random wire antenna
 

Hi all,
I installed a random wire antenna of about 80 ft. Inside the shack I
would like to run coax to the outside and connect it to the wire. The
question is now what kind of matching transformer (UNUN) do I need to
get a good match.
Thanks for any answers.

Fred
wb6iiq

On 19 Nov 2004 18:46:59 -0800, (Fred) wrote:
The question is now what kind of matching transformer (UNUN)
do I need to get a good match.

Hi Fred,

You are shy of a lot of information necessary to respond to your
particular needs. So to answer what is left:
1:1 Current BalUn
Tuner

73's
Richard Clark, KB7QHC

"Richard Clark" wrote
(Fred) wrote:
The question is now what kind of matching transformer (UNUN)
do I need to get a good match.

Hi Fred,

You are shy of a lot of information necessary to respond to your
particular needs. So to answer what is left:
1:1 Current BalUn
Tuner

Adding to Richard's comments, many antenna tuners have a built-in 4:1 Balun
in them, some only make this available on certain settings. A 4:1 Balun at
the feedpoint of a 70-80' random wire will typically match very easily (on a
tuner of course) from 160 meters through 40 meters or above. You can
additionally, mount the Balun on the top 12" of an 8' ground rod, and ground
one of the two Balun outputs to the ground rod, connecting the other to the
wire as a feed. This is one of my very effective antennas, and quiet even in
a highly populated area. Industrial Communication Engineers (ICE) also
makes a nice matching device with adjustable impedance setpoints where their
Balun is automatically grounded and provides lightning protection as well.
That device is however for receive-only.

Jack Painter
Virginia Beach VA

Hello:

Transceiver---- coax 50 ohms ------ balum 9:1 ------- randon wire of 42
meters long

It is an efective antenna to 3,5 to 50 Mhz.

Transceiver----- Match --------- coax 50 ohms ---------- balum 9:1 -------
random wire.

Bye.

Jesus.

"Fred" escribió en el mensaje
om...
Hi all,
I installed a random wire antenna of about 80 ft. Inside the shack I
would like to run coax to the outside and connect it to the wire. The
question is now what kind of matching transformer (UNUN) do I need to
get a good match.
Thanks for any answers.

Fred
wb6iiq

I accidentally found your discussion. Having nothing else better to do I
thought I would make the following remarks -

The 9:1 balun on a 'long wire', on the average, has no effect on what you
call the antenna 'effectiveness'. On receive, you may find the signal
strength marginally better at some random frequencies and marginally worse
at other random frequencies.

4:1 baluns have a similar negligible effect at different sets of random
frequencies with a very slightly smaller overall loss over the whole wide
band from MF to HF.

You may just as well omit a balun altogether. Omission of a balun means zero
balun loss. But loss in a balun is negligible anyway. It just means there is
nothing to be gained by fitting one.

Baluns can be useful in particular frequency bands. But if you are
interested in particular bands then a very simple tuned antenna, a coil or
capacitor, or changing antenna length, is much to be preferred.

Baluns in a receiving application are beneficial only to the bank-balances
of balun manufacturers and salesmen. In other words, don't waste you
hard-earned money!

(PS: The supposed 600-ohm Zo of a random length of wire has very little to
do with it. Concentrate on the exact particular antenna length. Please send
me the money you save.)

And forgive me for the interruption.
----
Reg , G4FGQ

The supposed 600-ohm Zo of a random length of wire has very little to
do with it.
===============================

Depending on length, height and wire diameter, Zo can vary between 450 and
650 ohms or thereabouts. What's yours?

Then what balun ratio would the guru's and old wives recommend? And to
confuse even further, receivers can have an input impedance anywhere between
50 and 1000 ohms.

Some tuned receivers have an indeterminate input impedance. Who needs a
balun?
----
Reg , G4FGQ

On Sat, 20 Nov 2004 21:28:54 +0000 (UTC), "Reg Edwards"
wrote:

The supposed 600-ohm Zo of a random length of wire has very little to
do with it.
===============================

Depending on length, height and wire diameter, Zo can vary between 450 and
650 ohms or thereabouts. What's yours?

Then what balun ratio would the guru's and old wives recommend? And to
confuse even further, receivers can have an input impedance anywhere between
50 and 1000 ohms.

Some tuned receivers have an indeterminate input impedance. Who needs a
balun?
----
Reg , G4FGQ

Well Reg need and want are two different things. Perhaps my inverted
L didn't 'need' a balun, however after installing an ICE-182A
DC-Isolated matching transformer (balun if you will) I had a
noticeable reduction in noise. The difference is real and as a result
I have a better S/N ratio that makes listening less fatiguing. Now
here's the $64,000 question ........"Was the difference due to
impedance matching, the DC isolation or did a previously un-noticed
loose ground get fixed when I put the ICE unit in-line?"

Howard

"Howard" wrote
"Reg Edwards" wrote:

The supposed 600-ohm Zo of a random length of wire has very little to
do with it.
===============================

Depending on length, height and wire diameter, Zo can vary between 450
and
650 ohms or thereabouts. What's yours?

Then what balun ratio would the guru's and old wives recommend? And to
confuse even further, receivers can have an input impedance anywhere
between
50 and 1000 ohms.

Some tuned receivers have an indeterminate input impedance. Who needs a
balun?
----
Reg , G4FGQ

Well Reg need and want are two different things. Perhaps my inverted
L didn't 'need' a balun, however after installing an ICE-182A
DC-Isolated matching transformer (balun if you will) I had a
noticeable reduction in noise. The difference is real and as a result
I have a better S/N ratio that makes listening less fatiguing. Now
here's the $64,000 question ........"Was the difference due to
impedance matching, the DC isolation or did a previously un-noticed
loose ground get fixed when I put the ICE unit in-line?"

Howard

You know Howard, it's mostly amateur radio operators who have read too much
and worked too little that make statements like "a balun for receiving is
just for the balun makers benefit". These hams have little idea how
hobbyists who have special interest in DX, especially utility, and have
tried and tested numerous receiver antenna systems over the years. As I said
earlier I too use ICE equipment on one receive-only antenna. I could care
less what a stuffed-shirt thinks that does for my receive ability, as I used
it first as a hobbyist and then professionally. It certainly does improves
my digital and analog signal reception. I have that Ice box impedance set to
favor the lower bands on the wire and it at times outperforms a matched
dipole in reception. The compromise is that I lose usefulness of that wire
much above 6 mhz,which is ok as it does it required job superfluously. Now
the 4:1 current-type balun use on another wire-set antenna provides quiet
listening as well as excellent transmit abilities from 2182 Khz through
11000 Khz. And of course I use a 1:1 current-balun on a long dipole. Would I
"have" to? Of course not. Does it improve the antennas abilities in
listening as well as transmit? You bet it does. Do what works for you and
God help anyone who argues with that.

Jack Painter
Virginia Beach VA

Decoupling reduces the noise (rf current) traveling on the shield of the
coax, both to, and from your shack, which would otherwise get pretty much
direct coupled to your antenna.

Hello,
you should try the Magnetic Line Balun (MLB).
It is a ferrite (not powderiron) core with a 9to1 ratio.
Take three wires, twist them and turn them around a ferritering.
Set them in series.
The lower winding to the (t)rx het high to the wire.
It simply works fine on the receiver and with a trx with a tuner.

"Dave VanHorn" schreef in bericht
...

Decoupling reduces the noise (rf current) traveling on the shield of the
coax, both to, and from your shack, which would otherwise get pretty much
direct coupled to your antenna.