Monday, December 31, 2012

Running a temporary syslog server

I'm trying to connect a SIP VOIP device VK2ASU kindly passed me to pennytel but it won't register with them. The device's web interface doesn't give much information but it does have the option to send logs to a syslog server on your network. I've figured out a very simple way to run up a server for temporary use using netcat.


$ sudo nc -ul 514
Password:
<13>[SIP]  | NOTICE | allocating transaction ressource 119 19277552-0131122292
<13>[SIP]  | NOTICE | allocating NICT context
<12>[SIP]  | WARNING| info: Name resolution requested.
<12>[SIP]  | WARNING| Doing asynchronous name resolution.
<14>[SIP]  | INFO   | MESSAGE REC. CALLID:19277552-0131122292
<12>[SIP]  | WARNING| OnEvent_New_Incoming4xxResponse!
<12>[SIP]  | WARNING| User need to authenticate to REGISTER!
<13>[SIP]  | NOTICE | allocating transaction ressource 120 19277552-0131122292
<13>[SIP]  | NOTICE | allocating NICT context
<12>[SIP]  | WARNING| info: Name resolution requested.
<12>[SIP]  | WARNING| Doing asynchronous name resolution.

This gets nc to listen to UDP on port 514 and it displays whatever comes in.

Saturday, December 29, 2012

Homebrew hangout

I've just participated in a Google hangout with a buch of homebrewers around the globe using Google's amazing Hangout video conferencing. Thanks Jason Mildrum, NT7S, for organising it.


Participants were on Linux, Windows, MacOS and iOS. There is a bit of confusion caused by Google's display of the time of the hangout in the zone of the organiser so for me it kind of looked like I'd missed it.

It seems like there is a limit of ten video participants but we think you can have ten sending video but many more if they are just viewers. More experimentation is needed.

The only other issue was echo from people who had their sound on a local speaker, we think that is due to the latency inherent in a global conference call. I think headphones are a must.

It was great to meet everyone and talk about projects. We discussed Antennas, arduinos, Raspberry Pi, making PCBs with a CNC, Beach 40, and got a tour of a station.

Thanks to Jason for organising this, can't wait for the next one.

Wednesday, December 26, 2012

Preserving our digital photographs


Holiday season is family photo season and now that we’ve transitioned from film to digital photography the number of pictures we take is at an all time high. But while our family albums often have pictures taken a century ago, it’s likely that the current crop of snaps will be irretrievable in just a decade, unless we work to preserve them.

The oldest surviving photograph, taken in 1826 by French inventor Joseph Nicéphore Niépce, titled “View from the Window at Le Gras” is still visible today while the ink jet prints on my fridge from 2005 are badly faded.

Niépce covered a pewter plate in lavender oil containing dissolved bitumen and exposed it for eight hours to the sunlit scene outside. The exposed bitumen hardened and the rest was washed off to leave a permanent image.

Photography has got progressively easier since then, including Kodak launching the brownie in 1900 with the slogan “you push the button, and we do the rest”. Later mass market innovations included 35mm cartridges and instamatic cassettes (although I never liked them).

Film based photography peaked in 2000 at 85 billion photos (this estimate is based on the global use of silver in the process) but this year, now that we’re digital and don’t run out of film, it’s estimated to hit 380 billion pictures. (Whether this four-fold increase in snapping actually produces any better images is debatable).

The largest single archive of current images is Facebook who noted that they had 219 billion images as at September 2012.

From the time I was in my teens, until about two years ago, I selected the best images from each roll and glued them in a series of albums. Recently I find I’m showing images to family and friends via Instagram, Twitter and Facebook. My album series has ended and I fear that my digital image narrative my have ended too.

Often it is the images that capture the ordinary, the view of the kitchen bench, the junk near the TV, rather than the false smiling relatives that are the most rewarding in retrospect. But being able to keep everything is a double-edged sword.

My digital archival storage plan


While digital storage is reliable it is ironically brittle. I’ve used and thrown out: punch cards, data cassettes, eight inch floppies, 3.5 inch floppies, zip disks and CD ROMs will be next in line.

My Aperture library, containing all my serious (RAW) images for the past few years is under 90 Gigabytes. Many other images have been posted directly to Instagram and only survive in 612 square pixel format.

