The N2PK VNA
an International Ham Radio Success Story
Oscilloscopes, spectrum analyzers and tracking oscillators are scalar instruments which we have used
for decades so what's new? A VNA is distinguished by the ability to generate, detect and analyze
signals with very precise phase relationships. Prior to the mathematical analysis of electro-magnetic
fields by Clerk Maxwell, vector analysis was probably carried out by physical means.Today affordable
PCs can perform the complex math involved and custom software turns the data into a wide variety of
functions for analyzing the behavior of individual components, networks,transmission lines and
The VNA designed by Paul Kiciak N2PK is unique in several ways. First and foremost design details
and extensive documentation were made available to Radio Amateurs about 15 years ago at no charge.
It has been diligently supported by Paul with new versions as the technology evolved. It is designed as
a homebrew project for the serious builder and experimenter. The technical performance has been
compared to professional products from HP, Boonton and others and found to be very close indeed.
Paul's documentation begins with a few illustrations of precision. For example analysis of a leaded 3.3
Ohm ¼ watt 1% resistor at 40MHz had a resistance of 3.41 Ohms and inductive reactance of 3.3 Ohms.
The superior quality of the N2PK VNA has attracted and encouraged others to contribute their time and
expertise. The associated software and PCB designs are developed and supported by Hams elsewhere
in the US, England, Canada and Sweden. Paul likes to call it the N2PKetal VNA as it is truly an
international Ham Radio success story. Visiting Paul's web site N2PK.com is highly recommended.
I built mine about 14 years ago and used it extensively. One example of the incredible power of aVNA
and associated software is the measurement of common-mode rejection as described in the Nov/Dec
2010 issue of QEX. Recently my own VNA showed no sign of life and after verifying the DC supplies
were OK I concluded that new software drivers were required. For me this became a major challenge
but fortunately a most talented Ham coached me using TeamBuilder; once more proving that members
of our hobby help each other.
The VNA story is incomplete without describing the incredible software and to do so is now on my to-
Ron Skelton W6WO March 2018