Monday, December 31, 2007

A chat with Ben and Pete - Episode 11

FlickrFan, the death of hi-fi and more.

This week we chat about the surprisingly technical Stephen Fry, Dave Winer's new application created using his OPML platform, FlickrFan, experiences with Kubuntu and KDE4, AOL cans Netscape Navigator, booting linux from a USB flash drive, and the death of high fidelity music.

Interesting links talked about in the show:

Subscribe in:

Killarney Heights space program

A very entertaining morning - thanks Pete and kids!

On a hot Killarney Heights morning, our intrepid gang of space heroes set out on a mission to launch a rocket high into the air. It was dangerous, possibly even fool-hardy (well, that's what my wife was suggesting).

The video shows just one launch but I think we did six until enough pieces had fallen off that the rocket became unstable in flight and was lost, presumably in a low earth orbit.

Friday, December 28, 2007

Newspapers not for breaking news any more

I remember a time when the morning newspaper had a box, outlined in red, with breaking news that was occurring as the paper was put to bed.

This morning, the Sydney Morning Herald arrived on the doorstep missing one of the biggest stories of the year - the assassination of Benazir Bhutto.

Now, I listen to the radio over night so it felt like the story was quite old by the time the paper came and it was surprising to see no mention of it.

In Wikipedia it is reported on her page that she died at 6:16pm local time, which is 12:16am Sydney time (a bit after midnight). Had the paper's front page been set in stone already?

Was the biggest story in the world the fact that NSW police didn't want a water cannon, or that the PM went to the cricket and didn't seem to enjoy it?

I know it's the silly season, but news doesn't stop and in recent years we've had some really big stories at this time of year, including a tsunami.

For three years I subscribed to Time magazine and there is some value to a publication that shows the news of the past week in a way that lets you get a feeling for what has transpired without any pretense of having the very latest news.

It's hard, (for me), to see the value of a broadsheet daily news paper. Our paper recycling bin is pretty much full of it. Perhaps it's time for a daily journal of opinion and analysis that doesn't pretend to have the news of the day any more.

Wednesday, December 26, 2007

Variable DC regulator V1

I'm getting really sick of those little "wall wart" power bricks for everything. My collection is getting silly, particularly as the multi-voltage ones seem to never quite have all the voltages I want.

My recent purchase of an Asus EEE PC is a good case in point, I imported it from Hong Kong so it has a power brick with a dodgy mains adapter plug on the back of it. This device needs 9.5V DC to charge - none of my existing adapters will provide this - hence this week's mini project.

It's a classic LM317 variable DC regulator in a box with a knob. The circuit is straight from the data sheet here. In my version I have 100R for r1 and the potentiometer is 1K. On the input I have a bridge rectifier so I can plug either polarity in to it without fear. Construction is on a tag board, probably a heatsink and some ventilation holes will be needed but the LM317 is well protected against over temperature and current problems.

I'm calling this project version 1 as it turns out it can't supply the 2.3A needed to charge the EEE PC, still useful for other things, but a version 2 is going to be needed for my original objective. Looks like I need an LM150 or LM138 for that.

Tuesday, December 25, 2007

A call for cheaper public wifi

We're staying at a nice hotel for xmas. The kids and I can't live without our internet fix for even 24 hours - is that addiction?

The internet is available here (Sydney) but only via an ethernet socket and it's AU$30 per day!

While I'm away, it's the Asus EEE PC for me, while my daughter in the next room has a PowerPC iBook running Tiger.

Obvious solution: plug the iBook into the wall ethernet, system preferences, sharing, internet tab, share internet connection over Airport - works really well. (Don't forget to adjust power management to avoid sleeping while plugged in).

While I'm on this topic, why don't cafes have free wifi? I've seen it in one cafe using an Unwired connection. This is presumably a very easy to deploy solution, an unwired (pre-WiMax I think) modem and a wireless router to share it in the cafe. Surely whatever the cost of this to the business would be outweighed by the extra sales to people staying longer to use the internet.

Finally, if we must use a commercial Wifi connection, provided by the same people that provide our home connections (Optus, Telstra) then why can't we log in with the account we already have at home?

Anyway, enough moaning from me, merry Xmas.

Monday, December 24, 2007

A Chat with Ben and Pete, episode 9

The Google Talk Babel Fish and more.

This week we chat about Google Talk's automatic translation service, developer frustration with the Android SDK, Firefox 3 and the large number of bug fixes, the Mac security update breaking Ben’s proxy functionality, Apple legal getting testy with Fake Steve Jobs and Think Secret, SSH configuration coolness, and comparing Windows and Mac vulnerabilities.

If you’re still listening, there’s a treat at the end of the show. We chat about the production and publishing of this podcast.


Thanks Ben for production.

I'll be appearing on ABC Radio National Breakfast with Steve Cannane on Thursday this week to talk about electronic book readers.

Thursday, December 20, 2007

Arduino controller board on a Mac

Having played with PIC microprocessors for many years and had good times with the 16f628, it's been hard for me to jettison that knowledge and move to another chip even though it looks much better.

The Atmel AVR chips are low cost but designed for running code generated by "normal" compilers like good old gcc, rather than the PIC chips that need hacked c or basic compilers that know how to use that banked memory.

I use a Mac and always feel like a second class citizen when it comes to software and hardware for embedded systems. Make magazine featured a little board called Arduino that carries an ATMega168 chip.

It's the fastest "greet postie" to "das blinken lights" joy I've ever experienced.

Here's my list of observations so far:
  • The Arduino is open source so you can make your own
  • I bought the Diecimila for AU$37.50 with it's USB connection
  • Chip programmed with a boot loader so it is re-programmed via serial (over USB)
    • The boot loader is freely available so you can burn it into your own chips
  • There is an IDE for Windows, Linux and the Mac that works really well
  • The IDE for Mac comes with the driver you need for the USB interface
  • IDE has gcc-avr built in
    • It links against AVR Libc
    • Language is most of c
    • Syntax colouring
    • Seems actually to use a c++ compiler
    • Has some useful built in functions for doing i/o
    • Comes with libraries for things like printing to serial (and you can do serial comms to the board in the IDE so that's how you debug)
    • There are third party libraries available for stuff like digital servo control
    • Libraries are installed by simply dragging them in to a folder
  • The board can be powered by USB or a separate supply 6-12V
  • When you compile your source the output, including the intel hex file is dropped into a folder with the source so you can even burn it to another chip with your own programmer
What held me back from trying the Atmel AVR chips is the fact that there's so many of them! Where to start? Well, it seems like the ATMega8 is a good start. All the tools are free and if you have a PC with a parallel port you can make a really simple programmer.

Incidentally, I ordered my Arduino from Little Bird Electronics here in NSW on 9-December and it only turned up today 20-December. I think that's a little slow.

