Tech news spot on ABC Radio

Scammers are a real threat to us all. Australians lost billions of dollars last year. 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. https://www.abc.net.au/listen/programs/nightlife/tech-talk-with-peter-marks/104622796 

Rosebud Radiofest most entertaining

Lots of useful parts for sale at good prices. I bought PL-259 crimp connectors for $3 each instead of the much higher prices I see them online. Tempted by one radio but the seller didn't accept my offer. Probably should have stayed until the end but it's a long drive back to Drummond. I did buy a few books and a nifty hot air gun.

It seemed a bit quieter than last year but there was lots to see.

Mostly, it was great to catch up with friends. Here's Peter, VK3YE being sold morse keys by Drew VK3XU:

Andrew, VK3BEK; Ralph VK3ZZC (who purchased yet more test equipment), Dave VK3ASE:

I bought a few books including the excellent "radio handbook" by William Orr. 

I looked it up on Amazon and find that a new copy is on sale for $749!

Jim, VK3ZKK and Judy VK3FJAD were representing the Radio Amateurs Old Timers Club.

As always, a very well organised event. It's marvellous to see the big signs on the roads leading up to the venue.

Tried Apple Vision Pro - a glimpse of the future

The Apple Vision Pro is a product they've been working towards for many years. The software progress has been public, in the form of ARKit, and the hardware in private. It shipped early this year and, while I've read many reviews, it's something I wanted to try myself.

You can book a personal 30 minute demo at Apple stores and it was easy to get an appointment.

The first step is that they put your glasses (if you wear them) in a machine that figures out your prescription. I had mine with me but they preferred to let the machine do it. My sight requires astigmatism correction and the magnetic clip in lenses they came back with seemed good.

There are some new user interface gestures to learn. Basically you "point" at things just by looking at them and "click" by touching your thumb and forefinger. It's hard not to try to point with your fingers at first.

After putting the headset on and adjusting the straps to keep light out the magical thing is when the outside world appears thanks to the high resolution cameras and high resolution screens in front of your eyes. It really looks like you're looking at the world through glass. Perspective seems the same and it's high dynamic range.

The first thing I did, which perhaps puzzled my demonstrator, was turn my head side to side rapidly to test the refresh rate. It's good but not perfect, the scene got a bit choppy.

There's a bit of calibration to do, looking at dots in front of you etc. It worked well.

Then a bunch of demos to run through. 2D photos, 2D video, 3D photos, 3D video and "immersive" photos and video. I have no interest in sport but the 3D video of basketball was quite impressive.

Most iPad apps can be used in a floating window and I looked up my WSPR Watch app in the App Store but it wouldn't let me install it.

The most impressive thing to me was how solidly user interface elements seem anchored in place around the room you're in. You can surround yourself in "windows" and pull or push them away.

The headset is bulky but didn't feel heavy on my head. After wearing it for about 20 minutes it did feel a bit hot and was a bit of a relief to take off. I could certainly imagine wearing one on a flight to privately watch a movie but I think that would be a waste of the technology.

I saw a couple of minor glitches during the demo but overall it was a solid platform.

The jury is still out on the future of spacial computing. One day the big flat screens we put on our desks will seem as dated as the deep CRT screens we used to use.

It was great to try this out. If you have time, take the opportunity. There was zero pressure from the demonstrator to have me buy one. At AU$5,000 and up, I wasn't tempted. If the price comes down to something similar to an 8k monitor they'll sell like hot cakes.

ChatGPT is incredibly useful for electronics calculations

When I wanted to calculate something in the radio shack, I used to google for the formula and then execute it on a scientific calculator. Just now I wanted to know "5dbm as peak to peak voltage across 50 ohms" so I asked ChatGPT which responded very helpfully:

This is really useful. I look forward to having it built in to my phone.

Having said that, this interesting video looking at whether high SWR causes common mode current on coax points out that ChatGPT isn't always correct but is useful.

Hole saw pad PCB construction

I generally use superglued on MePads from QRPme but burn through them at a great rate. Recently I had a go at cutting insulating tracks on PCB with a Dremel cutter wheel. 

I purchased a set of diamond (really?) tipped hole saw bits intending to use them to cut my own pads but this didn't really work as the thickness of the cut is so wide you make a big hole and get a very small pad. 

By using the hole saw to just cut the copper layer I get a nice insulated pad and it's not hard to add extra pads to a circuit under construction. Here's a diode ring modulator currently on the bench:

 MePads are great but it galls me to pay more for postage than the product. I wonder if a PCB manufacturer can make something like them?

