[BC] RF absorption by foliage

[Barry Mishkind]

Another possible answer is that one of the towers in a directional 
may be passing through "0" under modulation.   I had one array once 
that had one of the six towers doing a jump between two 
readings.  Our consultant said the low mutual impedance actually 
swung through 0 and then negative under modulation.

After he "reset" the system, the effect stopped.

At 08:31 PM 10/30/2005, DHultsman5 at aol.com wrote

>In a message dated 10/30/2005 5:37:16 PM Central Standard Time,
>paul at amtower.com writes:
>
>Also  around Flat Rock we have another strange anomaly.  I have seen
> >  locations in the middle of a clear square mile, can't blame it on  wires,
> > where the FIM read some number, say 1mV and a second later its  5 mV a
> > second later its back to 1 mV.  The meter will bounce  fast, not slow, but
> > fast between two numbers on one second intervals  and do it for hours.  On
>
>This problem usually occurrs when the null is very deep.  As  modulation
>occurrs the power in the sidebands is not nulled as is the 
>carrier  power.  This
>will cause the FIM readings to appear to jump.  My  experience was that this
>would happen on our deepedst null and only on the  deepest null.  My boss
>claimed something was loose in the system.  I  checked every 
>connection electrically
>and mechanically in the system at least  twice.
>
>Theoadore Giles with Ralph Bitzer came an looked at the readings and
>explained that the phasor was nulling perfectly at carrier but with 
>high  modulation
>the FIM would jump due to the ratios of the power in the  sidebands vs. power
>in the carrier.
>
>Dave Hultsman