Current baluns & longwire
 

I have made a couple of the NJQRP W1CG low power 4:1 current baluns.
See:
http://www.njqrp.org/balun/index.html

The author says they can be used for longwire. Inasmuch as the
balanced terminals seem to have identical circuitry behind them, it
would not appear to matter to which balanced terminal you connect the
longwire. Where do you connect the other balanced terminal? To RF
ground? To a tuned counterpoise? To the sheath of the coax on the
unbalanced side?

Ken KC2JDY


Ken
(to reply via email
remove "zz" from address)

On Tue, 03 May 2005 13:40:27 -0400, Ken wrote:

I have made a couple of the NJQRP W1CG low power 4:1 current baluns.
See:
http://www.njqrp.org/balun/index.html

The author says they can be used for longwire.

So you say, but there is no such claim at the referenced Web site or
in the Construction Manual. Also, does it make any sense to refer to
it as a balun if it does not have a balanced circuit on the balanced
side?

Inasmuch as the
balanced terminals seem to have identical circuitry behind them, it
would not appear to matter to which balanced terminal you connect the
longwire. Where do you connect the other balanced terminal?

Exactly my point. Where?

To RF
ground? To a tuned counterpoise? To the sheath of the coax on the
unbalanced side?

If it hurts, don't do it.

Bottom line - a long wire is fed against ground. There is no point to
a balun, unless you intend to use a balanced feedline from the
transmitter to the long wire feedpoint - in which case the balun is
applied in reverse - and of course you will need another balun at the
transmitter to make the transition from the unbalanced transmitter
output to the balanced line.



Bob, W9DMK, Dahlgren, VA
Replace "nobody" with my callsign for e-mail
http://www.qsl.net/w9dmk
http://zaffora/f2o.org/W9DMK/W9dmk.html

On Tue, 03 May 2005 18:42:10 GMT, (Robert
Lay) wrote:

The author says they can be used for longwire.

So you say, but there is no such claim at the referenced Web site or
in the Construction Manual. Also, does it make any sense to refer to
it as a balun if it does not have a balanced circuit on the balanced
side?

You are correct. I mixed up something I read about my LDG 4:1 voltage
balun:
http://www.ldgelectronics.com/rbalun.pdf

Is LDG correct? If so, then for a voltage balun and longwire, I
should use an RF ground on the second terminal. What if I don't have
one? Should I short it to the coax sheath? Or would a counterpoise be
better?

If I have a tuned counterpoise, should I use the current balun, or the
voltage balun?

If the voltage balun helps with a longwire, Can you suggest how to
change the wiring on the W1CG balun so that it is a voltage balun?

Also lost in the sands of time is the advice that a longwire needs a
9:1 or 10:1 balun. Is that true? If so, is that a current or voltage
balun?

Ken KC2JDY

Ken
(to reply via email
remove "zz" from address)

Just to confuse you more, balun is word constituted out of BALanced to
UNbalanced transformer. Assuming what you want to do is feed a long wire
with coax and do a "impedance match" to your long wire. What is needed is
an UNUN or UNbalanced to UNbalanced transformer as a long wire is feed
against ground and is an unbalanced load. The terms current or voltage do
not apply to UNUN's.


--
John Passaneau, W3JXP
Penn State University


"Ken" wrote in message
...
On Tue, 03 May 2005 18:42:10 GMT, (Robert
Lay) wrote:

The author says they can be used for longwire.

So you say, but there is no such claim at the referenced Web site or
in the Construction Manual. Also, does it make any sense to refer to
it as a balun if it does not have a balanced circuit on the balanced
side?

You are correct. I mixed up something I read about my LDG 4:1 voltage
balun:
http://www.ldgelectronics.com/rbalun.pdf

Is LDG correct? If so, then for a voltage balun and longwire, I
should use an RF ground on the second terminal. What if I don't have
one? Should I short it to the coax sheath? Or would a counterpoise be
better?

If I have a tuned counterpoise, should I use the current balun, or the
voltage balun?

If the voltage balun helps with a longwire, Can you suggest how to
change the wiring on the W1CG balun so that it is a voltage balun?

Also lost in the sands of time is the advice that a longwire needs a
9:1 or 10:1 balun. Is that true? If so, is that a current or voltage
balun?

Ken KC2JDY

Ken
(to reply via email
remove "zz" from address)

On Tue, 03 May 2005 13:40:27 -0400, Ken wrote:

I have made a couple of the NJQRP W1CG low power 4:1 current baluns.
See:
http://www.njqrp.org/balun/index.html

The author says they can be used for longwire. Inasmuch as the
balanced terminals seem to have identical circuitry behind them, it
would not appear to matter to which balanced terminal you connect the
longwire. Where do you connect the other balanced terminal? To RF
ground? To a tuned counterpoise? To the sheath of the coax on the
unbalanced side?


ok.... whether it's a BALUN or an UNUN, I'm using the same type
of "matching device" or "impedance transformation device" with an
end-fed wire that's roughly 1/4 wavelength at 160 meters (so I
guess that's about a 40 meter piece of wire). One "balanced"
terminal goes to the wire, the other goes to a ground rod. I'm
sure it would be just as happy, maybe happier, connected to a
counterpoise instead of the ground rod.

Works quite well.

--
-fb-

Yes, I am sure you are quite correct about it being as happy with the
counterpoise as a ground rod, however, it STILL would be an "unbalanced"
ant... and requireing an UnUn, IF my understanding is correct... a dipole
is "balanced".....

Regards,
John

"funkbastler" wrote in message
...
| On Tue, 03 May 2005 13:40:27 -0400, Ken wrote:
|
| I have made a couple of the NJQRP W1CG low power 4:1 current baluns.
| See:
| http://www.njqrp.org/balun/index.html
|
| The author says they can be used for longwire. Inasmuch as the
| balanced terminals seem to have identical circuitry behind them, it
| would not appear to matter to which balanced terminal you connect the
| longwire. Where do you connect the other balanced terminal? To RF
| ground? To a tuned counterpoise? To the sheath of the coax on the
| unbalanced side?
|
|
| ok.... whether it's a BALUN or an UNUN, I'm using the same type
| of "matching device" or "impedance transformation device" with an
| end-fed wire that's roughly 1/4 wavelength at 160 meters (so I
| guess that's about a 40 meter piece of wire). One "balanced"
| terminal goes to the wire, the other goes to a ground rod. I'm
| sure it would be just as happy, maybe happier, connected to a
| counterpoise instead of the ground rod.
|
| Works quite well.
|
| --
| -fb-
|
|
|

People continue to confuse "symmetrical" with "balanced". A dipole is
symmetrical. Twinlead feedline is symmetrical. Both can be balanced or
unbalanced. Coax can be balanced or unbalanced. I've done my best to
explain it, but I've obviously come up short.

Roy Lewallen, W7EL

John Smith wrote:
Yes, I am sure you are quite correct about it being as happy with the
counterpoise as a ground rod, however, it STILL would be an "unbalanced"
ant... and requireing an UnUn, IF my understanding is correct... a dipole
is "balanced".....

Regards,
John