Longwire balun. Which type?
 

I've just replaced my old cable with some nice shiney new 50ohm coax
attached directly to my 100+ feet of longwire. As I still want to suck that
little extra out of my antenna, I want to add a balun but I am confused with
this transformer ratio stuff. I realise that a long wire has quite a high
impedance. However, should I go for a 1:4 or a 1:10 ratio balun. If I went
for the 1:10 would it be overkill and will it make any difference over the
RF if I only had a 1:4. I ask because I can get a 1:10 a lot cheaper than a
1:4.

Confused? I am :)

MC

"MC" wrote in
t:

I've just replaced my old cable with some nice shiney new 50ohm coax
attached directly to my 100+ feet of longwire. As I still want to suck
that little extra out of my antenna, I want to add a balun but I am
confused with this transformer ratio stuff. I realise that a long
wire has quite a high impedance. However, should I go for a 1:4 or a
1:10 ratio balun. If I went for the 1:10 would it be overkill and
will it make any difference over the RF if I only had a 1:4. I ask
because I can get a 1:10 a lot cheaper than a 1:4.

Confused? I am :)

MC




1:9 is ideal for a longwire (ideal impedence is 450 ohms, matched to 50 ohm
coax, so 50:450 = 1:9), so go for the 1:10. The 1:4 is for something with
lower impedence than a longwire.

Not all baluns are created equal, however. What frequencies are they rated
for? This will depend on the turns count of the windings and also on the
ferrite material.

Try the LIM device. I have used it for 2 years and it works well on all
frequencies.

http://www.angelfire.com/mb/amandx/lim.html

See the above for more info

Shawn



"MC" wrote in message
t...
I've just replaced my old cable with some nice shiney new 50ohm coax
attached directly to my 100+ feet of longwire. As I still want to suck
that little extra out of my antenna, I want to add a balun but I am
confused with this transformer ratio stuff. I realise that a long wire
has quite a high impedance. However, should I go for a 1:4 or a 1:10
ratio balun. If I went for the 1:10 would it be overkill and will it make
any difference over the RF if I only had a 1:4. I ask because I can get a
1:10 a lot cheaper than a 1:4.

Confused? I am :)

MC

On Thu, 24 Feb 2005 00:29:06 -0000, "MC"
wrote:

I've just replaced my old cable with some nice shiney new 50ohm coax
attached directly to my 100+ feet of longwire. As I still want to suck that
little extra out of my antenna, I want to add a balun but I am confused with
this transformer ratio stuff. I realise that a long wire has quite a high
impedance. However, should I go for a 1:4 or a 1:10 ratio balun. If I went
for the 1:10 would it be overkill and will it make any difference over the
RF if I only had a 1:4. I ask because I can get a 1:10 a lot cheaper than a
1:4.

Confused? I am :)

MC

You may wish to try an ICE matching transformer, they are reasonably
priced and are built well. Another advantage is that you can play
around with the transformation ratio from 6:1, 9:1, 12:1 and 16:1.
http://www.arraysolutions.com/Produc...age%20Matching
I would suggest the DC isolation version and you might as well get the
one that goes to 100kHz in case you want to pursue beacons - that
would be model 182A.

Howard

In article 9,
Conan Ford wrote:

"MC" wrote in
t:

I've just replaced my old cable with some nice shiney new 50ohm coax
attached directly to my 100+ feet of longwire. As I still want to suck
that little extra out of my antenna, I want to add a balun but I am
confused with this transformer ratio stuff. I realise that a long
wire has quite a high impedance. However, should I go for a 1:4 or a
1:10 ratio balun. If I went for the 1:10 would it be overkill and
will it make any difference over the RF if I only had a 1:4. I ask
because I can get a 1:10 a lot cheaper than a 1:4.

Confused? I am :)

MC




1:9 is ideal for a longwire (ideal impedence is 450 ohms, matched to 50 ohm
coax, so 50:450 = 1:9), so go for the 1:10. The 1:4 is for something with
lower impedence than a longwire.

Not all baluns are created equal, however. What frequencies are they rated
for? This will depend on the turns count of the windings and also on the
ferrite material.

The impedance of the wire depends on the height above ground. The 1:9 is
most likely best.

