[Elecraft] Antenna tuners

[Fred Jensen]

I very vaguely remember there was a different optimum length for the 
others, thanks!

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 7/18/2020 12:25 PM, W2xj wrote:
> That only applies to class A stations with protected skywave. Otherwise, something near 225 degrees is best.
>
> Sent from my iPhone
>
>> On Jul 18, 2020, at 11:33, Fred Jensen <k6dgw at foothill.net> wrote:
>>
>> And the Texas Bug Catcher, Webster BandSpanner, SteppIR's, et al.  All represent changes to the antenna itself, which would also include changing the height [e.g. cranking the tower up and down] and possibly cutting down nearby trees or metal buildings [:=).  Any change to the antenna itself or its near-field environment will affect the feed point complex impedance.  This would include adding traps, inductors, and capacitors to the antenna.
>>
>> When you're done flutzing with the antenna itself, you are stuck with whatever complex impedance you find at the feed point.  AM broadcast verticals are generally engineered for coverage near the edges of the market area, meeting non-interference FS requirements, and minimizing self-cancellation between the ground and sky wave.  Something in the vicinity of 195 degrees is generally optimal.  They are not usually resonant and there will be fixed matching network(s) at the base(s) ... AM broadcast stations aren't known to QSY much.
>>
>> I'm not familiar with the TurboTuner however many mechanical antenna adjusters operated by driving the phase angle between voltage and current to zero, that is effectively bringing the antenna into resonance so the feedline sees a resistive load. It's up to you to design the antenna so that resistive load matches the characteristic impedance of the feedline OR put a matching network between the feedline and the antenna feedpoint OR tolerate the SWR on the line and put the matching network in the shack.  Pick one.
>>