Sunday, April 29, 2007

Organizing electronic components

I had a plastic box full of resistors collected over the years. When building some project, one of the hardest things for me is finding the right components in that jumbled mass. In the past I've tried tackle boxes with lots of drawers, but there's never enough for all the different resistors and they often need their leads bent to fit.

Found a great thread on slashdot on this topic where someone suggests this method.

I bought a bunch of 15cm x 9cm snaplock bags and a box that fits them nicely. Spent some time sorting out the collection (only resistors done so far, capacitors are next).

The plastic bags have a nice place to write the values on them and all. This system is very compact and if you get a value to file that fits between two others it can be simply inserted without the need to move all the drawers.

The point has been made that this probably isn't a good idea for static-sensitive components, but I just thought I'd put them in the bag inside their anti-static bag or foam pad.

No doubt this whole exercise is really just elaborate procrastination.

Saturday, April 28, 2007

New longwire hoisted by squid pole

The yard is filling with antennas. I think they look great. There is a very tall tree at the back of the block that I've been trying to run a long wire up to. Today I spent AU$39 on a 6m squid pole at a fishing shop.

Squid poles are great devices, it telescopes out from about 1.5m to 6m. Standing on top of a 2m ladder, holding the end of the 6m squid pole, I managed to feed two sinkers attached to a string over a branch. Yay! Not easy.

A 20m line goes to the bedroom on the second floor into an Emtron antenna match. There is a counterpoise of about 3m running down to the ground.

I'm able to tune this up nicely on 80m, 40m and 20m. I came up on 40m just now and had three quick contacts: Blue Mountains, Victoria and a guy down the road! Apparently you can get 18m squid poles, but they are significantly more expensive.

Ha, just noticed that if you google for squid pole, the first link relates to antennas, it seems they are also used sometimes for fishing.

Thursday, April 26, 2007

Home work space

This is a response to Alastair's excellent workspace post. My little home office is a mess. I have three main hobbies: photography, computers and ham radio. They all compete for space at home.

Regrettably I don't have a nice window to look out of at a calming garden so I've added a second screen to give me a wider panorama.

From left to right: A monitor supported by books I try to keep in my unconscious. Above, on the wall, a print from the master (well from his 8x10 negative). An Intel iMac. Altoids I'm munching to make way for electronics projects. iPod loading up with too many podcasts to get through. (I've recently ditched Scoble and Calacanis as they make too much).

On the right, below puzzled daughter Catherine, is my radio hobby. An MFJ-902 travel tuner (excellent), an FT-817 I had a great time with while camping, an old Emtron tuner that I only learned how to use from the instructions that came with the MFJ tuner, a receive only tuner just being used to hold things up, and finally my boxed DRM receiver.

The transceiver is tuned to 80m via a long co-ax run through the wall, then ceiling and out to the top floor to a very narrow trap 40m and 80m dipole. Lots of activity these days on HF.

Sunday, April 22, 2007

DRM Dream.exe on linux works nicely

I'm sitting in front of a shiny new install of Ubuntu 7.04 listening to the Radio New Zealand International digital broadcast on 7145kHz in perfect clarity.

This Ubuntu version is very slick as we've come to expect. For some time I battled to build the Dream receiver source code on this system without joy. Lots of roadblocks for me, mostly to do with Qt. Almost as an afterthought I installed the Wine windows emulator and tried the pre-built windows binary, after adding only a few DLLs (MSVCP60.DLL and qt-mt230nc.dll), it was up and running.

Sound in and out all just works out of the box and it runs indefinitely. Playing with the UI, for example, changing sound settings, causes it to exit, but it's perfectly usable.

Regrettably, Darwine isn't quite up to supporting this application just yet, seems to be missing some functions in the 3d graphics area which I think are used in those fancy spectrum displays. Can't wait for the day I can run this on my Mac.

Saturday, April 14, 2007

HF portable radio propagation while camping

Just returned from a couple of nights camping at Coolendel near Nowra in NSW. I took along some battery operated ham radio gear and constructed two antennas. The "good" antenna was a center fed half wave dipole for the 40m band fed with TV twin lead carefully suspended between two trees, the other was simply a long wire, perhaps 25m long, thrown into a tree with sinkers on the end.

As seems to be the way for me at the moment, the simple long wire worked much much better than the carefully made dipole. My guess is that using TV twin lead is a really bad idea even though my antenna tuner has balanced antenna connections.

With just 2.5W I easily had a contact in Melbourne and could hear very strong stations in Hawaii, New Zealand and every Australian state except WA.

The most striking thing, aside from the low power needed to communicate 1,000km, is just how quiet the band is out of the city. There is so much RF interference at my home QTH that it's difficult to hear many stations.

The random/long wire tuned up really well on 40m and 20m using an Emtron tuner I picked up on eBay, I've constructed a tiny tuner of my own, in an Altoids tin, but currently it doesn't work as well as the "bought one".

Friday, April 06, 2007

Built a tiny 80m AM transmitter

I've been attending the Amateur Radio New South Wales Homebrew Group meetings recently, both on air and in the flesh.

Most entertaining. This year they have a "challenge" (not a competition!) to build an 80m AM 20W transmitter. I haven't done any electronic construction for years and haven't really attempted RF projects.

To warm up for this challenge, I've just completed a tiny 80m AM transmitter based on a circuit found here.

This is my second attempt, the first time around, I tried to build it from the limited parts I had around. If the circuit said 5k1, I'd use 4k7, and so on. Anyhow, it didn't work so I went and bought the right bits and now it does work. The only substitution is that I used 2N2222a transistors in place of 2N4401s.

This is also my second project using the "Manhattan Pad" technique which I'm very comfortable with now.

FatBlog 75.1

Yeah, I know, not statistically significant.

Tuesday, April 03, 2007

Fairwell DRM, hello fingerprinting?

I'm as happy as everyone to see that it's going to be possible to buy music without DRM. I've only purchased a few tracks as I regard buying with DRM as being like renting rather than buying.

This move will surely stimulate more content sales, and perhaps better, will open up the market to iPod alternatives that will play your purchased content.

The purpose of DRM is to make it hard to pass on the content, the downside is so bad (honest customers losing the ability to play stuff they paid for because they upgraded or something) that it could be that less intrusive alternatives are being sought.

The obvious one to me is content fingerprinting. Add a unique customer code to the data in the content that doesn't affect the play but can be used to trace where the copy came from. Sure, there'll be ways to strip them out in the end, but for most consumers, if they know their purchased tracks can be traced back to them it will dissuade them from "sharing".

I'm making this up, it might not be on the agenda at all, but it is possible.