Tech news spot on ABC Radio

Peter Marks, software developer and technology commentator from Access Informatics joined Dom Knight with all the latest in tech news. It's been 40 years since Microsoft Excel was developed, touchscreens are out and buttons are back! listen at: 

https://www.abc.net.au/listen/programs/nightlife/nightlife-technology-peter-marks/104564546

HF FM transmitter with Franklin oscillator

Recently I've been working on an AM transmitter for 40m. It occurred to me that FM should be much simpler to produce. I had ordered some varactor diodes recently and first tried to FM a crystal or ceramic resonator. I can't get much deviation and the audio did not sound good.

Then I remembered a post on Soldersmoke about a largely unknown but surprisingly stable oscillator called a Franklin oscillator. It has two transistors and has a very light load on the tuned circuit.  

Rather than the variable supply transistor I fitted a 5V three terminal regulator. Coupled to the tuned circuit is a varactor diode with an electrolytic capacitor through which line audio is inserted. There's a trim pot to set the DC to the diode.

Initial results are quite promising.

The brilliant Charlie Morris, ZL2CTM, has an excellent video on the Franklin oscillator.

Thanks Stephen, VK2BLQ, for the tip.

Tech news spot on ABC Radio

A new online safety code of practice to protect children online has been released by the Digital Industry Group for public consultation. The key principles of the codes is to protect and support children and provide all end users, including parents, with more control over what their children see, read and hear while protecting privacy. 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. Listen here

3LO turns 100

The (now ABC) station called 3LO turned 100 last week. The ABC pulled out all the stops to put on a wonderful live broadcast followed by an ex-staff party in Melbourne. 

I've heard that everyone who was asked to perform was more than keen to be there. Aside from amazing musicians there were many notable celebrities in the crowd.

The first guest was no less than the Prime Minister, Anthony Albanese, who was wearing ABC Sox.

Some names that stood out for me included: Brian Nankervis, Colin Denovan, David Anderson, Deborah Cheetham Fraillon, Jacinta Allan, Jacinta Parsons, John Pesutto, Jon Faine, Mark Seymore - (hunters & collectors), Paul Higgins, Pete Smith, Peter Couchman, Raf Epstein, Red Symonds , Sarah Blasco, The Teskey Brothers, Tina Arena, TISM, Vicka & Linda Bull, and Virginia Trioli.

Danny Tran was there doing interviews for a TV news spot. Daniel Ziffer was sitting behind me. (I wanted to tell him how much I enjoyed his coverage of Sam Bankman-Fried's hair).

The show opened with the ABC news with the theme played live. Here are a few clips:

The Athenaeum Theatre was a wonderful venue for all this.

WIA historian Peter Wolfenden, VK3RV, kindly sent me this list of the first stations:

Warm thanks and congratulations to the team that put all this together. A memorable event.

As well as those of us who've worked at 3LO in the past, the current staff gathered for a photo:

John Amies wants to know why Peter Evans wasn't there.

Comms Connect Show in Melbourne

Today I joined some other amateur radio operators at the Comms Connect trade show at the Melbourne Exhibition Centre. Check in was efficient. Ralph VK3ZZC, Peter VK3YPG and Nigel VK3DZ were there too.

It was mostly pretty dry commercial stuff but Icom was there and even had some amateur equipment on display. Knowledgeable Craig Norris was there with all the Icom news.

Kenwood had a stand but there was no amateur gear, mostly DMR commercial stuff.

Telstra had some sort of life-saving drone idea but "it's going to have to be at least three times bigger than this" to be useful.

After the show we went for a very nice Yum Cha and then headed for one of Nigel's family bars "The Sherlock Holmes Inn".

Very nice. My thanks to Ralph for the bag of semi-conductors and happily I had a bag of NE602s for him.

On the train home I ran in to Ray VK3ACR, the world if full of Amateur Radio operators if you pay attention.

QRP Kits Easy Receiver

As a refreshment after all my recent home brew activity I built a nice little direct conversion receiver kit from QRP Kits aka "Pacific Antenna".

It's a classic NE602 + LM386 direct conversion receiver as described in Experimental Methods for RF Design. I've built these before. This version ads an RF bandpass filter to the front end and has an unbalanced audio chain to the LM386. It drives headphones just fine but is a little soft into my bench receiver.

Even though it only covers a small portion of the band - you move that portion with the trimmer capacitor - tuning is very sensitive and they do suggest that a multi-turn pot would be a good idea. I find it drifts a bit. Some of the supplied capacitors had very tiny and indistinct markings but the kit went together well and it worked on first power up.

Here it is receiving a parks operator:

The documentation is good and available on the web page. My kit arrived here in Melbourne, Australia, three weeks after ordering. Pretty good.

