Topband: High Impedance RX Antennas

[John Kaufmann]

Another tool I've found indispensable for setting up and troubleshooting phased vertical RX arrays is a two-port VNA.   I use an Array Solutions VNA-2180 (now discontinued) for critical measurements.  I also have a NanoVNA H4 (https://nanovna.com/) which is a very "affordable" VNA that can be used as a portable, handheld, standalone instrument and that you can take out in the field.  In most cases, the NanoVNA H4 is more than good enough.

There is a learning curve to using a VNA.  However, once you learn it, you'll be able to make very accurate measurements of delay line lengths, preamplifier gain and phase, phase combiner gain and phase.  Most VNA's also have a TDR function, although it is usually based on frequency domain measurements that are transformed to the time domain.

I'm running a homebrew RX array and it would have been almost impossible to get it running as well as it is now without a VNA.

73, John W1FV