The Melbourne chapter of the Radio Amateurs Old Timers club had an informative and entertaining presentation by Nigel Holmes, VK3DZ about the role of the Shepparton International High Frequency Transmitting Station in researching the ionosphere and even reflecting HF signals from the Moon’s surface.
There's a good train service from central Victoria down to Melbourne and then on to the Caulfield RSL where we meet so, naturally, we ended up on the train together. Here is VK3MO, VK3ACR, VK3XW, VK3WQ and VK3RV. Also in attendance was VK3CCR.
The meeting was well attended and the food was very good.
The Radio Old Timers Club is a national organisation but to my knowledge only Melbourne and Perth have lunch events.
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Graeme, VK3CDO, came and gave a great presentation about portable operations gear at the Macedon Ranges Amateur Radio Club recently. He brought along a terrific folding chair and table which I immediately ordered. He suggested an outing and I was up for it. We set up on a beautiful day here in Victoria on Mount Macedon.
The weather was perfect. We both brought our chairs and tables. I brought a tent in case the weather turned (not likely). Graeme used a very nice MA-12 vertical antenna which was easy to set up and worked well. I strung up an end fed but had problems tuning it to either 40 or 20m. (I think the Unun I grabbed was not working).
Graeme operated a low cost, uSDX QRP radio with just the internal battery and easily made a contact.
We both brought small metho stoves which worked very well for cups of coffee & tea. Later we each cooked up a lunch. Graeme went for gourmet sausages while I tried a freeze dried meal which was very nice.
Graeme put me on to the chair and table. Both excellent: "Naturehike Camping Chair, Portable Backpacking Breathable Chair with Storage Bag, Compact Collapsible Lightweight Camp Chair (Green-M)" & "Naturehike Camping Detachable Table with Aluminum Alloy Material, Portable, Lightweight, Outdoor Furniture for Camping, Picnic, Hiking, and Other Outdoor Activities".
The tent is a "Night Cat Backpacking Tent fo 1 Person 2 Persons Easy Setup by Clip Waterproof Lightweight protable Camping Hiking Tent for Adults Kids Scouts Tent". I like it because it's under 2kg and has a convenient side entrance.
I kept John “lofty” Wiseman’s excellent SAS survival handbook at hand but luckily there were no emergencies requiring reference to it.
I look forward to even more ambitious outings in the future.
The much anticipated wait for the amazing software update to the QRP-Labs pocket radio, the QMX, is out in beta. Today I installed the third release and called CQ from my location in central Victoria. Dave, VK7DD in Northern Tasmania responded and gave me up to a 57.
The radio is sure to be popular with portable operators. It must be one of the tiniest SSB transceivers available.
Reports of my transmit audio are good and as you can hear in this clip, reception quality is beautiful.
The microphone plugs in to the paddle port and is wired with PTT on the tip and audio on the ring. I had several mics around from Xeigu radios and they have the connections the other way but it wasn't hard to swap one over.
I found that extra audio gain was needed but this is easily adjusted via the serial terminal interface or built-in menu.
Even without SSB capability the QMX is a fantastic transceiver for FSK digital modes (and CW) but now it can do modes that need SSB such as PSK31.
Having had a wonderful time with the Soldersmoke direct conversion receiver and after that a very simple double sideband transmitter, I'm now formulating a DC/DSB transceiver. From the experience of those that have tried, it seems that a traditional VFO on the transmit frequency is not a good idea as the transmit signal gets back in to the VFO and causes problems.
My plan is to use an Si5351 clock generator (<$2) based VFO which should not be affected. Recently I've been playing with the tiny RP2040 Zero boards which can be purchased for under $2 and are an impressively powerful computer.
The RP2040 CPU is powerful enough to run MicroPython. While I'm comfortable in C++ I love python's clean syntax and library. The code is quite simple and I've put it up on GitHub here: https://github.com/peterbmarks/micropython_vfo
Pushing the rotary encoder button changes the step size. You can see it in action here:
My display is a tiny 128x32 OLED board with an ssd1306. I imagine many builders will swap this out for something grander.
The hard part is done with libraries created by smart people:
I'm on ABC RN Download This Show again this week. Generative AI has officially infiltrated the world of gaming, could games created entirely by AI be the future we've all been dreading?
Also, speaking of, so many games, so little time... could a dating app for choosing games be the answer?
Plus, what are personality rights and could they help us defend against deepfakes. And what ever happened to those astronauts stranded in space?!
