Month: May 2010

Posted on

USB morse key

Via Julian G3ILO news of an Arduino based project to build an inteface to enable direct input to a computer with a morse key. Lots of information can be found here.

It looks like a neat little project. I don’t get the feeling it’s going to be offered as a kit or anything. Most of what you’d need to know to make one is on the site including a schematic and the code that decodes the morse code!

USB morse key
USB morse key

This is similar  – in concept at least – to those iPhone morse apps where you can tape the screen in the same way you would a straight key, and the app gives you feedback on your morse – at the most basic level by translating it back to what you hopefully intended to say.

What would be even more exciting would be an interface that could also handle paddle input to PCs … a bit like the $1.99 iPhone app iDitDahText by Marc Vaillant. You can only load this one on to jailbroken iPhones. It’s available via the Cydia Store. It enables you to enter text in all iPhone apps using the equivalent of an iambic keypad on the screen up to 50 wpm. Great party trick!

Or better still isn’t there a way to connect the output of the iPhone or even the iPad – electrical not audio – to control a keyer and a transmitter. Throw in PTT control while you’re at it!

Posted on

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.

Posted on

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.

Posted on

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.

Posted on

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.

Bitnami