An excellent shed

While in Melbourne I caught up with the convener of my favourite shed. Ralph, (ex) VK3ZZC, pictured here in front of said shed.

In all the years I've known Ralph, he's always had numerous impressive projects on the bench. Increasingly his shed has been filled with highly desirable test equipment from times' past.

Ralph has a keen eye for the value in things thrown in the dumpster and has built a fine collection.

I remember having a contact with him via a 2m repeater, I was using a commercial rig, he was using a home built, valve rig. It was very very impressive.

One of his children has Autism Spectrum Disorder, which Ralph has written up in a very straight forward and moving way here. I think this is an example of what blogging is really for.

Thanks for sharing.

Ham radio catchup in Melbourne

Aside from family duties during my recent visit to Melbourne, I also caught up with some ham radio identities from near and far.

VK3ASE runs a very professional operation which transmits high quality AM on 160m and 80m often on Saturday nights.

Dave has a full studio full of ex-ABC equipment including a desk I used to use myself many years ago. His transmitter for 80m includes an exciter he built with a 6V6 driving an 807.

This feeds into some sort of beacon transmitter. Anyhow, the whole setup works rather well and I know the audio sounds fantastic on air.

We had a great chat and although my first home built HF transmitter puts out just 0.25W, Dave was very encouraging and suggested that a 1940s radio handbook might be all that's required.

Later I caught up for coffee at Cafe Bagatelles with Paul ex VK3BEK and Ross T61AA and VK1UN who operates out of Afghanistan on 2 and 6m moonbounce.

Here's Ross:

And here's Paul, who currently transmits on big power TV throughout Victoria but really needs to string up an HF antenna of some sort...

Anyhow, we had a nice breakfast, a friendly chat and I learned a bit about WSPR and WSJT.

I've known these guys for a quarter of a century and it's great to see that everyone is going well.

Helping an absolute beginner use the internet

I've just spent three and a bit days helping my step-mother to get on to email for the first time in her life.

I thought I'd make a note of the problems she had as it might be useful for others on the same path.

She's a highly motivated user, with a great desire to live in the world of email and be able to look things up on the web, but while she's seen people using computers, she never has herself.

• Familliar with a typewriter but not the following keys: Return, Tab, Delete, caps-lock (as it works on a computer)


• No idea about the flashing insertion point in text fields


• No idea about how text editing works, concepts such as inserting a new line by pressing Return have no meaning


• When the screen dims and goes off due to power saving, it's a crisis that may well involve calling the manufacturer or store


• Using the mouse and clicking on something is very difficult, further - clicking, dragging and double clicking (or more) seem to all be equivalent


• After filling in a form, such as a login form, it's surprising that a button needs to be pushed to make things happen


• Computers seem oddly picky about the spelling of usernames and passwords, surely near enough is good enough?

Anyhow, after a few days of practice every few hours, I can report that she is reading and sending email.

Some of the secrets of success for me in this case were:

• I bought her a Mac - no problems with viruses, less mysterious user interface


• Put her on to webmail, gMail in this case, so she can go to any computer and it will be pretty much the same. Also, if the computer is lost, no past mail or contacts are lost


• Turned off all extra mouse buttons, no right button, no expose, as she kept triggering these things and getting confused


• Stripped back the dock and basically focussed on launching Safari


• During my stay, lots of constant repetition of opening the laptop, logging in, reading mail, archiving mail, sending mail


• Left a folder with all the key information, not so much for her but for any future computer helpers trying to assist


• Yes, it's bad, but left a post-it note with her username and password on the laptop

Having been away for a day, she did ring to report that she couldn't log in. Turned out she was using a different username for some reason. Wild clicking had also resulted in filling the screen with web pages.

Good on her for giving it a go, computers and the internet are an amazing way to interact and it's easy for me to forget how much implied knowledge we have absorbed.

80m QRP AM Transmitter - first contact!

Encouraged by the success of the beacon transmitter, I've built another version that is amplitude modulated using a 600 ohm telephone transformer.

The transmitter is just 2 transistors, (not counting the mic pre-amp and audio power amplifier), here's how it looks:

Whistling into the microphone looks like this on the cro:

I'm certainly not getting 100% modulation.

I've just had a contact with Sam, VK2BVS, who reported that with his pre-amp in I'm 10dB over S9, with excellent quality audio "like the BBC".

