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

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

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

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.

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

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

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

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

There is a very active AM net here on 7.125Mhz and quite a few of the stations come up with home brew transmitters. (There's also a few using IC-7300s which do sound good on AM).Dave, VK3ASE, mentioned recently that a good way to generate high quality AM is by using a diode ring mixer (which would normally produce double sideband with suppressed carrier) but with a DC offset added to the audio

ABC Radio legend and beloved presenter of ABC TV's BackChat program, Tim Bowden has died. He was a wonderful broadcaster, producer, writer and man.Here he is with his wife Ros (who died a while ago).We became friends when I was working for the ABC in Sydney. Mostly around Apple technical topics.I vividly remember listening to his radio series Taim Bilong Master about the Australian involvement

Looking at digital modes for talking with people with high local receive noise I noticed Contestia in Fldigi. It's derived from Olivia but has a smaller character set. It only sends upper case letters. Stephen, VK2BLQ, has fairly high local noise. He's about 700km from me. To check if we have a suitable path for a QSO we both ran WSPR on 40m. He received my 2W at +3dB SNR so we switched to

Regular readers will know that I'm one of those commentators you hear on the radio. I've always been keen to have my audio sound as close to the studio as possible and I think I'm getting close.Without a noise dampened studio I need to get close to the microphone to avoid reverberation but I have a tendency to "pop" the mic so I need to monitor my local audio as well as hearing the host. We used

A new ID system for Australians. At a speech at the National Press Club today, Government Services Minister Bill Shorten announced the trial of a new way for us to identify ourselves that is more secure than things like our driver's license but will require a phone. Also, have you ever got to the checkout to find that the price is different to what it was on the shelf? Have you ever looked at a

The house here has 6KW of solar power, when the sun is shining and hitting the panels. I like to watch what's being generated so I can use power from the sun if available so some time ago I reverse engineered the Envoy inverter's web display and made some M5 Stack devices that display the info. They have an ESP-32 for Wifi built in. Sometimes the sun also shines on the LCD making it hard to

It's been many years since I've built a quadcopter from parts. What triggered this project was stumbling across the SpeedyBee flight controllers which have a powerful STM32 F405 and bluetooth so they can be configured wirelessly from a smartphone app. The controller has the motor controller (ESC) board mounted under it which makes for a much neater arrangement than the last time I did this which

This year I fulfilled a long term ambition of visiting Uluru in the centre of Australia and I couldn’t help thinking how spots from there might look on a WSPR map. Here's a spoiler (plotted in WSPR Watch):Operating QRP from a motel room is a challenge in several respects. From past experience I knew that receive noise would be high and while it’s possible to hang an antenna up inside the room,

Billboards are said to be one kind of advertising that can't be blocked or skipped. That's all about to change with a revolution in outdoor advertising in Switzerland. Also, the devastating Windows CrowdStrike raised many questions, but it looks like Microsoft is working to make Windows more robust in the face of software bugs that could bring it down. Plus, flying cars were one of the

A recent podcast from Freakonomics titled Why do your Eyeglasses cost $1,000? explains the EssilorLuxottica monopoly we face here in Australia as well as the US.  Their markups are described by one analyst as "obscene". They mention Warby Parker as a possible monopoly breaker but sadly they don't seem to have come to Australia.My prescription is relatively complex with astigmatism and

This week on ABC Radio Nightlife, we talked about Samsung's product updates and how much they look like Apple products, a new way to migrate your photos from Google to Apple's cloud, future cars that won't let you speed, Android's coming desktop mode, some old technology (8 inch floppy disks) that are finally being retired and the US ban on Kaspersky Anti-Virus. Listen here.