Amateur Radio

Amateur Radio is for people who want to learn about, use and experiment with wireless communications.

I have been a licensed Radio Amateur since 1995 and currently hold a Full UK licence, callsign G7UHN.  Although I started quite early, I was inactive in Amateur Radio for many years partly due to the hobby turning into my career in communications engineering.  Over the last few years, my interest in Amateur Radio has been rekindled.

What is Amateur Radio anyway?

I read a great description once, so great that I’ll just reprint it here (with some slight alterations for a family audience!):

Imagine that you have a light. A small, not very powerful light, maybe 2 watts or so. You read somewhere on the internet that the ionosphere (yeah, that’s up in the sky, way above the trees – REALLY high) can bounce light back to the earth if the light is the right color. You read a bit more and find out that different heights do different things and that if you get just the RIGHT color, you can actually bounce it down, up, down, up and then down again to the other side of the planet. Like God’s fiber optics in the sky. Deep stuff.

So you screw around by adjusting the color and you send a message in Morse code. Or if you’re really fancy you change the color of the light depending on the waveform of your own voice. You actually get just the right frequency so that the light is visible (just barely) to somebody that lives 8,000 miles away.

And here’s the really crazy part: not only does somebody over there see the light and decode the Morse code (or your voice), they send you a message back. Apparently this guy saw the same instructables article as you and bought the same kit from some website somewhere.

And you guys talk for a while. But really it’s way more fun to try and see if you can find somebody in a whole different country on the other side of the world. Eventually you decide that if you’re really a good with this thing that you can reach somebody in every country in the world if you really try hard enough. So you sit up late at night, or you spend your entire weekends morning and afternoon, trying to reach people with your little light (which you put on top of your house now, just because it’s easier). And, well, you start to look like somebody that hasn’t come out of a cave in a while, but you’re sort of obsessed and you just can’t stop now anyway.

But it’s not enough… you decide to bounce that light off of the moon (OK, you need a slightly brighter light here) or bounce it off of meteor trails. Or you decide you are only going to use ultraviolet light that doesn’t bounce of of the sky, but that’s cool because you can use your grow light and a filter and it doesn’t cost you any extra and hey, that thing’s pretty bright maybe it will work.

Oops, now you’re hooked. Welcome to Amateur Radio…

73 de K5EHX

I’ve also heard Amateur Radio described as “a hotbed of eccentricity” which seems pretty accurate too…

What do I do with it?

Working in the communications domain, I have used well-specified radio installations often with optimal and/or large antenna systems.  At home I can’t expect to replicate such systems and the challenge therefore is to see what can be achieved within the constraints of a relatively small home in Southern England and a limited amount of spare time!

An 85ft wire antenna suspended from a box kite (line enhanced for visibility in the image). Glorious!
An 85ft wire antenna suspended from a box kite (line enhanced for visibility in the image). Glorious!

I’ve put together a small radio station here working around the constraints of a family home, low power operation and relatively small antennas.  I don’t have any dedicated space in the house for radio so my equipment is hidden away, network-enabled by Raspberry Pi and BeagleBone Black hardware and Linux software and accessed across the network from a laptop, described in more detail here.  In putting all this together I’ve learned a lot about RPi, BeagleBone, Arduino, serial-over-IP, audio & video streaming, done a bit of coding and really improved my Linux skills.  Rather against some people’s expectations, the Internet-age hasn’t killed off the Amateur Radio hobby.  Instead, we now have more technology available at lower costs and access to online resources that allow learning and experimentation with techniques that are also relevant in the professional domain.

I’m interested in HF digital modes as a means of making the most out of low transmit power and disadvantaged antennas.  I’ve built an Elecraft K2 radio with some minor modifications and that is part of my networked radio setup.  I also quite like taking radios outdoors and trying things I can’t manage at home, flying large antennas from kites or using the International Space Station as a communications relay for instance.

What else?  What, more than learning stuff, building stuff and doing fairly eccentric things?  Well, I still get a thrill out of every contact over the radio, particularly far away contacts, and I get a childish pleasure out of putting pins in a map.  You can have a look at my radio contacts on this Google Map and the most recent are listed below…

Recent Radio Contacts:

Recent Posts:

Mumble/iCW on Linux

Just a quick post so I don’t lose this command… (!) $ parec –latency-msec=10 -d alsa_input.pci-0000_00_1b.0.analog-stereo –stream-name=Sidetone-source | pacat –latency-msec=10 -d alsa_output.pci-0000_00_1b.0.analog-stereo –stream-name=Headset-sidetone & I’m setting up for iCW (Internet CW) on Linux and this is the pulseaudio pipe command to get a low latency monitor of my laptop’s line in (FT-817 audio is plugged … Continue reading “Mumble/iCW on Linux”

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First play with Red Pitaya

Finally got around to hooking my new Red Pitaya up to the PA0KLT VFO and having a play around with the oscilloscope and spectrum analyser applications.  Very easy to hook up on the dining table, connected to the laptop via WiFi and seems fairly responsive given that it’s driven through a web browser so a … Continue reading “First play with Red Pitaya”

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PA0KLT VFO in progress

A couple of quick snaps of a PA0KLT VFO coming together on a 3D-printed test panel:

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Antarctica calling…

2200 UTC Friday night and I’m parked right beside the sea wall at the bottom of Southampton Water.  This is the scene for my biggest ‘DX’ contact yet and a very special one: 9000 miles to the south my friends and former colleagues at Rothera Research Station, Antarctica are about to give me a call … Continue reading “Antarctica calling…”

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Clear weather approaching…

Rain Alarm – 09:00

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Waiting to go Portable

Currently on a short break down in Cornwall and I’m keenly watching weather data to see if there’s a chance of going out for some portable radio.  I have it in mind to fly a kite antenna from Lizard Point or nearby but obviously weather is a deciding factor.  A great tool to enhance the … Continue reading “Waiting to go Portable”

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SDR receiver back on line and contesting…

Thanks to some inspiration from 2E0DFU I have repaired my network connection to the attic (it had been cut to use as a pull-through when I installed new feeders to the loft!) and have my SoftRock Ensemble II SDR receiver back online. I’d forgotten just what a great bit of kit the SoftRock is and I’ve … Continue reading “SDR receiver back on line and contesting…”

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Notes on Linux on a Dell Inspiron 17 5000 (2014, model no. 5748)

Driven by changes in daily use and a need for a bigger screen, I have decided to retire my venerable Toshiba Tecra M9 laptop from active duty and replace with a 17″ laptop.  But 17″ laptops have fallen out of favour with the computer manufacturers over the last few years and the whole laptop market … Continue reading “Notes on Linux on a Dell Inspiron 17 5000 (2014, model no. 5748)”

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G7UHN is now invisible!

G7UHN has entered a new phase this weekend – the home station equipment has disappeared from sight and is now located on a shelf in a utility cupboard!  Operation of the station is enabled by a pair of Raspberry Pis serving out audio, serial and video feeds to a laptop computer which can be located anywhere … Continue reading “G7UHN is now invisible!”

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Remote audio improved…

A quick post.  I’ve just discovered an improvement to the remote audio software I’ve been using to stream audio from my SDRs in the loft to my laptop over the home network.  Previously I have been using IPSound and, while excellent for connections between Windows PCs, it has some trouble running under Wine in Linux … Continue reading “Remote audio improved…”

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