Could anybody let me know how to contruct a bulun to match a longwire
antenna to a receiver. A step by step guide would be appreciated as I
am a non technical person.

On Sat, 5 Sep 2009 20:58:16 -0700 (PDT), skk203
wrote:

Could anybody let me know how to contruct a bulun to match a longwire
antenna to a receiver. A step by step guide would be appreciated as I
am a non technical person.

Ummm... you don't use a balun to match a long wire. Balun means
"balanced to unbalanced". A long wire is unbalanced. So is the 50
ohm output from your radio. If the antenna were a dipole, which is a
balanced antenna, you might need a balaun, but not a long wire.

Search Google for an "antenna tuner" claiming to match any antenna to
50 ohms. There are plenty of construction articles online, but you
need to know if you're building a QRP tuner, or a kilowatt monster.
Some indexes:
http://www.arrl.org/tis/info/tuner.html
http://www.dxzone.com/catalog/Antennas/Tuners/

If you wanna buy something ready to go, I like LDR automatic tuners
and MFJ for cheap tuners. Be sure to build or buy something that will
handle the frequency range and power output of your unspecified
xmitter.

http://www.ldgelectronics.com/c/252/products/1
http://www.mfjenterprises.com/Catergories.php?sec=16

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" schreef in bericht
...
On Sat, 5 Sep 2009 20:58:16 -0700 (PDT), skk203

wrote:

Could anybody let me know how to contruct a bulun to match a
longwire
antenna to a receiver. A step by step guide would be
appreciated as I
am a non technical person.

Ummm... you don't use a balun to match a long wire.
Could it be he means an 'MLB', a Magnetic Longwire Balun?

A small MFJ tuner will do a better job, especially since he
claims he'll only needs it on a receiver.

Note: a 'longwire' starts at abt 5 x wavelength. That's not the
same as a random end-fed wire.

73 - Gerard - PE1OUD

E-mail:

skk203 wrote:
Could anybody let me know how to contruct a bulun to match a longwire
antenna to a receiver. A step by step guide would be appreciated as I
am a non technical person.

The design impedance of a balun is determined by
taking the square root of (the input impedance
multiplied by the output impedance). Do you know
the output impedance?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

On 6 Sep, 15:09, Cecil Moore wrote:
skk203 wrote:
Could anybody let me know how to contruct a bulun to match a longwire
antenna to a receiver. A step by step guide would be appreciated as I
am a non technical person.

The design impedance of a balun is determined by
taking the square root of (the input impedance
multiplied by the output impedance). Do you know
the output impedance?
--
I think that the OP is not referring to a balun, but instead to an 'un-
un'. This is, in this application, a
9:1 impedance transformer used to 'match' a long(ish) wire to 50 or
75
ohms. A typical use is with an inverted-L antenna, where the feedpoint
is
remote from the house, and coax is used to bring the signal back to
the
shack. The advantage of this arrangement is that the antenna usually
picks
up much less interference from domestic electrical sources. It's
essentially a receive-only device, but can be used for low power
transmit (so I'm told).

The transformer is usually wound with a 3:1 turns ratio, on a ferrite
ring or
rod and, using the correct grade of ferrite and actual number of
turns, it is
possible to obtain a frequency range of 1 to 30MHz (ie the whole of MW
and
SW spectrum).

Of course, the 'matching' is only approximate. It's just that, at
most
frequencies, the insertion of the transformer provides a better match
between the coax and the antenna than you would have if there was
simply
a direct connection. It makes no attempt to be an antenna tuner. For
some
information, may I direct the OP to a recent thread in this newsgroup
(1
August), the subject of which was "UNUN Cores?How To Wind?". The OP
was "Greg ".

And then there's Google. There are a few useful links he
http://groups.google.com/group/rec.radio.shortwave/msg/
1abc6a2bf8acc12d