Next step is to box all this up and make it a bit easier to switch from receive to transmit. (Currently I have to clip a clip lead on to power it and switch a co-ax switch).

The circuit is closely based on the beacon by Alan VK2ZAY. My construction is huge compared to his.

For the audio amplifier to drive this I used a Jaycar "Short Circuits 3" #13 High Power 12V amp which seems to do the trick quite nicely.

80m QRP Beacon on the air

After biting off more than I could chew a few times recently, I've successfully built a QRP (low power) beacon for 80m.

It's on air at the moment on 3.686Mhz sending a morse ident with my email address so I'm hoping to get a few signal reports.

I think it's putting out about 250mW.

There are some obvious faults, I can hear chirp, clicks and when it's off carrier from the oscillator leaks out to some extent.

The keyer is an Atmel AVR ATMega816 which is complete overkill in this case.

The circuit is very closely based on Alan VK2ZAY's design except that I didn't have any 2N7000s so I've used a single IRF510 with a bit of bias.

I used perforated board with just a copper spot under each hole and it went together rather well (for me).

I don't speak morse yet, but here's what I'm sending:

Anyhow, please tune in to 3.686Mhz and let me know if you can hear my slow morse.

Update

Hi Peter,

Read about your 80m QRP beacon mentioned on hamnews and had a listen.

It’s peaking about S5 in Canberra. I’m using a TS-480SAT with a 40/80m trapped dipole. Here is some of what I decoded using Ham Radio Deluxe DM780 software:

LE EK*E PM VK2TPM VK2TPM PLS EMAIL RPT PETER DOT WARKS AT OBOX COM THIS ISE A QRP BEANION TRANSMISSIOLE VK2TPM VK2TPM VK2TPM PLS EMAIL RPI PETER DOT MARKS AT POBOX COME THIS IS A QRP BEACON TRANSMISSION DE VK2TPM VK2TPM VK2TPM PLS EMAIL LPT PETER DOT MARKS AT POBOX CON THIS IS T *RP DEACON N E IS E UK2TPM VK2TPM VK2TPM PLS EMAIL RPT PETER DOT MARKS AT POBOX COM THIS IS A EQRP BEACON ARANSMISSIXD DE VK2TPM VK2TM VK2TPM PLS EMAIL RPT AIETER DOT MARKS AI POBOX /OM THIS IS A QRP BE P EHANSN ESSIO N DE VK2TPM I ERM VK2TPM PLS EMAI D RP E NETER DOT MARKS AT POB3X COM E I IS A QRP BEAON TRANSMISSION DE VK2TPM

As you can see I’m missing/badly reading some characters and have interference but the message is coming through, probably be better received by a human than a computer…but I’m no morse code expert…

Had QRM from SSB and another CW signal nearby by managed to filter most of it out.

Regards

Ian Sinclair VK1DI

Update 2

I'm taking it off air while.

Valve technology needed for post nuclear sked

The NSW home brew "trash n treasure" meeting today at Dural was great thanks to the work of John Hale VK2ASU (left) and Stephen Lowing VK2BLQ (below).

Together they presented on the theory and practice of constructing using valve technology.

John handed around common valves including a tiny device and told the story of his first home made valve radio. The theory of how valves work, by using heat to emit electrons and then using charged grids to control their flow in the vacuum chamber is at once, both simple and sophisticated.

Stephen talked about where to pick up common valves even today and showed some of his past projects which are beautifully constructed.

The board he's holding here is a regenerative receiver that is powered by batteries including just 9V for the plate voltage.

It was pointed out the the electromagnetic pulse from a nuclear explosion (or even a devices specifically designed to generate an EMP) will kill most modern technology and if we want to have a chance to participate in the post apocalyptic radio skeds we'd better get on and build some valve equipment.

Luckily, the group that turned up managed to fit into the air-conditioned WIA hut today, but it's great news that the construction of a larger shed on the Dural block is finally going ahead.

I can still remember valve equipment (aside from that big tube at the front of televisions until recently), but my children have no idea about this technology.

It won't be long until all living memory is gone.

The best hi fi system

Last night we were fortunate to have a wonderful experience - we sat in on a bit of a rehearsal of the Australian Chamber Orchestra.

I was able to sit right in the middle with the orchestra very close and all around. The communication between the players and Richard Tognetti, all done with body language and eyes, is fascinating.

The most impressive thing for me was the quality of the sound. I listen to too much music through small computer speakers and headphones, but it's amazing what poor reproduction even good headphones produce compared to the real thing.

