[Elecraft] Antenna Analyser - Phase Angle Sensor

[dave]

> IF it is increasing with frequency it is inductive 
> reactance, (+); if decreasing with frequency increase, it is capacitive 
> reactance, (-).

This is not quite true.

The reactance change over freq is something like a sawtooth waveform.  
Assume we start at reactance=zero (resonance) and freq is increased. 

Reactance then increases and is inductive up to some max, then decreases 
(while still inductive) until it crosses zero and becomes capacitive.  
Note that it was decreasing and inductive.

If we continue to increase the freq. the reactance continues capacitive 
and increases (while still capacitive and freq is increasing) until a 
max is reached where it begins decreasing.

It then returns to zero and we begin the sequence over again.

The reversal from inductive max to capacitive max happens quickly, but 
the reactance can be decreasing while inductive and increasing while 
capacitive. 
We have to know where we are in the cycle.


73 de dave
ab9ca







Stuart Rohre wrote:
> It is not too simple to measure phase with a additional circuitry.  However, 
> it is simple to move the frequency of the antenna analyzer and see the 
> Reactance change,  IF it is increasing with frequency it is inductive 
> reactance, (+); if decreasing with frequency increase, it is capacitive 
> reactance, (-).
>
> Once you get used to that, and make a little reminder note to paste on the 
> analyzer case, you can do the check easily and remember which type of 
> reactance change you are seeing re frequency.
>
> Stuart
> K5KVH 
>
>
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