There have been a series of articles recently in Break-In (the http://www.nzart.org.nz) and also one from Australia about antenna analysers. Having digested the maths (which is really cunning), I now understood enough to design one myself, but that was patently silly as it’s be yet another case of wheel- reinvention, so I got out the plastic and ordered the antenna analyser designed by VK5JST and now supplied by the South Coast Amateur Radio Club
http://www.scarc.org.au/projects.html.

It’s a complete kit including case for AU$140 (about US$120) and while I have a well stocked junkbox, there always seems to be one or two bits that are missing …

This is just a placeholder page – I’ll add some photos later, but here are some of the links that I want to remember:

####How is it?####

It works well (once I’d figured out that the PN2222 transistors – just to be perverse – had pinouts opposite to both the datasheet and component overlay).

I’ve installed the VK3DPM software upgrade so now it measures C & L as well as R/Z/SWR – very pleased :-)

The opposite pin-out transistors were a bit hard to find. I knew the amplifier Q11-Q12 was the problem as when I disconnected them the voltage driving them was very flat with frequency whereas when Q11-Q12 were connected the output fell off badly with increasing frequency. The puzzling bit was that the components were all correct and so were the DC voltages (more or less).

I’m really grateful to VK3PE on EHam.com for mentioning his problem with the PN2222.

Now I’m just tweaking the accuracy …

####Related Links####
VK5JST’s own page on the analyser
http://www.users.on.net/~endsodds/analsr.htm

The  reviews on EHam.com – these are what convinced me to buy it, together with the fact that the project is based on the PicAxe microcontroller which is programmed in Basic so there are lots of user contributed software updates.

**Mods to increase frequency range and accuracy:**
http://members.optusnet.com.au/dpmilne/Amateur_files/AntennaAnalyser/HW_Mods/VK3XPW/VK3XPW.htm

A Russian page (no idea what it’s about but there’s lots of words and following discussion – included for completeness):
http://www.cqham.ru/aa_VK5JST.htm