B&W coils

I was surprised to see that one longtime brand I associate with my earliest days playing around with radio, Barker and Williamson, is still thriving – and even better, still providing the product I associate them most closely with, air wound coils, specifically the Miniductors.

B&W coil
B&W coil

There’s a list of the types they have available here. They’re not cheap, but they are convenient. They don’t appear to have a local Australian distributor. They do sell an attractive looking 13-42pF butterfly variable capacitor for US$25.

Homebrew ladder line spacers

It never ceases to amaze me what wisdom is simmering away amongst those email discussion groups I read.

Out of the blue today – prompted by mention of a commercial solution on the Elecraft list – came a sequence of brilliant ideas about making effective and easy on the budget ladder line spacers.

The commercial spacers from K&S Ham Radio Parts look great, but the fact they’re made of nylon prompted concerns about their survival against UV. At 25 cents a piece I think they look fine!

In response there was a pointer to a YouTube video showing how to turn a box of ballpoints into very neat and secure spacers using black cable ties.

And then a pointer to another commercial solution from True Ladder Line, and a hint about how to replicate the effect at home using ‘drip sprinkler tubing’ which is the right size and and has just the right amount of rigidity for the job. And there’s Dave ZL1BJQ with his approach based on those plastic chopping boards you can buy at any $2 shop, cut into spacer pieces, notched then pushed on to wires and held in place with hot glue.

Spacer
Spacer

And then there’s this approach by VK2YE using plastic coat hangers, cut to length (5cms) and drilled to fit wire, and then glued to stay in place. In fact this is just one of 138 videos on his YouTube channel.

WSPR

Prompted by Julian G4ILO’s musings about the possibility of volcanic ash being responsible for propagation he observed a few days back, I’ve been looking deeper into WSPR, the application that produced the data that inspired the notion.

First stop was the main WSJT site where Princeton physicist Joe Taylor K1JT outlines the application along with other weak signal communications applications. The WSPR page points to the 20pp. User’s Guide (pdf).

There’s also some information at the WSPRnet site – especially the stunning map and the detailed database of recent spots.

Map of WSPR contacts
Map of WSPR contacts

Full circle – when I searched for a general introduction to the software and the mode it’s based on – sure enough I end up back with Julian, G4ILO. He’s published a very readable and comprehensive article which quite rightly comes up #4 on a WSPR google search. He describes how easy it is to become part of a global beacon network and contribute to the generation of up-to-the-minute propagation reports.

Right now, I’d really like to know how to interpret the colour and thickness of the lines tracing the transmission paths on the map.

FT-817 resources online

There’s a wealth of digested experience on this particular radio online.

ka7oei has a detailed site which has pages devoted to the following topics:

Yaesu's FT-817 transceiver
Yaesu’s FT-817 transceiver

Other FT-817 related sites include:

One of G4ILO’s ‘Radio topics’ pages is devoted to the FT-817. His document points to 817-Mem, a program to manage memories on the radio.

A123 batteries

There’s been a great explanation posted on the Buddipole list about the practicalities of using the A123 battery packs Buddipole sell from their site.

A123 4S2P battery
A123 4S2P battery

The advantages of the A123 chemistry are low weight, fast charge times and ability to deliver high current. As well their voltage – 13.2v for a four cell pack such as the one shown – is well-suited to modern amateur radio gear.

The email exchange is yet another example of how an innocent newbie’s question can draw out the best information which benefits the broader group. Mark KD5RXT’s explanation of duty cycle and the unique qualities of this new battery chemistry are almost text-book ready!

I’m still keen to find out more about the selection of the best solar cell and charger system to keep such a battery topped up. I sense that a system that could take advantage of its fast charge rate might dwarf the rest of the radio gear. And I also sense that current portable solar panels, especially the expensive roll-up ones might barely keep track even at QRPp levels.

iPad date announced for Australia

News this morning from Apple that the delivery date for iPad (both WiFi & 3G) – in Australia – is 29th May.

The new Apple iPad
The new Apple iPad

I’m so looking forward to seeing how an iPad might fit into a portable QRP operation. Or even a remote one. I’m also hoping that Apple will retain enough of open protocols so that the device does not simply become an expensive personal front end to whatever shops they wish to set up, like the sadly not ready for primetime Kindle.

Lack of a camera on the iPad is odd – given the next iPhone will actually have two – one in the front as well as the existing one on the back. Bluetooth keyboard sounds like it could be fun. I also imagine that ham radio apps to track satellites (ProSat) and monitor solar activity (Space Wx, 3D Sun etc) should look amazing. A work colleague showed me his new Android phone with a graphically brilliant astronomy application that you could use to locate, stars, planets and constellations easily. It felt like visual velvet and the images were much richer than I’ve seen so far on the iPhone.

Even a straighforward app to display bandplans should be able to be made to look clear and brilliant and enable you to get different views depending on mode, QTH or licence class.