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Balun

Posted: Fri Apr 12, 2019 3:29 pm
by Jekko
Hello,

because of the low price i decided to buy and test this balun, like the raccomandation of the rtl-sdr site.

https://www.amazon.com/NooElec-Balun-On ... 62d4d89808

I tested it with a 16,2mt long wire and somehow works. It works just the same if i put the wire into a hole of the balun or if i put the wire into the other hole.

Which is the difference between the two holes?

Should it be a good idea if i cut two pieces of wire with the same lenght and i make a "V inverted balcony dipole" inserting one wire into a hole and the other wire in the other hole? I think i can cut the wires long about 2,5meters to use my balcony.

What about using a coax TV antenna cable instead of a single wire? Should i get some benefit? But in this case i would have (in the two arms of wire) four terminals: signal (wire1), signal (wire2), ground (wire1), ground (wire2). How could i connect those to the TWO holes of the balun?

Thank you very much

Re: Balun

Posted: Thu Apr 25, 2019 11:44 am
by snn47
BAL(anced/ UN(balanced)is needed when you want to connect an unbalanced coax cable. to a balanced (symetrical) cable or antenna .
Some BaIun retain the Impedance some provide transformation eg. 1/4 (Folded Lambda Dipole of ~240 Ohm to a 60 Ohm coax, but often also 50 Ohm to 75 Ohm).
A BalaUn is used with 2 elements with equal length not just one .
you can use a Coax instead of a wire but you have nearly no benefit except a slightly better bandwidth .
Fora single wire you need an UNUN with the proper impedance matching