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We have designed a long wire balun that can dramatically improve the reception on any Short Wave receiver.
The tests we carried out from 500Khz to 30Mhz gave an average improvement of 4 S units, when tested with our current balun incorporated into the design we had computer and electrical interference drop by up to 10 DB....We had to run the tests a dozen times to make sure the readings were correct.
This same balun can be used for feeding an original Windom antenna against ground, 3.5 to 30 Mhz with very good results (100W) transmitter power.
By grounding the balun directly under the vertical radiator of a Windom a very low noise installation is realised.
We used a multitude of long wire lengths and had very favorable results with our balun connected.(Both receiving and transmitting)
Baluns...What is the best balun?
There are 2 types of baluns used in antenna matching networks for HF antennas,
1 is the Voltage or Ruthroth balun, the other is the Guanella or current balun.
There are others which are derived from the above namely quarter wave coaxial balun and air core baluns.
The best balun in my humble opinion is the Guanella type balun using a toroid with an initial permeability between 125 and 300.
I do not recommend aircore baluns for wideband impedance matching or choking the outside conductor on coaxial cable. The reactance for an effective choke should be in the order of ten times the antenna impedance, this can be achieved with as few as 10 turns on a toroid but the air core would need from 80 to 100 turns to give the same reactance values.
The air core would suffer from self resonance in the hf spectrum and would also suffer from poor high frequency performance when built to choke at a couple of Mhz.
When I hear people talking about not using baluns because of high core losses it makes me laugh, a correctly constructed balun can be easily 99% efficient, and by not using one who knows what efficiency your antenna is...?
How much power is being radiated of the feeder cable, coupling into the house guttering and electrical wires?
Keep in mind that most baluns of the ferrite type have losses of about .1 to .2 of
1db, an antenna system at non optimal height without a choke balun can lose a fair bit of the radiated power by coupling into the surroundings back down the feeder cable.
VK3KCG
Our top selling longwire Balun.
     
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