There is a richness of tone from a bow being drawn across a string, I think the cello in particular, that doesn't seem to come across in recordings.

I recall hi fi sales blurb that used to claim that certain systems were "just like having a symphony orchestra in your living room", the reply was always to ask if that was really desirable as they'd drink your house dry.

One tree dies, an antenna will live

Today is tree lopping day. We're getting rid of a pesky liquid amber and a pine tree. Both of these shade the garden.

The huge gum tree is staying but I noticed that the tree men climbed the gum to tie ropes to liquid amber branches to control their fall. I had a bright idea and have asked them to run a line for me over a very high branch in the gum tree. "No worries" they said.

This means I'll have a loop of venetian blind cord going right up that very tall gum tree which I can use to raise up awesome long wire antennas or support one end of an 80 dipole.

These tree lopping guys are both smart and fit, here's a time lapse video with one frame taken every sixty seconds.



The job's done and I can definitely recommend Aura Tree Services they were efficient and professional. Great blokes too.

We have a lot more sky now and I'm back on 80m with good reports.

When I mentioned I'd made a stop motion video they were very interested and I gave them a CD with the high quality video on it.

Update

The loop of venetian cord is in place so I can easily hoist things up 10m or so.

I first tried an end fed long wire but the noise on 80m was bad, so I've put up my old 40/80m trap dipole with one end up in the gum tree and the other end over the house to a tree in the street.

The new antenna is working really well. The extra height has further reduced noise, I've had some PSK31 contacts on 40m (7.040) and am hearing some magnificent signals on 80m.

BaristaReview site build

I'm pleased to report that I've built a real application in Django on Google App Engine.

BaristaReview is a site that I've always wanted, specifically to let me find (and review) coffee shops near where I am.

Although it's loaded with Australian cafes to start with, it's not localised except for it being in English.

The great benefit to me of Google App Engine is the low cost of entry and ultimate ability to scale right up to whatever success we might achieve without having to supply any hardware ourselves.

It's been a fascinating little project with lots to learn about:

• Google App Engine


• Google Maps and geocoding


• Django 1.0


• Serving images from a database


• memcache(d) for caching images


• integrating blogger into a sub-domain

There's still lots to do, not to mention the iPhone version people keep asking for, please let me know if you see bugs or unexpected behaviour.

Google App Engine is a little new and I do run into a few issues deploying sometimes, but generally the site seems to perform pretty well.

Please look up your favourite cafes and if they aren't there, go ahead and add them!

Trying to build transmitter for 20m

A personal objective for a long time has been to have a radio contact with a home made transmitter. After many false starts I've focussed on a transmitter for 20m.

The oscillator now works nicely. Early attempts, it turned out, were running on totally the wrong frequency, that's now fixed (with a different circuit) and the waveform looks nice and puts about 1V peak to peak into 50 ohms which I think is 2.5mW.

The next step is to raise this level up to a few watts so that I can be heard at least by VK2BVS who lives near by.

In a burst of foolish enthusiasm, I added a gain stage followed by a class C driver and an IRF510 final, rather messy but the box will be good for the next iteration.

Alas the final oscillates magnificently, presumably my construction is far too spread out. I'm not deterred by this and will have another go this time using a design from Drew Diamond rather than random circuit snippets found on the internet.

I feel I'm making real progress, despite no outright success, my debugging skills are improving with experience.

Fence troubles

Last week's demolition of the back yard went so smoothly (if a little behind schedule) that I was starting to think that I had the knack of dealing with trades people.

With the demolition, the fencing and the (still to come) tree lopping, I went through the local papers and chose three companies to get quotes from. The winner was on a combination of the price, clarity of the quote and how much I liked the person (Geoff) who came out.

I won't name them, yet, but the fencing company that won the fierce contest to replace the old wire fence with a new colourbond fence has different people doing the quoting to the people who do the work.

Today the worker guy Bill came out and balked at the amount of work required to clear the brush along the fence line.

The quote said it would take 1.5 hours, he feels it's at least a day's work and I'd have to agree. Some of the brush, as you can see above, is really quite substantial trees.

My first inclination was to simply cancel and engage one of the other quotes, but the materials have already been delivered and I fear this could get messy.

Anyhow, the worker guy has now left and the company is coming out to have another look... more breaking news as it comes to hand.

