UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Aerials, Feeders, Transmission lines, AMU's and ATUs. Matching.

Mike. Watterson · 21st Jul 2019, 2:22 pm

Yes, dipole for the frequency, high enough up and ends far enough from objects. Or the "ATU" between the aerial and the feeder. Then the feeder can connect direct to radio assuming they are the same. Converting 75 / 50 / 300 is simple, no ATU needed. Actually using 75 Ohm coax on 50 Ohms input or 450 Ohms feed on 300 Ohms in (or a 300 to 75 Ohm balun = 2:1 turns) isn't much of a mismatch as long as the aerial matches the feeder or the ATU is between the aerial and the feeder.

21st Jul 2019, 2:22 pm	#11
Mike. Watterson Heptode Join Date: Dec 2014 Location: Limerick, Ireland. Posts: 901	Re: Aerial for old valve sets. Yes, dipole for the frequency, high enough up and ends far enough from objects. Or the "ATU" between the aerial and the feeder. Then the feeder can connect direct to radio assuming they are the same. Converting 75 / 50 / 300 is simple, no ATU needed. Actually using 75 Ohm coax on 50 Ohms input or 450 Ohms feed on 300 Ohms in (or a 300 to 75 Ohm balun = 2:1 turns) isn't much of a mismatch as long as the aerial matches the feeder or the ATU is between the aerial and the feeder. Last edited by Mike. Watterson; 21st Jul 2019 at 2:28 pm.