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.

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.

Elecraft KX3 first contact

The Elecraft KX3 serial number 371 arrived this morning. First contact was with Patrick, VK2PN, who immediately drove over, delivered a congratulatory QSL card and snapped this fine picture:

Before giving some impressions of the device, I want to moan a bit about the process of importing such a gadget in to Australia. When Gerry Harvey says that local retailers are threatened by online shopping he fails to realise what a fine job our Customs department is doing in putting people of importing goods of any value.

Once Elecraft shipped my KX3 it was here in three days, it took another 14 days to make it through Customs. Here's the trail:

Shipment Activity        Location                               Date & Time
--------------------------------------------------------------------------------
Delivered                AUSTRALIA                              06/29/12  8:19am

Customs clearance        AUSTRALIA                              06/28/12  1:39pm
processing complete

Customs Clearance        AUSTRALIA                              06/18/12  6:41am

Customs Clearance        AUSTRALIA                              06/15/12  4:51pm

Processed Through Sort   AUSTRALIA                              06/15/12  2:51pm
Facility

Processed Through Sort   ISC SAN FRANCISCO (USPS)               06/13/12  4:43pm
Facility

Arrived at Sort          ISC SAN FRANCISCO (USPS)               06/13/12  4:40pm
Facility

Electronic Shipping                                             06/12/12
Info Received

Processed through USPS   SAN JOSE CA 95101                      06/12/12  6:11pm
Sort Facility

Processed through USPS   WATSONVILLE CA 95076                   06/12/12  4:53pm
Sort Facility

Shipment Accepted        WATSONVILLE CA 95076                   06/12/12  3:58pm

The box was accurately declared, there was no duty to pay (a little GST), and I had the correct classification. Surely there has to be a more efficient way to import an off-the-shelf product?

KX3 First Impressions

I've been looking forward to this day since May 2011. Thirteen months. I'm not disappointed. Very compact, it looks like the remote head to a larger transceiver. A few early comments, and bear in mind that I've never owned an Elecraft device before and have only had this for a few hours:

• The knurled knob arrangement which tightens the fold out feet is instantly annoying. Opening one side loosens the knob, the other side tightens its knob. The manual has special warnings about this part and surely it can be improved in the future.
• Mine came with rather scrambled initial settings, every band seemed different, it didn't know it had roofing filters, audio was set to stereo "effect", and so on. Took me a while to get things sorted out.
• Works great with a Mac, the KX3 Utility checked firmware version and works nicely with PSK31 with just the included cable.
• I love the receive audio, really quiet, wonderful filter narrowing effect. Great to have a "normal" long-press button to get back to a starting point. Looking forward to the noise reduction which is coming in a future update.
• The built-in speaker and audio section is under-powered. Great for headphones but in a base station it is really improved by an external amplified speaker.
• Patrick reported that my transmit audio was good and even sent a spectrogram from his K3 panadapter to show that I need to reduce the bass a little.

This is a very feature rich radio and it's going to take a while to get the hang of it. So far so good.

Update - I busted it

I found a cable from a video camera that looked like it might be handy - four conductors and it was wired out to RCA plugs. I pushed it in to the mic jack and it turned out to be too long and damaged the socket!

It kind of worked if I held the elecraft mic plug in just the right position - but it was not good.

So, I opened up the kx3 hoping to do some light bending, but it's a sealed socket. I raced down to Jaycar but 4 conductor sockets are not available off the shelf.

So now I've replaced it with a standard 3.5mm stereo socket with tip wired to the mic, the up/down and ptt are currently unconnected. There's a transmit button on the rig so it's not a big issue.

The good thing about this arrangement is that I can now use a standard PC headset right into the rig although the mic gain is rather low. I had to try a second headset as the first one didn't have enough output.

My kx3 has now been modified, perhaps it's a good step to take as I won't hesitate to do more to it in the future. Perhaps it's time to start a KX3 modifications page?

Update 2 - more contacts

Called CQ on 40m and got an immediate response. I've had several contacts now including assistance from Mal, VK2BMS, to get the transmit equalisation set up nicely to match my PC headset mic. (I cut the lowest frequency 10dB to get rid of some close mic boom).

So far the audio reports have been excellent and even running 5W has resulted in good contacts over hundreds of kilometres.