Tuesday, December 18, 2007

A look at Sun's Blackbox

Attended a very nice function by Sun at Darling Harbour in Sydney today to take a look at their server in a shipping container.

Racks are squeezed into a standard shipping container in a front to back packing arrangement. Between each rack are fans with heat exchangers that cool the air by using cold water. So the air flows into the front of one rack, out the back, through the heat exchangers and then in to the front of the next one.

Water is much more efficient for removing heat than air. I note that the standard unit contains a dehumidifier...

Racks slide out for access to both front and back. It's a clever idea and achieves higher density than you get in a normal data centre.

The warm water is cooled either in a building's system or in an external cooler and then it re-circulates. The air flow is a loop inside the box too so it all stays cool when closed.

Applications include things like:
  • Temporary data centre (perhaps for the Olympics or to render a film)
  • Building a data centre in a car park or warehouse (because you don't need an expensive space with false floors and airconditioning)
  • Door stop
  • Paper weight
It's a clever idea, although there must be some consternation about Google getting a patent on the same idea. Sun is a much more interesting company than it was a few years ago, there was a genuine buzz of enthusiasm from staff and customers at the event today.

Monday, December 17, 2007

Django Book 1.0 as an A4 PDF

I've been hanging out for this book for more than a year.

Having just done a formatting pass through it, I can confirm that it's truly a great piece of work. 

I ordered it over 12 months ago and can't wait to get the printed copy in my hands but in the mean time, I've grabbed it and done some basic formatting to turn it into a PDF with a useful table of contents which I present for your download entertainment here.

My reading of the licensing is that this is perfectly OK, and indeed others have done it, but they are in strange non-metric formats and none that I've seen have a useful (clickable) table of contents.

(If I have done the wrong thing, please let me know ASAP and I'll remove it).

I did the formatting rather manually by copying the web pages into Apple's Pages. Must say, Pages is a superb word processor these days and I have no desire to run anything else again.

A Chat with Ben and Pete - Episode 8

Amazon SimpleDB, Google Knol and more.

This week we chat about and viewing long-form videos using flash, VoIP on the iPod Touch, Web services interfaces into databases, the Amazon SimpleDB announcement, KDE4, USB vs. Firewire, “upgrading” to Windows XP, and Google’s unit of knowledge.


Saturday, December 15, 2007

80m loop antenna experiment failure

Just a brief post about some experimentation that has failed.

I've been trying to build a loop antenna for 80m (3.5Mhz) to reduce local electrical noise.

The idea was a 2m diameter square loop built from 1m lengths of electrical conduit. First I built with 1 turn and a 300pF polyvaricon capacitor and it resonated nicely at about 20Mhz. Next went to 3 turns and it seemed to resonate around 9Mhz, then 4 turns and I can't get this thing to resonate at all.

No idea what I'm doing wrong or why this won't work. The family is a little bemused about the structure in the back yard - I tried to pass it off as my version of a Xmas decoration.

I did learn a bit about conduit - there are two main kinds around, electrical and water. Water pipe is designed to carry water under mains pressure so it's much stronger.

Update: Check out Alan's excellent response. I will get back to this project soon.

Monday, December 10, 2007

A Chat with Ben and Pete - Episode 7

Project Blackbox, Songbird and more.

We chat about the world of XWindows on Leopard, Sun’s Project Blackbox, developments in the python based web framework, Django, more wake from sleep problems with the Mac, an iPhone MMS application, the Google charts API, and an amazing iTunes clone, Songbird.

Subscribe or just download.

Sunday, December 09, 2007

Bus driver of the year 2007

What an honour, to be driven by the Bus Driver of the Year 2007. We know because he has it embroidered on his shirt sleeve.

Richard drives a shuttle bus around a local loop that includes some retirement villiages. He's amazing in that he seems to know everyone's name and is completely patient with those who take a while to get on or off.

When I took this shot, he said "this isn't going to turn up on MySpace is it?". I said no, not MySpace.

Sunday, December 02, 2007

A chat with Ben and Pete - Episode 6

Facebook Beacon, Google Maps and more. We chat about routers, Peter’s domain woes, Facebook backs down on Beacon, Google and the FCC 700Mhz auction, Google maps and cell triangulation, offline web apps, an interesting SPAM solution, broadband over powerlines and the Eee PC launch. Golly!

We’re now listed in the iTunes directory. Click here to subscribe directly in iTunes.

Also check out the Facebook group. Click here.


Thanks again to Ben for production.

Thursday, November 29, 2007

Tracks for evaluating Hi Fi

Headphones and the amplifiers to drive them have become a bit of an obsession around here. For me, Alastair started it here for me. 

Clearly my hearing is not as good as it was when I was in my teens but there is a visceral pleasure in high quality audio even now.

Not all music shows it up and here is a little list of tracks I use to evaluate a new amplifier or headphone. It doesn't mean that these are particularly Hi Fi tracks, just that I know them and they reveal the differences for me. YMMV.
  • Jean Michelle Jarre, Equinox Part 4
  • Ry Cooder, Bop Till You Drop, I think it's going to work out fine.
  • Eagles, Hotel California, Hotel California - not really Hi Fi but so familiar that I can pick difference easily and hear the bad edit in the middle
  • Keith Jarrett, The Koln Concert, Part 1 (well any part really)
  • Dire Straits, Love Over Gold, Love over gold
  • Music for the Funeral of Queen Mary, John Eliot Gardiner; Monteverdi Choir, March 1
  • Steely Dan, Remastered: The best of steely dan then and now, Hey Nineteen
  • Talking Heads, Stop Making Sense, Psycho Killer
  • Eric Clapton, Unplugged, Tears in Heaven
Hmm, maybe this list reveals something about me rather than Hi Fi evaluation. Anyhow, it's my little list for what it's worth.

Wednesday, November 28, 2007

A chat with ben and pete - podcast episode 5

Latest episode of our podcast, we discuss:
  • Amazon Kindle
  • Australian Election
  • Google developer podcast

On traditional media I reviewed the Asus EEE PC in the morning on Radio National Breakfast with Fran Kelly you can hear it here.

Chu Moy Headphone amp PCB design

I've built a number of Chu Moy design headphone amplifiers over recent months and recommend them so highly to friends I end up giving them away. Previously written up here.

Ugly construction is fine for one or two off, but it was time to try manufacturing a printed circuit board.

When I last made a printed circuit board, it was done photographically, by exposing a chemical resist to ultra violet light. Having just dismantled my dark room, it was time to try a different technique.

I used some blue "press-n-peel" transfer film. The design was done manually in OmniGraffle, printed on the film with a little HP laser printer, ironed on to the board on a wool setting, etched and drilled all in a couple of hours.