When much loved Panda the cat died recently after keeping us company for fourteen years, I realised how few images remain.

I have images all over the internet, on Google Picassa, Yahoo Flickr, DeviantART, MySpace, and MobileMe. The last ones, on MobileMe web albums were deleted when Apple closed it down earlier this year. Yes they gave me plenty of warning, but no, I never got around to looking at them or saving them.

Paying for online image storage provides some assurance that they’ll make an effort to contact you before disappearing. The act of renewing the payment details every few years also serves as a reminder. It’s not expensive, Google charges $5 per month for 100GB of storage, Yahoo charges $25 per year for “unlimited” storage - although I’m always a little suspect of unlimited things.

Hard disks get cheaper very fast and currently a terabyte drive is about $100 so a good plan is to purchase a new one each year and copy over the whole archive from last year’s disk plus all the new images. The act of re-copying, plus keeping a few past years disks provides some redundancy in case of mechanical failure.

Apple has photo stream and iCloud but at the time of writing I’ve seen enough weirdness to not trust their cloud services just yet. (Jobs should have purchased DropBox).

The answer for me is a combination of the annually refreshed external hard disks plus some online storage (in case the whole house goes up).

I’ve also started printing out a few pictures and the bound books from Apple and others are a nice update to the glued albums I used to keep.

More pictures are being taken than ever before but I don’t think they’re better. Sometimes I like to use a camera that slows me down and doesn’t track the faces automagically. My new years resolution is to take fewer, better pictures and make an effort not to lose them in a disk crash.

I discussed this topic with John Doyle on ABC RN Breakfast this week.

Friday, December 21, 2012

Correspondence with planning minister Brad Hazzard about ham radio antennas

I wrote the following letter to the NSW planning minister, Brad Hazzard on 18 November 2012:


The Hon. Brad Hazzard, MP
P O Box 405
Dee Why NSW 2099



Dear Mr Hazzard,

I am a member of your electorate and a licensed ham radio operator, VK2TPM.

I’ve recently heard that your new planning system for NSW does not include the streamlining of approvals for the antennas that we ham radio operators need to put up to pursue our hobby.

The antennas that most of us put up are no more unsightly than TV antennas and much less unsightly than many of the tall masts which are common in suburbs on the northern beaches. Further, I find the power poles and lines, along with the low hanging cable TV and internet wires, to be much more unsightly than the occasional ham radio antenna that my colleagues put up.

Ham radio is a wonderful hobby and serves an important public service in times of disaster when conventional communications is unavailable. 

Specifically, what I’d like to see is:
  • Ground mounted radio masts or antennas of up to 10m height (or 5m above a roof if attached to a building) be exempt from a development application.
  • Masts up to 15m should only require a simplifying permit based on given standards.
Victoria and South Australia have regulations like this. Can you explain to me why we can’t match this in NSW?

If I can be of any further assistance, or you’d like to visit my ham radio shack for a cup of tea, you’d be most welcome.



Sincerely,


Peter Marks

He replied:

17 Dec 2012

Dear Mr Marks

I refer to your letter concerning the construction of radio antennas without the need for
approval, as exempt development.

I would like to acknowledge the valuable work performed by amateur radio operators in
transmitting vital information during natural disasters and other emergencies when
traditional infrastructure fails.

Provisions of State Environmental Planning Policy (Exempt and Complying Development
Codes) 2008 (Codes SEPP) allow antennas and aerials to be erected on most lots in
NSW to a height of 1.8m above the highest point of the roof on a dwelling. This includes
aerials and antennas which may be erected at ground level such as those used by
amateur radio operators. In situations where there is a two storey dwelling, this allows for
the erection of an aerial or antenna that is around 10m high.

These standards are designed to balance the rights of owners to erect these structures
which are suitable to the scale of existing buildings, while minimising visual and other
impacts on adjoining neighbours.

I note your reference to the approval and location of traditional infrastructure and the
impacts they have on amenity. The erection and development of power poles and lines as
well as cable TV and Internet wires is governed by other legislation, including the
Telecommunications Act 1979, administered by the Commonwealth Government.

Amendments to the Codes SEPP have recently been exhibited for public comment.
Amateur radio operators raised concerns regarding the Codes SEPP and the ability to
erect radio masts and antennas. Each submission is currently being reviewed and I have
asked the Department of Planning and Infrastructure to pay particular attention to the
concerns yo rail- in finalising the SEPP amendment.

