression that RG-8X is somewhat more
durable...can't say where I heard that, however.

Bruce Jensen

Coax Choke For Receiving Antenna ?
 

bpnjensen wrote:

I'll agree with that for short runs, but RG-8X is only slightly larger in
diameter and less than half the loss per foot.

That's flat out factually inaccurate.

http://users.erols.com/rfc/attenrat.htm#RG8MINIX

The latter seems correct - this table indicates that the difference in
loss between the two at 10 MHz is only 0.1 dB, very small. I was,
however, under the general impression that RG-8X is somewhat more
durable...can't say where I heard that, however.

Yep, get the non-contaminating version with the black jacket, which is suitable
for direct burial.

dxAce
Michigan
USA

Coax Choke For Receiving Antenna ?
 

Yep, get the non-contaminating version with the black jacket, which is suitable
for direct burial.

In this case, what does "non-contaminating" mean? Does it refer to the
inert chemical makeup of the jacket, or does it refer to some
electrical property in which signal is able to pass through unaltered
(as compared to the "contaminating" type :-/ )?

Thanks,
BJ