Sunday, November 25, 2018

An all "show n tell" home brew group meeting

This week we dispensed with a lecture format at the ARNSW Home Brew Group meeting and just went with show and tell.

Actually it worked out well. Normally the show and tell tends to be a delay before we get to the lecture but this time it was nice to take it all at a relaxed pace. Of particular interest (to me) was Peter R Jensen, VK2AQJ (author of "Wireless at War") who brought along a compact HF radio that used to be used by the CIA and SAS called an AN/PRC-64.

Great to see everyone, some had travelled great distances to attend.

Clifford Heath demonstrated the HackRF One and got me motivated to go home and fire mine up. Last time I tried it there was no operation but it turned out I'd mistakenly grabbed a USB cable that was charge only.

As always, Tim was working to keep everything running smoothly. A national treasure.


Saturday, November 17, 2018

Transcribe Helper macOS App in the app store

In recent years I've worked on and submitted many iOS apps to the Apple app store, but today, I've submitted my first app to the macOS app store.

My wife, Phillipa, is doing a PhD and interviewed numerous people. I was roped in to help transcribe those recordings. She had some software that worked with a dictation recorder and used a foot pedal to control pause/play and rewind but it was old and dreadful.

I've also been transcribing interviews of past winners of GovHack, so this was an application I needed. Searching the app store turned up nothing.

The app is a simple text editor but it lets you drag in an audio file and then control the playback with some keys that are not normally used in transcribing speech.

  • ] is play pause
  • [ backs up 5 seconds
  • \ plays at half speed without changing the pitch
The keys, and the number of seconds and slowness are all configurable. 

In the main window you see how far though you are, the number of words typed (one of my transcriptions was 10,000 words from a very fast speaker), and how far to go.

While writing software in Swift is a joy, compared to developing for iOS, the macOS AppKit framework is very dated and overcomplicated. Some tasks, like making the help bundle, are poorly documented and it was only some small clues in StackOverflow that helped me get through it.

I wrote this utility for myself, but I've had valuable feedback from Terry and Jill Brett.

While it's a simple utility, I've decided to ask for a small amount of money, AU$10, as I think it brings great value to those who need it. My thinking is that this is cheap enough to avoid purchase hesitation and just enough to encourage me to continue working on it.

SDR software on macOS survey

This morning I thought I'd listen to the ARNSW Sunday broadcast on a Mac using an RTL-SDR dongle, just for a change.

First I tried my old favourite, CubicSDR.


I like CubicSDR largely because of the nice keyboard commands for tuning around and zooming.

Next I ran GQRX 2.5, which works well. I noticed I could also receive the broadcast on 1273.5MHz.


Finally I stumbled across waveSDR in source code format by Justin England or getoffmyhack.


This is a wonderful piece of source code in modern Swift, very clearly written. Thanks Justin! It seems to have a memory leak and there's a runtime warning about reading a view's bounds off the main thread.

I had a bit of trouble figuring how how to tune it, the secret is to choose Tuner from the popup in the left panel. You can also click on the spectrum but dragging doesn't seem to work.

Saturday, November 03, 2018

QRP By the Harbour November 2018

Yesterday we held another QRP By the Harbour meetup in Sydney at McIlwaine Park, Rhodes. A small friendly group turned up and happily the weather was kind. (Yesterday was 36C and a previous event was hailed out).

I set up a simple end fed antenna with a counterpoise. The end was held up on a 6m squid pole tied to a steel garden stake. I had a contact on 40m. Peter, VK2EMU, hung a giant dipole out to two trees and operated on 80m.


The most interesting station was Colin, VK2JCC, who put up a magnificent squid pole supported vertical. The rig was a wonderful military radio called a Clansman PRC320 that seemed to work very well.