This technique works pretty well, I've had a little trouble with the ironing phase, the transfer moves a bit when I iron it on. On one occasion I had to rub off the bad transfer and iron on again. The instructions say to set the iron to polyester, but our iron doesn't have it so I set it to wool.

The actual circuit for this board uses two OPA134 amp chips (rather than the dual chip) and a TLE2426 rail splitter. I don't include any volume control as the device driving it, generally a computer or digital player has one.

I present here revision 2 of a PCB design. It works but could be more compact and has two links. PDF here, OmniGraffle source here. Note that the writing will be mirrored on the copper side when you make it. (I haven't figured out how to mirror text in OmniGraffle..) 

You are free to use these for any purpose. (Let me know if you improve it).

Be careful that your printer is close enough to 100%, I suggest test printing and lining up the 8 pin IC which is the only critical spacing.

Sorry for the break in transmission expired and for various reasons I didn't realise until it was too late. Unfortunately it has taken five days for me to get it back and running again.

Very sorry to anyone who came to this humble blog over recent days. I'll try not to have this happen again.

Monday, November 19, 2007

Dismantled my darkroom - a sad day

I'm a habitual early adopter in every area except one, photography. I stuck with film long after it was becoming clear that digital was superior. Digital isn't better in every way, but that's a whole other topic...

Looking back at my prints I can see that I was somewhat blind to the dust and scratches that would not go uncorrected in these digital days.

I've had a darkroom in the house, on and off, pretty much since I was in my early teens. Many deeply satisfying hours have been spent huddled over the enlarger, with my fingers in the chemical trays, and walking with dripping prints to the laundry to wash. I will miss just having the room there, even though a year has gone by with no activity.

Digital equipment goes out of date within months, some of my darkroom gear is technology that hasn't changed in 40 years.

I'll still keep a few film cameras, they are pieces of industrial art. I wonder if there is a film processing service that develops the film and sends back a really high quality negative scan? Last time I tried Kodak Photo CD it was very disappointing.

A Chat with ben and pete - podcast episode 4

Latest episode here.

Advertising, Outages, Android and Eee PC.

We chat about Time Machine, Back to my Mac (still not working for us), the Rackspace outage, the Android SDK and I have an Eee PC.

Thursday, November 15, 2007

Asus Eee PC mini review

I've just spent a full day using the new Asus Eee PC as my main desktop computer. It was a surprisingly smooth experience.

This tiny laptop, with just a 4Gb solid state drive and 512Mb of RAM is amazingly snappy to use.

The built-in screen and keyboard are tiny but usable if necessary - today I plugged in an external USB keyboard, mouse and screen. The video output goes up to 1280x1024 and looks just fine.

All the applications I need are built right in, including:
  • Firefox web browser
  • Thunderbird email client
  • OpenOffice word processor, spreadsheet, presentation package.
  • Pidgeon instant messenger client
  • Skype telephone
  • KDE's excellent file manager
  • KDE's nice terminal
The Xandros linux distribution browsed my network well and found printers and samba shares with ease. Sometimes finding the local WiFi network was a little slow but worked in the end.

While there is only 1.3Gb of disk space free for documents, it was easy to mount a shared file system (included NFS) or plug in an SD card for document storage.

As a command line user, I welcome all the standard utilities such as ssh, wget, python (regrettably only 2.2.4), nano, java, and about 1600 others.


It's hard to complain about a highly portable notebook that costs just AU$500. Of course it would be nice if the screen was bigger and took up the available space, you can't make the keyboard larger without increasing over all size, the trackpad defaulted to a very insensitive setting but that was soon fixed.

Scanning for wireless networks seems a little slow, but gets there in the end. There are rather a lot of icons in the system tray and the overall look of the KDE based desktop looks unnervingly like Windows XP.

I'd like to leave a large SD card in the slot all the time, but each time I start up it pops up a dialog asking what I want to open it with - probably a work around involving fstab but this needs a gui solution

The single click button below the track pad seems very stiff and I've just realised that it's because it's actually a rocker switch with a left and right button part. Perhaps a little clue such as a line in the middle would avoid this mistake.


I'm writing this post on the device right now, still getting used to the keyboard, but certainly very usable. The only moving part is a small fan so it's very quiet, strange not to hear any disk activity at all.

I think these low cost but feature packed Linux based devices represent a new category of consumer devices. Cheap enough to give to the kids without taking out extra insurance, powerful enough for real work.

A chat about the Google phone

This morning on ABC Radio National, I had a chat with Fran Kelly about the new Google phone platform. You can hear it here.

Monday, November 12, 2007

A Chat with ben and pete - podcast episode 3

GPhone, AWS and Linux.

The big news of the week is the launch of the Open Handset Alliance and the Android OS backed by Google. We chat about its possible effects on the market and the developer scene. Other topics discussed include GMail IMAP, Amazon Web Services and Redhat, the Asus Eee PC, Radiohead and Fedora 8.

Saturday, November 10, 2007

ITunes feature creep getting out of control

iTunes started out as a fantastic tool for organising, searching, browsing and playing digital media files. The ability to browse by genre, album, date added and so on, was a revelation to me - and it was really fast too.

But now, iTunes has changed so much the name doesn't even suit it any more. 

Here's my list of features that have ended up in what used to be iTunes:
  • Update firmware in telephones
  • Purchase electronic books
  • Synchronise calendars
  • Monitor RSS feeds
  • Share music on the local network
  • Burn CDs
  • Enforce parental controls on content
  • Backup phones and one model of iPod
  • Movie rentals soon too?
Does this sound like feature creep to anyone else?

When Apple created iSync and the whole Sync Services concept, it sounded like we would get a single place for doing that hard task of synchronising our computers with our portable devices.

Of course it's more extreme on Windows where an install of iTunes also installs QuickTime, I think they should extend this software beach head and also install Safari 3 (weird how it's still a beta even though Leopard has shipped).

It's easy to be a critic, so here's what I'd suggest:
  • Split up the iTunes functionality, give us back that simple media player with fantastic slicing and dicing features
  • Create a "device manager" that is responsible for talking to devices, including media players, Apple TVs, phones, cameras, tablets, and doing the syncing that needs to be done.
  • Put the iTunes store on a web site and just make it part of the general excellent Apple online store experience, sure you can link from tracks but don't make me shop inside that little box.
iTunes must be well overdue for a re-write, I still see the old watch cursor from classic days so my guess is that it's still a carbon app - that must be a nightmare code base to work on!

There's no doubt that the iTunes team has been the first to show us new user interface features that have ended up in the OS: smart folders, live search, and now coverflow. That must be a hot team, but I think it's time to split up and focus.

