I will made a dipole for 10.1 Mhz v inverted, with total lenght 15 mtrs.
What is the appropriate balun ? 1:1 1:2 1:5 or others ? tnx

condor wrote:
I will made a dipole for 10.1 Mhz v inverted, with total lenght 15 mtrs.
What is the appropriate balun ? 1:1 1:2 1:5 or others ? tnx

What kind of feedline are you using? In any case,
a good 1:1 choke-balun is preferred.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote
What kind of feedline are you using? In any case,
a good 1:1 choke-balun is preferred.
=========================================

How do you select a good choke balun from amongst all the others.
---
Reg.

Reg Edwards wrote:

How do you select a good choke balun from amongst all the others.
---

The important characteristic is common mode impedance. Tie the two input
conductors together and the two output conductors together, and measure
the input-to-output impedance. This can be done in various ways, most
easily with an antenna analyzer, or by other means. The higher the
impedance, the better. 1000 ohms seems to be a good number to shoot for,
with 500 ohms probably being ok for most applications. The angle of the
impedance doesn't matter unless you're running high power, in which case
it might be necessary to keep the impedance more reactive than resistive
to prevent excessive core heating.

A good choke balun for multiple band use will have a high common mode
impedance on all bands on which it'll be used. Narrower band ones can be
connected in series as an alternative.

Roy Lewallen, W7EL

Reg Edwards wrote:
How do you select a good choke balun from amongst all the others.

I roll my own. I have 8 FB-77-5621 cores over a piece
of RG-400 in series with an FT-240-61 with ten turns of
RG-400. The latter comes in a ~$10 balun kit from Amidon.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote in message
. net...
Reg Edwards wrote:
How do you select a good choke balun from amongst all the others.

I roll my own. I have 8 FB-77-5621 cores over a piece
of RG-400 in series with an FT-240-61 with ten turns of
RG-400. The latter comes in a ~$10 balun kit from Amidon.
--
73, Cecil http://www.qsl.net/w5dxp

===========================================

Ten or more turns of twin, 18 awg, stranded, speaker cable is even
better.

Easier to make and has higher choke impedance and lower loss.

I don't know why you mess about with coax.
----
Reg.

Reg Edwards wrote:
Ten or more turns of twin, 18 awg, stranded, speaker cable is even
better.

Easier to make and has higher choke impedance and lower loss.

I don't know why you mess about with coax.

The optimum Z0 for the wire that is used is the square root
of the product of the input impedance and the output impedance.
I vary the length of my ladder-line to accomplish resonance
in my antenna system. The impedances seen at the output of
my balun averages 50 ohms. Thus, the optimum Z0 for my
balun wire is 50 ohms. Magnet wire will do that but speaker
cable won't. Ten turns of RG-400 is really convenient. I use
RG-400 for everything inside of the shack. All the 1/2" dia.
stuff is outside.
--
73, Cecil http://www.qsl.net/w5dxp

Ok sofar....

I want to receive low frequencies 500 Khz.
Planning to build long wire for it inside the house.

How to connect this longwire to coax?

Only for receiving, do I need balun then also ?



"Cecil Moore" schreef in bericht
et...
Reg Edwards wrote:
Ten or more turns of twin, 18 awg, stranded, speaker cable is even
better.

Easier to make and has higher choke impedance and lower loss.

I don't know why you mess about with coax.

The optimum Z0 for the wire that is used is the square root
of the product of the input impedance and the output impedance.
I vary the length of my ladder-line to accomplish resonance
in my antenna system. The impedances seen at the output of
my balun averages 50 ohms. Thus, the optimum Z0 for my
balun wire is 50 ohms. Magnet wire will do that but speaker
cable won't. Ten turns of RG-400 is really convenient. I use
RG-400 for everything inside of the shack. All the 1/2" dia.
stuff is outside.
--
73, Cecil http://www.qsl.net/w5dxp

You don't need a balun or coax.

A feedline at low frequencies is very much short of a wavelength.

Just extend your antenna wire direct to the receiver. Perhaps use a
tuned preselector. And away you go!
----
Reg.