Category Archives: Talks

A Life in HAM Radio, by Peter, G4VUN

On Wednesday 19th June, CRDARS hosted a talk by Peter, G4VUN, on his experiences in amateur radio.

Peter brought along a variety of classic radio equipment, including second hand and ex-military transceivers and ATUs that had been repurposed for use on the amateur bands. He was keen to point out that he’s had many successful contacts with people all over the world, using cheap equipment and simple wire antennas, fed with ladder line. There’s plenty of older but perfectly serviceable equipment in circulation, and getting started with amateur radio doesn’t have to cost a fortune.

Peter was also keen to discuss the challenges facing amateur radio in 2019, from weak propagation and high levels of noise to the lack of apparent activity on many of the amateur bands.

All present were encouraged to get on the air and operate as much as possible. Whether by calling CQ, or coming back to other people’s calls, any activity on the bands is welcome, and the more people we have making even basic, boilerplate contacts, the better.

When it comes to HF, Peter recommends taking the time to check whether the higher frequency bands, such as 21 or 28MHz are open, as propagation may be possible even if the band appears to be dead. When it comes to the 28MHz band, Peter suggests tuning down and listening for Citizens Band signals around 27MHz, as if the CB users’ signals are propagating, there’s a good chance that the 28MHz amateur band is also open.

Regardless of our individual opinions on amateur radio, the evening was certainly thought provoking, and prompted some interesting discussion. On behalf of our members, we’d like to extend our thanks to Peter for coming to visit, and for his perspective on our hobby.

Upcoming Talk “A Life in HAM Radio”, by Peter, G4VUN

On Wednesday 19th June, Peter, G4VUN will be presenting a talk “A life in HAM Radio”. We hope that many of our members will join us for what will hopefully be a fascinating journey through everything Peter has experienced during his many years as a radio amateur.

As always, our Meetings page is where you can find full details of our upcoming events programme. We’ve got a few other guest speakers pencilled in between over the coming months, and we’ll be updating the web site once we’re able to confirm that they’re available.

Summer 2019 Events Programme

The proposed calendar of club events is now available on our Meetings page at Between now and October, we’re hoping to have presentations by several guest speakers, participate in a 6m contest night, and try our hands at Amateur Radio Direction Finding.

We’re still checking the availability of some of our guest speakers, so please watch this space, as we’ll be updating the calendar once we receive confirmation that a particular talk is going ahead. Some upcoming events will not be taking place at Hudswell, so please keep a close eye on our Meetings and News pages, as we’ll be posting meet up times and locations closer to the day of the event.

In a change to our usual routine, we’re planning on adding an extra date to our calendar on Thursday 11th July for the RSGB 6m contest. The usual July meetings on Wednesday 3rd and Wednesday 17th July will go ahead as normal in Hudswell.

We currently intend to hold an Amateur Radio Direction Finding event on Wednesday 21st August, at a location yet to be determined. Please note that there are no meetings at Hudswell Village Hall in August.

Finally, please note that the date for the CRDARS AGM has provisionally been set for Wednesday 2nd October at Hudswell Village Hall.

Optical Communications using Lasers

On Wednesday 20th March, the club hosted a very interesting talk and demonstration by Charles, G4DXP. Charles has been experimenting with line-of-sight transmission of audio, using lasers and pulse width modulation. He brought along his two home-built laser transceivers for members to play with, and gave us an explanation of how they work and how they are constructed.

Charles’ laser transceivers are based on a design by Ron Jones, K7RJ, and are elegant in their simplicity. In fact, most of the complexity in making the system work is in finding a reliable means for aligning the lasers over long distances, rather than in the electronics.

If you’re interested in trying to build something like this, always remember that even low power lasers can be hazardous. Never use a laser in a way that might endanger another person, or where the beam might come close to anyone’s face. Many countries have legal restrictions on the use of lasers, so do your research before buying or using any laser light sources.

Charles clearly loves his construction projects, as he also brought along a differential windlass that he’d built for members to have a play with.

On behalf of Colburn and Richmondshire District Amateur Radio Society, we’d like to extend our thanks to Charles for taking his time to come and visit us, and show off his various projects.

Upcoming 6m VHF Talk (17th October)

On 17th October, Clive (G4FVP) will be giving a talk on the VHF amateur bands. Clive has a reputation for being extremely knowledgeable when it comes to VHF, and the 6m amateur band in particular. If you’re interested in taking a step beyond basic “line of sight, plus a bit” FM contacts and would like to explore more of what the VHF bands have to offer, this is an opportunity to learn from one of the experts.

We’re always happy to see new faces at our club meetings, so even if you’re not a CRDARS member, you’re more than welcome to join us for what will no doubt be a very interesting evening.

HF digital modes talk postponed

The proposed beginner’s introduction to HF digital modes, originally scheduled for 19th September has had to be postponed.

Both Andy and Martyn were originally planning on experimenting with HF digital modes (such as FT8 and PSK31) from home, with the intention of providing a practical demo of what we’d been doing and what we’d learned along the way. Unfortunately, we’ve both run into problems getting our rigs, interfaces and software to communicate with each other, so neither of us have had any real success so far. We’ll both continue to experiment, and hope to be able to reschedule our demo for a future date, once we manage to get the kinks ironed out.

In the meantime, several club members have offered to assist with getting the club’s G5RV antenna erected so that it’s available for members to use during our weekly meetings. We’d like to extend a big thank you to everyone who’s offered to assist, and we look forward to reaping the benefits of a permanent antenna in the not too distant future.

C4FM for Beginners

On 18th July, members were given a beginner’s introduction to simplex operation using Yaesu’s C4FM (Fusion) digital mode.

Yaesu have an introductory video for Fusion, which I found quite helpful when preparing for the talk:

In the UK, 144.6125 is designated as the 2m digital calling channel. Use this for CQ calls using C4FM or other digital modes. Once you’ve established contact, move to a standard FM simplex channel, or use the all modes section of the band. The 144.6375 – 144.7875 range is recommended.

Most Yaesu C4FM radios are capable of five different modes of operation:

Mode Appears as Used for
FM FM Conventional FM for communication with non-digital users.
V/D (Simultaneous Voice and Data) DN Error corrected digital voice. This is the “normal” C4FM mode.
Voice FR (Full Rate) VW Higher bitrate digital voice, allowing for better audio quality when error correction is not required.
Data FR (Full Rate) DW Sending text or images between C4FM radios. You cannot select this mode manually. Your transmitter will automatically switch to this mode when you use a feature of your radio that requires it.
AMS (Automatic Mode Select) Bar above active mode The radio will transmit using the displayed mode, but will automatically switch to other modes upon receiving a transmission using one of the other modes.

The following two videos provide an introduction to analog to digital conversion, and to digital error correction techniques.

A few things to take away from these videos:

  • We need to sample our audio at twice the highest audio frequency we wish to transmit.
  • We have a fixed amount of bits that we can transmit over a 12.5KHz FM channel.
  • Higher audio quality requires more bits to be dedicated to audio data.
  • Error correction requires more bits to be dedicated to checks on our audio data, at the expense of audio quality.
  • We have to make trade-offs between audio quality and reliability, hence the two different voice modes with different priorities.