TAPR Vector Network Analyzer

USE YOUR PC AS LOW-COST RF VECTOR NETWORK ANALYZER

This new $ 655 VNA gives experimenters, designers and educators their first affordable access to many capabilities of conventional bench-top Network Analyzers. Even a used conventional Analyzer sells typically for $ 5000 and up. The VNA covers 200 kHz to 120 MHz. Use it to test low power amplifiers, characteristics of coax cables, measure and adjust filters, check antenna impedance vs. frequency, antenna SWR, even measure the length of transmission lines using TDR feature (Time Domain Reflectometer). The VNA measures forward/reverse gain and phase response of a circuit. Also measures input and output reflection (complex impedance) and provides S parameters. Make measurements of one-port networks (input, ground) and two-port networks (input w/ground, output w/ground). VNA also functions as general purpose signal generator. Frequency accuracy in either analyzer mode or signal generator mode can be enhanced with use of customer provided external frequency reference.

Load the software on your Windows based PC and connect to a USB 1.1 compatible port. Software currently provided with the VNA was developed by TAPR (Tucson Amateur Packet Radio Corporation). An open-source version is available for download on the TAPR web site. TAPR also plans to host mailing lists and other resources for users and developers. A Linux version is currently under development.


Click on a button above to download the latest software and/or view the VNA operation manual.
The CD was compiled on 2006-03-25.

All of the various displays and plots are derived from these four measurements:

S21 Magnitude: gain or loss of two-port network from input to output.

S21 Phase: the transfer phase of two-port network from input to output.

S11 Magnitude: return loss of one-port or two-port network referenced to input of the network.

S11 Phase: the phase angle of return loss of one-port or two-port network referenced to input of network.

Specifications

Frequency Range: 1 MHz-100 MHz at full specification. Operational with degraded performance up to 120 MHz and down to 200 kHz.

Resolution:
.1 dB for amplitude measurements
1 degree for phase measurements

Dynamic Range:
in forward mode, 80 dB at lower frequencies
75 dB mid-range and higher frequencies
In reverse mode, -35 dB at lower frequencies
-25 dB at mid-range and higher frequencies

Output Power: nominal +3 dBm (approx. 2 mw) at TRANSMIT connector

Maximum Input Level: +10 dBm (2 V P-P) into TRANSMIT or RECEIVE connector.

Requirements for host PC: Windows 98SE, 2000 or XP. Also requires Windows installer program and .NET 1.1 framework (provided on CD) run time package.

Included with Model 6000 VNA: printed instructions to assist with installation. The latest version of PC software and detailed operating manual are provided on CD. Set of testing and calibration accessories: 1meter & 3meter cables, 10dB & 30dB attenuators, 50ohm load, shorted connector and barrel connector. 100-240 VAC, 50/60 Hz power supply with removable cord.

Click here for detailed circuit description and theory of operation. This article appeared in the July/August 2004 issue of QEX Magazine, a technical journal for amateur radio and communications professionals. Reproduced here in .pdf format with the permission of copyright holder American Radio Relay League, Inc.

The VNA was designed by TAPR member Tom McDermott, N5EG, and Karl Ireland. Model 6000 is co-branded by TAPR and TEN-TEC. It is manufactured and marketed under license by TEN-TEC in Sevierville, TN. TAPR’s fundamental mission is to provide leadership and resources to radio amateurs and experimenters for the purpose of advancing the art of radio across the spectrum.