By david, on June 17th, 2013
Last Saturday I had my first Summits on The Air (SOTA) attempt on top of Mount Remarkable here in South Australia.
As a first step on Friday I registered my SOTA attempt on the Sotawatch web site
On Saturday morning I started by testing my FT-817 and Alexloop magnetic loop antenna at our camp. While tuning up I managed to talk to a VK2 (portable in VK5) who was few 100 km away in the Flinders ranges. Good test.
I then hiked for a few hours to get to the top of Mt Remarkable, set up my radio and antenna, and called CQ on 40m and 20m. Alas, I made no contacts. However it was so nice to experience S0 noise on 40 and 20m, so much different to my urban S9 hash experience on those bands. I couldn’t hear much activity on 40m but could hear many international stations on 20m. They just couldn’t hear me!
The members of the SOTA Australia Yahoo Group have been most helpful with many suggestions on how I can do better next time. In particular I can “self spot” using a smart phone app like sotagoat or a web site. I’ll certainly give it another go in future.
Some pictures of my little adventure:
In the last picture the magnetic loop is just behind my head, the FT-817 just visible above the white note book. I use a 1m dowel as the antenna mast which doubles as a walking stick for the hike. A large part of this walk is over paths covered with large rubble. as shown in the pictures above. I was told this is from ancient volvanic activity. The rubble moves a bit under your feet, making for slow going. There is a light plane crash about 2/3 of the way up – the alloy remains of the plane still shiny after 30 years. The walk was about 6 hours return for me from the caravan park at the base of Mt Remarkable. However I am a slow walker, and had a sore knee from a bike crash a few days before!
By david, on June 10th, 2013
This weekend I have been attending the SERG Ham radio convention in Mount Gambier where I have enjoyed the company of some good friends and learnt a lot about fox hunting.
A group of us decided to go 3 weeks ago. The well-connected Mark VK5QI has been scouring Adelaide for fox hunting equipment, including beam mounts, . . . → Read More: Fox Hunting and Ham Radio as Therapy
By david, on March 18th, 2013
Since the last post I have explored some improvements to PAPR, and tested the 1600/2000 modes introduced in the last post in real time. These tests have given me a little more insight into the problems with HF channels and led me to better understand the requirements. This has lead to a new 1600 bit/s . . . → Read More: FreeDV Robustness Part 3
By david, on March 6th, 2013
Since the last post I have been working on two new FreeDV modes (1600 and 2000 bit/s), designed to improve the performance of FreeDV over HF multipath fading channels. This involved modifying the Octave and C modem code to support a variable number of carriers, a new 1600 bit/s Codec 2 mode, and some C . . . → Read More: FreeDV Robustness Part 2
By david, on February 25th, 2013
Here is the next installment in my adventure of making FreeDV work as least as well as analog SSB over HF multipath fading channels. I’ve included the command lines I am using for those who want to play along with me.
Incremental Improvements
Over the past few weeks I have made some incremental improvements:
Bill Cowley pointed out . . . → Read More: FreeDV Robustness Part 1
By david, on February 11th, 2013
About a week ago I returned from LCA 2013 after being away from home for 1 month. My EV was parked at a house close to the airport. It burst into life and off I went. However about 1 km from home the front lights and dash went dim and the EV ground to . . . → Read More: Dead DC-DC converter in my EV
By david, on February 10th, 2013
I am working on improving the performance of FreeDV on HF channels. As a first step I have been exploring the bit error patterns from the modem using some samples of a 1300 km HF radio path. These samples were kindly collected by Mark, VK5QI and Brenton, VK2MEV.
The FDMDV modem has 14 DQPSK data . . . → Read More: HF Modem Bit Error Patterns
By david, on February 7th, 2013
Last week I attended lca.conf.au 2013, my sixth LCA. It was a very well organised and enjoyable conference for me. After a few days back I miss it. I have made some good friends at LCA over the years, and catching up with them is as important for me as the conference talks. It . . . → Read More: linux.conf.au (LCA) 2013
By david, on January 21st, 2013
This post is rather technical, and assumes a knowledge of PSK demodulator design. I apologise if it is difficult to understand for the general reader. I have spent the last few weeks working on this part time so felt compelled to record the results somewhere. Thanks to Bill Cowley VK5DSP and Peter Martinez G3PLX . . . → Read More: Coherent PSK Demodulation on HF
By david, on December 15th, 2012
A very pleasant Ham Radio day. My friends Joel and Mark (VK5QI) visited my home to build Peter Parkers (VK3YE) “Porta 40″ DSB receiver (from the November 2012 issue of “Amateur Radio” magazine). Joel did the assembly work, with Mark and I helping test the receiver.
We started with the local oscillator, . . . → Read More: My First FreeDV Contact
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