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5 Band Cobweb Feeder?
Posted: 19 Aug 2019, 19:56
by acting_strange
Hi
Is there any reason why, when I build my own 5 Band Cobweb, Instead of using a 4:1 Balun inside the links box, I just use my favourite, the good old Ladder Feeder and use my home built Z Match ATU to get the balance I need to keep the SWR down?
Re: 5 Band Cobweb Feeder?
Posted: 20 Aug 2019, 10:58
by FAFFER
Because it's a nest of folded dipoles and you'll cock the impedance up, and the performance.
The balun is a 1:4 btw.
Re: 5 Band Cobweb Feeder?
Posted: 20 Aug 2019, 19:43
by acting_strange
FAFFER wrote: ↑20 Aug 2019, 10:58
Because it's a nest of folded dipoles and you'll cock the impedance up, and the performance.
The balun is a
1:4 btw.
But surely with an ATU I can match the impedance to any of the antenna used?
Re: 5 Band Cobweb Feeder?
Posted: 20 Aug 2019, 19:55
by ch25
The point is to have resonant antennas, not to tune barbwire with ATU. That's why Cobweb is built the way it is.
Chris
Re: 5 Band Cobweb Feeder?
Posted: 08 Sep 2019, 22:48
by FAFFER
acting_strange wrote: ↑20 Aug 2019, 19:43
FAFFER wrote: ↑20 Aug 2019, 10:58
Because it's a nest of folded dipoles and you'll cock the impedance up, and the performance.
The balun is a
1:4 btw.
But surely with an ATU I can match the impedance to any of the antenna used?
You could fool the radio into thinking the antenna's 50 ohms, but the antenna will still be poor.