Sunday, July 29, 2012

Amateur Radio Home Brew group meeting

A great meeting today at Dural. Perhaps it was the weather but the biggest turn out I think I've seen.

The topic of the day was switched mode power supplies, but regrettably I had to rush off to be a taxi so missed all but the start of that part. There were two great 'show and tell' presentations about valve transmitters.

It had not occurred to me how valuable microwave ovens are as a source of components and particularly high voltage, high power power supplies.

I brought along my little 40m AM rig but it looks terrible next to Stephen, VK2BLQ's wonderful construction style:

But just look at the board:

Stephen was also showing a nice valve CW rig built on two rails of angle aluminium.

One of the speakers said that he'd been ringing Drew Diamond with questions about the design he'd built - sounds like Drew was taking calls and answering enquiries with good humour - what a national treasure that guy is!

Peter, VK2EMU, brought along the nifty KN-Q7A SSB 40m transceiver for under $200, which does look like a nice robust little radio for camping or emergency use.

Great to catch up with everyone and I'm looking forward to Winterfest on August 26th.

Thursday, July 26, 2012

KX3 on air with a Signalink USB

Today I roughed up a cable to get on air with WSPR and the new KX3 via a Signalink USB.

Ground, PTT and audio are wired from the RJ45 plug to the TRRS 3.5mm plug, while speaker out goes to the SPKR socket on the back of the Signalink. If WSPR spots are anything to go by it seems to be working pretty well and on air my transmissions sound reasonable (no outlandish hum or anything).

Looking at the received WSPR signals, it seems that the KX3 drifts a little in frequency compared to the FT-817. Here's a screen shot using the KX3 after running for about 30 minutes:

Here's an old shot of reception with the ft-817:

However, after running for a few hours the KX3 looks much better:

It's now been a day of operation at 2W 10% transmit and I feel that the receive drift is pretty clear:

Ever helpful Wayne Burdick from Elecraft responded in the Yahoo forum to say "I'm experimenting with algorithms that reduce short-term drift." It seems like the issue is related to VFO temperature compensation so it's possible they might be able to slow the effect for narrow, slow, digital modes in a future firmware update.

I'm really loving the KX3, the latest firmware update gave us really good noise reduction, and I'm starting to think about selling off the FT-817 which is really redundant. My hesitation is that the ft-817 is kind of compact and robust compared to the KX3 which really needs a case to be carried without worrying about bashing a knob off.

Saturday, July 14, 2012

Australia Network iPhone app

If you have an iPhone and are interested in all things Australian, including news, sport, learning English and Radio Australia then you might be interested in the second app I have in the iTunes store called AustNetwork.

While I wrote the code this is very much a team effort including a project manager and graphic designer. One key thing I learned from the "One more thing" conference was that most apps require a team effort between a designer and a programmer.

Climbing the iOS programming learning curve has been a great pleasure and I look forward to more apps in the future. If you have an iPhone please click to install the app (or search for Australia Network in the store), and of course I'd appreciate ratings and reviews.

Thursday, July 12, 2012

Let's have unmetered ABC on the NBN

We are regular users of the ABC iView service. Combined with an Apple TV, Boxee, or other AirPlay capable TV device, this is the best way to watch ABC programs.

The problem for many users is that they run the risk of exceeding their internet plan's limit.

It occurs to me that a great synergy that the Australian Government could take advantage of would be to make the streaming of ABC content unmetered over the National Broadband Network.

I think that so called "catchup TV" is actually the future of TV. Podcasts are the future of a great deal of radio. Tablet based news aggregators are the future of newspapers (it feels archaic even using that term already).

We'll have broadcast TV and radio transmitters for a while yet but in the end it's all data. Making the NBN a free distribution channel for ABC content seems like a logical idea. Anyone in favour?

Wednesday, July 11, 2012

Softrock Ensemble RXTX with Quisk on Ubuntu

I recently purchased the nice box for the Ensemble RXTX from the KM5H store and it does make it into a very professional looking little software defined radio.

The audio labels are ambiguous, "line in" means "this connection goes to your line in". There is an amazing bit of python/C software called Quisk that can be used to control the Ensemble.

Here it is receiving a station from Kuwait (I'm in Sydney by the way).

To get this working on Ubuntu 12.04, I did try using the install from the Ubuntu software centre but I couldn't get it to talk to USB so I ended up simply downloading the software, doing a 'make', and running it from the command line.

Quisk comes with a config file preset for the Ensemble RXTX at quisk-3.6.2/softrock/ which I copied to ~/ and edited to point the audio to my creative USB external sound device.

Tuesday, July 10, 2012

Stop spamming me Ebrahim Kariel

I keep getting these emails:

I click No.

So, why are you sending these messages? Then when I try to leave the page "flipora" does this:

Which really gives me a bad feeling about this scam. Stop it or you'll get a bad reputation on the internet. We now return to our regular transmission.

Sunday, July 08, 2012

KX3 to KX3 contact

Patrick, VK2PN, received his Elecraft KX3 kit, quickly constructed it and we had a contact which we recorded on both ends.

While I'm receiving, you can see me adjusting the passband control. We're both very happy with these new radios. Patrick built the kit and has a blog here.