[Amps] Understanding S Parameters

[Drax Felton]

I am trying to understand S Parameters for a RD00HHS1 transistor.

The S11 parameters listed in the datasheet are as follows:
10 MHz		1.002 (mag)	-3.6(ang)
30 MHz		1.003		-9.9
50 MHz		1.005		-16.8
100		1.007		-33.5
150		0.989		-49.8

I'm trying to estimate the input impedance at 0.475MHz.  But I am uncertain
what it means when the mag is greater than 0.999.

Using the 10 MHz S11 value because it's available I get:

Gamma = 1.002 = (ZL-50)/(ZL+50) --> ZL= -50050 ohm impedance or a VSWR of
negative 1001:1.

What am I doing wrong?  What does this mean?  
My other attempts at calculating input Z also result in negative impedances
in linear form like -50.58-1589j
My RF books do not seem to say anything about this.


Kb3x