With a bit of board trimming I was able to fit the receiver into a low cost compact case.

"Socketry" this is called.

It seems more stable now that it's boxed up securely.

Tech news spot on ABC Radio.

I was a guest on ABC radio's "Nightlife" program talking about the amazing "audio overview" feature of Google's NotebookLM that generates a conversation about a topic you give notes on. 

Also Pig butchering scams are targeting Australians and are social media platforms really biased against conservative users? 

Listen here:

https://www.abc.net.au/listen/programs/nightlife/nightlife-tech-talk-with-peter-marks/104446916  

Dremel cut PCB construction

Prototyping small circuits where it's not worth designing and etching a board can be done in many ways. I've used "ugly" (which I think is rather beautiful) where components float above the copper ground plane; MePads where small copper pads are superglued to the base plane; or strip board with track cuts.

Recently I've converged on a system that's working quite well for me.

The circuit is drawn out in pencil and the outline of the PCB rectangle is traced.

Working through what should not be connected to what, I draw the cut lines under a spaced out version of the circuit. Here's my drawing and below the final working board.

I mark up the board with the planned cuts.

To make the cuts in the copper, I lay the Dremel with a cutting wheel on the bench and lean it so that it just cuts the copper. I draw the board along the wheel, leaving the Dremel stationary. I can get pleasingly straight cuts this way. It is worth checking for non-conduction between areas with a multi-meter as sometimes a strand of copper can be left at a corner.

To hold components against the board for soldering you need some sort of "helping hands" but the one I learned about from an Adam Savage video is called Omnifixo. They are not cheap but are well worth it for all the cleverness.

For years I've been using a little, rather low power, bench soldering iron but I find that quite a lot of power is needed when soldering to large copper areas. I have switched to a 70W iron and it is a revelation.

Naturally, I first had the transistor in the wrong way around, but after that was fixed. The joy of oscillation was experienced.

I'm sure this is not news to any readers but I thought it worth documenting for some who might be getting started with home construction. It's not as compact as other techniques but lends itself to making changes.

One other thing I do these days is add an LED (and resistor) to the power line. It looks nice and I can't tell you how much time I've wasted wondering why an un-powered circuit doesn't work!

Experimenting with an SSM2167 compressor limiter board

The home brew AM transmitter on the bench at the moment has thrown up the issue of either low or over modulation from my mic audio. Some time ago, I purchased a couple of interesting boards described as "SSM2167 Preamp Compressor Limiter Noise Gate Dynamics Processing Module DC 3V-5V Microphone Preamplifier". They are under AU$5 from AliExpress and really tiny.

To aid with experimentation, I've mounted mine on a carrier board.

R1 on the board controls the noise gate, which I'm not too interested in. R2 controls compression and came with a 1k resistor in place. The data sheet has this table:

1k would give almost no compression. A strange choice given how the boards are marketed. Happily there are big through holes available on the board for both resistors.

With the un-modified board I fed a 1kHz tone in and get peak to peak voltages:

50mV -> 440mV

100mV -> 880mV

200mV -> 1.43V

Higher inputs do not give higher output. The output waveform looks pretty good, so not clipping. Gain is rather low for my dynamic mic however.

I replaced R2 with a 100k resistor and it has much more gain.

5mV -> 880mV

10mV -> 960mV

20mV -> 1.06V

Output level stops there and again gain is being reduced.

Stephen, VK2BLQ, brought this idea to my attention as it has been discussed as helping the uBitx radios.

First contact with home brew AM transmitter on 7.125

For too many weeks I've been tinkering with a small transmitter for the active AM frequency of 7.125Mhz and just now I called CQ and was kindly answered by Ross, VK3ARW. He reported good signal strength both where he is (west of Bendigo) and on the Ironstone ridge SDR in South Australia. The transmitter is home brew (although I used a Jaycar mic preamp kit).

I've been testing by listening to myself on the PKLoops SDR.

The transmitter uses an Arduino Nano that simply boots up and tells an Si5351 to put out 7.125MHz. There's an RF buffer using a 2N2222. The magic happens, the generation of AM, using a simple diode ring mixer that is set to be off balance. Mic audio, from the preamp, is fed in and out comes AM. (This technique was mentioned by Dave, VK3ASE, who also uses it). There's another 2N2222 gain stage then a low pass filter. Next I have the three stage RF power amp from Drew Diamond's 80m transmitter. Finally another low pass filter for 40m.

To answer Ross's question.. out of all this I get about 1.5W so, for the sake of getting some contacts I've fed this in to a little RF amp that gives about 25W peak.

