As part of my objective to take the SolderSmoke DC receiver forward to be a double sideband transceiver I've been messing about with an Si5351 based VFO. The CPU is an RP2040 Zero board which I program in Micropython. I've just bought a couple of these handy boards that include a 1.3 inch OLED display, a rotary encoder and two extra push buttons.
No documentation comes with it but the edge pins are nicely labeled on the back.
When I hooked it up and tried my existing code, written for an SSD1306 OLED, the display showed mostly noise. It turns out the boards with a larger, 1.3 inch, display require the SH1106 driver which I found here. Both drivers subclass the Micropython Framebuffer class which is a very interesting thing in its own right.
The display / encoder board has nice big mounting holes on the corners as you can see.
I paid AU$6.79 each for the larger display version on AliExpress. For you in America I guess they'll be about $100. ;-) The board seems to be widely available and is called "0.96/1.3-inch OLED Display Module With Button EC11 Rotary Encoder IIC Interface LCD Screen"
I've seen an OSError stack trace when trying to talk to an I2C device on the wrong address and wondered what EIO means. It would be nice to have a list of all the error codes and what they mean.
From what I've read, error numbers are different for each hardware port of MicroPython. I'm using a Raspberry PI PICO and can get a list like this:
MicroPython v1.24.1 on 2024-11-29; Raspberry Pi Pico with RP2040
Cyber criminals were able to breach a number of super funds, stealing hundreds of thousands of dollars from members. The breach was unsophisticated, and likely came about because some super funds had not implemented basic security protocols on members' accounts
An interesting discussion of Digital Radio Mondiale. Some comments about how the west has retreated from Shortwave broadcasting are particularly pertinent at the moment.
The good news, to me, is that there are modules coming that will make it easy to make consumer receivers with DRM reception.
Thanks to the good folks at World Radio TV Handbook.
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.
If you are a 23andMe customer, like me, you should consider deleting your data. Are you a Windows 10 user? Microsoft is suggesting that you trade in your old computer soon to upgrade to 11. Do you read the lengthy terms of use many sites require - there may soon be an alternative that puts the user in the drivers' seat. Apple's Intelligence rollout hasn't gone well and now they're being sued for false advertising. All in Nightlife tech with Peter Marks. https://www.abc.net.au/listen/programs/nightlife/nightlife-tech-talk-with-peter-marks/105095170
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.
Regular readers will know that I'm a big fan to the SolderSmoke blog and podcast. Inspired by their recent direct conversion receiver challenge I built the receiver. It did not go smoothly and in retrospect that's good as I learned many valuable lessons along the way.
After the success of the receiver, it's not a big leap to make a double sideband transmitter. I built one for 80m using some circuits described by Peter VK3YE and Drew VK3XU. It went amazingly well and last Wednesday I called in to two 80m nets and got good reports. My audio was described as "highly fidelic" and a glance at an SDR showed that my audio bandwidth was over 10kHz (and because of double-sideband twice that). Bad boy!
Along the way, I made videos of the receiver and transmitter, including audio sent in of my signal received in Tasmania and Bill posted a nice item about it all on his blog.
I would be calling for Bill and Dean to grace the cover of Time Magazine but that may not be a positive thing any more.
Now I'm worried that he'll have a link to this post which links back to his post and this could cause internet feedback.
A breakthrough in computer chips, a new and supposedly cheap phone from Apple and how to avoid to paying higher prices for Microsoft Office 365. Peter Marks, a software developer and technology commentator from Access Informatics, joined Philip Clark on Nightlife to discuss the latest news in technology.
Great fun tonight. First I joined the Tasmanian tech net with the double sideband transmitter and later the Macedon Ranges net. Good reports from both. It's a pretty rough and ready transmitter:
There were reports of my wide bandwidth, not just the other sideband, and I can see on a local SDR that my signal is very wide.
Despite all this reports were quite positive and I'm grateful for that.
It's a very encouraging start. Thanks for the valuable feedback.
With all the government radio going to digital trunk radio I was surprised to find that communication between driver and guard, and sometimes station and driver, is via standard FM radio. Today I caught a train from Kyneton to Southern Cross station and recorded what I heard.
Mostly it's the guard saying when passengers have finished getting on and off but at about 48 seconds you'll hear Sunbury station ask us to wait due to a train broken down ahead.
To record this I made a 30dB pad with DC isolation so I could listen in headphones and also feed audio into the powered mic input on a voice recorder.
Amusingly I heard the driver refer to a city train as "the sparks". I guess they are electric while the country trains are diesel electric.
Today Nigel, VK3DZ, Ralph, VK3ZZC and I visited the National Communications Museum in Hawthorn, Melbourne, Victoria. It's a very modern museum, a bit expensive to get in the door but they have a great collection of old communications gear of historical note.
There's a huge collection of telephones, from payphone, to dial to mobiles.
There is also a working telephone exchange and some wonderful switchboards.
