View Single Post
Old 21st Jul 2019, 1:35 pm   #10
Skywave
Dekatron
 
Skywave's Avatar
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 6,906
Arrow Re: Aerial for old valve sets.

Quote:
Originally Posted by Mike. Watterson View Post
A feeder is ONLY a feeder if matched at the radio AND the aerial ends. The radio end is simple.
Overall, I agree with that.
You can call the wire / cable / w-h-y that connects the receiving or transmitting end to the aerial proper a 'feeder' by all means, since it is acting as a 'feeder' in the mechanical sense, but will only be a 'feeder' in the electronic sense if it 'sees' it appropriate termination resistance at each end. At the receiving / transmitting end, that can be achieved with an ATU / AMU. Not so easy to replicate that at the aerial end, especially since many aerials change their impedance as the received frequency is changed. The classic way to achieve that match at the aerial end is, of course, the half-wave dipole, but even with that, its effective height above ground must exceed a certain minimum value.

Al.
__________________
Chard, Somerset - The birthplace of powered flight and prosthetic limbs.
Skywave is offline