Should you have any further enquiries about this matter, I have arranged for Mr Michael
File, Acting Executive Director, Assessment Systems of the Department of Planning and
Infrastructure, to asist. Mr File can be contacted on telephone number 02 9228 6407.

Yours sincerely

HON BRAD HAZZARD MP
Minister

Tuesday, December 18, 2012

Codec2 and modem on a raspberry pi?

Encouraged by early success with FreeDV digital voice with codec2 it occurs to me that a great project would be to build the equivalent of these AOR digital voice modems. Looks like they sell for US$449 so to build something functionally equivalent based on a $38 Raspberry Pi is very attractive.

There's an interesting thread on the codec2 mailing list about running codec2 on a raspberry pi.

I imagine AOR are not too pleased about this prospect - if they are watching the road ahead, they would be working to build codec2 right in and they will pick up a potentially interesting early adopter market.

Looks like I'm not alone and ON1ARF is already working on this. Although he's using a pandaboard for decoding at this point.

We are at a fascinating time in Amateur Radio.

Update - audio on Raspberry Pi

Downloading and installing codec2 on the raspberry pi couldn't be simpler:

  • sudo apt-get install subversion
  • svn co https://freetel.svn.sourceforge.net/svnroot/freetel/codec2-dev codec2-dev
  • cd codec2-dev
  • ./configure
  • make
To get the play utility, install sox:
  • sudo apt-get sox

The test that encodes and then decodes out to the rpi's built-in audio works great:
  • cd src
  • ./c2enc 1400 ../raw/hts1a.raw - | ./c2dec 1400 - - | play -t raw -r 8000 -s -2 -
Next step, where I'm a bit stuck at the moment, is to record audio from an external USB headset. I plugged it in and you can list devices as follows:
  • arecord --list-pcms
My USB Headset is a little Sennheiser one, so I get:

$ arecord --list-pcms
null
    Discard all samples (playback) or generate zero samples (capture)
sysdefault:CARD=headset
    Sennheiser USB headset, USB Audio
    Default Audio Device
front:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    Front speakers
surround40:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=headset,DEV=0
    Sennheiser USB headset, USB Audio
    IEC958 (S/PDIF) Digital Audio Output


Copy the device name from the list above and use it in arecord and aplay below. To record 10 seconds of audio from the USB headset:

  • arecord -D sysdefault:CARD=headset -d 10 test.wav
To play that back to the USB headset:
  • aplay -D sysdefault:CARD=headset test.wav
I can hear my voice but it sounds terrible. It would be an abuse of codec2 to use it as input. Any tips would be appreciated!


Friday, December 14, 2012

First HF Digital Voice contact with codec2 and FreeDV

I'm very excited to report that I've had two digital voice contacts on HF using FreeDV which runs codec2 by David Rowe. (There's also a very active digital voice Google Group).
Here's how Patrick VK2PN looks to me running 5W.


This mode uses about half what a sideband radio would use and is perfectly intelligible when it's working. The other bonus with a digital mode is the complete lack of background noise.

Here's how I look to Patrick on his panadapter:



Patrick has written up our contact from his side on his blog.

FreeDV is very easy to get going on Windows, I had a go at building it for Ubuntu Linux but ran into a few bumps in the road.

Here's a video from my end where you'll hear how Patrick sounds to me as we both reduce power.


After the contact with VK2PN I was also able to talk with Graeme, VK4CAG pretty well.

So, this is an extounding day! Great work by David Rowe and all those involved. It's fantastic to have a good quality low bit rate voice codec that is public domain. This is a great thing for Ham Radio and I would think will have reverberations through the voice over IP business as well.

Update - FreeDV under Wine

Stephen, VK2BLQ, has just pointed out that FreeDV seems to run well under Wine on Linux.


Update - FreeDV now builds on Ubuntu 12.10

The latest code from subversion now builds smoothly on Ubuntu 12.10 but for me the audio stutters for some reason so I'm still using the Windows version under Wine. I just heard VK4BD on 14.236 but couldn't decode more than the call sign.