Thursday, November 08, 2007

VNC client built right in to Leopard

After installing Leopard I've been gradually re-installing the apps I need only as required. Just now I wanted to connect to a server via VNC and was about to re-install ChickenVNC but instead thought I'd try something...

We know that Leopard supports screen sharing and that it's built on top of VNC. It turns out that you can do a Command-K in the finder, connect to server, and use a url like this: vnc://hostname to connect. If it's not running on the default VNC port of 5900 you can add the port in the usual way as shown in the picture.

As dreena is a a linux box, I get a warning dialog box as shown. The client seems very snappy and works nicely.

When I connect to an old Panther MacOS X Server it works just fine and obviously doesn't give the warning about keystroke encryption. Digg this.

I've noticed that the built-in VNC doesn't interoperate too well with the RealVNC server for windows. In this case Chicken Of the VNC seems to start up the session much faster for some reason.

Monday, November 05, 2007

A chat with ben and pete - podcast episode 2

Episode 2

We discuss our thoughts on MacOS X 10.5 a week into installing it. Topics covered include Time machine experiences, launchd, Mac malware, XCode 3 and more DTrace. The big news of the week is Google's OpenSocial API and we chat about our thoughts on all things social.

Sunday, November 04, 2007

GNUstep quick start on Linux

I'm enjoying tinkering with Cocoa on my Leopard Mac and I thought it might be fun to take a peek at Objective C and the framework on Linux in particular for developing command line tools.

My thinking is that it would be nice to develop the code under XCode and then just compile for Linux if I can figure out where the frameworks diverge and keep to compatible code.

Here's a quick start guide for Fedora Core 5 assuming that you already have the basic gcc (I'm sure it's basically the same on others):
  • sudo yum install gcc-objc
  • wget
  • tar xzf gnustep-startup-0.18.2.tar.gz
  • cd gnustep-startup-0.18.2
  • sudo ./InstallGNUstep
  • Edit your ~/.bash_profile to add the line . /usr/GNUstep/System/Library/Makefiles/
  • (note the leading dot in the line above)
Here is a little test program, called first.m:

#import <foundation/foundation.h>

int main(int argc, char** argv, char** env)
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

NSMutableArray * array = [NSMutableArray new];
[array addObject: [NSString stringWithString:@"one"]];
[array addObject:[NSString stringWithString:@"two"]];
[array addObject:[NSString stringWithString:@"three"]];
[array addObject:[NSString stringWithString:@"four"]];
[array addObject:[NSString stringWithString:@"five"]];
[array addObject: @"six"];

NSEnumerator * e = [array objectEnumerator];
NSString * string;
while ((string = [e nextObject]))
[pool release];
return 0;

Create a file called GNUmakefile:

include $(GNUSTEP_MAKEFILES)/common.make
TOOL_NAME = first
first_OBJC_FILES = first.m
include $(GNUSTEP_MAKEFILES)/tool.make

Then make and run:

[marksp@homelinux first]$ make
Making all for tool first...
Compiling file first.m ...
Linking tool first ...
[marksp@homelinux first]$ obj/first
2007-11-04 04:38:40.246 first[1257] Hello
2007-11-04 04:38:40.276 first[1257] one
2007-11-04 04:38:40.277 first[1257] two
2007-11-04 04:38:40.278 first[1257] three
2007-11-04 04:38:40.278 first[1257] four
2007-11-04 04:38:40.279 first[1257] five
2007-11-04 04:38:40.279 first[1257] six

The same code can be built in Xcode and will run on the mac.
The GNUstep framework is very well documented here

One immediate incompatibility I ran into was the starter code for a Foundation command line tool ended with [pool drain] instead of [pool release] - a little DTS humour no doubt!

A brief review of XCode 3

Spent much of Saturday getting in to XCode 3 which ships with Leopard. My project was to build a Cocoa native version of the AppleScript Studio app I built last week to read and ultimately control a Yaesu FT-817 radio via a serial interface.

Having used Microsoft's developer studio, Borland's C++ Builder and the beloved Metrowerks CodeWarrior, the old XCode seemed like a step backwards in programmer friendliness.

XCode 3 is a major step forward. 

It's taking me a little while to stop fighting it and go with the new work flow. Here's my observations:
  • You don't really need to go to the debugger window, variables are now inspected by rolling over them. The open up so you can inspect structures within objects very nicely.
  • The output console doesn't open automatically and until I found it I used the system-wide console to view my NSLog() printouts. 
  • Interface builder has been completely re-written and the vast array of available NIB objects are available in an easily searchable window.
  • I'm having a bit of trouble with the synchronizing between my XCode project and Interface Builder, I end up putting declarations in my .h file and dragging it to IB each time.
  • There's a handy link at the bottom of the IB window to take you to the XCode project.
  • When there are build errors they appear in red balloons right in between lines of your code. At first I found this a bit annoying but now I think it's pretty clever.
  • Code focus is where you put the mouse in a little left margin and blocks of code are highlighted - it's a bit alarming when you first do this by accident but now I think it's neat.
Still to try out
  • Cocoa 2 with garbage collection and automatic synthesis of getters and setters.
  • Project versioning - although I'm loving having Time Machine taking care of me all by itself (tip, watch the console for a while and see all the clever things it's doing)
Cocoa compared to AppleScript

It took me a lot longer to get this going in Cocoa compared to AppleScript mostly because I had to figure out how to drive the serial port. In AppleScript I found an extension that did it all for me, in Cocoa I found some classes from Andreas Mayer and others that are fantastic.

In AppleScript I used the idle handler, in Cocoa I had to use NSTimer.

I'm really enjoying Cocoa now that I'm up and running. It feels really solid and my only complaint is the sheer richness of the library, it's getting really huge and when you can't remember the method name you have to hunt through a huge list. It would be great if code completion could first show the most commonly used methods rather than the whole list.

We desperately need a new edition of Hillegass.

Monday, October 29, 2007

A chat with ben and pete - podcast episode 1

Together with the always interesting Ben, we've decided to join the weekly podcast gang, starting off with some discussion of our Leopard experiences. 

Click here to add it to iTunes.

I'll also be appearing on ABC Radio National Breakfast at around 8:05am tomorrow, (Thursday), discussing the Leopard vs. Vista vs. Linux operating system competition.

You can hear this chat here.

Sunday, October 28, 2007

An AppleScript studio application

AppleScript studio is kind of the Visual Basic of MacOS X. (I'm sure some people will correct me firmly on that statement).

In order to try it out under Leopard I picked a simple project to give me something to shoot for.

I have a little Yaesu FT-817 that supports a remote control serial protocol they call CAT. It's 4800 baud, 8 bit, 2 stop bits. Each packet is 5 bytes, the last byte being the command and the other bytes are the data to go with it.

