[Amps] Baluns / UNUNs in QRO

[Tomm Aldridge]

Well, it varies all over the map as far as I can see.  Good question, I 
will have to noodle that one out.

doc wrote:

> Is the impedance of of your antenna flat from 160-10M or does it
> vary from below 50 Ohms to the hundreds or perhaps 1,000's of
> Ohms?
> 
> The Tuner will handle that but will your plate tuning circuit?
> 
>  > Tomm Aldridge wrote:
> 
>> Rather than put an antenna tuner in series with my amp, why not add a 
>> wide band RF impedance transformer to the output of the amp and go 
>> directly to the feedline?  Seems that adding the plate tuner in series 
>> with the antenna tuner is just compounding losses.  For example, I run 
>> 450 ohm ladder line to my (non-resonant) antenna.  It is now fed by a 
>> balanced-balanced tuner (2 26uH motorized rollers and 2 500pF 
>> variables that can be moved from input to output as Z determines) that 
>> is fed by my solid state 50 ohm out rig.  It seems to me that I could 
>> just design the plate tuning circuit to match 4k to 450 and add a 1:1 
>> current mode BALUN to the output of that and be done rather than going 
>> from 4k to 50 to BALUN to 450 as would be the case with the current 50 
>> ohm output designs.
>>
>> Am I missing something here? 
> 
> 
>