Update - FreeDV on MacOS via wine

FreeDV appears to run ok on MacOS under wine but again I'm hearing audio stuttering. It looks pretty good though:


I installed wine with brew. Note that to get it installed you need to do the following:

  • brew rm libpng
  • brew install libpng --universal
  • brew install wine
Then you cd to the directory with freed-windows and wine freed.exe



Monday, December 03, 2012

Current project - the "Beach 40" DSB transceiver

Peter, VK3YE, is an inspirational home brew designer and constructor. In a series of YouTube videos he demonstrates and then walks through the design of a simple double side band transmit, direct conversion receive, transceiver he calls the "Beach 40".

The minimalist QRP Transceiver group has drawn the circuit up (in the files section).

I started construction over the weekend but my oscillator didn't.


I'm using the "manhattan" or "paddy board" construction technique using bits of PCB cut with tin snips and superglued on to the base board as insulating islands. It's not as compact as "ugly" construction but the circuit is more obvious and it's very low profile. I'm thinking of stacking boards one above the other in the final box.

After some tips on non-starting oscillators from VK2ASU and VK2BLQ (who's also building one), I put a variable capacitor in place of the 390pF in the Colpitts oscillator and it started.


Peter's design has evolved through the YouTube video series, mostly in the receive audio switch to an LM386 but I am attracted to the all discrete transistor version if it can be made to work. It's much quieter in my shed than it is on Elsternwick beach.

Update

Stephen, VK2BLQ, is also building and it's looking good (click to embiggen):


His CRO is much fancier than mine but I'm a bit suspicious of that waveform from modulation of a 1kHz tone on 7144kHz:


VK2BLQ is powering ahead of me:


But I own Saturday....

Update. Does this look right?

I'm still on the balanced mixer. I'm feeding in a 2.2V peak to peak 1kHz tone and here's the modulated RF output I get.


Seems very low level and somewhat non-symetrical. The variable resistor changes it but the trimmer capacitor has very little effect.

Stephen is powering ahead and now can transmit, here's his latest work (I wish mine was as good).


Stephen writes "Hi Peter, seems to be real QRP final current less than 250mA can't read any power
on  the meter.

As can be seen on the CRO, the PEP is 20v p-p which is about 250mW or 1 watt if it were CW. I think the final transistor  is not right. It is  a CB radio final and should be good for 4W. Time to cook dinner and have a look later"



Update - My power strip

Like Stephen, I'm getting 20V p-p or 1W out which seems a little disappointing.


Don't worry I will find some heat sinks. Here's a top view:



Saturday, November 24, 2012

Software Defined Radio talks

Today at the ARNSW Home Brew Group, we had two talks on Software Defined Radio, one dealing with VHF and up, the other on HF. First here's Gary, VK2KYP, who kindly gave me permission to post this video. Gary has previously purchased a FunCube dongle but finds a $20 DVB tuner works pretty well and is great value.



And here's Stephen, VK2BLQ, on HF SDR:

Friday, November 23, 2012

Feld Hellschreiber QRP beacon with arduino

I have been using a digital audio recorder to provide Hellschreiber test signals but this is clearly silly. So, thanks to Mark of the fabulous brainwagon blog I now generate test signals with an Arduino.


The Arduino sends port 13 (the one with the on-board LED) high and I use it to turn on a transistor to pull my final low. Off air locally it looks pretty good and the drift is quite mild.


I'm still running milliwatts with my big 2N2222a final transistor but Stephen, VK2BLQ can hear me 10km away fairly well over the noise. Here's how I look at his place:



On Sunday, November 25 2012, Stephen and I gave a little presentation about all this at the ARNSW Home Brew Group meeting at Dural NSW:

Saturday, November 17, 2012

How to fix poor iPhone battery life

My iPhone 5 wasn't making it through the day. I was disappointed, but after a few simple changes it looks like it could even last two days.

My usage pattern is that I charge over night, get up at about 6am, listen to podcasts for an hour going to and an hour returning from work.

During the day I make a few calls, and use a lot of Wifi data. On the way home I use a bit of LTE cellular data to catch up with news feeds.

With the changes below, as you can see from the Usage screen to the right, after 11 hours without a charge my battery is still at 74%.

