Friday, March 30, 2012

First production Elecraft KX3 has shipped

Great excitement as the Elecraft KX3s are starting to ship. The first one, ordered on December 27, has left the building.

I got my order confirmation early on December 28 but from what I can tell from the newsgroup, that means I might have thousands of orders in front of mine.

By all accounts this rig seems like a very modern, power efficient, technically advanced HF transceiver that is set to replace the FT-817 around here.

Elecraft has slipped a bit but their communication has been first class and customers like me feel informed and respectful of the quality job they have done bringing a complex new product to market under the bright lights of the internet.

Ultrabooks have a way to go still

I'd recently read the BoingBoing piece title "Anything an ultrabook now" when I noticed this in the mail:

An Asus Ultrabook and just 1 inch thick - impressive.

Monday, March 26, 2012

Home Brew Group challenge project

At the meeting on Sunday at Dural, I proposed a construction challenge for the Home Brew Group: To build an AM transmitter for 40m, specifically 7.125MHz.

As in past years, these challenges are not a competition, although we do get together to compare what everyone came up with.

My reasons for suggesting this project are:
  • 7.125 is very active with AM activity here in NSW
  • AM sounds lovely on air
  • There are quite a few ways to generate AM
Crystals are available for 7.122 from Expanded Spectrum Systems for $2.55 ($2.15 in lots of 10). I used a technique suggested by Peter, VK3YE, to pull the crystal to 7.124 - which is near enough for AM.

Note that I couldn't get Peter's design to oscillate (I had substituted a 2N2222a I had at hand) but values from this page worked fine.

Ways to make AM

  • Series modulation, either with a modulation transformer or heising modulation which passes the audio through an RF choke.
  • Make DSB and re-insert the carrier - there's a bit on this in EMRFD.
  • Pulse Width Modulation
  • Software defined radio
The idea is that we'll build our transmitters, have a few contacts, and get together for a show and tell before the end of this year.

There seemed to be a good amount of interest at Sunday's meeting, I hope you'll join me.

Sunday, March 25, 2012

Digital Modes history and introduction talk

Cameron McKay, VK2CKP, was kind enough to give an excellent presentation at today's ARNSW Home Brew Group meeting at Dural NSW. I've broken it in to two parts and posted them on YouTube.

Part 2:

Comments on the HD AppleTV

I like the AppleTV. It's tiny, runs cool, has AirPlay and the remote is very simple. As soon as the HD version was announced I ordered online. Weeks later it had not arrived. I followed the status on TNT Express.

The "Card Left Not Home" is untrue. I was here and there was no card left.

When I rang to ask to see the "Proof of Delivery Image" they admitted that it was not any kind of proof of delivery signature.

Turns out when Apple has a major bump in shipping TNT outsource deliveries and they lose real tracking.

In the end they admitted that my package had been lost. Apple was advised. Rather than risk another lost shipment I cancelled the order, was credited, and I dropped down to the local Domayne and bought one off the shelf.

The user interface is 1080p and looks great. Although it came out before this new hardware, the updated software seems a bit of a step backwards to me. I find it hard to see which tile is currently highlighted, the indication is a thin blue glow line.

Last night we hired a movie in HD. Normally when we hire a movie they are ready to play within a few seconds, this one took over an hour. The status showing how long until it can play seems worse than it was in the old version and the estimated time jumped up and down alarmingly.

Compared to other TV boxes we have here, a Boxee, a WD TV Live, and a few no-brand gadgets, the AppleTV is certainly the best but not up to the standard I expect from Apple. 

The hardware is great, I just hope the software gets some love soon.

Wednesday, March 21, 2012

New iPad 18 percent hotter - how's your grip of physics?

I love the tech site The Verge, but this made me laugh.

Relative to 0 Kelvin, this would be a pretty big increase in temperature - if that's how you'd express that... They've fixed it now.

More Digital Radio Mondiale (DRM) on Radio Australia

It should get easier to receive high quality short wave digital radio mondiale from April 1, 2012.

"RA will commence a DRM schedule from its main Pacific station at Shepparton, Victoria, from 1 April 2012. Average power is 40 kW from a Continental 418G transmitter. Reception reports welcome especially notifying interference to the RA transmissions.

Broadcasts to central Pacific may also be audible in North America; broadcasts to the south-west Pacific and PNG may also be audible in eastern Australia. Broadcasts to south-east Asia may be audible in Europe."

Here's the new schedule from Radio Australia. Times in UTC.

0100-030019000Central Pacificmode C 10 kHz 16QAM level 1 11 kb/s
0700-09007410South-west Pacificmode B 10 kHz 64QAM level 2 24 kb/s
0900-11009475South-west Pacificmode B 10 kHz 64QAM level 2 24 kb/s
1100-13006080West Pacific and PNGmode C 10 kHz 16QAM level 1 11 kb/s
1300-15009890Wentral Pacificmode C 10 kHz 16QAM level 1 11 kb/s
1500-17005940SE-Asiamode C 10 kHz 16QAM level 1 11 kb/s
1700-19009475SE-Asiamode C 10 kHz 16QAM level 1 11 kb/s

It's great to see DRM starting to get some traction. The combination of All India Radio, Radio New Zealand International and Radio Australia means that there will be plenty to tune in to. The AIR DRM schedule is here.

