 BackgroundThe “$50 HF Antenna Analyser” started off life as a presentation for Pacificon 2013. The inspiration was what someone could do with a $5 DDS module found on eBay and a $35 Arduino micro-controller. During early development it was discovered that using a PIC instead of the Arduino brought the price down to under $25. The PIC is used to sweep an AD9850 DDS and measure the forward and reverse detector voltages from an SWR bridge at each frequency and return the values to a PC for plotting on the screen. The following picture shows a comparison of the Antenna Analyser shown at the top of the page with the Anritsu VNA Master hand-held VNA:  Both were testing my Buddipole antenna set up for 40m. This grew into a design that incorporated and LCD so it could be used without a PC (although the PC is still required to show the plots), a prototype of which was shown at Pacificon 2013. Development was done on a HamStack Dev-1 board from Sierra Radio Systems.  An early prototype as well as the materials presented at Pacificon 2013 have been kindly hosted on the Hamstack project gallery. There was a great deal of interest in a kit, so the PCB at the top of this page was created. This kit is usable both stand-alone, and with a PC program (free download, source available). It feature both USB and RS232 connections, and can be powered through a DC jack or can take power from the USB port. Although it will always work the way it is, there is included a programming header for updating the firmware as improvements are made. A write-up and information for building your own is in the attachment below "K6BEZ Antenna Analyser". A Yahoo Group has been setup for people interested in the project to ask questions.
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