Long life suggestions

  • Avoid polling for email. I was polling for GMail every 15 minutes, I switched to the GMail client (as I use Exchange for work email). So mail is pure push and it's instant.
  • Turn off LTE unless you're in a good LTE reception area and actually plan to use it. LTE is very patchy here and I've noticed the phone running hot in my pocket trying to contact cell towers.
  • Screen brightness under 50%.
  • Choose a carrier with good strength at your home and office. Phones turn up transmit power is signal strength is low.
  • Reset network settings: Settings>General>Reset Network Settings. I'm a little sceptical about this one but it forgets all those Wifi networks you've used once and stops the phone trying to join them again, unless you specifically want to.
Using Push instead of polling is the big one I think. Push is very efficient, it's a single TCP connection to Apple which all notifications come over (so I don't believe the number of apps that can push will make much difference).

Incidentally, all those tips you see about quitting applications that you aren't using are nonsense. iOS will only allow them to background for 10 minutes and then only for specific tasks like completing a download. The only exception is playing audio which you want anyhow.

Before the iPhone 5 I had a 4 (not the s). The battery was losing capacity after almost two years of daily cycles. The solution was to pay $9 for a replacement battery on eBay. It came with the tiny screwdriver and there are instructional videos on YouTube. It's easy and cheap to do.

I hope this clears up some mis-information I see around the place. Let me know how you go.

Update

Here's how my phone looks after 27 hours of not being plugged in and normal use for me. That includes quite a few hours of internet and podcast listening but no tethering. If you think you have a problem it would be useful to compare your usage with mine by the time you drop below 20% battery.



Feld Hellschreiber QRP beacon test

Stephen, VK2BLQ, and I continue to experiment with Feld Hellschreiber and I'm pleased to say that next Sunday, November 25th, we'll be presenting to the ARNSW Home Brew group meeting at Dural.

Today I did a test transmission with this little setup:


I've recorded "this is a test transmission from vk2tpm" on a digital recorder which is driving the simple audio keyer to key a two transistor QRP CW transmitter on 7027kHz.


Stephen is about 10km away as the crow flies:



He demodulated me like this:


Not great but amazing considering my transmitter. Come along next Sunday and we'll try to demonstrate across the room.

Thursday, November 15, 2012

Red Blue 3D maps from Nokia

I'm a bit of a 3D fan. Nokia has a maps web app at here.net, somewhat like Google and Apple's and it has a unique feature of displaying in red/blue 3D. Here's a shot:


The view is somewhat similar to that which you get from Apple's map, clearly taken from a low flying plane. It's great to see some competition in the maps business.

Saturday, November 10, 2012

Pixie 2 based Feld Hellschreiber transceiver

I've figured out that my keying of the CRK-10 CW transceiver is flawed and that I'm not shifting frequency so I've decided to start work on a dedicated Feld Hellschreiber transceiver based on the popular Pixie 2 design.


This clever little design uses the output transistor as a mixer during receive and my modification is to key it with rectified audio from the computer. It's putting out a very pleasing little signal (barely moves a power meter but thats fine for a mode like this) but my audio keying circuit needs work.

Friday, November 09, 2012

Digital QST now available via iPad app

I switched from a paper subscription to the ARRL's QST magazine some months back and have been distressed about the poor experience of having to read it through a terrible web based copy protection scheme.

Just noticed that there is now a QST app for iOS that makes it considerably more pleasant to read.


It's better but still pretty clunky. This feels like the output from some sort of cross platform publishing system. User interface buttons look alien. It surely should be in the Apple Newsstand and should use Apple's subscription system.

QST is laid out for print and it needs to embrace digital publishing by letting us read articles as tall scrollable streams rather than two or three columns of text.

It seems that it's published as images of the page, which makes it big and slow. While there are links, such as from the contents page, there is no text search. (In the end I'll want to search my whole collection for a phrase).

This is a good step in the right direction but it still needs work.

Friday, November 02, 2012

Tiny CW transceiver for Feld Hellschreiber

This morning I had a Feld Hellschreiber contact with Stephen, VK2BLQ on 40m. Here's how he looks to me:


And here's how I look to him:


Comparing the two waterfalls above I think I have too much RF gain which is leading to a noisy receive display.

My goal here is to be able to use a very simple, very small, CW transceiver with a digital mode. Next step is to get an audio driven keyer working.

Update

I've now got this working with the tiny CRK-10 CW transceiver via a simple audio keyer interface.