Now we need a new generation of low cost, low power consumption receivers to make it take off.


Bad news I'm afraid. It looks like management have decided not to go ahead with the DRM transmissions from Shepparton at this stage. Very sad.

Sunday, March 18, 2012

Alternate WSPR display map

The WSPRnet map is great but it hasn't been updated to Google Maps v3 so I've started working on my own version here.

Currently I'm scraping the spots from the WSPRnet database display page every ten minutes but I'd love to work with whoever is responsible to make this a bit more efficient.

I've done more work on the map and now it emulates the official map in that you can click on a marker to see who they're hearing and who's hearing them.

Let me know if you see any bugs.

Thursday, March 15, 2012

Weekend of sailing and horses

A bit quiet here due to a very nice weekend away with old friends.

Regrettably I've returned a sunburnt wreck. Yes, they're playing polo.

Thursday, March 08, 2012

An orgy of Apple updates

What a morning! Up at 5:15am to follow the Apple keynote. Great job gdgt by the way.

Now the software updates are flowing in:

  • iOS 5.1 for iPhone and iPad
  • AppleTV update
  • iTunes 10.6 for OSX
  • Garageband, iBooks, Remote, Find My Friends, Keynote, Pages, and Numbers for iOS
  • Xcode 4.3.1, GarageBand and iPhoto for OSX
I covered the new iPad on ABC Radio National Breakfast this morning. Looking forward to seeing the new iPad in person.

Tuesday, March 06, 2012

Upgrading my iTunes library bit rate with iCloud

There's been a lot of talk about the inadequacy of 16/44.1 compressed tracks recently. The thing that makes a big difference is the bit rate of the compressed files and one of the side-effects of the iCloud music storage system is that it matches your low bit rate tracks and lets you "upgrade" them to 256kbps.

Good instructions on how to go about the upgrade are here. Basically you sign up to iCloud match (just do it in iTunes), submit your collection, then delete all the matched tracks with a bit rate under 256kbps. Finally you re-download them.

I was pleasantly surprised by the number of matches I got. The vast majority of my music is ripped from CDs I own but there are a few others in there that were happily matched.

So now the big download is taking place here. Looks like it will take a day or so to complete. I'm getting 900 KB/sec from iCloud at times which is pretty snappy.

The new collection will be quite a lot larger than before but with the price of disks these days I don't see it as an issue.

Apple's recent announcement about "Mastered for iTunes" and the future prospect of upgrading to uncompressed tracks shows the way forward.

All this is more reason why we need faster broadband now and in the future when we want to listen to our collection streamed live from the cloud.


Over night my library finished re-downloading all the matched tracks. My iTunes folder was 85GB before, now it's 98GB.

Replaced iPhone 4 battery for $8.95

My iPhone 4 is starting to lose battery capacity. Apple says that after 400 cycles the battery loses 20%. I charge each night and recently I've been getting warnings in the early evening. There are kits on eBay that give you a battery and the tools you need. I purchased one for $8.95 with free postage. It came next day.

It's curious that the QR code is defaced. I wonder why. The screen suction cup wasn't needed and I soon had the battery replaced.

It was nice to remove a bit of pocket fluff that had crept in too.

Instructions on how to replace your battery are widely available on YouTube. I watched this one.

It remains to be seen what effect this has (the battery came virtually discharged). It was an easy and cheap process.


I'm very happy with the new battery. At the end of of a day of normal use I was getting the 20% warning, today (after a full charge over night) I'm still at 89%. It's like having a new phone again for $9.

Saturday, March 03, 2012

Physical USB tuning knob for software defined radio

Tuning a radio by pressing keys or even mouse movement doesn't quite have the familiar feel of an actual knob. Griffin makes a nice knob called the PowerMate and I've now hooked one up to PowerSDR and it works well. Here's a demo.

While setting it up I learned of a great collection of keyboard shortcuts available in PowerSDR. I set the knob to send 100kHz up and down keys but in time I'll probably add accelerator modifiers for quicker tuning when needed.

There is a delay in the decode audio so you can't really spin the dial the way you would on an analog radio but perhaps a faster computer and lower latency audio driver will improve this.

Weather Radar movie

We're having widespread rain in NSW at the moment, so much so that the Warragamba is overflowing for the first time since 1998. It's interesting how much havoc widespread sustained rain causes compared to a local intense storm.

We live near the Terry Hills BOM Radar which is great because I can watch the radar to choose when to go for a walk or when to bring in the washing.

The animation above is captured from the BOM site with a cron job that runs every 5 minutes and runs this script:

now=`date "+%Y-%m-%d_%H-%M-%S"`
curl -o ~/Desktop/radar/${now}.gif

The captured gif images are converted to a movie with Imagemagick like this:

convert -delay 5  *.gif radar.mpg

I used to be able to make a movie from an image sequence using Quicktime 7 but that feature seems to be broken under Lion.