[BC] "Cusp Rotation"

[Kent Winrich]

You are expecting the manufacturers to provide this info??? 
HAHAHAHA  They dont know half of what they put out.  Heck I couldnt 
even get a simple thing like BTU output from Continental for their 
816HD (you know so I could spec out an HVAC system??) let alone a 
bunch of measurement points on their own transmitter.

I like the idea of your Vector analyzer.  Sure would be easier than 
going through the OIB and what have you that I did for my two HD 
installs.  UGH.

Kent Winrich


On 3/13/07, Phil Alexander 
<<mailto:dynotherm at earthlink.net>dynotherm at earthlink.net> wrote:
This whole "phase rotation" / "cusp rotation" business
drives me slightly nuts, because what we are really
attempting (as best we can) is indirectly "de-rotating"
or moving the **actual** PA load at the true output of
the PA to R = x j0 at the operating frequency with the
sideband frequencies "horns up." Where "x" is the true
output resistance of the power amplifier(s). IOW it is
almost like what we did by tuning and loading a tube
box "back in the day" by operating slightly off
resonance for best load to yield best modulation b/w,
except today we must approximate it and set it in the
blind.

What is really needed is for manufacturers to include
a dynamic measurement point(s) for the **actual**
dynamic, complex impedance across the range of operating
frequencies as seen at the **true** PA output before
combining/matching to the Tx output spigot.

That is to say something approaching the idea of a
**true** PA load sample that might be read by a RF
vector analyzer.