Topband: New MFJ 259C available

Jim Brown jim at
Wed Mar 5 00:24:56 EST 2014

On 3/4/2014 7:04 PM, Charlie Cunningham wrote:
> I'd also like to be able to apply VNA measurements to some of my HF antennas
> and I might be willing to take a laptop out there to do that, but I could
> also just calibrate out the feedline to move the measurement plane out to
> the antenna and do the measurments from indoors! Would be nice to have the
> capability!


Virtually all of the major vector analyzers can write impedance data 
files in a standard plain text format (called Touchstone) that can be 
imported by modeling programs like SimSmith. They also allow you to do 
TDR of the system, so you can subtract out the feedline. From there you 
can design matching networks.

There's a piece on my website that lists several decent analyzers, then 
shows you to use SimSmith to do these things. SimSmith is FREE, and runs 
in Java. Dan, AC6LA, has some wonderful Excel spreadsheets that work 
with this data. One of them will take open circuit and short circuit 
sweeps for a piece of transmission line and compute Zo, Vf, and 
attenuation vs frequency. Most of his spreadsheets are free. Dan also 
sells a spreadsheet that automates EZNEC and, I think, will do 

73, Jim K9YC

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