My objective is the program shown above, it periodically retrieves the current frequency and mode from the transceiver and shows it.

To interface with a common PL-2303 USB serial device, I installed the excellent (and free) Serialport X scripting addition. Thanks Art Coughlin!

To install you create a folder called ~/Library/Scripting Additions/ and stick it in there.

Prototyping was done in straight AppleScript until I was able to read and display the frequency. Next to XCode where I created an "Applescript Application". It reminds me a bit of HyperCard, you open the .nib file and in the Applescript properties tab you can set a handler for a button to call an "on clicked theObject" method in your script for example.

After some frustrating messing about, I've achieved my objective. Once you've chosen the serial device an idle handler refreshes the frequency. 

To make the built application run on a machine without the Serialport X applescript already installed you need to bundle it in the application. Thanks to the instructions here I was able to automate this. Note that I needed a -r after CpMac to copy recursively.

I find the AppleScript language frustrating for reasons I can't fully fathom, this "Applescript for python programmers" table was a great help to me as I'm very comfortable with python.

For what it's worth, I've put my xcode project here, hope it helps someone.

Friday, October 26, 2007

Leopard, great, but not totally without problems

Ben and I were first in line at MacCentric at Chatswood in Sydney to buy MacOS X10.5 Leopard today.

I rushed home and installed it as an upgrade on my Intel iMac. An upgrade takes quite a long time.

When done, Spotlight didn't seem to be doing anything. For some reason it had excluded my internal drive, a preferences change was required to fix this.

After removing my internal drive from the exclude list it seems to be taking hours to index. After an hour it's only 3% done.

So far, all my applications work just fine. Safari seems clearly faster than before, Mail is good. I showed my daughter some of the new features in iChat and she collapsed in laughter when seeing fish swimming behind Ben - this OS is going to be a hit for all the wrong reasons I think.

Tried to get started with Time Machine backups but I need a really big drive by the looks of things. Fair enough.

I ran in to some problems with .Mac syncing. I kind of got stuck in a loop resolving conflicts.

It's a pity that a new install these days involves indexing a large drive which takes time and kills the CPU for some time (hours). This gives an impression that things are going slowly - perhaps this phase should be deferred until the user has played with all the new toys for a while.

Anyhow, lots of new things to play with: Spaces looks great, I do like the new Dock, Mail seems more capable, and I can't wait to learn about Cocoa 2.0. A fun weekend lies ahead...


I've done a few installs now and here's my notes on an updated machine:
  • Installs are much faster than an update
  • I've had some minor problems with PPTP VPNs (for one thing the connect/disconnect menu item gets a bit confused) I've also had traffic stop and attempting to ping then gives me some error about being out of space.
  • iTunes has hung on me
  • Previously I built my own python but this causes problems for xcode
  • I can't build python 2.5.1 at the moment - compile error
  • All my apps just work
Due to the messing I've done under the hood, such as building my own python in the past, I'm now backing up and preparing to do a fresh install.

Sunday, October 21, 2007

Dxpedition with OziPole at Sydney's North Head

Alan VK2ZAY and I went bush this morning in search of a low noise HF location where we could play with antennas, balans, tuners and annoying flies.

I recently built the excellent Ozipole kit and this was a good opportunity to try it out, primarily on 7Mhz.

I've been searching for a location close to Sydney but as far as possible from power lines and houses and Fairfax Walk at North Head seems perfect.

View Larger Map

As expected, this was a superbly low noise location, and as it was the Scout Jamboree of the Air today there were tons of stations about. Unfortunately VK2WI was on low power on 40m and pretty hard to hear.

We played with several antennas and generally had a pleasant time. Notes for the next outing:
  • Take a table of some sort
  • Shade if possible
  • Find a way to carry the gear, (the battery is rather heavy)
  • Something to repel flies
It was wonderful to hear stations perfectly clearly at less than S1, at my home they need to be overwhelmingly strong to be heard. I'll go back to this location - any other suggestions around Sydney would be most welcome.

Thanks Alan for the fine company. He has blogged about this outing here, which refers back to this post so I hope the internet doesn't get runaway feedback and explode.

Update: Turned on 80m this morning at home at 6am and there is no noise. Here's a sample. So the band noise at my QTH must be from an appliance or power supply or something. I need to go hunting for it and I'm also reading up on receiving loop antennas that might let me null out the signal.

Sunday, October 14, 2007

Linux on a low end laptop

This weekend I've been playing with an old IBM ThinkPad 600X. It has 300Mb of ram, 12G hard disk, 450Mhz Pentium 3 processor, dead li-ion battery and no built-in ethernet or wireless.

My goal is a machine for use on ham radio, most likely running one of the psk31 software packages. I'd also like to be able to use a web browser and check imap email.

There are some very tiny linux distributions around but I figured I'd like something fairly rich so I've been playing with xubuntu which can run in 128Mb of ram. My approach was to use the Ubuntu 7.10 (release candidate) alternative install - as the live CD wouldn't install and then install xubuntu-desktop as explained here.

The normal Ubuntu desktop, Gnome, eats 250Mb before you start up any extra applications. Xfce, used in Xubuntu, eats 244Mb so I don't see much benefit in not running gnome. (I must be missing something here...)

The show stopper has been sound. Sound out works fine, sound in doesn't seem to function. I can see lots of other folks running old hardware with the same problem. I'm using a Lucent PCMCIA wireless card that Ralph kindly sent me. (It actually has an antenna socket on it!). This was detected just fine and works really well. Ubuntu seems to be lacking some user interface for seeing wireless networks though.

Bottom line: A 450Mhz legacy laptop is perfectly usable with Ubuntu. Firefox is everything I want (with a plugin it even plays YouTube videos reasonably), OpenOffice is great and just gets better every month, Evolution email is fantastic, and the overall desktop experience is really solid.

If I wasn't addicted to MacOS and hanging out for Leopard, I could use this desktop every day.

Oh, and I really hate that little IBM nipple mouse thing. Trackpads are much better.

Cleaned the very dusty case up with eucalyptus oil which can dissolve all the sticky gunk under the silly "made for windows 98" and "Intel inside" stickers.

Sunday, October 07, 2007

Getting started with PSK-31 on Mac

PSK-31 is a recent digital mode that is very efficient in terms of bandwidth use and is excellent for keyboard to keyboard chatting on noisy HF.

I've been listening around for the distinctive warble sound on 80m and 40m for some time and hadn't found anything I could decode, then I read about 14.070Mhz (20m) and that seems to be where the action is. Several strong stations were heard without trouble.

