Wednesday, December 28, 2011

Xmas present to self: Sony MDR-7506 Headphones

In this age of tiny computer speakers, or worse - laptop speakers, it's easy to forget just how good music can sound in a decent set of headphones.

I must be a bit of an addict as over the years the headphone collection has grown to more than ten pairs. While you generally get what you pay for, it's not always the case.

There's a bit of a balance to be struck between comfort and quality. When walking (where I listen to podcasts) I use either a little Bose on-ear pair or the Apple in-ear headphones - although I don't like the noise I hear as the cord moves around.

At my computer I've ended up using a Sennheiser HD 212Pro which I find very comfortable and pleasant despite a pronounced bass boom.

On the podcast front, I was a dedicated listener to Leo Laporte's TWIT network but the ads have grown to be so long as to sometimes go for five minutes or more. I'm also finding the density of useful information and unique insight has dropped. They do a great job and it must be hard to keep up the pace.

This year, 2011, I've discovered Dan Benjamin's 5by5 podcasts. I'm addicted to Hypercritical with John Siracusa and Talk Show with John Gruber. Host Dan Benjamin is a great host and sensitive interviewer, further he clearly cares about audio quality. Dan sounds great and chastises guests when their audio breaks up (I'm looking at you Gruber).

Dan has kindly published details of the equipment he uses and when he raved about the Sony MDR-7506 for just US$85 I thought I'd track down a pair. Foolishly, my first thought is I'd visit the local Sony Centre, imagining it would be like an Apple Store with every thing they make. The Sony store looks like an Apple store without any customers. They told me that the 7506 is obsolete and sold me the nearest thing: MDR-ZX500. While comfortable, they are disappointing lacking sparkle and I was soon back to the 212Pros.

In a Twitter exchange, Dan urged me to get the originals and today they arrived.

I really like the MDR-7506 headphones, wide response, smooth low end, sparkling high end response. They are comfortable and the curly cord is convenient (I often run over the long Sennheiser cord with my chair).

Here in Australia I ended up paying AU$167 (including fast shipping) via eBay seller onlyonline.

Tuesday, December 27, 2011

Shed visit from VK3ASE

Dave came to check out the shed. Unfortunately during coffee he was struck by a car...

Seems OK now.

Incidentally, WSPR on 20m is the busiest I've seen it:

Sunday, December 25, 2011

Apple Lion Internet recovery a good thing

It used to be that I was in a tiny minority who used a Mac. I've always regarded this as a competitive advantage - I got on with my work while others fought with viruses, weird behaviour and a generally hostile environment.

Something's changed and a few years ago fellow programmers all switched to Macs, now this has broadened to the extended family too.

One potential drawback is that I'm the tech support "go to" guy.

A sister-in-law, who's never used a Mac, recently went wild and purchased a second hand 17 inch Macbook Pro. She used it for a day and then dropped it which killed the hard drive. Very upsetting.

She left it with me on Xmas day and I've just had the pleasant experience of using Apple's Lion Internet recovery feature.

Lion has a recovery partition on the boot drive which lets a tech person do a disk utility Repair or even a clean install. In this case the drive was damaged and so by booting holding down Command-R and choosing a Wifi network, the machine downloads this software from Apple.

In the future, when most machines out in daily use have this feature, it will be fantastic for front line support people - in the past we've had to build up a collection of software CDs for every different model.

I replaced the damaged drive with an old drive I had lying around. Turned out it contained Ubuntu which booted up and looked great. After re-formatting the drive, the install takes about half an hour.

Thursday, December 22, 2011

Elecraft KX3 is coming

A new ham radio is about to become available and like too many others, I'm waiting to find out the price and place my order. The Elecraft KX3 looks like a worthy successor to the popular Yaesu FT-817 for portable low power operation.

This radio covers 160-6 meters, power 10W, weighs 0.7kg, and can draw as little as 150mA on receive.

Elecraft have said that they plan to start taking orders in December with delivery in February. As I write, December is running out rapidly.

