VK5DJ's Amateur Radio Site


VHF/UHF Yagi calculator page

Satellite system 28 May 2009

Beam indicator
Beam indicator page
V7.06 - 25 June 2010
V8.40 - Jun 2010

V951 - Jun 2010
V10.0 - Jun 2010

Repeater project
Repeater controller page

Contest logger
RD logging program for 2008
Version 6.16
Updated 11/8/09

Weather Stations
Data converter for WM918

GPS Quality Checker
GPS checker page

John's email address




GPS checker 29 April 2009

Satellite system 28 May 2009

Updated repeater controller page on 14 Dec 2009

John in the radio shack

The purpose of this site is to make available some amateur software and describe a number of projects, including a repeater controller, a beam indicator system, and an adapter to convert weather station data to APRS format.

My interest in amateur radio was kindled by friends while I was still at High School in 1956. We built modulated oscillators and super regen receivers and operated on the 1 metre band. I gained my first licence, VK5ZBF in 1957 and almost immediately my full call VK5DJ in January, 1958.

It was probably the interest cultivated on the 1 metre band that led to a lot of my operating on VHF. Complemented by an interest in computer programming, this interest in VHF resulted in the four projects available from this page.

Click here for a nostalgic photo from 1956 of Doug (now VK3UM), Brian (now VK3BCZ) and John (still VK5DJ) push bike mobile on 288MHz.


The first is the yagi antenna program and is a Delphi based follow up to my 1991 yagi program written in Borland Pascal. Many successful antennas have been built using it.

With a move away from DOS to the Windows environment it became clear it needed an update. I also took the opportunity to update a couple of the algorithms.

The new version is again based on the work of DL6WU. It is used to calculate the dimensions of long yagi antennas (2 or more wavelengths) for VHF and UHF. Dimensions, Gain, Stacking Distance, and Matching are covered. A simple SWR calculator is included. The help file covers some of the issues involved in yagi construction. The program works in all screen definitions. Latest version 2.6.2 on 4 May 2009 (bug fix for display of boom size for insulated but through boom elements). Versions 2.6.0 and 2.6.1 added facility for square or round section booms and square and flat element materials. Added calculation for folded dipoles through boom (previously assumed it would be insulated). Latest version has improved resizing of the forms.


The controller is the subject of an article in Amateur Radio Magazine October 2004. Since the article was submitted in 2003, the controller has some important improvements.

The use of a 16F628 or 16F648 is now 'standard'. Support for the 16F84 is no longer provided. The 16F628 and 16F648A have more memory and permit more options. Currently the code fits into a 16F628 (2K) but in future the 16F648A (4K) may be required as options are increased. Click here to access the VK5DJ controller page.

Repeaters have been a real interest for me and I have been instrumental in the building of VK5RMN in the Mid North, VK5RPM (digipeater near Millicent), VK5RMG the Mt Gambier 2M Repeater, VK5ROH the Mt Gambier 70cm repeater and gateway, VK5RKN (Kingston) and VK5RBT (Bordertown) gateways.

The Kingston, Bordertown, Naracoorte and Mt Gambier Repeaters are linked. The board in this photo is now operational at Willalooka near Bordertown for their gateway into the south east repeater system.

The homebrew board for Bordertown gateway (less LEDs)

GPS Quality Checker

Some amateurs require extra frequency stability for their equipment and so use GPS derived sources.

This project is to provide a visual (or audible) indication of GPS lock and the correct UTC time.

The project makes use of a PIC16F628A to decode the serial data from the GPS and extract a quality variable and the UTC time.

The quality variable is used to switch three outputs, one LED lights on "No Lock", another on "2D Lock" while a third indicates a full "3D Lock". The collector of the "No Lock" switch may also be used to operate a buzzer.

In practice the project is hooked to the RS232 output of the GPS to read the NMEA string.

Australian RD Contest

The RD logger for 2009 is similar to last year's version and the name RD log for 2007 remains but version number is 6.16.

I uploaded 6.16 on 11/8/09. Version 6.16 fixes a bug in using the higher UHF bands. Download the "RD setup.exe" file from the links section and run the program to install RD logger.

Warning: Make sure that the new file downloads correctly. I have had trouble with Firefox remembering that I had a previous download and just handing up the old file again. Check in the 'About' screen to see that you have 6.16.

