Does a long wire antenna need a balun?
Long-wire Feed using a 4:1 Balun. The antenna ground side should be attached to a radial system as with a vertical antenna. Like any other antenna system that involves high SWR, use the shortest length and best quality coaxial cable possible.
What is a 9 1 balun used for?
These are sometimes known as a Magnetic Longwire Balun. Its really an impedance transformer (9:1) to feed a high impedance, end fed (unbalanced) random wire which is likely to be a few hundred ohms, and transform it into something closer to a 50Ω (unbalanced) coaxial input, hence UnUn.
Are end fed antennas any good?
End fed wire antennas can work very well under many circumstances. They have some disadvantages, but with careful installation, they can work well and be particularly versatile offering multi-band operation.
How long can a long wire antenna be?
It is important to use a counterpoise. A standard recommendation (see QST, March 1936, p. 32, “An Unorthodox Antenna”) is an 84′ long end fed and a 17′ long counterpoise (6.5′ for 20m)….Wire Lengths for Various Band Combinations.
| Group | USA Bands |
|---|---|
| a | 40-30-20-15 |
| b | 40-30-20-17 |
| c | 40-30-20-17-15-12-10 |
| d | 80-40-30-20-17-15-12-10 |
What is the transformation ratio of a long wire balun?
Here i present the fabrication steps for a long wire balun having a transformation ratio of 1:9. This balun is simulated with LTSpice and measured with a VNA. The power handling has also been tested with a 50 W (SSB) of injected power without any problems.
What is a current balun?
A current balun isolates the ground path from the counterpoise to the shack. The balun must be a high quality current balun, not an unun or voltage balun. It should be a 1:1 ratio with high common mode impedance and high voltage breakdown.
How do you wind a wire wire for a balun?
Wire winding should be done around two FT114-61 toroids (cf. photo) with the respect of the scheme (cf. photo). Wires should have some isolation coating (e.g. enameled wires). In my case i used a 50 mm diameter PVC tube to enclose the balun.
Can a balun wire be connected back to the station ground?
It just cannot connect back to the station entrance ground, or the balun’s ground. If it is a single wire or a few wires, they should be insulated from earth and kept a little distance above earth.