A simple wire dipole for 20m was constructed and strung between two trees. I have a Yaesu FT-817 portable rig which has a mini-din 6 data jack on the back so an interface box (pictured above) was constructed. As I run a Mac the excellent cocoaModem software is in use. To key the transmitter, (as the FT-817 doesn't support VOX on the data port - a great pity) I first tried making a simple vox circuit but in the end used cocoaPTT which toggles the RTS line on a USB serial cable. One diode was used to save the radio from the +ve swing, so it just pulls PTT low to transmit, otherwise no electronics, just soldering, seems to work fine.

I called CQ, running just 5W into a very flaky antenna and was immediately called back by JA2LCN in Ogaki City, (this person seems very active).

If you run Windows there is lots of software about for PSK31, there's also some Linux software with a reasonable GUI.

In use, you leave the radio tuned to 14.070Mhz and watch the waterfall display. When you see a signal you click between the lines and start reading. It seems like a very nice way to chat, particularly if you can touch type. (A lot of receive errors I noticed now seem to be bad typing in retrospect).

I note there's some interesting kits around for minimal, low power transceivers designed for PSK31 use specifically. It's interesting to consider that a little board like this, a roll of wire, antenna tuner and a laptop and you can chat half way around the world pretty easily.

Friday, October 05, 2007

HF QRP pleasure with an FT-817

I've just spent a few very pleasant days south of Sydney at Gerroa.

We hired a house on a hill looking out over the beach and I took a Yaesu FT-817 and a slightly modified MFJ random wire tuner along for fun (all I did was add banana sockets for attaching a wire to it).

I strung out about 20m of wire from the balcony to a piece of wood in the yard and it tuned up nicely on 80m, 40m, and 20m. Had a few contacts running just 2.5W (on the in-built rechargeable batteries).

80m is blotted with interference at home. At this location it was magnificently quiet until about 5:30pm when bad televisions get turned on. I really want to find a location with no noisy power lines or TV sets to disturb by HF listening.

Only a few contacts, mostly listening. Just before we packed up I tuned around on 2m and found a very active local community.

Spent the time reading the ARRL Handbook, 2007 and a book by Melvyn Bragg, both really dense and fascinating.

On our last morning, went for a walk with my wife who slipped on a ramp and broke her leg. So quick, so easy. My thanks go out to the good folks of Gerroa who helped us to a car, a doctor and a hospital.

It's amazing how easily we can be injured. Such fragile creatures.

Saturday, September 29, 2007

Degen DE1103 shortwave radio mini review

Can a low-cost digitally controlled radio have the same feel as an analog receiver?

The audio/touch combined feeling that you get while tuning across short wave in the evening on a true analog radio is much more usable than the chop/chop/chop effect experienced on low cost digital radios - until now.

The benefits of a digital radio, accurate frequency read out, full band coverage, and memories are great, but if it's painful to tune around it's just not worth it.

I picked up a Degen DE1103 for AU$159 from the very friendly AV-Comm here in Sydney. Significantly more expensive than I've seen them on eBay, but it came with a local power adapter and a smile on a Saturday morning.

The good:
  • Very sensitive, in fact it overloads on the AM broadcast band (there's a switch for local which must be used).
  • Comes with re-chargeable AA batteries which can be charged in the unit with the supplied power adapter. It has a timed charge system built in.
  • Includes a generous long wire antenna and cloth pouch.
  • Tuning up and down the dial is really smooth, you would think it was an analog system.
  • Direct input of frequencies using the row of number buttons.
  • Remarkably good on single side band.
  • 0xFF memories (255)
  • Short wave broadcast bands for easy finding of the big broadcasters.
The bad:
  • Audio volume is adjusted by pushing a button and then using the tuning knob.
  • Mine doesn't sit flat, there is a pop out stand, otherwise it rocks when laying flat
  • The big digital simulation of a short wave band dial is pretty funny really, tuning is actually continuous.
  • A little cryptic to operate, eg: memories are recalled by pushing a button and spinning the dial. I'd like to store frequencies in those buttons on the front but they just seem to do direct frequency input.
In summary, it's a good little radio. Perfect for travel, with decent sound and great sensitivity. I wish manufacturers would make appliances easy enough to use that you don't need a manual at all - you do with this one.

I wish we had an iPod short wave radio.

Saturday, September 01, 2007

Ultra high quality headphone amplifier

I read Alastair's post about high quality headphones with great interest. 

After finding the excellent Headwize site, I rushed down to Jaycar this morning for bits, and built the cmoy headphone amplifier (in an Altoids tin, with space to spare, as shown above right).

What really got me was the data sheet for the OPA2134 operational amplifier from Burr-Brown which says, in part, "The distortion produced by OPA134 series op amps is below the measurement limit of all known commercially available equipment."

Further: "THD+Noise is below 0.0004% throughout the audio frequency range, 20Hz to 20kHhz".

My experience.. 
  • This is easy to build. I did a hack job, as you can see above, and it worked perfectly first time.
  • I'm driving Sennheiser HD 212Pros.
  • Ripped some CDs at AAC 256kbps as sample content.
  • iPod shuffle has noticeable hiss
  • iPod 30Gb has less noise
  • Switching the headphones between the iPod direct and via the amplifier makes the iPod sound relatively dull.
It's hard to explain, but this little amplifier gives a real sparkle to the sound. It's not artificial or boosted in any way, but things like cymbals sound quite different - better. Sometimes there is too much bass for my liking.

Other notes:
  • Jaycar don't advertise the OPA2134, I went to buy the NE5534AN which is in their catalog and they gave me what I really wanted as a substitute - excellent! (AU$3.95)
  • This chip is broadband, when I touch the input it picks up all sorts of hum, I expect that it will be susceptible to RF from things like mobile phones and will need to be in a well shielded box (Altoids tin for example) with filtering to avoid picking up hash.
  • I used "ugly construction" which works well for RF projects so it's probably pretty stable as it's all ground plane.
  • Didn't bother with gain control as I figure whatever is driving it has it's own volume control. Mine has a bit too much gain for my listening levels.
So, one more thing to carry on the train.. thanks Alastair.


I've spent a very entertaining evening re-importing some of my old favourite CDs at 256Kbs/AAC and of course listening to tracks in different headphones. There is a story around about how your brain works harder listening to music which has been compressed for space (no, not level - that's another topic). Basically masked parts of the audio are removed to reduce the data rate, but in fact you miss those parts of the signal and have to imagine them yourself.

In my youth I was very interested in "hi fi" and well remember the arms race that would follow the upgrade of one component in the system: a new moving coil cartridge would show up the noisy amplifier, upgrading that would show up the speakers, and so on.

Recent years have seen my music move totally on to computers and mostly in to headphones. Loud speakers are always a compromise existing as they do in a room that resonates to some extent. Little computer speakers have advanced tremendously in recent years and work damn well at low level. Headphones can reveal detail and texture in an audio track that will be missed on even the most high end speaker system.

