Wednesday, August 13, 2025

New shack Mac and first FreeDV contact with ZL2TJM

Just brought an unused old Intel iMac up from Melbourne. These feel very slow compared to the current M series CPU Macs but they do have a beautiful screen and it seems a pity to sell for just a few hundred dollars.

Anyhow, plugged it in, installed FreeDV and immediately heard a New Zealand station, ZL2TJM making his very first FreeDV transmission. I asked Rob what prompted him to try FreeDV and here is his reply:


Sounding pretty good on 40m from across the ditch from New Zealand. "You won't believe how good eighty meters is on FreeDV".

Upgraded to macOS Sequoia 15.6 by installing OpenCore Legacy Patcher

The iMac is 11 years old and was stuck on macOS Big Sur 11.7.10. While everything worked OK some software for the old OS is no longer being updated including the Chrome browser and, of course, tools like Xcode.

There is a thing called OpenCore Legacy Patcher that will take a macOS installer, modify it so it will install on the unsupported hardware and add the drivers needed to support the older hardware.

It's not for the faint of heart but after a few hours I got through the process and now have the configuration you see in the About this mac window shown on the right.

One, pretty major, problem I encountered is that it recommended Sequoia 15.7 but when it booted the software couldn't find the drivers and not much was working. It didn't draw the desktop properly and there was no dock.

A bit of searching and I found that one should go back a version to 15.6. I tried downgrading over the working system but that failed so I ended up doing a clean install of 15.6 which is now working very well.

A few small things don't work - I think. One is Watch unlock but that's a bit flakey in normal use. Overall I feel like this machine is getting a second life. It's a wonderful 5K screen and as you can hear from the FreeDV audio above, the speakers are very good.

An 11 year old computer being this good strikes me as excellent value. Congratulations to the good folks behind OpenCore. Make sure you back up your data before attempting this (I did).

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