Sunday, August 22, 2010

Winterfest Ham Radio Festival in Sydney

Dropped in to Winterfest today. It was a stunning day and I took a few shots with the HTC Desire. Here's the Home Brew table where I displayed a "Retro 75".

Home brew table.jpg

There was lots of electronics on sale at crazy prices, all I came back with were some nice little SMA cables for $2 each (I recently paid $17 for one so that was a bargain for me).


Here's a look around the room including the morse key display.

Thanks to the organisers for a very professional setup.

Wednesday, August 11, 2010

Some thoughts on broadband policies

I had a chance to chat about the broadband policies of the government and the coalition this morning on ABC Radio National. You can hear it here.

At the end I had an opportunity to mention a few technology policies that are missing from the current debate including:

  • Net neutrality
  • Government 2.0
  • Open Source in Government
  • Electronic text books for schools

Tony Abbott is my local member, if he comes door knocking I've got a few ideas for him..

Sunday, August 08, 2010

Uniwave DRM receiver

Digital Radio Mondiale is the digital radio system for short wave. There are few broadcasters and even fewer receivers. Here's one of them that's available locally:

The video shows reception of Radio New Zealand International (RNZI). (One of my kids came in at one point to ask if "Seven periods with Mr Gormsby" was on the radio).

Kindly loaned to me for evaluation by the fine folks at Radio Australia, I've had the Uniwave receiver for a few months and while fun to play with, especially "expert mode" you see in the video above, there's not much to listen to.

The Uniwave 100 DRM receiver is available locally but I honestly can't recommend it for Australian users.

In the heart of Europe it is probably a different deal and the features of DRM seem compelling, but here in the Pacific I'd stick with an analog receiver for battery life alone.

Having said that, the "expert mode" display is fantastic.

Pico life e-book reader W960 review

Why would I need an ebook reader when I already have an iPad? The iPad is a fantastic device and works wonderfully indoors, but I wouldn't take it to the beach and it's not too good even in normal outdoor light.

Officeworks are now selling a range of ebook readers and today I plunked down $238 for the Pico W960.

pico front on table.jpg

E-ink screen, superior to the old Sony one I've had for years. 2GB of internal storage and a slot for an SD card (not micro SD as the box says by the way). 800 x 600px, support for text, pdf, epub, html, unicode text, lrc, pdb, fb2 and wtxt.

It also plays music in mp3, wma, ape, flac and aac formats.

The best feature is the e-ink display seen here in direct sunlight:

pico sunlight.jpg

Opening an epub book, like the one above takes an intermidable 15 seconds so you'll be looking at this a bit:

pico please wait.jpg

(That's an epub book I purchased from O'Reilly and it works just fine).

Page turn speed is typical for e-ink displays. You change pages either with the four-way rocker on the front or with the up down buttons on the back - this is a great feature and saves putting little buttons on the edge that get clicked by accident.

pico rear.jpg

The device comes loaded with 118 text files from Project Gutenberg but they are so poorly named (A065.txt, A123.txt, etc) that I just took a copy and deleted them all. It's too slow to go in and figure out what each one is.

You plug the device in to your computer using a Micro USB cable and it simply mounts as a storage device.

pico ports.jpg

I had a few minor issues using it with my Mac - the hidden .Files that MacOS creates show up in the book list and so I use Hidden Cleaner to get rid of them, also as soon as you unmount the device it mounts again right away meaning that my quick unmount and unplug action normally leaves me with a warning about unplugging a mounted disk.

After changing the books on the device you need to select "Content Update" to get it to realise they are there.

The buttons on the front, marked home, music, zoom, and back are touch sensitive and potentially a bit too easy to trigger. Oddly the button with a home icon on it is called the "options" button in the manual and doesn't seem to work at all on my device.

All up it's a useful gadget for the money and it's great to see a range of book readers on the shelves at low prices.

Update: doesn't like some epub

I tried to open a commercial epub "Python in a nutshell", it said "please wait" so I did for about half an hour. The reset button is the little hole between the up and down buttons on the back.

It will open smaller epub files but it simply shows the text content devoid of any images or even basic text formatting. Annoyingly all text is justified.

PDFs do show up in graphical form but any A4 pdf it too small to read so this isn't really useful.

My conclusion is that this is a good little reader for just reading text files. For real books I'm going with the iPad.

Tuesday, August 03, 2010

MiniVNA Pro first impressions

A new toy arrived today, a MiniVNA Pro.


It's a very nice bit of gear and comes with calibration loads.

I've failed to get it going reliably on my primary machines, MacOS X and Linux so for now I'm using it on a Window virtual machine.

After calibration I connected up my 40 and 80m dipole antenna (both in parallel) and it gave me this wonderful SWR plot in about a second:


It also produces a Smith chart but I don't know how to interpret it.


It's astonishing that a home constructor can own test equipment like this.

I have much to learn.

Update: Now working under Ubuntu

The software for linux is a java application vna/J

The trick is to use the serial library installed like this: apt-get install librxtx-java

Here's the calibration dialog:

And here is the resistance of a 50 ohm terminator swept up to 180Mhz.

Here's a sweep of a 3.6864 crystal.

Very cool.

Update: Now working under MacOS X

I grabbed a copy of the rxtx library from here that works 64bit and copied it to /Library/Java/Extensions/ but as soon as the software tries to use the serial port, like during the calibration run, I'd get "VNADriverSerialPro::init() Unknown Application".

The trick, thanks to this page, is:

sh-3.2# mkdir /var/lock
sh-3.2# chmod 777 /var/lock

Now everything's fine.

minivna mac.png