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.