I must say I'm astonished that I didn't get RF feedback or other instability given the construction. Despite Ross's kind words on the audio I can see that a peak limiter is needed to keep modulation up without over-modulating.

Python code to generate WSPR audio tones

Ross, EX0AA, is working to do WSPR on very low frequencies and asked for some help generating WSPR tones as audio directly. There are several projects around that generate WSPR via GPIO pins, Si5351s or an AD9851 DDS.

I grabbed the AD9851 code from PH0TRA, removed the DDS code, and with the help of ChatGPT, modified it to generate audio directly using pyaudio. This works both on my Mac and on a Raspberry Pi with no modification. The audio comes out of the default device, and if you plug in a USB audio dongle it comes out of there.

It seems to decode just fine with acoustic coupling.

My code is here. You'll also need genwsprcode.py modified by PH0TRA from code by the fabulous Mark VandeWettering K6HX.

You'll need to use Python 3 (of course) and install pyaudio and probably numpy.

Usage: python3 wsprgen.py CALLSIGN GRID dBPower BASE_AUDIO_FREQUENCY

Thanks Ross for the push to make this. It could be handy for others.

Installing on a raspberry Pi

Thanks for the prompt from AA7US asking how to get going on a raspberry pi.

• Grab my code from the GitHub gist. (you can download the file or copy and paste).
• Grab PH0TRA's code from here. Put it in the same directory.
• Install the needed python modules:
• sudo apt install python3-pyaudio
• sudo apt install python3-numpy
• In a terminal run the program like this:
• python3 wsprgen.py --no-delay CALLSIGN GRID4 DBM 1500

Obviously replace CALLSIGN GRID4 DBM. 1500 is the base audio output frequency in Hz.

--no-delay starts outputting right away, good for testing. Remove that to have it wait for the top of the 2 minute block. You'll get a bunch of output from the audio software but it seems to work after a few complaints. Here's my output:

python3 wsprgen.py --no-delay vk3tpm qf22 33 1500

symbols

 3,1,0,0,0,2,0,0,1,2,0,2,1,1,1,0,2,2,1,0,2,3,0,1,3,1,1,0,0,2,0,2,0,0,1,2,2,1,0,3,2,2,2,2,2,2,3,0,3,1,2,0,3,3,0,3,2,2,0,3,3,2,3,2,2,2,0,1,1,0,1,2,1,2,3,2,3,2,0,3,2,0,3,2,3,1,2,0,2,1,1,0,3,2,1,2,0,0,3,2,2,2,0,0,3,2,2,3,2,2,1,3,1,2,3,1,2,2,3,1,2,1,2,2,0,1,1,3,2,2,2,0,2,1,2,3,2,2,3,1,0,0,0,0,0,0,2,1,1,2,1,2,3,3,0,2,2,3,1,2,0,2

ALSA lib pcm_asym.c:105:(_snd_pcm_asym_open) capture slave is not defined

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.front.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM front

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround51.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround21

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround51.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround21

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround40.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround40

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround51.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround41

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround51.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround50

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround51.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround51

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.surround71.0:CARD=0'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM surround71

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.iec958.0:CARD=0,AES0=4,AES1=130,AES2=0,AES3=2'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM iec958

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.iec958.0:CARD=0,AES0=4,AES1=130,AES2=0,AES3=2'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM spdif

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.iec958.0:CARD=0,AES0=4,AES1=130,AES2=0,AES3=2'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM spdif

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline

Cannot connect to server socket err = No such file or directory

Cannot connect to server request channel

jack server is not running or cannot be started

JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

Cannot connect to server socket err = No such file or directory

Cannot connect to server request channel

jack server is not running or cannot be started

JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

ALSA lib pcm_oss.c:397:(_snd_pcm_oss_open) Cannot open device /dev/dsp

ALSA lib pcm_oss.c:397:(_snd_pcm_oss_open) Cannot open device /dev/dsp

ALSA lib pcm_a52.c:1001:(_snd_pcm_a52_open) a52 is only for playback

ALSA lib confmisc.c:1369:(snd_func_refer) Unable to find definition 'cards.0.pcm.iec958.0:CARD=0,AES0=6,AES1=130,AES2=0,AES3=2'

ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory

ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory

ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM iec958:{AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2 CARD 0}

ALSA lib confmisc.c:160:(snd_config_get_card) Invalid field card

ALSA lib pcm_usb_stream.c:482:(_snd_pcm_usb_stream_open) Invalid card 'card'

ALSA lib confmisc.c:160:(snd_config_get_card) Invalid field card

ALSA lib pcm_usb_stream.c:482:(_snd_pcm_usb_stream_open) Invalid card 'card'

ALSA lib pcm_dmix.c:999:(snd_pcm_dmix_open) unable to open slave

Cannot connect to server socket err = No such file or directory

Cannot connect to server request channel

jack server is not running or cannot be started

JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

Waiting for next WSPR TX window...

