Except for the TV balun, this is your standard issue twinlead 2M Jpole antenna. Difference here is the use of the TV balun, and where that balun attaches to the antenna. TV baluns are 4:1, here it's a 200 ohm to 50 ohm. It connects to the Jpole at its 200 ohm impedance point, instead of the usual 50 ohm point. More importantly, the balun provides the Jpole a balanced feed, which is what it wants to see. And we avoid RF radiating off the coax cable. Easier and cheaper than ferrite beads and coiled coax. You'll need to get an F to BNC adapter, though. Or if you have some RG58 with a solid center conductor, and some screw on F connectors, you can connect the 50 ohm coax directly to the balun.
Built it and I get good results and good SWR too.
07-05-2015, 03:53 PM
Threaded Mode