Just let the installer do its thing and install in 'RD Contest Logger 2007'.

A problem with resizing on the new widescreen portables is largely fixed (it's hard to deal with all the widescreen combinations of late). It may also have overcome a display problem on some other machines.

Don't forget to clear out all the old logs before starting the RD using the item in the file menu. If you experimented with Zipping or generating the CSV files for the contest manager the new 'New Contest' command will have cleaned these for you.

Old version information

Version 6.15 added a 'new contest' command in the file menu deleted the old data file for the log file in use but left the CSV and ZIP files from an old contest. I have now ensured that these old files are deleted to avoid the embarrassing possibility of emailing an old file to the contest manager.

The main difference with the 6.14 file was the addition of totals at the bottom of the printed pages to assist the contest manager. There has been a correction to the emailed files. All these additions make it worthwhile downloading this version 6.15.


Old fixes for RD

Since 2006 I have made a couple of small fixes and created a different method of entering your details for the log printout/CSV for the contest manager to comply with his recommended layout.

Version 6.12 on 10/8/07 fixed a problem with the 'Clear' button when used after a 'Cannot work own area' message. A loop bug with the error message. Fixed. It was usable before but this makes it nicer.

Version 6.10 Fixed finding help file, added a calendar and ensured the ZIP function was included. (A file was missing in the last package).

Added a global name change in 5.06 to ensure every occurrence of a logged call has the name updated if editted (see "Names" in help file). Also simplified the name of the ZIP file and stopped zero length files being added to the ZIP. Version 5.07 re-arranged the entry boxes to make it a bit more logical and fixed a problem with the enter key moving around the entry boxes.

Fixed an error in the number received checking process in 5.09.

Feedback is valued, send it to me at

I will continue to add niceties as I think of them.

A shortcut is placed on the desktop and in Programs.

When the program is first run you will be invited to insert your callsign. The program will then generate two log files. One for HF and one for VHF. Up to 3 callsigns may be included providing a total of 6 logs.

This program took power/volts/mA for forward and reflected measurements and calculated SWR. Great if you use Bird inline power meters. There is provision to take coax losses into account when using a SWR bridge at the rig end of the coax. This program is now integrated into the yagi calculator program.

Weather station adapter

I've been working on a program to convert the data from a WM918 weather station to packet radio format. There is currently at least one other solution available but I wanted more flexibility than that offered. I wanted a 'connected' mode as well as an option for position and positionless data.

See here for details

Beam position indicator
The latest project is a beam position indicator. It uses a variety of encoder solutions. The project began with a home brew construction using the magnetic absolute encoder chips AS5040 (10 bit) or AS5045 (12 bit) indicator with magnet to provide 0.34 degree or up to 0.1 degree positioning. The shack unit can also convert a variable voltage of 0-5V from a linear potentiometer to degrees. Alternative sensors include the MA3-P12 magnetic encoder and SEI optical systems from US-Digital. The MA3-12P is a PWM device probably using an AS5045 and requires different software in the AZ/EL unit. There is another encoder available in Europe with a listing of HH-05 and HH-12 that works with the original AZ/EL code. A screwjack option has also been developed.A 16 bit gray coded encoder has now been added. Support for an inclinometer chip SCA61T is added (October 2008). Further encoders will be added as they become available to the author. This project was described and demonstrated at GippsTech at Churchill, Victoria on 10/7/05 and updated at Churchill on Sunday 9 July 2006.

The Beam Indicator page has a discussion regarding accuracy and downloads of diagrams for the whole project (thanks Russell VK3ZQB for drawing up my messy drafts) and an update on the masthead circuit. An extensive menu system manages the options in the shack unit while switches on the antenna unit offer several options. There are options for internal (shack unit), manual or external computer control.

I've developed a system that allows for different encoders including a screw jack option, gray code encoders etc. Tests over a 100m of Cat 5 cable from antenna to shack have been successful. Read the project description for further details on the beam indicator page.

South East Radio Group
See http://serg.mountgambier.org for information about the club and its projects. A special page is dedicated to photos and descriptions of the South East Repeater network. Recent happenings report general activites and is frequently updated.

Last updated 25 June 2010

I know, it's a bit kitsch but I like it, and it's my page!

since 1 January 2009