Some technical advice on feeding a resonant mono-band dipole with ladder line please folks:-
I’m trying to mount a dipole on some reasonably high masts (somewhere between 10 & 20 meters above the ground).
Normally I would use 3 supports (one for the balun in the middle & one at each end) but in this case I only have two supports available. I think that the weight of the balun & feeder cable in the middle will cause the antenna to sag by an unacceptable amount.
Yes, I know that most people would normally feed with ladder line & use a balanced tuner (I guess that this arrangement then effectively becomes a doublet).
For a couple or reasons, I don’t want to mess about with tuners and wondered if I could feed it with ladder line but not bother with the tuner.
This antenna is going up at a remote site. The antenna will be set up permanently but all of the radio equipment will be removed when not in use.
The site will be used by several different people at different times who will be bringing their own radios, but using the fixed antennas. Some of them don’t have a suitable balanced antenna tuner. I also want to minimise the amount of complexity with tuners & the amount of equipment needed.
Basically I want to have a plug & play resonant antenna that I can just plug the coax straight into any radio without the requirement for a tuner.
Can I feed a resonant dipole with 450ohm or 300 ohm ladder line down to the ground and then put the balun on the ground (so that it isn’t hanging on the entenna wire)?
Google posts seem to be a little vague but what I’ve seen so far seems to suggest that I need to use a ½ wave of ladder line (factoring in the velocity factor of the ladder line) to get the same impedance/SWR at each end of the ladder line.
If I have this correct, I should be able to use ladder line to connect to a 1:1 balun at ground level, then connect coax running directly to the radio without the requirement for a tuner.
Have I understood this correctly?