I love this radio. It's the best receiver I have and after only a few days I'm feeling very comfortable with the features and controls.

Installed the bleeding edge software updates: DSP 092 and MCU 106. All seems good. The most noticeable improvement is the action of the AGC which is much smoother. I understand this update will go live on Monday. The great thing about a software defined radio is that we get upgrades purely in software in the months ahead (there's a few features that come up as not available that I'm looking forward to including voice record and noise reduction).

Headless raspberry pi on the network

A raspberry pi finally arrived. Amazing embedded linux platform for very little money.

I'm not really interested in using it to drive a TV, but more as an embedded device for some ham radio project, so I wanted to get it on the network in a headless configuration that I could easily locate. Here's what I did:

• Grabbed the recommended Debian Squeeze image from here.
• Wrote it to an 8GB SD card using dd on the mac as per instructions here.
• Mounted the card and enabled remote ssh by "sudo mv /boot/boot_enable_ssh.rc /boot/boot.rc"
• Unmounted the card, stuck it in the raspberry pi, connected ethernet
• On my Mac, did an "arp -a" to note the network devices on my lan
• Powered up the raspberry pi (I'm using an iPhone charger which seems to work fine)
• Waited a few minutes, until the lights stabilised, did another "arp -a" and looked for new ip addresses
• In my case "ssh pi@10.0.1.16" (but your address will be different) {password is 'raspberry'}
• I'm in! For convenience I create my own user account using "sudo useradd -m USERNAME" and then add the account to /etc/sudoers

The Debian image only uses 2GB of my 8GB card, so I followed the instructions here to resize the root partition up to use it all. After a reboot, it looks like this:

I prefer not to give things fixed IP addresses so to make it easy to locate on the network I install avahi-server with "sudo apt-get install avahi-daemon". Then I add the following configuration file as /etc/avahi/services/ssh.service

Now I can simply "ssh raspberrypi.local" to log in.

I must be getting old, but it's astonishing that I'm using a computer for under $50 that is much more powerful than systems I used to share with dozens of users only a few decades ago.

Now to think of a good application for it!

Terry's homebrew Tricopter

I am working but a distraction dropped in.



And in a park.


I recently bought a tiny key fob shaped "spy" camera which we put on board one of the tricopters:



These Tricopters were built from instructions on RCExplorer.

iPhone app to watch your WSPR spots

If you use the WSPR propagation beacon system and frequently visit wsprnet.org to see who is reporting your signal, I'm pleased to announce that there is a simple alternative if you have an iPhone, WSPR watch.

It's a free app and it's my first app to be accepted in to the store.

WSPR watch pulls it's data from the old database page on wsprnet.org but focuses in on people who can hear you and who you can hear. It plots the location of stations on a map and can show you all the available info on a spot if you tap it.

I hope you'll download it, send me feedback and feature ideas, and even rate it. There is a much more complex app by me, not ham radio related and for a commercial client, coming soon and going through the process of getting an app in the store has been very interesting.

One more thing conference 2012 in Melbourne

Today I've had the pleasure of attending the One more thing conference in Melbourne.

I can't praise the organisers highly enough, the conference was well run, well designed and the speakers represented a galaxy of stars from the ranks of successful iOS developers around the globe including Flipboard, Tapatalk, ShipFinder, Pano, Trainyard, Calvetica, Doodle Jump, Elements and others.

Much of the discussion was about gaming the App store and dealing with the inconsistent Apple review process. Clearly the store, while extremely successful, is broken in important ways.

I came out of the day inspired, motivated and informed. Many of the developers gave valuable real data about their earnings, what worked and more valuably what didn't.

See you next year.

What's the most used browser?

There's been a bit of controversy about claims this week that Google Chrome is now the most popular browser. According to stats to hand for a site I manage, it's been ahead for some time.

Obviously it would be different for different sites but my evidence is pretty clear.

Receiving WSPR with tiny indoor loop antenna

A new toy, a PK Loop Antenna. This one tunes from 6MHz to 18MHz, so it's designed for shortwave broadcast listening.

Even indoors, amongst all sorts of electronic equipment, fluorescent lights and computers, it tunes up well and band noise can clearly be heard. The best way to evaluate an antenna is by comparing with my normal outdoor wire dipole decoding WSPR signals on 20m. The big drop is where I switch from the outdoor dipole to the little indoor loop.

