Topband: Antenna Analyzers

[Ford Peterson]

One of the nifty features of the Autek VA1 is the F-1/4 mode.  Use this mode to set the autek to calculate the factors at the other end of the feedline.  Adjust the frequency to the 1/4wL of the line connecting the antenna and set the F-1/4 frequency.  Then, when you measure the impedances at the shack, you are actually measuring the impedance at the antenna!  Beats climbing the tower!

I've used it and it does work.  Although it takes some fussing with the instrument, the results are pretty good.  I suspect working with a lousy feedline would be a problem in terms of accuracy.  But at 160M?  It takes a lot of feedline or a very lousy feedline to introduce much loss (error).

Ford-N0FP
ford at cmgate.com