Saturday, September 06, 2014

Back home, back on lower bands

For the past eight months we've been living in an apartment and while I enjoyed learning about antennas on a balcony, it's good to be back at the normal QTH. The neighbours behind us have a magnificent gum tree which supports my new 80 and 40m dipoles.


You can't see the thin wires so hopefully it won't annoy the neighbours too much. I don't really have enough space for the 80m dipole which runs along the side fences, but 40m works really well and tunes up beautifully.

It's good to be back and while I have lots of unpacking and re-organising to do my hope is that ham radio projects will again get some time.

Saturday, August 16, 2014

iPad version of WSPR Watch coming

Here's a sneak peak:


It updates itself every few minutes but I am concerned about loading wsprnet.org too much.

Saturday, July 26, 2014

New transceiver for the shack - with valves!

Great day at Dural today. Particularly impressed with the home brew moving coil compass built for a model boat. I didn't mean to but ended up walking away with a beautiful Yaesu FT-101E for $200.


Had a contact with Stephen, VK2BLQ, who reports that I sound normal so that's all good. Plate and Load knobs are new to me but fun to learn about.

For my younger readers, this is what a valve looks like:



The compass was fascinating, it uses a spinning coil with an amplifier in the centre. Power is fed in through the ball bearings and the output is sent by an LED light.


We turned it on and compared with a compass in a smartphone.


A wonderful device, but I think technology may have moved on.

Update

Here's a video of what it's like to tune across 20m on the FT-101E back in the flat with a dipole on the balcony.


We're moving out of the unit back to the normal QTH in a few weeks so I thought I'd capture this for future reference.

Tuesday, July 22, 2014

Appearance on RN's Download this Show

A busy week, media wise. I was on RN's Download this Show:


Also wrote an opinion piece about how the BitTorrent technology can be used for good as well as evil, published by the ABC.

Saturday, July 19, 2014

What's cheaper than a Raspberry Pi and runs linux well?

I'm interested in playing with some of the new virtualisation technologies, such as docker. For this stuff my usual go to toy, the Raspberry Pi doesn't quite cut it. This morning I spotted a Dell Optiplex PC, Core 2 Duo 2.5GHz, 2G Ram, 250GB disk for $35 on eBay with no bids.


Ending an auction at 7:15am on Sunday morning may not be the best way to sell technology.

So far I've installed the 64bit version of Ubuntu Server 14.04 and following the instructions from the excellent Ubuntu documentation created a virtual machine in which I've installed another copy of the Ubuntu Server.

This works magically, the qemu environment can be set up to share the virtual console via VNC and from my desktop machine I answer the install prompts as if sitting at an actual machine. Here's how it looks:


Now I can safely try all sorts of crazy things in this virtual server and just delete anything I'm not happy with.

Here's the giant new server (with a Raspberry Pi next to it for scale):


There are bargains out there, but I should say that this was a crazy price. You can pick up similar systems for under $200 pretty easily though.

Sunday, June 29, 2014

Balun day at Amateur Radio NSW

Today was "balun day" which began with breakfast followed by a terrific talk from Mark, VK2XOF, about the theory and practice of building current baluns. The biggest mystery for me is what core to use.


After the theory, and lunch, we all received out balun kits from TET-Emtron. I went for the TB-11K 1:1 kit rated at 1kW peak. We then built our kits under the guidance of folks who had built them before.


Finally there was a spectrum analyser and antenna analyser on hand to measure the baluns. Some home constructed baluns were found to have high reflected power which was very interesting to see.


The method for assessing a balanced to unbalanced balun's operation is to attach a 50 ohm load on to the antenna terminals, feed it from an antenna analyser and connect one and then the other of the antenna terminals to the ground of the input and see if the impedance changes very much - if all is working well it should not change.

My sincere thanks to the ARNSW committee and all who clearly worked hard to make this day a great success. Thanks also to TET-Emtron for producing the fantastic kits and for their support.

Saturday, June 28, 2014

Windy in Sydney this afternoon


Up here on the 28th floor it was pretty windy today. The doppler wind radar looked pretty interesting. RNDSUP seems like a fun technology.