AI is being used to check for errors in research papers, but just how accurate are its results? And is your collection of classic DVDs still playable? You might be surprised. Peter Marks, a software developer and technology commentator from Access Informatics, joined Philip Clark on Nightlife to discuss the latest news in technology.
Lots of fun and lots to learn from the Soldersmoke Direct Conversion receiver. It seems simple but there are some traps for young players like myself. Building with others and being able to compare observations is incredibly helpful.
My approach is Manhattan construction spaced out and arranged to look like the circuit diagram. This makes it easier to spot the inevitable errors but there is a downside that it's more likely to have instability. In the past few days I've re-built each stage in a more compact form and the result works well and has no instability. As an example of before and after here's the diode ring mixer prototype laid out for clarity:
Here's the new compact version of the mixer:
The compact VFO board:
Most challenging and most improved is the audio chain which is now stable even with the gain turned all the way up and the pot off the board connected with platted wires.
I did have a wiring error on the audio board that took me a little time to figure out. Having a working board to compare with really helped of course.
I'm about done with this project but it has been a wonderful learning experience. I would recommend this as a group project for any beginning constructors like me.
I visited my dear uncle Robert Glasser yesterday. Yes, Bob is really my uncle! He's 96 years old and doing pretty well considering.
Robert's short term memory is in serious decline. He introduced me to a carer about a dozen times. His long term memory is as sharp as ever and he was most entertained when I showed him a video of the Soldersmoke Direct Conversion receiver I'd built. He knew exactly what a direct conversion receiver is and was pleased that I'd gone on and built a double-sideband transmitter.
Robert told me that he'd got his call at age 16 and was W6HA (which he spelt out in phonetic letters). His carer was rather astonished at his sudden detailed technical conversation I think.
80 years a ham! I suggested he might be eligible to join the Radio Old Timers Club we have here. He doesn't get out much these days though. Here's a photo I took when I was quite young and clearly my focus was more on the gear than the person.
Wonderful to have him around but I fear our time is limited.
At AU$33 I couldn't resist ordering one of these little all band receivers with sideband.
Putting aside the speaker, which is so tiny as to be a joke, it does actually work rather well. Plugging in headphones or a powered speaker and you have a reasonable radio. However, the operation is quite annoying. The single knob with centre push must be double pressed to bring up a menu to choose things including volume by scrolling up and down.
A large part of the excellent screen is taken up with a silly dial display. Happily clever people have created improved firmware that makes better use of the screen and makes it more pleasant to use.
Then select the three files and enter the memory addresses like this (click to enlarge):
Note that you must use the "..." buttons and choose the files from your own downloaded and unzipped files. The offsets are 0x0, 0x8000, 0x10000.
When plugged in via the USB-C port and powered on, my radio came up as COM4 but yours might be different.
Click the Start button. When it finished, unplug the radio, power it off and on again. If all went well, it will show the version number. The first time I powered on I long pressed the encoder to wipe the flash.
There is at least one video showing this process but I find reading a web page a much better way to find out this stuff than watching a video.
The software is written using the Arduino platform and the ATS_MINI.ino file gives lots of technical information about the configuration of the radio including the display which is a TFT-eSPI device.
I had a shot at building the software in the Arduino IDE but ended up bricking the device. The Windows flash download tool was unable to write to it, even though the serial device was visible. Reading up on how other people got over this they recommended esptool which I used on the Mac and was able to get it running again.
Flash will be erased from 0x00010000 to 0x0006dfff...
Compressed 381552 bytes to 222197...
Wrote 381552 bytes (222197 compressed) at 0x00010000 in 2.8 seconds (effective 1082.1 kbit/s)...
Hash of data verified.
Leaving...
Hard resetting via RTS pin...
There is a PDF in the zipped firmware file that contains lots of information about the capabilities.
In the top bar there are two circular indicators. The first one flashes green each time the screen is updated. The second one flashes red each time settings are written to EEPROM. Saving settings happens about ten seconds after a change so delay turning the receiver off until you see the red flash or it will forget your latest setting change.
Victoria seems to have a good number of hamfests and today's at Yarra Valley was excellent. I bought a variable power supply which I hope is lower noise than my current one (remains to be seen), a bag of trim pots and capacitors for $2, an excellent electrical engineering text book, but mostly it was a chance to meet up with friends.
Nigel Holmes VK3DZ and Jim Gordon VK3ZKK
Ralph Klimek VK3ZZC
Drew Diamond VK3XU and Dave Stuart VK3ASE.
Warm congratulations to the organisers for a fantastic event.