Update

Today, Friday, I decided to keep ringing "Pete's Local Fencing" of Collaroy until I got some kind of commitment that something was going to happen. After four calls, I'm told that Greg will pop by either Saturday or Monday to take a look, and that the job has been given to Matt to do.

Update 2

It's Tuesday. Greg didn't turn up. I left a message on Monday but they didn't ring back. Called again and Greg is in the yard for about an hour and will call me.. (I doubt it).

Cleared the back yard

Previous owners of our house felt compelled to fill the back yard with stuff. We've now cleared it and are on our way to a nice garden.

Here's before:

And after:

A few trees to go and then it's time for a veggie patch.

If you're in Sydney and looking for a company to do demolition, I can personally recommend C.J.E. Excavation & Demolition - very professional, polite and efficient.

Lost another hard disk - we love Time Machine

We seem to lose a laptop hard drive about every twelve months and yesterday my daughter lost the drive in her MacBook.

There was music, documents, bookmarks, settings and of course a few vital assignments in progress.

A few years ago this would have been a devastating event but the good news is that Apple's Time Machine backup system is so simple to use that she actually does back up. She had done a backup the morning of the loss.

The drive was out of warranty so I trotted off and bought a replacement, re-installed Leopard and restored from the external Time Machine backup.

The process was smooth and easy. Great stuff.

Update

I tried to get over the air Time Machine backup to work but kept getting an error saying it was "unable to mount" the server. It turned out that my problem was that I'd already mounted the server (in order to set it as the backup volume in TM). Unmounting it before starting the backup appears to be doing the trick.

The first backup looks like taking 5 hours for me.

Update 2

We now have wireless TM backups working from two laptops to a drive connected to an Airport Extreme. It's obviously not as fast as a local drive and I'm not sure what happens if you put the computer to sleep with that disk mounted, but it's certainly convenient.

Current Dr Who series is excellent

I remember being really scared by the Daleks as a young child, and I've always had a soft spot for Dr Who.

This current series started out looking a bit like the high production value was out of balance with the plots but the last three weeks, here in Australia, with the two part "Silence in the library" and "Forest of the dead", and last week "Midnight" were really great.

7:30 Sunday nights ABC1.

Backyard sun path stop motion

I'm trying to figure out the best part of the garden to put the vegetable patch so today I recorded a full day of stop motion video using a little Nikon point n shoot.



It's not looking too good unless we do some serious tree downsizing. Of course it will be better in summer.

As you can see the removal of the swimming pool is pretty much complete, just some topsoil to come.

This stop motion feature of the Nikon coolpix is excellent. The camera ran from about 6:30am until after 5pm without going flat. None of my other cameras seem to have this ability.

Incidentally, I searched for something to turn a series of still pictures into a movie and couldn't find much. It turns out that good old QuickTime Player has this feature built in:

You just open any image in a folder containing the series, choose how many frames per second you want:

And you have a movie.

QuickTime Player is such a strange application, it does lots of useful things that make it more than a player.

VK2BVSs Awesome antenna

I've been pretty active on 14MHz again lately, mostly PSK31 where I chat with VK2ATC, VK2VFV, VK2PN, and if he gets back on, VK2ZAY. It's an amazing mode where, this morning I chatted with UA0QGG in Russia on just 5W.

Was tuning around and heard very very strong signal from VK2BVS who is quite near by. Today I dropped over to inspect his impressive antenna array. He's on all HF bands from 160M up and uses two collections of inverted V antennas connected together.

I don't think I'd get away with such a structure, err flagpole, here but it's something to aspire to.

Thanks Sam for your hospitality.

Reclaiming the back yard - removing the pool

When we moved in, we really didn't want a pool, but it came with the house.

I've maintained it for more then ten years, mostly cleaning leaves, adding chlorine, fixing pumps and supplying electricity.

It was the electricity that finally tipped me over the edge. As part of a daughter's school project we went around and measured the power consumption of things around the house. The pool pump, which runs between 5 and 8 hours a day uses 1,600W.

The other funny thing about this house is that aside from the pool, which really chops up the back yard, there's a two-car garage - in the back yard.

We decided to get rid of both monstrosities in one go. I'm working from home to the sound of jack hammers, but already I'm excited about the prospect of a larger back yard space and more sunlight.

This should be over in a few days, a new fence goes up next week. Later we'll add a small garden shed to take all the implements which are currently stored in a tent:

When the subsiding has settled, we have grand plans for a small vegetable garden. I've been listening to the excellent digitdownunder podcast for tips and ideas.

