[TowerTalk] Front to Back Measurements

[n4kg@juno.com]

On Thu, 13 Dec 2001  "Bob Alexander" <realex@flash.net> writes:
> 
> Hi Kim,
> It is not possible to get an accurate F/B measurement (or any kind 
> of pattern measurement)from any rig that has the AGC turned on.

	HUH?  IF the S-meter is used as a fixed level indicator
	in conjunction with a calibrated external step attenuator
	there is no problem.  N4KG (Receiver Design Engineer)

	If you want to *hear* small differences, *then* you must
	turn the AGC OFF.

> Also, the  signal must be a constant carrier, not SSB.  I am not 
> familiar with the 756 but...
> 
> If it has an IF output available, turn off the AGC and use a scope 
> or RF voltmeter to measure the signal level as the antenna is 
> switched from 0 to 180 degrees.
> The voltages can be used to calculate the F/B of the antenna.

	This will work ONLY if you have sensitivity on the scope
	to see the weakest signal.  N4KG

> 73, Bob, W5AH
> 

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