Experiment with live noise removal from an HF SSB signal

Today at the Macedon Ranges Amateur Radio Club coffee morning, Eric, VK3EJD, brought along a new gadget that he hopes will remove noise he experiences from a neighbour's solar system.

I used to have a noise reducing speaker from BHI but was never terribly happy with it. He reminded me that I'd started building a live noise reduction application for macOS using RNNoise so when I got home I did some tinkering and got it working. Here's a demo - although the noise is not terribly bad. (I switch it in and out during the video.

Here's an example of removing solar panel noise from an AM transmission:

It's promising but needs to be trained for your specific noise. In this I'm using the default model. This runs easily on an Apple M4. I wonder when we'll start to see this built in to amateur radio gear?

Convert HackRF Mayhem Portapack capture to a format playable with hackrf_transfer

I had a nice capture of a busy 40m band done using a HackRF Mayhem portapack and I wanted to play it back using a HackRF connected to a computer using hackrf_transfer.

Even though the native format of the hackrf IQ is 8 bit signed interleaved samples, for some reason the portapack pads these out to 16bit so conversion is needed.

A utility to do this is here.

Here's how it looks being played back:

These captures are excellent for demonstrating receivers and playing with decoders for digital modes. Note that the files can get rather large.

I play the output file back like this: hackrf_transfer -t 40mssb.iq8 -f 7100000 -x 1 -R

FreeDV Sunday net - good rollup

Conditions were so bad last week that I didn't bother writing up the net. Virtually no NVIS. This week was much better. 

Stations on frequency included: VK5KHZ, VK5KVA, VK5AG, VK5ABE, VK3ZD, VK3MS, VK3KEZ, VK3JCO, VK3GTP, VK3FC, VK3DQ (welcome), VK2UMZ (rx only), VK2KNC, VK2AWJ, VK5RA, VK3XCI and me, VK3TPM.

Thanks everyone for coming up. The net is held on Sunday mornings from 10:30am eastern time on 7177 unless the frequency is in use.

My experiences of using AI for ham radio projects

At this week's Radio Old Timers Club lunch in Melbourne I presented a talk outlining the good success I've had recently using Claude Code for ham radio applications. Also there's a bit of an overview of how FreeDV RADEV1 uses machine learning already.

A few AV hitches and the crowd was finishing lunch but feedback was pretty good.

Tech Talk on ABC Radio - Microsoft sorry about Windows 11

This week on ABC Radio's Nightlife program we discuss a recent post by Microsoft acknowledging a list of things that users complain about. They promise to address these in the year ahead. The complaints about Windows comes at a time when Apple CEO Tim Cook reports that, with the launch of the low cost MacBook Neo, Apple has seen the highest number of new users to macOS in the company's history. 

Continuing a trend in recent months, layoffs in tech firms are being blamed on AI being used to replace workers - but is that really the case or just an excuse to downsize?

Finally there are rumours that Amazon is having another go at a product in the mobile space. Code named "Transformer" it's likely to be an AI driven portable device. Inevitably something will replace the mobile phone but is this it?

https://www.abc.net.au/listen/programs/nightlife/microsoft-makes-a-slight-apology-for-windows-11/106492726

Tech Talk on ABC Radio - Apple goes low

This week on ABC Nightlife I spoke with Rod Quinn about Apple's new MacBook Neo, a sub-$1000 laptop that competes very well with Windows laptops in that price range. Apple has made some compromises but kept their quality standards up.

We discussed the US AI controversy where Antrhopic, makers of Claude, asked the Department of Defence to not use its products for widespread domestic suveillance or autonomous weapons. DOD would not agree to those limitations and has done a deal with OpenAI, who presumably are ok with that.

Finally, the ban on social media for Australians under 16 introduced in December seems to be spreading with Indonesia announcing they'll introduce it gradually from March. They join Denmark, France, Germany, Malaysia, Spain, the UK and Greece in either announcing or at least considering a ban.

Too early to know how effective it's been in Australia but we do see that VPNs are booming...

https://www.abc.net.au/listen/programs/nightlife/nightlife-tech-talk-with-peter-marks/106439260

FreeDV Sunday net - Good rollup, four states

The Russian FSK transmissions were very strong this morning which ruled out using 7045 so I parked the net on 7177 and didn't expect too many stations to find me but there was no problem. 

Stations heard: VK2AGU, VK2AWJ, VK2KNC, VK3GTP, VK3KEZ, VK3PCC, VK3PTR, VK3ZD, VK5AG, VK5KVA, VK7DMH, VK5ST, VK3CDH, VK2KO, VK5ST, VK2BLQ and me, VK3TPM.

A warm shout out to Joe VK3SRC who several stations credited with helping them with various aspects of getting FreeDV going nicely. Thanks Joe!

Also a shout out to Dave who's OpenWebRX+ is now decoding FreeDV RADEV1 over at Normanville.