A fine collection of test gear is on display although we have some concerns about the CROs which are left on sometimes with a very bright spot showing.
I particularly enjoyed the optical disk talking clock.
We had the place to ourselves today although I imagine at times it's teeming with kids. I do recommend a visit although I'd have to say at $30 to get in it's a bit steep. The website is very modern looking and very bad to use. The staff seemed nice though.
There has been some discussion on the Soldersmoke direct conversion receiverDiscord chat area about a possible next project for builders who have got the circuit (as described) going. One idea that comes to mind is to re-use the VFO and perhaps the diode ring mixer and make a double sideband transmitter.
On Wednesday I participated in the excellent Northern Tasmania Amateur Radio Club's tech net on Wednesday and was entranced to see VK3DGE was running double sideband. (7:30pm on 3567).
It sounds a little bit funky but fully readable to me. He mentioned he's using a home brew amplifier but didn't mention anything about the exciter.
Last night on ABC's Nightlife program Philip Clark and I discussed AI going mainstream, in that it was featured in Super Bowl ads, the UK wanting a backdoor to Apple's iCloud encryption, and will the US mandate AM radios in cars as part of emergency communication infrastructure?
There's nothing more satisfying than listening to a radio you've built yourself. The Soldersmoke Direct Conversion receiver has given me that satisfaction in spades. Here's a little demonstration and discussion of things I learned along the way.
Now, to re-visit the shelf of shame and try to get some past failed projects working!
The Soldersmoke DC receiver project has been great fun but also quite frustrating. I got it working nicely if I used an external amplifier but the described three transistor high gain audio chain gave hardly any volume into my speaker. This has out-foxed me for far too long. I'm using 2N3904s with no particular manufacturer marking on them so had determined the leads using my fancy new FNIRSi component tester.
It's a bit hard to read in the photo but facing the flat side, the tester says the leads are C B E. The audio chain was working and had gain but I never got enough volume in the speaker. Nate, KA1MUQ, questioned the orientation of the transistors. I turned one around and there was lots more gain! Testing again, with my old clunker component tester gives the correct pinout.
Again, facing the flat site, but now the pins go E B C. Surprisingly different gain too hFE=170 compared to hFE of 215.
I was able to listen comfortably to sideband contacts with the amplifier driving a speaker directly.
Now my problem is "heartache of oscillation" (contrasting the "joy of oscillation" when building the VFO). The audio chain is very keen to take off at hundreds of kHz.
I found that even having the volume control off the board was enough to create instability. I've put it right back on the board and now all is working well.
Lessons learned: Component testers might not be right and transistors will work to some extent if wired with C and E swapped.
Discord is a kind of chat board where a group of people can create topic channels and basically talk back and forth in real time - if they wish.
Bill and Dean at Soldersmoke have embraced the form and created a fantastic place where many of us are sharing our issues, if they arise, and helping each other to debug things. The "smokers" are both there but also there's a good deal of constructors helping each other out.
My receiver has been re-built a few times and currently looks like this:
Bill urges us to stick to the design but some of us have had to substitute components or, in my case, due to the lack of an audio transformer that works, add a bit of extra audio gain in the form of an LM386 module.
Several builders have found that we get less output from the VFO than Bill or Dean do and the tell-tale squared off waveform at the input to the diode ring mixer isn't there. It's hard to know what the root cause is but presumably it's component variations or perhaps the "brass" screw material, which, in my case quenches oscillator level as it goes in to the coil. (Adding a 0.1uF cap across the resistor in the source of the buffer FET helps).
The Discord is broken out into channels for the oscillator, mixer, bandpass filter and audio amplifier.
You can join via this link (which will expire in a week). After that check out the Soldersmoke blog for new info.
Congratulations to Bill and Dean for this innovation.
My receiver is working quite well, thanks in particular to VK3ZZC who gave me some NP0 capacitors that have stopped the massive thermal drift in the VFO. It is very satisfying tuning 40m listening to stations - sounding really good - on a home made receiver.
If you are new to home brew radio construction, this is a good way to get started with a community of helpful people.
One important note, if you are going to attempt this project, there have been some changes to the schematic and the latest version is on the Discord in the #schematics channel.
Nightlife Tech Guru Peter Marks, a software developer and technology commentator from Access Informatics, joined Philip Clark on Nightlife to discuss the latest news in technology. This week: China’s new AI chatbot tool, Deep Seek has launched and its capabilities have shocked the technology sector and it rocketed to the top of app stores around the world. Has American pre-eminence in artificial intelligence been obliterated?
In the past I've used some of the ESP32 boards with a small OLED display on them. It's very handy having the display already there. Recently I saw mention of a "Cheap Yellow Display" (CYD) board with a large colour LCD for AU$20.
It's a very capable board with extra GPIO available.
My first project was to build an NTP synchronised clock:
It's a resistive touch screen but I'm not sure I'll use that feature.