There is an active Google group with over a thousand members who are currently all asking if there's any updates yet. Actually, the conversation turned amusing yesterday with people joking that they'd received theirs yesterday and others offering second hand units for sale. Elecraft's Wayne Burdick N6KR is chipping in every now and then to politely answer every question but the big one.

I can't remember seeing so much excitement before the release of a ham radio product before. Merry Xmas Elecraft, now finish it off and we can all take a break.

Elecraft are so quaint. I love how they've configured their Apache web server so we can view directories.


Just placed my order on 28-December.

Huge archive of scanned 73 Magazine

Stephen, VK2BLQ, sent around an email pointing to a great archive of scanned issues of a popular ham radio magazine from my childhood, "73 Amateur Radio".

They come up in a rather strange order, like all the Decembers together, but they are high resolution scans saved as PDFs so perfect for reading on an iPad for inspiration.

It's a great way to see the march of technology from 1961 through to 2003.

Early editions are valve technology, later there are hybrid rigs with solid state drive to a valve final. Gradually digital frequency displays creep in and there's a marvellous time when having an LED is a feature worth advertising.

There's lots of ads featuring girls with big hair caressing equipment.

This collection, for me, represents what may be a golden age, before everything in electronics just turns into computer chips surrounded by surface mount components.

A few of the home brew group seemed interested in grabbing the set for later viewing so I wrote a little python script to download them from to share around. (I think I'm being throttled but it's going pretty well).

Download pdfs of 73 magazine.

Items at:
import os
import urllib2

MONTHS = ('January', 'February', 'March', 'April', 'May', 'June',
          'July', 'August', 'September', 'October', 'November', 'December')

END_YEAR = 2003
OUTPUT_DIR = "73 Magazine"
MISSING = ('73 Magazine/73-Magazine-1975_11.pdf',
'73 Magazine/73-Magazine-1975_12.pdf',)

def main():
    if not os.path.exists(OUTPUT_DIR):

    for year in range(START_YEAR, END_YEAR + 1):
        for month in range(1,13):
            monthName = MONTHS[month - 1]
            fileName = "%s/73-Magazine-%d_%d.pdf" % (OUTPUT_DIR, year, month)
            if not os.path.exists(fileName) and fileName not in MISSING:
                editionString = "%d-%02d/%02d_%s_%d" % (year, month, month, monthName, year)
                url = "" % editionString
                print("Downloading: %s..." % url)
                print("To: %s" % fileName)
                pdfData = urllib2.urlopen(url).read()
                outFile = open(fileName, "wb")
                print("Skipping: %s" % fileName)

if __name__ == "__main__":

If you stop the script and re-start it, it will not re-download any that it has. Otherwise it's pretty basic stuff.

Thanks! Look out for the ladies with tech:

iMac mysteriously shutting down

My wife's 24 inch iMac recently started exhibiting an annoying fault - it would, seemingly at random, just switch off.

Not a crash, not a shutdown, it just powered off.

My first thought was some sort of thermal problem tripping the power supply but oddly it did not seem related to the machine being busy or having been on for a long time.

I ran the Apple Hardware Test software which on very recent machines is built right in (you boot while holding the D key). On this machine it was on the second install CD, you insert the CD, reboot and hold the D key to get it.

Hardware test is a blast from past and uses the old System 7 GUI. I ran all the tests in the most thorough version, which takes hours, and everything came up clean.

The most reliable way to trigger a power off was rapidly launching a bunch of apps so that lots of icons were bouncing together. Very mysterious.

In the end the quickest way to trigger an instant power off was to run the iTunes visualizer. There's the clue - the graphics card.

The local Apple store took a few days and $600 to replace the graphics card and now we're good to go. I've never bought AppleCare, my Apple equipment has been fantastically reliable and the most likely problem - hard drive failure, I can fix myself. AppleCare on this machine would have been $268 per year so it would have broken even on this fault.