Amateur radio activities at VK1DA, Canberra, Australia

VK1DA portable Mt Ginini Nov 2007

This picture shows the VHF/UHF Field day station set up in November 2007 and operated by my brother Chris VK2DO and me. The location was Mt Ginini, ACT, elevation about 1800m ASL, about 35 km SW of Canberra. This photo was taken just before sundown, with the sun almost directly behind the camera. There is a trace of a rainbow above the tree on the far left, after a recent rain shower. Camera: Canon A20.

144/432 MHz desk at VK1DA portable, Nov 2007

The 2m and 70cm operating position used in that event.

In the 2008 Spring field day I used the 13cm band as well as the 4 lower bands previously used. The FT290R was the IF radio for that band and is seen here between the IC910H and the IC736. The IC736 was used on 6 metres. The IC910H was used on 144, 432 and 1296. Camera: Canon 350D

The other addition for the Spring field day was 10 GHz, using equipment borrowed from Dale VK1DSH. The dish is mounted onto the transverter waveguide output and the IF radio is an IC202 on 144.2. You may be able to see that the dish is elevated above horizontal by some 5 degrees or more. This was required to get the signal through the nearby communications compound fence and towers, possibly reflecting the signal off one or more objects in the compound and about 25 km to VK1BL.

VK1DA Amateur Radio

Blog articles

Photo Gallery

My gallery at Flickr.com also has photos of my amateur radio events and activities.

Books about Amateur Radio and Electronics

See a range of books about Amateur Radio, both technical and general, at Andrew's Book Store. You'll also find books about Electronics and other technologies there.

Recordings of VHF/UHF beacons while mobile

On a recent trip to Sydney I checked for the VK2RSY beacons on 28.262, 144.420 and 432.420 to see how far out I could hear them.

I was surprised to find I could hear the 28 MHz signal at Sutton Forest and within a few km the 144 MHz beacon was also clearly audible. The 432 MHz beacon was very weak at that point but in the next 20 km it became quite readable. It was interesting to compare the signal levels from these beacons over the next 100 km or so of my trip. The best signal strength from the 144 and 432 beacons was at the start of the downhill slope on the highway just after Mittagong, heading towards Sydney. At that point the 432 MHz beacon signal strength indicated S5, with the preamp ON.

On the way back home from Sydney I recorded the beacon signals and the files are available here, in both MP3 and AMR format. I used a Nokia mobile phone to record these signals - not the most elegant recording method but it's a start. If you have software to play or convert the AMR format, the AMR file format produces more compact files. I used Miksoft.com's converter to produce the MP3 versions.

Recording 1 in MP3 format 1.4 MB - 1 minute, mostly the 432 MHz signal but at about 15 seconds you hear the improvement in signal strength and quality when I switched over to the 144 MHz signal and then back to the 432 MHz signal a few seconds later. AMR format 42kB

I was struck by the apparent change in quality between these signals. When I was stationary, both signals sounded clean and pure. While mobile the 432 MHz signal showed considerable multipath and smear like a 10 GHz sigal with doppler or rain scatter. I am not sure exactly what caused that effect on this signal . Apart from the blur or smear of the signal there was also at times a second version of the signal on a slightly different frequency, which I assume was an aircraft reflection with doppler shift.

Field day log sheets

Here are some log sheets and summary sheets for use in the Australian VHF field days. Printed on your printer and with your ink! Click and save, or right-click and save as...

You don't have Excel? no problem, download and install Openoffice, its spreadsheet opens and saves Excel sheets and it is free. Included on the cover DVD of recent Australian Personal Computer (APC) and other magazines, or downloadable from www.openoffice.org.

Field Day Techniques and checklist

My field day techniques page provides some ideas and describes my approach to field operation on VHF/UHF bands. Also here is my field day checklist. Some things such as clothing vary depending on the time of year, but basically I aim to be self contained, have backup equipment in case of total failure, be adequately clothed, fed and sheltered during the field day and to enjoy myself. These notes may help you plan your own field day operations.

Radio Links

Links to sites relating to amateur radio, including national organisations, clubs, special interests such as digital modes, moonbounce, HF DX, slow scan TV, VHF/UHF/Microwave communication.

VK-VHF Mailing List

Grid Squares

Maidenhead Grid Square locator codes are now in common usage around the world by most vhf/uhf operators and contest organisers. Make sure you place your Grid Locator on your QSL card and be ready to exchange grid locator codes with stations you contact.

If you don't know what they are or how to figure yours out, this article by Guy VK2KU explains it all really well.