--
Telamon
Ventura, California

Telamon wrote in
news:telamon_spamshield-D142D9.21371823022005@newssvr21-
ext.news.prodigy.
com:

In article 9,
Conan Ford wrote:

"MC" wrote in
t:

I've just replaced my old cable with some nice shiney new 50ohm
coax attached directly to my 100+ feet of longwire. As I still want
to suck that little extra out of my antenna, I want to add a balun
but I am confused with this transformer ratio stuff. I realise
that a long wire has quite a high impedance. However, should I go
for a 1:4 or a 1:10 ratio balun. If I went for the 1:10 would it
be overkill and will it make any difference over the RF if I only
had a 1:4. I ask because I can get a 1:10 a lot cheaper than a
1:4.

Confused? I am :)

MC




1:9 is ideal for a longwire (ideal impedence is 450 ohms, matched to
50 ohm coax, so 50:450 = 1:9), so go for the 1:10. The 1:4 is for
something with lower impedence than a longwire.

Not all baluns are created equal, however. What frequencies are they
rated for? This will depend on the turns count of the windings and
also on the ferrite material.

The impedance of the wire depends on the height above ground. The 1:9
is most likely best.


Is there a site that explains this, with a formula that can be used? I
found one once that was for a straight horizontal wire at a fixed
distance above a ground plane, but it wasn't for antennas... I just
assumed 450 ohm was a good value.

In article 9,
Conan Ford wrote:

Telamon wrote in
news:telamon_spamshield-D142D9.21371823022005@newssvr21-
ext.news.prodigy.
com:

In article 9,
Conan Ford wrote:

"MC" wrote in
t:

I've just replaced my old cable with some nice shiney new 50ohm
coax attached directly to my 100+ feet of longwire. As I still want
to suck that little extra out of my antenna, I want to add a balun
but I am confused with this transformer ratio stuff. I realise
that a long wire has quite a high impedance. However, should I go
for a 1:4 or a 1:10 ratio balun. If I went for the 1:10 would it
be overkill and will it make any difference over the RF if I only
had a 1:4. I ask because I can get a 1:10 a lot cheaper than a
1:4.

Confused? I am :)

MC




1:9 is ideal for a longwire (ideal impedence is 450 ohms, matched to
50 ohm coax, so 50:450 = 1:9), so go for the 1:10. The 1:4 is for
something with lower impedence than a longwire.

Not all baluns are created equal, however. What frequencies are they
rated for? This will depend on the turns count of the windings and
also on the ferrite material.

The impedance of the wire depends on the height above ground. The 1:9
is most likely best.


Is there a site that explains this, with a formula that can be used? I
found one once that was for a straight horizontal wire at a fixed
distance above a ground plane, but it wasn't for antennas... I just
assumed 450 ohm was a good value.

Assuming medium ground conductivity:

Wire impedance = 138 log (4 * height / wire diameter)

Height and wire diameter are in the same units.

An 18 gauge wire 10 foot off the ground would be around 560 ohms.

--
Telamon
Ventura, California

MC,

Isn't there a frequency component?

On Thu, 24 Feb 2005 07:03:25 GMT, Telamon
wrote:

In article 9,
Conan Ford wrote:

Telamon wrote in
news:telamon_spamshield-D142D9.21371823022005@newssvr21-
ext.news.prodigy.
com:

In article 9,
Conan Ford wrote:

"MC" wrote in
t:

I've just replaced my old cable with some nice shiney new 50ohm
coax attached directly to my 100+ feet of longwire. As I still want
to suck that little extra out of my antenna, I want to add a balun
but I am confused with this transformer ratio stuff. I realise
that a long wire has quite a high impedance. However, should I go
for a 1:4 or a 1:10 ratio balun. If I went for the 1:10 would it
be overkill and will it make any difference over the RF if I only
had a 1:4. I ask because I can get a 1:10 a lot cheaper than a
1:4.

Confused? I am :)

MC




1:9 is ideal for a longwire (ideal impedence is 450 ohms, matched to
50 ohm coax, so 50:450 = 1:9), so go for the 1:10. The 1:4 is for
something with lower impedence than a longwire.

Not all baluns are created equal, however. What frequencies are they
rated for? This will depend on the turns count of the windings and
also on the ferrite material.

The impedance of the wire depends on the height above ground. The 1:9
is most likely best.


Is there a site that explains this, with a formula that can be used? I
found one once that was for a straight horizontal wire at a fixed
distance above a ground plane, but it wasn't for antennas... I just
assumed 450 ohm was a good value.

Assuming medium ground conductivity:

Wire impedance = 138 log (4 * height / wire diameter)

Height and wire diameter are in the same units.

An 18 gauge wire 10 foot off the ground would be around 560 ohms.

y'all leave me sitting at the post with that technical radio jargon,but
that is ok,I do learn something once in a while.Thanks for that.
cuhulin