Start of transmission on: 03:20:04

Frequency: 1,500 Hz

symbol = 3, out_frequency = 1504.39453125

symbol = 1, out_frequency = 1501.46484375

symbol = 0, out_frequency = 1500.0

symbol = 0, out_frequency = 1500.0

symbol = 0, out_frequency = 1500.0

symbol = 2, out_frequency = 1502.9296875

symbol = 0, out_frequency = 1500.0

You'll hear the tone on the default output. In my case I plugged in a USB audio dongle.

The Secret Life of the Radio

Thanks to Lindsay, VK3GX, for bringing this wonderful BBC program to my attention. The team shows the development of radio and makes various transmitters and receivers. They build a coherer and demonstrate it for example.

Keep watching after the end credits for some comments from the presenter.

Incidentally, the cartoon depiction of Marconi's home are quite accurate. I visited it some years ago.

Tech news spot on ABC Radio

How do you remember your passwords? Making up and remembering unique, complex passwords is a struggle for many of us. Those days are ending. What are PassKeys and how will they help? Plus, Modern cars have many "driver assist" features. Things like lane following and emergency braking. Car speed-warning devices are spreading, all cars sold after 2030 in California will be equipped with either GPS or a front-facing camera that will give warnings if a driver is travelling more than 10 miles over the limit. Tech Guru Peter Marks, software developer and technology commentator from Access Informatics with Philip Clark on Nightlife with all the latest news and issues in technology. 

You can listen here.

Radio Old Timers Club AGM

The Radio Old Timers Club annual general meeting and lunch was well attended by members of MRARC. Peter VK3RV, Jen VK3WQ, Ray VK3ACR and Peter VK3TPM attended. Old friends Nigel VK3DZ and Peter VK3YPG were also there. 

First the meeting kicked off with the annual general meeting which was conducted efficiently by Jim Gordon VK3ZKK with some members on Zoom.

Next a hearty lunch was served.

Mick VK3CH gave a detailed presentation about microwave operation.

Lots of gear was on hand but unfortunately wasn't turned on.

Don VK3BIG brought along what must surely be a new disruptive technology that could spell the end of FM radio - an AM stereo receiver.

Wonders will never cease! Nigel, VK3DZ is clearly boggled by this advancement.

50 Years of G-QRP Book review

Australian QRP and home brew enthusiasts typically subscribe to two fine newsletters, the local Lo-Key from the VKQRP club and the British SPRAT from the G-QRP club. Both are A5 format newsletters packed full of interesting projects and ideas. They are of sufficient quality to stand many re-readings over the years but it’s sometimes hard to find an item that comes to mind in the pile.

Lo-Key has an index and SPRAT sells back issues on CD or USB key.

When I heard of the publication of a book to celebrate 50 years of SPRAT, I didn’t hesitate to order a copy.

The G-QRP club was founded in 1974 by Reverend George Dobbs G3RJV (SK) who commented that there might be a demand for a newsletter “if there’s enough interest”. It turns out that there is.

Ed Durrant, G8GLM, has put together a fascinating selection of articles drawn from SPRAT over time. They are clearly marked with the year of publication and show the progression of technology available to the hobbyist over the 50 years. Beginning with low valve count gear and ending with SDR technology.

The book’s selection of projects is broken down into Transmitters, Receivers, Transceivers, Antenna systems, Test equipment, and Miscellaneous topics.

Although widely available components have changed over the years there is lots of great ideas within the collection that are still relevant today. There are charming mentions of the help that writers have received from other home brewing QRP operators. 

Many of the articles mention familiar names from other writing including Doug Hendricks KI6DS, Pete N6QW, Charlie ZL2CTM, Eric ZL2BMI, Roger G3XBM, and Wes Hayward W7ZOI. There’s a good number of VKs mentioned. I haven’t spotted VK3YE, but he’s probably there somewhere.

A few of the articles are reproduced with low contrast – I guess they’ve been scanned. Early items are charmingly typeset on manual typewriters. For the 100th edition I’d like to see an index added.

The book is available via the RSGB shop for £17.99 and less for members.

Tech news spot on ABC Radio

I appeared on ABC radio last night discussing the tech news with Philip Clark. "Google's new "pixel 9" phones were revealed last month, and this morning, Apple hit back with new products, including a new iPhone. Tech Guru Peter Marks, software developer and technology commentator from Access Informatics with Philip Clark on Nightlife and the latest news and issues in technology."

You can listen here.