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.

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.

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.

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.

80 Years of ABC display at Ultimo

If you can get to the Australian Broadcasting Corporation's Ultimo Sydney building there is a wonderful display of historical equipment from the archives in the public area. Here's a few snapshots.

I spotted John "magic fingers" Diamond setting up along with a retired camera operator. Great work by all involved. Thanks for the memories.

Model helicopter for antenna examination

Checking out the antenna with a model helicopter, no it seems that antenna wires draw in helicopters due to some sort of, as yet, explained force. Picked up a model helicopter for under $100 at Jaycar complete with an on board video camera.


You get a nice view of the shack and we quickly collide with the G5RV antenna and then fall to earth. It's a bit windy today and our back yard is full of obstacles but this is a fun toy for the money.

Low cost 40m SSB rig from China - KN-Q7A

While there are several decent but very low cost VHF/UHF rigs out of China so far this is the first HF transceiver I've come across. For $200 built, including Icom compatible microphone, a few of us have bought them.

Here's a video of a QSO with Stephen, VK2BLQ.



The KN-Q7 was designed by BA6BF and uses familiar components such as NE602s. The kits or assembled units are available from CRKits from US$115. It's a crystal VXO arrangement and you order according to the sub-band you want.

The case is very solid and will survive a trip in a backpack with no trouble, coupled with low power requirements, this makes an excellent QRP rig for camping or emergencies.

Adam Rong, BD6CR/4, provides excellent service and communicates well via email.

The manual, which includes a full circuit diagram is here.

Update

I received a nice note from Adam, thanking us for the writeup. Cheers Adam!

Prominent ham radio antenna

Each morning I travel to work by bus. Mal, VK2BMS, drew my attention to an interesting antenna that is visible on the left as you start on the Sydney Harbour Bridge.

I captured this on my phone through the bus window and high speed, that's my excuse.

Mal writes: "The domed rod on the right is a lightening conductor and left is a Hygain 40 to 10mx trap vertical 14AVT of the late Ray,VK2BBP.

It looks professional and repair people on the roof probably think it's part of the building or don't know what it is and frightened to touch it."

Not sure that being pointy and higher than a nearby lightning conductor is a good idea.

Model helicopters old and new

We headed for a local park armed with two model helicopters, one traditional, the other was a Parrot AR drone version 2. The difference is amazing.


To be fair, the old one is pretty beaten up and the gears are grinding. Still good fun.

The Parrot AR drone creates a wifi network that you join with an iOS device. The software has "absolute" mode where you tilt in the direction you want the drone to fly and it takes care of figuring out which way it's facing, which is the hardest part about flying these things.

Let's hope the military never gets hold of this technology..

Radio-Kits Digital SWR/power meter kit review

Ross, VK1UN (and several others) writes: G'dday Peter,

Yesterday afternoon, I finally got the Digital SWR/power meter kit from Radio-Kits in the UK and built it last evening.

A very straight forward build as all the parts came in separate zip-top bags wit a component list in each. Instructions for building are down-loadable from the above site and are quite complete.

I added all the resistors first, capacitors, diodes, transistor and then the op-amp IC. The PIC was socket mountable so that remained out until the "smoke test!"

There are two boards, firstly the main meter and control board and the detector board, both can be built concurrently as there are resistors, caps and diodes on the detector, as well as the toroids and sockets.

It passed the "smoke test" - a check of DC resistance (using diode setting on the meter to make sure semiconductors did) and then I connected the 9V battery. Display lit up and no pops, bangs or smoke!
I then adjusted the display contrast pot and the display showed all the right screens so all appeared to be working OK and first time, no diagnosis needed at all!!

I waited until morning to test on RF as the WSPR station was in use all night.

Morning, put the device in line between the SGC MAC-200 tuner and the transceiver and got readings that I was able to play with. The SWR showed 1.72:1 so I was a bit suspicious, however a dummy load showed 1.0:1- good! I then QSYed from 40m I was using for the initial test to 17m and the SWR dropped to 1.29:1, better but not wonderful. I do realise that the MAC-200 is not designed to auto-tune at low powers, so maybe I was a bit unfair.

I then calibrated the power readings using my coffee can dummy load with diode inside to measure the peak voltage across the dummy load. It calibrated nicely.

Finally, I thought I would insert the LDG Z11ProII inline and got a nice low reading on 17m of 1.04:1 - much better. The LDG is much happier tuning at very low powers.

I've attached some photos of the device on the test bench with a ruler lying beside, so one can see the dimensions clearly. My only criticism is that the only case available tom R-K with the kit, is way too big - I could probably fit a couple of Ensemble RxTxes in with it!

Very happy with the kit as with the built-in 9V battery it is entirely stand-alone.

73

Ross

Thanks Ross!

Big winds but the right rig for reception

We've had very big winds here in Sydney over the past 24 hours. The half G5RV between tree and house broke at the centre insulator due to unexpectedly large tree movement. I've repaired it today and have been tuning around listening to all the stations in the contest today.

My favourite rig these days is the Elecraft KX3, which has always seemed very quiet and well behaved. Turns out it's just topped the chart at Sherwood labs.

Their ranking is by "dynamic range narrow spaced", which I don't fully understand but presumably means it behaves well when a strong signal is very close to the frequency you are listening to. The next rig on the ranking has a list price of $7,700 so that makes the KX3 a real bargain. It looks like it's uncommonly sensitive too from the table snippet above.

I find the KX3 a very quiet receiver, my only wish is that the tuning knob would spin freely but that's a minor quibble.

Congratulations Elecraft!

VK2BLQ's USB Powered Radio

Stephen wrote: "I fired up a SDR board, not sure whose circuit I used, very similar to
YU1LM. The oscillator is a 28322 osc block, so is 7080 when I/Q'd. It is
powered by the USB port. What is significant is the USB sound card,
Jaycar type, actually works. The software is from Italy, I2PHD. Software
provides for a +/- 24KHZ bandwidth and the USB sound card seems to work
to that B/W."



Great work! You also get a glimpse of Stephen's excellent new home built workbench.

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.

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.

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.

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?

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/conf_rx_tx_ensemble.py which I copied to ~/.quisk_conf.py and edited to point the audio to my creative USB external sound device.

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.