With the falling cost of storage it's now time to re-import my CD collection at a higher bit rate - or perhaps I should just bite the bullet and go loss-less at last.

Update 2

Hmm, not sure if the higher bit rate AAC is worth it for me. I created this test which chops back and forth between 128Kbps and 256Kbps every ten seconds and I can't tell the difference. Of course I'm getting old and probably not listening in the best equipment.

Monday, August 27, 2007

Video stores dead... again (Quickflix review)

I've long assumed that the days of the local video store are numbered, but the reason I thought was direct rental with download over the internet. It seems there's another competitor that is very compelling - the online DVD rental businesses.

When Ingmar Bergaman died (actually a week before, which is weird) I felt a desire to watch some of those beautifully lit black and white movies. A visit to the two local video stores proved fruitless. The nicer, more disorganised store couldn't even search their database for anything except titles!

I looked for an online DVD rental service and stumbled across Quickflix. They have a 14 day free trial with unlimited rentals during that time (with 3 out at a time). You can keep a DVD as long as you like with no penalty, (except your monthly fee), but of course they don't send you more until you return some. Sound too good to be true!

They have a catalog of 25,000 titles, you create a queue of what you want, in order, and they send them out with a pre-paid return post envelope and a nice stiff DVD holder. As a new member, I've been a very efficient viewer. When a disk arrives, I watch it and post it back the very next day.

Here's what I like about this vendor:
  • Good web site, quick, good searching, queue management a bit clunky but functional.
  • Reviews by David Strattan and Megan Spencer are a good thing, I'd like more lists to prompt me as well
  • Email notification of what they've just posted and what they've just received back from me is great and clear.
Here's my pretty minor grumbles:
  • The limiting factor is the postal turnaround time. I work in North Sydney and they are in North Sydney, even so it takes three (or mostly four) business days for the posting of one disk back before the next one is sent.
  • They don't send items from the top of my queue. Perhaps they only have a few copies, but I generally get things from number four or more from my queue. It might be good to give some idea of the stock and demand.
  • After your free trial, you go on to the $40/month plan "unlimited" with three DVDs out at a time. Given the turnaround time, this doesn't seem like the best value - I've dropped back to the $20 plan which is a maximum of 5 DVDs per month.
And why is the local DVD store dead? $4 per DVD with a post paid return envelope and a catalog probably 100 times larger beats $6 per DVD and the waste of time going to the store when they are open - hands down.

How about downloading? I hear that a DVD converted to H.264 video takes up about 700Mb. For most of us on current "unlimited" broadband plans (ha!), five movies would be 3.5Gb which is a fair proportion of "unlimited". For this to be really attractive, it would need to be unchargeable download of some sort. Pretty soon, we'll all be renting HD/DVD or BlueRay and these will be much bigger to download so I predict that delivering data by disk through the post will remain pretty attractive for some time, at least in this country...

Friday, August 17, 2007

Solution to Keychain update hang on MacOS X

MacOS X has fewer weird problems than Windows but it's not totally without issues. For the past month I've had a terrible problem where anything that needed to update the keychain would kill the machine to the point of needing a reboot.

Normally, I don't need to do much maintenance but I tried the following:
  • Booted from my install DVD and ran disk utility (that did fix some problems including a file I couldn't previously delete)
  • Running Utilities/Keychain Access and getting it to repair my keychain (it found nothing wrong)
  • Deleted keys with Keychain Access that were used by apps that gave me trouble.
In the end I found a pointer on an Apple mailing list to this article. In the end all I did was:
  • sudo mv /var/db/CodeEquivalenceDatabase /var/db/CodeEquivalenceDatabase.old
  • reboot
And all is well.

Reading around, it seems this is a rare but repeated problem.

Saturday, August 11, 2007

iLife & iWork 08 in use

We're making a DVD at the moment and I've just purchased iLife and & iWork 08.

This DVD has a video component that is being edited together using iMovie and a slide show that we're preparing in Keynote.

Anyhow, iLife and iWork came out this week so I jumped in and bought them. Here's my rundown after giving them a hammering for a day.

The stand-out is iMovie, they seem to have massively re-designed the program around the concept of "event" organised film strips that show you the video as if a film strip that has been unravelled along a light table. You can "scrub" the mouse over the clip and see it animate as if you were spooling a tape over a tape head. It's incredibly fast and smooth to use and a great way to find the best bits in a sequence of video.

iMovie has a sort of all grey look and makes excellent use of the big wide screens we all have now. My impression is that iMovie is pretty much professional grade, with a simple to use user interface. It's rock solid and if it's possible the DV video looks better than it did before for some reason. Update: a feature I rely on, splitting the audio from the video, is actually missing. It turns out others have noticed missing features too. I had assumed it was there but I hadn't found it yet.

The actual video is now stored in Event folders inside your Movies folder in your home directory. The thumbnails for the fast video scrubbing are built and stored there too. I like the way the actual storage is now more transparent - I know what to back up and what to transport to another machine.

Keynote looks pretty much the same but has some features I was wanting such as the ability to crop images inside it. There's an amazing "magic alpha" feature that I have ended up using in this production - this lets you punch out an image from it's background by making the background transparent.

I'm disappointed at the quality of the exported movie from Keynote, given how fantastic it looks on screen. An 800x600 DV export shows jaggies on the text for some reason. I'll try exporting at higher resolution and letting iDVD do the downrendering. Update: I exported as full resolution H264 and it does look much better.

Pages just gets better all the time, advanced features like change logging, and a formatting tool bar make it more familiar. I really love it but it has always seemed a bit sluggish to use. At the office we've pretty much standardised on NeoOffice/OpenOffice, they do a particularly good job of exporting to PDF which is the standard way to publish now. In particular, OpenOffice's export to PDF generates the table of contents that is displayed down the side in PDF readers, Pages doesn't do that for some reason.

Only played with Numbers a bit. Looks good and they've taken a page layout view of a spreadsheet where bits of spreadsheet can float between images and superb charts. I'm a bit puzzled why they don't just merge it in to Pages and make it like Works used to be.

All up, these programs handle large graphics embedded in documents far better than Microsoft's products ever do, and that's increasingly the way we work today. Combined with OmniGraffle for drawing (there's no need for Apple to compete with such a great product), this is all I need to work.

Wednesday, August 08, 2007

Stop printing phone books!

I haven't used a printed phone book in years. They turn up on the doorstep each year and go straight into the recycling.

Happily it turns out that you can opt out here in Australia by ringing Sensis. I did this and while it's not one of the options they offer on the menu they did mark us to not receive printed books.

The call centre person obviously didn't get many opt out calls, it's pretty hard to find how to do it.
Personally I think printed books should be opt in and probably paid for.