I'm thinking of one of those built-up style beds where you don't have to grovel on the ground to work on it.

Tony sent me some information on seeds, small fruit trees and a compost bin he recommends. So much to learn.

I am a bit worried about the lack of sun, you can see the shadows from the large trees here:



I plan to do a full day stop motion to see where the problems are soon.

On the bench - double sideband exciter

I recently constructed the Bitx20 kit and so far, despite willing help from the Yahoo! group, I've failed to get it working.

It's hard debugging a densly packed circuit board, so I decided to build a duplicate transmitter chain ugly style as you see here.

This is most instructive for me. It's laid out pretty much as the circuit diagram and I can easily measure at any point.

The Bitx20 is a marvellous design and there are lots of handy guides to construction and tuning around but, for me, what's missing is a circuit diagram with both DC and AC waveforms at every stage in both transmit and receive mode.

Anyhow, it's all for the best. I've often built a kit that's just worked first go and really it doesn't teach me anything. I'm hoping that after getting something similar going in this way I'll be able to go back and compare with the PCB version and figure out what's wrong.

Blue mountains amateur radio Winterfest

Spent a very pleasant morning at the Blue Mountains Radio Club Winterfest.

Great weather (I was expecting to freeze) and a great turnout.

Lots of junk to look at and try not to buy (even at very good prices).

Lots of vendors there too, who seemed to be doing pretty well. Great to chat to a few folks and share a sausage sandwich.

In the end all I bought was a couple of books but did lots of tire kicking. I'll certainly be back next year. Congratulations and thanks to the organisers. Great to see Tim Tuck, VK2XT, who I've known for many years as a co-worker and had no idea he was a ham!

Chinese Embassy site links to a Trojan page

My daughter noticed this, thankfully we are running MacOS X here.. If you visit the web site of the "Embassy of the People's Republic of China in Australia" there is a "Useful Links" item to "China Association for Preservation and Development of Tibetan Culture", sounds very positive.

However, if you're in Firefox, which checks sites with Google to see if they are known for bad things, you see this:

If you click through, Google provides the following advisory:

"Of the 1 pages we tested on the site over the past 90 days, 1 page(s) resulted in malicious software being downloaded and installed without user consent. The last time Google visited this site was on 08/22/2008, and the last time suspicious content was found on this site was on 08/22/2008.

Malicious software includes 5 trojan(s). Successful infection resulted in an average of 15 new processes on the target machine.

Malicious software is hosted on 10 domain(s), including..."

(I won't link to any of the bad domains here though).

So, either the site controllers want to install a trojan on the computer of people interested in Tibetan culture preservation or the site has been compromised by someone without their knowledge.

Update

I discussed this on ABC Radio National this morning.

Where are all the induction cookers?

Apart from a rice cooker, the other gadget we picked up during our stay in Hong Kong is an induction cooker.

You don't see them in stores in Australia for some reason.

Now that the big element on our electric stove top has died, again, I've brought it out of retirement.

Induction cookers work by inducing an electric current in the metal base of the pot that's sitting on it. This means that the heat generated in that metal is transmitted directly to the food being cooked rather than being partially lost in the kitchen. As you can see from the picture, the device itself remains cool.

In use, the induction cooker is very responsive and includes some advanced features for running a program of temperatures over time, but we never use those.

I read on Wikipedia that induction cookers are twice as efficient as electric elements or gas cookers, [although citations are needed].

The only downside is that it only works on pots with a thick, non-laminated base. If the pot isn't suitable the cooker sits and blinks until it feels something it can induce.

Works nicely with my coffee maker:

I wonder why they aren't in the stores here?

Three ideas for the Olympics

Medal auction

It's reported that each Olympic gold medal in the last 20 years has cost Australian tax payers about 40 million dollars. I hear that the UK is now reaping the rewards of extra investment. Why not save a lot of bother and just auction the medals off the highest bidder?

Anything goes

Many events in the past have been won with the aid of performance enhancing drugs, advanced computer modelled training, or special suits or shoes. Complex rules currently control which techniques are legal and which are illegal. No doubt new drugs, for example, are being used this year that won't be detected until after the event.

Why not remove all the rules and let the teams pull out all the stops. The most performance enhanced, steroid soaked, android, with atomic shoes would win - if they don't have a heart attack first.

