[TowerTalk] TowerTalk 5-/72 ohms

[Jim Lux]

On 12/14/13 10:03 AM, Pfizenmayer wrote:
> Awww gee - I thought HE made antenna tuners so one could present a 1:1
> load to the transmitter so one could  tune up their amp into a 1:1 dummy
> load and just switch over to the tuner /antenna without having to touch
> the amp and avoid the endless tuning on air, esspcially on the DX
> freq.  Some people however never did get the message.
>
> Hank K7HP

This is a good point.. what the amplifier output network does is tune 
the decidedly non 50 ohm output impedance of the amplifier which is 
frequency and drive dependent as well to 50 ohms.
The antenna tuner changes the non-50 ohm impedance of the antenna system 
to 50 ohms also, so you CAN just flip a switch.

The whole thing would work equally well if you tuned up into a 75+10j 
dummy load, and adjusted the antenna tuner to present a 75+10j ohm 
impedance as well.

Or, you can use the single output network in the amp and "absorb" the 
antenna tuner effects into it.