This graph shows signal to noise ratio of my reception of VK2UX, a station I watch as he has wonderful low noise reception compared to mine. The amazing thing is not the drop in SNR but that I can still receive low power WSPR signals at all with this little indoor antenna.

The loop is well constructed and seems to work remarkably well. I just have to remember not to transmit into it!

Fix for ubuntu remote desktop redraw problems

If you access a recent (after unity) Ubuntu via remote desktop with VNC you'll have a lot of trouble with the screen not repainting. I'm accessing 12.04 but it happened in 11.10 as well.

The fix is to log out, then in the login screen click the little ubuntu circle next to the user name and select "Unity 2D". Maybe when you enable remote desktop it should warn us about this?

Demo of BHI noise reducing speaker

Recently I "traded down" from an IC-7000 to an IC-725. One thing I missed was DSP noise reduction. Mal, VK2BMS recommended a BHI NES10-2 MK3 speaker. Here's a demo, the best performance is after I stop talking by the way.



It does seem to be better than the DSP built in to the IC-7000 and has the advantage that it will work with anything, including little home brew receivers.

Antique radio builder - Jack Meijer

Through local ham, Robert, VK2ZNZ, I've had the privilege to meet Jack Meijer who restores and more amazingly builds valve radios. Jack has a wonderful workshop in the garage.

The radios he builds are often in perspex so you can see the interesting components such as the variable coupled inductor on the left in this regenerative receiver.

Jack is 87 and while he has a few physical complaints he's clearly very healthy, alert and doesn't even need glasses!

A very neat workbench too. There was a time that valves were manufactured here in Sydney Australia:

Some of the older valves came in elaborate metal tubes too:

The list of patents show that these valves had a very long life span as the current technology.

Jack constructs really beautiful equipment, the last time I saw wiring like this was in the 80s when I had the pleasure of working with Wally Chaimberlan at 3DB.

Note: I previously mis-spelt Jack's surname - sorry about that.

ARNSW Home Brew 40m AM challenge attempted contact

It's great to see a few people working on the latest ARNSW Home Brew group "challenge" project - to build a 40m AM transmitter. I'm on the way, but my design only puts out 2W, but Stephen, VK2BLQ is running his IRF510 on 24V and getting 5W or more. His design features a beautifully stained breadboard base to give the machine "soul".

I was able to receive Stephen readability about 3 and we coordinated on 2m (on my old favourite channel "D", 147.475MHz) to get things set up. Unfortunately, he couldn't hear my transmission but just look at the wreck of a rig I was using (the one in the foreground).

One thing that has worked out pretty well is the piece of aluminium I bent into the simple "U" shaped chassis you see above.

Incidentally, the $220 IC-725 is going well. I replaced the right hand dial lamp with a 12V yellow LED. It's not as bright as the light on the left (that hasn't blown) so I might replace it too to balance things up.

The band noise on sideband sounded very different between upper and lower and I've now adjusted the BFO on the upper side to bring them in to line (that's the one that sounded out of kilter). This was purely done by ear but it seems to have done the trick.

Keen eyed viewers will note a new addition to the shack - a BHI NES10-2 MK3 Noise Eliminating Speaker. So far I'm very impressed and will post a review shortly with a demo.

Bad Yahoo Groups user interface

The only thing I've used Yahoo for in recent years is a few groups that are hosted there including the active KX3 discussion. Something bothers me and I've just figured out what it is. When you first go to the Messages view, the footer is this way:

So I read that page and click Older (on the right). The next page of messages is shown and now the footer is like this (direction is swapped):

I'm sure Jacob Nielsen would have something to say about this...

Yahoo doesn't seem to know which way is the past and which is the future, I think whoever is in charge should be sacked, oh, he just has.

20m WSPR

Just turned on the FT-817, running 2W on 20m with WSPR. Very first transmission, here's the people who heard me:

Amazing. Minimum distance, 11,824km away, up to 15,745km. Gotta love WSPR.

Interesting, it must take a little time for reports to trickle in, there's a few more for the first transmission and then reports on a second.

At this point I've only heard 5 stations so clearly my reception is no where near as good as other stations'.

Incidentally, this is running on an Acer Aspire One netbook with an Atom processor running Ubuntu 12.04.