[TowerTalk] Antenna Analyzers
jim at audiosystemsgroup.com
Thu Jun 6 14:20:01 EDT 2019
On 6/6/2019 9:45 AM, Máximo EA1DDO_HK1H wrote:
> But, if you can afford it, you can go to a mighty KC901, a two ports true vectorial VNA:
I've owned and loved this Vector Network Analyzer for about five years.
Very well supported by the designer, EE prof DG8SAQ, and by the small
company run by British hams that build and sell them. I recommend the
VNWA3EC, Cost is $526.
The same company also sells this very nice Vector Antenna Analyzer. I
bought one last fall, and like it a lot for more portable operation.
Cost is $185 plus shipping.
The VNWA is built and tested. The FA-VA5 is a kit that took be about
three hours to build. Both units can do precision TDR measurements when
run from a computer using DG8SAQ's software.
The difference between a Vector NETWORK Analyzer (VNA) and an Vector
ANTENNA Analyzer (VAA) is that the VNA can measure the GAIN (or loss) in
a system or device. For example, it can measure the isolation between
antennas, and the response (rejection) of bandpass filters. Both can
measure impedance and do TDR (that is, find faults in a feedline). With
a well designed test fixture, a good VNA can also measure high values of
impedance with greater precision than a VAA. I use the VNWA to measure
multi-turn ferrite common mode chokes for use at HF.
For either analyzer, I do NOT recommend the carrying case, and I DO
recommend the better BNC calibration kit listed with the FA-VA5. As I
recall, shipping was in the range of $25-$35 to my QTH near San
Francisco. They ship by British mail, and it comes via USPS.
A major advantage of the VNWA and FA-VA5 is that both can be powered
from the USB port of the computer that runs the software. The FA-VA5 can
also be used "stand-alone" on a pair of internal AA batteries.
73, Jim K9YC
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