I'm using a little USB audio adapter and then you can see my simple audio transformer, full wave rectifier and 2N2222a transister to key the CRK-10. In the video below I test transmitting into a dummy load.


Stephen wrote "Good to work you on 40 Hell again.

The CRK10 has a very narrow filter, I was calling you back on 7030 several times, but not until I QSY to 7131.2KHZ that you heard me.

Your RST was about S3-5 but letters were good. Goes to show a microrig and pc  has possibilities.

The narrow filter kills the noise and makes the letters clearer.

I dug out  a couple of older T/R  boxes to mod for keying the tube TX directly. Don't think a relay is fast enough and is noisy. I'll use a powerfet rated for 100v and 1 amp as the Cathode current is 100mA and key up volts is quite high."

Here's how the QSO looked to me:


So aside from the fact that I'm off frequency, my reception is superior to my main rig.

Here is the simple keyer circuit. Small signal diodes, a 2N2222a and a few 0.1uF caps. The transformer is a little audio transformer, not sure what ratio.


I added a 3.5mm socket to the CRK-10 and connected it to the top of C22 where the transistor pulls low to key the carrier.

Thanks again to Stephen, VK2BLQ, for all his help at the other end but it looks to me that a truly minimal Feld Hell transceiver is quite practical.

Friday, October 19, 2012

Digital modes for a CW transceiver

As I don't know morse code and software decoding of morse seems pretty poor in my experience, I've been looking in to digital modes that could be used with a very simple carrier on/off transmitter.

So far, there are two I've found:

  • Feldhellschreiber - an on/off fax like transmission of letters using 1ms dots
  • CCW - "Coherent CW": an accurately timed version of morse with extra characters supported by MultiPSK. It runs at 12 words per minute and includes a start sequence to allow synchronisation.
  • Any others?
There's an informative thread in the Yahoo? digitalradio group.

CRK-10 Tiny 40m CW Transceiver kit review

Just completed construction of a delightful little CW transceiver from Crkits in China.


This US$52 kit comes with all the surface mount components already in place so construction is easy and low stress.


Just two toroids to wind and then only 10 and 12 turns respectively. The kit went together in a relaxed hour or so (I like to take my time and take breaks to try to avoid hard to unsolder mistakes).


The instructions are very clear, all components were there (in fact I scored one extra trim capacitor and a spare screw - much better than being one down). When it all goes together the metal case looks fantastic and it will make a very solid little unit.


The only glitch I found is that the super clear directions on how to wire J1 and J2 for straight key support are reversed. Oddly this error is in both the instruction manual and the quick guide Rev. B.

I also had a bit of trouble with the push button switch's alignment with the front panel hole, reaming it out a little fixed that easily.

Mine puts out a solid 3W and the receiver sounds good and narrow. On the advice of Stephen, VK2BLQ, I ordered mine for 7030kHz.

Now to learn CW.

Update

Adam has confirmed the error, he wrote: "You are correct about J1 and J2 jumpers. It is a mistake and nobody else told me about it. Probably most of them use paddles so they really don't care too much."

Sunday, October 14, 2012

It's Microsoft vs. Google while Apple runs free

We're on the eve of Microsoft's launch of Windows 8 and their big new push into tablets. I work with some folks who would have been hard core Windows experts a few years ago but I was surprised to hear them chatting enthusiastically about their Android embedded sticks and hackable low cost tablets from Ainol Novo.


Microsoft's delay in competing with Apple in the consumer tablet market has left the door open for Google to gain huge traction amongst windows geeks with their eminently hackable Android tablets. As Google doesn't make money on Android and Microsoft's business is based on making money from Windows Android tablets will always be cheaper and they are sophisticated enough to fascinate the IT crowd.

Meanwhile, Apple is left to capture the mainstream tablet market while the others fight it out for the geeks.

Microsoft has dropped the ball in recent years but they are doing everything right at the moment, it's just that it might be too late to catch up. If corporate IT departments find that their users have Android or Apple tablets and phones they may start to move off Exchange and that will leave Microsoft out of the picture.

Friday, October 12, 2012

Bargain 12V 32A HP PS-3381-1C1 Power Supply pin out

At the last trash and treasure at Dural I was lucky enough to be steered to a bargain at $10 each. There was a pile of switching power supplies that are known for the low RF noise. HP PS-3381-1C1s.


