Balun or UnUn

[AE0TD]

What would be better? I am putting up a 31' EF antenna. Should I use a 4:1 UnUn or would I be better served using a 49:1 Balun?

 

[vagrant]

49:1 transformer and 33’ of wire. Add a 1:1 choke on the coax before it enters the shack. If you can do 66’ of wire you’ll get more bands.

 

[K6GBW]

What band(s) are you trying to work? That length kind of close to a quarterwave for 40 meters. If you're trying to make it multi-band then 36 feet would be a better then with a 9:1 Unun. Let us know what you're trying to accomplish and we can give you a better idea.

 

[RidingDownUnder]

I would recommend a 9:1 transformer and use a 1:1 choke b4 it enters your shack. The choke will help with noise that wire antennas are known for and they help choke off any RF running down the outside of the coax back to your station to help prevent those nasty RF burns. Ouch. With this long-wire it makes ã excellent HF receiving antenna. When used for transmitting you DO need ã antenna matcher or impedance matching device. The antenna tuner that is installed in most transceivers should work fine. Even the fussy ones.
Below are some wire lengths you can experiment with. 53’ seems very common and if you have the realestate 124.5’ maybe better.

 

[vk6ysf]

For an end fed wire for all of HF I would suggest a 1:9 Balun not a 1:9 Unun. You also need a counter poise. see below.
Also I would install a choking Balun between the 1:9 Balun and the coax feed.

Balun 9:1

Balun Choke HF 2 (With a SO239 on both sides).

Portable HF Inverted L (This site shows Unun transformers, however will work better with a Balun)

 

[spanky15805]

Give this page a once over.

Random Wire Antenna Lengths

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