Thursday, February 15, 2024

Listening to shortwave on my 80m loop antenna

Recently I strung 80m of wire up in a loop attached to trees. It's not as good as my dipole for transmitting but it makes an excellent receive antenna. I've got an AirSpy HF+ SDR running with SDR++ in server mode so I can tune from the house (which is separate from the shack). This is running over two Wifi links but as you'll see it's a pretty good experience.


I'm currently reading Geoff Heriot's excellent book about International Broadcasting titled "International Broadcasting and Its Contested Role in Australian Statecraft - Middle Power, Smart Power". An informed and thoughtful examination of the topic.

Saturday, February 10, 2024

WSPR Watch 4.10 - fixed a long standing thread crash

WSPR Watch, my iOS app for quickly looking at spots on WSPRnet, is 12 years old. During that time it has been updated as the software tools and frameworks have changed.

First it was Objective C and UIKit. Next came the move to Swift. Version 4 was a move to SwiftUI.

I've always used background threads for doing the time-consuming requests to the different data sources. Most recently I've been using async/await and Actors. 

When I moved the app from storyboards to SwiftUI about half of the old code was no longer required. Things look much neater now. For a long time I've had a few crash reports coming in. These have been mostly in the map view. This app really hammers the map by drawing, sometimes, 10,000 or more overlays on it. 

I'd heard of the ThreadSanitiser that is part of the LLVM toolchain and available in Xcode. When I turned it on and ran the app in a Simulator it quickly showed me three data races that I hadn't noticed. My mistake was adding to an Array from a background thread when that Array was also available from other threads.

Having fixed these, I am now seeing zero crashes from users of version 4.9 and later. I expect to see a few due to being out of memory of killed in other ways but so far it looks good.

My thanks, as always, to my wonderful testers and users for their suggestions.

Sunday, February 04, 2024

Enjoyed the Ballarat Radiofest 2024

A few friends came from around the state including Shepparton, Bendigo and Melbourne. We stayed at a local motel and had a nice dinner and walk the night before to check on shortwave reception.


It was a warm day but thankfully there was a very pleasant breeze to keep things comfortable. By opening time, 10am, the crowd was keen to get in to see the gear for sale.



There were lots of older generation transceivers for sale at fair prices but I wasn't particularly tempted.


Quite a few members of my club, the Macedon Ranges Amateur Radio Club were on hand as were members of the Bendigo club who even organised a bus.


I picked up a few 27Mhz AM transceivers in the hope I could find one I can move to the 10m amateur band. I couldn't resist an Icom IC2A 2m handheld transceiver for $3.


A very enjoyable day. My thanks to the organisers.