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.

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.

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.

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.

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."

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.

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.

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.