True competition

If the medal tally is really a measure of the performance of the people of a nation, perhaps no preparation should be allowed. In the days leading up to the Olympics, representatives should be picked at random from each country. These true representatives of the country would compete with only a brief explanation of the event before it starts.

Oh, and praying should be banned as presumably that is performance enhancing.

Then we'd have a real Olympics.

HF antenna height improvements

Did some work on my 20m (14Mhz) dipole antenna and managed to raise it about another meter above the (2nd story) roof.

The difference is clearly noticeable in reception, the background noise level is reduced - meaning I can hear stations I previously couldn't and early reports of my transmission are that my signal is perhaps 1 S point higher. (I'm a bit wary of that observation as HF radio is extremely variable).

Note that 1 S point is four times the power.

I shouldn't be surprised that the extra hight helps, there's lots of research on this, but I didn't expect it to be so clear.

This new support is the pole from a free standing netball hoop, then an iron pole, and finally an aluminium pole. Up the top is a pulley so I can easily raise and lower the dipole balun with ease.

Anyhow, I'm happily back on 20m PSK31, chatting near and far on 25W.

Incidentally, I'm tired of getting RST reports of "599" all the time. Firstly on PSK31 it's pretty meaningless (a better measure is IMD dB), and secondly how on earth can I be S9 all over the place?

Enhancing video by using still images of the scene

I don't normally do this but there is some amazing work being done at the University of Washington.


Using Photographs to Enhance Videos of a Static Scene from pro on Vimeo.

Spotted on CrunchGear.

I was impressed by smile and blink detection in my little point n shoot. That's nothing compared to what these folks are doing.

They take some still images of a scene and then a video. The still images, including HDR images, can be used to enhance the quality of the video scene. There is also a brilliant image stabalisation system that works after shooting.

My only question is just how much of this requires operator skill and how much is automatic?

Stop printing phone books 2 - You can't opt out!

It's a year since I posted about how I thought printing phone books and distributing them was a waste in the days of the on-line phone directory.

As I researched I discovered that you can opt out by contacting Sensis on 1800 810 211 and opting out. So I did opt out, but here we are, a year later and they delivered the White pages again.

Who's paying for these unwanted giant print runs? What is the impact on the environment? Why is it apparently impossible to opt out?

According to the Australian Bureau of Statistics (2006-07), the internet is widely available in households, 31% had dial-up access and 68% had broadband. (Does that make 99% or do some households have both?).

In 2006-07 5.1 million households have home internet access, (it went up from 2.3 million in that period so no doubt it's even higher now).

Sensis "Green Office" program is not working. I've contacted them about this and received an acknowledgement but so far no actual reply.

iTunes movie rentals in Australia - at last!

So happy to finally see iTunes movie rentals in Australia. I immediately jumped in and rented a movie through iTunes for AU$3.99.

It took 65 minutes to download, then I had to transfer it to the Apple TV.

On Apple TV I chose the movie and pressed play, it went away and authorised, then... a black screen and no sound. The movie was playing, I could pause and play and see chapters. Hmm.

In the end I did a reset settings and it played.

Quality is ok, not HD but no annoying artefacts in the one I'm watching now. $4 is a reasonable deal (plus my internet bandwidth of course). The main problem is the small range (700 by some reports), compared to my current provider QuickFlix with 32,000.

Some movies are only available for sale which seems weird.

Once a movie is downloaded you have 30 days to start watching, once you start watching you have 24 hours to view it (which didn't impress me when I had a blank screen).

Alien DAC + Chu Moi = Headphone bliss in a box

Regular listeners will know that I'm always searching for high quality headphone audio. In the past I've built a CMoy amplifier and an Alien DAC USB audio device.

Yeah it's a bit rough but it fits nicely under my computer monitor.

It was time to put them together in one box and dispense with the excess wires.

I started with some 0.5mm sheet aluminium:

Marked out to make a box 50mm x 100mm x 100mm. It was cut with tin snips and simply bent over the edge of a bench by hand. The sides were joined using angle aluminium stock drilled 4mm and tapped.

For now I'm powering the amp on 12V supplied by an external AA battery pack with 8 cells. Can't wait for GreenPlug to arrive..

I thought I was doing the right thing choosing metric screws but even in a metric country the range is severely limited and I've had to saw off the rather long machine screws I got.

This is not a bad way to make a small project box. Even 0.5mm aluminium feels pretty rigid with the help of the angle stock.

Sounds great with my HD560s by the way.