Author Archives: Andrew Thornton

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.

Summer Hiatus and Nets

Please note that CRDARS does not meet during the month of August. Our next meeting will take place on Wednesday 5th September.

Some of our members have suggested a club net during the summer break. We’d recommend listening out for fellow members on the 1st and 15th August on the GB3IR repeater (145.7625) at around 19:30.

Planning, equipment and finances

At our last meeting on 16th May, some more discussion took place regarding the future of the club.

Finances have been tight lately, with the club making a net loss on many of our recent meetings. This is due to a combination of a more expensive venue, increasing costs and a slight drop in the number of members attending on a regular basis. It has been suggested that the cost per meeting be increased to £3 each, and there has also been a proposal to increase annual membership fees from October. Our Annual General Meeting is provisionally scheduled for 3rd October, and we expect to formally put these proposals to our members during the AGM.

We’re keen to have radio equipment available for use at our future meetings. To tide us over until Dave has chance to repair the Yaesu rig, Richmond School has offered to provide an ICOM IC-735 on loan. AJ has also offered the club a 2m radio, which should allow us to establish a regular presence on VHF.

Once we’ve got an antenna permanently erected, Colin is keen to do some more promotion of the club, through local media such as richmond.org and Richmondshire Today. Chris Watkins has offered to set up a YouTube channel, giving us both a promotional platform and somewhere to preserve footage of some of the club’s activities. Colin also intends to begin promoting Jamboree on the Air within the Scouts, and has suggested hosting the event up at Hudswell this year.

Finally, we’ve got a couple of presentations scheduled for the meeting calendar. A few members have expressed an interest in C4FM and HF digital modes, but aren’t really sure how best to get started. A couple of members have therefore offered to “have a go” at home, and provide some demos showing what they’ve learned. We’ve had a look at some of the more interesting capabilities of these modes in the past, but we’d like these events to be a bit simpler and more practical, in the hopes that we can get a few more people “over the hump”, and get them up and running with these modes. Dates are on the meetings page.

Antenna Installation and Meeting Planning

With the weather finally having made a turn for the better, Wednesday’s meeting turned into an impromptu antenna mast installation session.

Dave was hard at work up the ladder, installing brackets and attaching our mast, whilst the rest of us held ladders, passed parts, and provided constructive criticism/moral support.

If the weather permits, we’re hoping to carry on with erecting antennas at the next meeting on the 2nd May.

After the sun went down and members retreated inside to enjoy a tea or coffee, some discussion took place regarding our upcoming meeting schedule. Some of our members are reaching out to possible guest speakers, and a few other ideas for activities have been suggested.

With most of the proposed ideas being dependant on other people’s schedules, we’ve decided to hold off putting together a formal events programme for a few more weeks, giving the people involved some time to figure out feasibility and availability. We’re now planning on holding a more formal planning meeting on Wednesday 16th May, when we hope to finalise a schedule for the rest of 2018. If you’re able to attend the meeting on the 16th, please come and have your say.

Upcoming Events

Colin has arranged for CRDARS members to give a practical demonstration of amateur radio for the Brompton-on-Swale Scouts on the evening of Tuesday 24th April.

Mac and Andy will be on site at Brompton-on-Swale Community Sports Hall. Several other members, including Chris and Dave have offered to help by being on air on HF and/or 2m so that we have some guaranteed stations to work on the night.

Plans for the night are still being made. We’ll update the news page once we know exactly what’s happening.

If any other club members would like to assist on the 24th, whether in person or on air, please contact Colin as soon as possible.

CRDARS has been based at Hudswell Village Hall for several months now, and it’s getting to the point where we really need to start putting together an event schedule to take us through to the summer. As a result, we’ve provisionally designated the 18th April meeting as a planning meeting to try to get some activities scheduled in the calendar. If you’ve got any ideas for club activities, please have them at the ready for next Wednesday.

Congratulations and Thanks

Congratulations to Kevin for passing his Foundation examination. We hope to hear you on air with your new M6 callsign over the coming weeks.

We’d also like to extend our thanks to Peter, G4VUN, for his donation to the club. Many thanks for your support, we really appreciate it.

UKEICC 80m SSB Contest

During our 7th February meeting, several of our members participated in the UKEICC 80m SSB contest.

Members participate in the February 2018 UKEICC SSB contest. Photograph by Chris Watkins.

Under Chris Kirby’s guidance, several of our members managed to achieve a total of 18 contest contacts during the 60 minute contest, using 100W and a G5RV. Our longest distance contact was with H1G1, a distance of approximately 1500km.

Overall, this put us in 42nd place in the contest, out of a total of 58 entrants, which is pretty respectable for a fairly casual first effort. Results are available on the UKEICC contest results page.

Hudswell Meeting Dates

Our next meeting will take place at Hudswell Village Hall on Wednesday 7th February. All of our regular club meetings will take place at Hudswell from now on. I’ve updated the meetings page to include dates up to the end of 2018.

Our events programme is yet to be determined, and will be decided by our members over the coming weeks.

Our examination venue is still Colburn Village Hall, and we will continue to hold the amateur radio exams at Colburn for the foreseeable future.

Changes to January/February Meeting Schedule

Dave has been busy arranging our new meeting schedule at Hudswell. We now have confirmed dates for our move to Hudswell, and our meetings page has been updated.

Please note that we have one remaining meeting at Colburn Village Hall on the 25th January. All other meetings will take place in Hudswell on the first and third Wednesday of each month.

Hudswell move in February

Colin currently intends for the January 25th meeting to be our final scheduled meeting at Colburn Village Hall. From February onwards, we expect all of our meetings to be held at Hudswell Village Hall.

Please note that our published meeting dates for February/March are expected to change, as our Hudswell meetings will probably not take place on a Thursday. Once the new dates are finalised, we’ll update the web site accordingly.