When you power them up the +12V rail isn't active and a few jumpers are needed to get this going. I found the necessary wiring in a radio control group so I guess these supplies are also used for charging big batteries. Here's the three jumpers to earth I added to get it started:


And here's the 12V out at up to 32A (although I'm not sure my wiring would cope with that for long).


The fan isn't too bad, particularly given the high current capacity. Mine outputs 12.3V but I understand there are modifications for pushing that up to 13.8V to get the most out of some transmitters.

Saturday, September 29, 2012

British spy "paraset" transceiver duplicate

Today at the ARNSW Home Brew group meeting we had a terrific presentation about the world war two "spy set" transceiver which was given out to resistance forces in Europe. There is a popular construction project that aims to build a pretty accurate replica.


Peter Jensen, VK2AQJ, has done a wonderful job of re-creating one of the versions of the set and in tracing the history of these interesting rigs. The simple design uses three metal valves and the receiver covers about 3.2 to 8MHz.

Peter is a wonderful speaker and I understand has published at least one book which I'll track down.



I bought a little bit of junk for the shed today although there is lots to temp me in the Dural disposals room.


Thanks as always to the organisers and it was great to have Mal, VK2BMS, along for the day.

Sunday, September 23, 2012

iPhone 5 LTE speed test - better than home cable

Rather than queuing on Friday, I simply wandered in to a Telstra store at Warringah Mall on Saturday at about 10am and got an iPhone 5 within minutes. Very smooth. This morning I checked my home Cable speed test and then on arrival in the Sydney CBD checked Telstra's LTE performance:


That's 24.39Mbps down and 23.36Mbps up. Really impressed apart from ping but even that isn't bad. More than enough people have reviewed the phone and I'm very happy with it so far too.

Update

It's amazing what LTE can do if you're the only user, check this out from a Brisbane tester reporting on Whirlpool.


87Mbps! But faster than 99% of AU tells the true story.

Friday, September 07, 2012

Swipe 2012 iOS developer conference in Sydney

This week I was lucky enough to attend the "Swipe" conference here in Sydney.


The highlight for me was the keynote presentation by Horace Dediu who I listen to on the "Critical Path" 5by5 podcast. The image above shows revenue from digital music sales compared to revenue from app sales, the interesting thing is that apps are now a bigger business than music.

Horace took us through the history of personal computing by using animated graphs showing the rise and fall of different products and brands. The stand out is that tablets have taken off faster than any product before them. While traditional "big screen" personal computers continue to experience some growth it is fairly flat compared to new devices such as smart phones and tablets.

The iPad is particularly profitable and in fact the iPad alone is worth more than the entire PC business. Microsoft's revenue for operating systems is rapidly declining. Android and IOS have completely re-defined what growth can be.

I asked Horace why, if Android is the number one platform, does iOS still see 70% of the internet traffic? He said it's about engagement. Android users wanted a smart phone or tablet but what you can do with it is less "discoverable" and this is a problem for customer loyalty. Many Android buyers bought a smart phone but they're using it as a feature phone.

Other highlights were the "ABC Art Maker" case study from Amy Nelson and Meena Tharmarajah, "iOS Performance Tuning" from Bill Dudney, "Designing Accessible iOS Apps" from Jake MacMullin, "Blocks and Block based APIs" from Cameron Barrie, "Australia Post case study" with Chris Van Raay, and "Automated testing with KIF" with Chaise Hocking.

My compliments to the organisers and I look forward to the next conference.

Tuesday, September 04, 2012

A look inside ABC News Radio

In contrast to the display of historical radio equipment in the foyer, I was privileged to get a personal tour of the ABC News Radio operation today. It's a very striking layout that appears to genuinely (almost) paperless.


Journalists and producers surround and face in to a "fish bowl" style studio.


 News Radio is transmitted on over 60 frequencies and reaches a million listeners each week.


Inside the studio it's a one person operation with the presenter who controls everything and reads directly off screen.


Thanks to on-air announcer Steve Chase, and everyone who cheerfully greeted a regular listener and fan. Sometimes seeing a radio station and the staff breaks the magic, in this case it's the opposite - I came away more impressed with the efficient and well designed News Radio operation.