vk2rh: a blog about ham radio

  • DATV and bands in VK

    Traditionally ATV and its associated analog 7 MHz bandwidth has been restricted to UHF and microwave bands, and bandplans have reflected that. With the global emergence of DATV and RBTV (reduced bandwidth TV) experimentation is now taking place on lower bands, down as far as 10m. During a recent radio club meeting where there was…

  • Portsdown 4 project back on track

    I’ve been building bits and pieces of what will become a digital amateur TV capability for just on five years! I lost my momentum after building a number of components and it’s only in the last few weeks I’ve found a renewed enthusiasm to get on with it! One of the main prods has come…

  • AMR100

    A few weeks ago at the ARNSW Dural site I was talking with Mark Blackmore about the classic radios incorporated into the VK2WI broadcast building. He showed me some beautiful Collins receivers and some Racal sets. Also occupying a position on the equipment rack was a very shiny Kingsley AR7, the famously unauthorised copy of…

  • British Amateur TV Club

    This is the day I joined the BATC which must surely be one of the best value amateur radio groups in the world. They produce a professional colourful quarterly journal CQ-TV with top quality practical technical articles and manage a growing global community of amateur TV enthusiasts. The BATC has become a focus for effort…

  • Vertical antenna for 15m

    Our small group of CW ops and learners meets on a weeknight on air but have found it hard to find a band that works for all of our group. The logical choice of 80 or 40 is considered out of the question for the apartment dwellers. So we’ve looked at using the upper HF…

  • Australian Code Breakers

    On Wednesday evening I went along to a talk at a nearby library by David Dufty about his recent book ‘The Secret Code-Breakers of Central Bureau – How Australia’s signals intelligence network helped win the Pacific War’ published last year by Scribe. It’s a great story that does uncover previously unacknowledged contributions. Dufty’s interest was…

  • Learning morse and touch typing in tandem

    I’ve been wondering whether I should try to synchronise my most recent efforts at learning and improving my morse with a similar complementary neural mapping exercise of simultaneously learning to touch type as I practice copying morse code. I was googling around – on the off-chance someone had developed the ultimate piece of software which combined…

  • K3 and digital modes

    Using WSJT-X as my example digital program, here are the steps to getting digital modes to work with the K3 using an external sound card, the ASUS U7. The process is almost identical to the one I use with the KX3, an external soundcard dongle and a MacBook Pro. First, it is simple and easy…

  • The book I’d like written/to write about FT8, WSPR & other digital modes

    I’ve spent the last couple of weeks spending some continuous and focused time finally getting some consistent results out of my radios using digital modes, especially WSPR and JT8 using WSJT-X. Like everything else I do with ham radio, they reveal the woeful inadequacy of my antennas here. In fact, one of the benefits of…

  • Magnetic Loop – step by step

    Well, the replacement stepper controller chips arrived early this morning. Didn’t take too long to replace them and connect everything up for a test. The good news is that after a slight adjustment of VR2 the stepper appeared to be controlled by the rotary encoder. It made the right noises. Try as I may, I…

  • Magnetic loop progress

    Finally found some time to re-orientate the two transformers. I decided to remove the eight bypass 10nF capacitors to give my soldering iron more wriggle room to remove the transformers. The solder on the transformer pads needed some encouragement – in the form of more molten solder – to loosen up. This allowed me to…

  • Magnetic loop fault finding breakthrough

    Maybe my mistake has been not to refer more directly to the actual code. Over the last 24 hours I have been steadily working through the last two years of email conversations. Loftur keeps the group informed of each new version of the firmware and the newly added features. Sometimes he jumps the gun, but…