The irony to me is all the environmental chatter on their site, saying that doing searches help save the environment. Surely the best thing they could do right now is to drastically slash the number of books printed by asking exactly who requires them. My guess is that it would be under 20% of the households.

Sunday, August 05, 2007

Efficient news reading and manipulation by Dvorak

I'm a news junky. Radio, including short wave radio, used to be my primary source of world news. As the internet ramped up in the '90s I used to visit a bunch of sites each morning to get my update on what's important to me.

It took maybe 15 minutes, while eating breakfast, to read the sites. I also appreciated their design, sometimes clicked deeper in to their content and viewed their banner ads.

Now I use RSS readers, it used to be NetNewsWire but now that web apps are getting good, I use GoogleReader. I can skim all the headlines in seconds, view a bit more info a few more seconds and drill right to the site if I want more very quickly.

Content is king and it's a great deal but I do feel bad that the sites I read every day (actually many times a day) don't get the benefit of my ad impressions.

Some sites are smart, or manipulative - if you like. The king of traffic manipulation is John C Dvorak. I like his story sense - he's been around a long time reviewing technology, so he's a skeptic and tends to dismiss the hype around new product announcements which is actually a useful approach.

John has a rather broken RSS feed that gives you just the headline, which is often incomprehensible without the image. If you click through, you get the comments about the story, but not the story. So you are forced to go and visit the home page. He's getting several page views through this strategy.

Dvorak and his (new) team of hhopper, Eideard, Uncle Dave, SN, and Gasparrini don't seem to publish any original content on the blog (presumably that's saved for commercial journalism outlets that pay a bit better). The value they are adding is mostly editorial - they find interesting stories and re-publish a bit, often embedding video segments. They always give attribution and links - so that's good for the original content creators.

The big secret in the news business used to be how much of the news (90%?) was simply copied or slightly edited from the wire services: AP, Reuters, etc. It's no longer a secret to anyone who views GoogleNews and sees how the same story appears, word for word, in all the world's news papers.

The news business is changing, I'm amazed to still see the giant pile of newspaper we recycle every week, full of stuff that was old news before it was printed. I think there are the following distinct points in news production where value is added:
  • News gathering - reporters on the ground
  • Editing and researching
  • Editorial selection - choosing stories of interest to different consumer groups
  • Editorial ordering - sorting the stories, choosing the top story
  • Linking relevant stories
  • Packaging into periodic wrapups - news of the day, news of the week, news of the year
  • Opinion - interpreting a bunch of stories to deliver some insight about "what's really going on"
  • Presenting - reading aloud, rendering on paper or HTML or whatever
  • Delivering - to browsers, TVs, phones 
The scary thing is how much of these are able to be done pretty well by automated computer programs.

I love news, but right now the only people being paid by me is my internet provider. This doesn't seem quite fair.

Monday, July 30, 2007

Free stepper motors

Another entertaining meeting of the Amateur Radio New South Wales Homebrew Group on Sunday at Dural. Peter O'Connell VK2EMU presented an introduction to the use of stepper motors.

He explained how they work, (by stepping normally 200 little steps per revolution), how they are wired (4 wire, 5 wire, 6 wire arrangements), and how to drive them with a few darlington transistors and a PC parallel port.

It will be a great loss when no computers are available with parallel ports any more but I guess the wide availability of USB chipsets will help here.

A few interesting projects were discussed such as a plotter that can directly cut the copper on a circuit board to make printed circuit boards without etching, and home built milling machines for manufacturing.

The great thing about stepper motors is that they are one piece of precision equipment that can be obtained free. All of those ink jet and laser printers that get left out on the curb during council junk collections contain one.

Show and Tell was great too, Graham VK2GRA showed how he was using electric fence insulators for dipole construction, Stephen showed off his excellent 80m AM challenge transmitter, and Alan VK2ZAY had built a 2M AM transceiver in an Altoids tin plus a fantastic tiny short wave receiver.

Tuesday, July 24, 2007

OpenWRT router fun

Recently we've been debugging some network issues with clients that connect through broadband routers to remote servers. The best way to solve this type of thing is to capture the traffic right on the broadband interface with tcpdump -w filename.cap (plus some suitable filters) and then decode the capture with the fabulous WireShark.

The only "hard" router I've used that can do these network captures is the Netgear FVS338, it's a great feature. I wanted this at home, where I normally run an Apple Airport so I decided to fork out $95 and get a Linksys WRT54GL so I could flash the firmware with OpenWRT.

Flashing firmware was very smooth. What you get is a very basic web interface for configuration, enough to get up, and the ability to ssh in and do very powerful stuff with iptables.

The things I needed were:
# forward port 999 to 22 on the home linux box at
iptables -t nat -A prerouting_wan -p tcp --dport 999 -j DNAT --to
iptables -A forwarding_wan -p tcp --dport 22 -d -j ACCEPT

Also, to allow for PPTP passthrough I had to:
# ipkg install kmod-ipt-nat-extra

and reboot. See here.

The hardware and software seems totally reliable so far. I hope there is more in the web interface in future. For me, what is great is that I can get a command line for pings, traceroutes and tcpdumps (there is 7Mb available in /tmp for saving the captures).

For $95 you get a very powerful router, similar to devices costing an order of magnitude more. Recommended for network geeks.

Friday, July 20, 2007

To infinity... and beyond, internet plans

Our house has four active internet users. Wifi everywhere, desktops, laptops, Wii, DSlite, etc. We're already on the "unlimited" plan but for the second time in recent months, this turned out to not be enough.

Silly me, I thought that "unlimited" was as high as you can go, but no, it turns out we can upgrade to "unlimited pro"!

You've got to agree that this sort of naming is dishonest, or at least short sited.

Secondly, when you look around and see other countries getting 100Mbs (symetrical) fibre connections for $50, while we in Australia pay $95 for 1.5Mbs/.235Mbs, you've got to wonder if we're paying too much.

Sunday, July 08, 2007

Antenna hoist installed

It's great to be back home after a few weeks away. Apart from cleaning up the pool (which had gone green), doing my washing, and trying to sync up with local time, I've been trying as always to improve my HF antennas.

Hanging an 80m dipole on a suburban house is no easy task, my goal is an inverted V from the tree at the front of the house to the tree at the back of the block with the feed point above the roof of the (two story) house. 

Shown here is a vertical pole with a pulley at the top that raises up the balun feed point. This arrangement is still not idea, it doesn't clear the peak of the roof and those palm trees you can see in the image are a real problem on our block - they invariably grow and catch on wires I string up.

Just before I went away, "Experimental Methods in RF Design" by Wes Hayward and others, arrived. What a fantastic book! For anyone interested in designing and building RF projects, this is a must get book, clearly it has influenced many other designers.