[Boatanchors] GR 1606A RF Bridge question

[Ispoulin--- via Boatanchors]

I have a question on the  procedure for testing  antenna  impedance with 
the General Radio 1606A RF Impedance bridge. I interpreted the  manual as 
saying to do the initial balance with the unknown input shorted  to ground and 
the detector (HF Receiver), and signal generator at frequency of  interest 
connected,adjusting for a null on the receiver. Recording the  reactance dial 
reading. Then connect the unknown,my antenna( A long wire) to the  unknown 
bridge terminal and and adjust the resistance dial and reactance dial  for 
the best null. Is the correct procedure to subtract the 2 reactance  
readings,then divide by the frequency in Mhz?This resulted in a lower than  expected 
reactance for the antenna,which I assumed  to be around 1,000 ohms  for an 
end-fed long wire. my example is 3400 ohms initial balance, antenna null  at 
4200 with r =82. 4200 minus-3400=800. 800 divided by 3.9 Mhz =205. So my  
equation  is 82+ j205 (.I found it to be inductive by increasing the  
frequency and seeing a higher null reading) . Does my procedure look correct and  is 
this reading accurate?  73, Al, W4TUK