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Current Feature Articles   Sep 05 Surfin': Skimming the Code   Sep 01 Planning for the ARRL's Second Century   Aug 29 ARRL In Action: What Have We Been Up To Lately?   Aug 29 CQ China   Aug 29 Surfin': Opening Up APRS   Aug 27 The Amateur Amateur: Doing It in the Street   Aug 25 Ohio State Parks on the Air   Aug 22 Surfin': Batten Down the Hatches   Aug 20 Antenna Go-kits   Aug 15 Surfin': Conferencing in the Center of the USA ARRL Products: Low Power/QRP (More) The Electronics of Radio -- Temporarily Out-of-Stock! -- This advanced-level textbook uses the practical approach of making a real ham rig (the NorCal 40A) to teach radio electronics. ARRL's Wire Antenna Classics -- An entire book devoted to wire antennas, from the simple to the complex. ARRL's Low Power Communication with 40-meter CW Cub Transceiver Kit -- Now Shipping! -- Build and operate low-power radio gear--the QRP way! 3rd Edition. Includes the 40-meter CW Cub Transceiver Kit. More QRP Power -- More equipment, accessories and antennas for low power radio operating! ARRL's Low Power Communication -- Now Shipping! -- Build and operate low-power radio gear-the QRP way! 3rd Edition.

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This week, visit Web sites where very useful, previously expensive test equipment is now readily available as an addition to your Amateur Radio tool box.

Roll your own or buy it off the shelf, a Vector Network Analyzer (VNA) is now on your ham radio horizon budget-wise.

VNA is the initialism for “Vector Network Analyzer” -- a very useful test tool that was previously prohibitively pricey, but today its price tag fits in the budget of most Amateur Radio operators. You can buy a VNA or you can roll your own, but first things first: Why do you need a VNA?

According to the “Roll Your Own” VNA Web page of Paul Kiciak, N2PK, a homebrew VNA capable of both transmission and reflection measurements can measure among other things, gain/loss magnitude, phase, group delay (on the transmission side), complex impedance and admittance, complex reflection coefficient, VSWR and return loss (on the reflection side).

“Unlike other impedance measuring instruments that infer the sign of the reactance (sometimes incorrectly) from impedance trends with frequency, a VNA is able to make this determination from data at a single frequency. This is a direct result of measuring the phase as well as the magnitude of an RF signal at each test frequency.”

According to the “Buy It Assembled” VNA Web page of Ten-Tec, “The VNA is one of the more useful pieces of test equipment for designers and experimenters. It can measure the forward and reverse gain and phase response of a circuit, and the input and output reflection properties (complex impedance). The VNA is used to measure and adjust filters, coaxial cables, amplifiers, antenna input impedance vs. frequency, just to name a few.”

Roll your own or buy it off the shelf, the VNA connects to a computer running software that performs and displays the network analysis from the VNA’s measurements.

Additional information concerning the VNAs is available at W8WWW’s N2PK VNA page and at the TAPR VNA page (the “Buy It Assembled” VNA was a joint effort of TAPR and Ten-Tec.)

Until next time, keep on surfin’!

Editor’s note: Stan Horzepa, WA1LOU, used homebrew beer and ham gear and he recommends not sampling the two simultaneously. To communicate with Stan, send him e-mail or add comments to his blog. By the way, every installment of Surfin’ is indexed here, so go look it up.

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