Bramble Bank

Covid lockdowns changed our behaviour patterns in many different ways. On the Isle of Wight, Radio Society members took to the airwaves as never before, replacing physical club meetings with well‑attended nets; and so did our neighbours at the Fort Purbrook ARC. Almost immediately, these nets collided and, in a spirit of friendly co-operation, became a joint net; controlled by each club on alternate weeks. The combination was soon christened The Bramble Net – a kind of polite nod to the fact that neither club actually ‘owned’ the joint net.

“Ho! Ho!” I joked on the IOWRS shiny new website (with tongue firmly in cheek), “If we’re going to call it The Bramble Net, then perhaps we should have a radio station on the Bramble Bank.”

“That’s a good idea!” responded our Chairman, “I’ll supply the boat.” (You can say that when you are a senior captain in a company that has lots of boats.)

There was no going back. My bluff had been well and truly called, and we had to make it happen.

Preparation – the secret ingredient

JOTA 2021 had given us an opportunity to meet local scout troops, and to show off amateur radio to many young people. The experience was clearly enjoyed by both sides, and some of the scouts had shown considerable interest in radio. Now, a few emails to scout leaders quickly identified two willing volunteers.

“You’ll need to be licensed,” I explained. “OK. How do we do that?” There was no time for the niceties of good teaching practice. I pushed a Foundation Licence Manual into their hands. “Read that and then sit the exam on-line.” It was a big ask. At just 14 years of age, our youngest volunteer had not yet covered some of the basic physics in school. But with gentle encouragement, a bit of support from the on-line invigilators, and a lot of their own hard work, both candidates secured M7 calls in the few weeks available before the event. ML&S recognised this achievement, and kindly gifted a Baofeng radio for use by our new recruits. Our Chairman kindly gifted a second radio.

ML&S also gave us a light-weight HF radio for the event, and a couple of our more-established M7s immediately began training on this, guided by one of our most experienced HF operators.

Happily, our operators were no strangers to boats. All had completed RYA courses and spent many hours on the water; but they were still novice radio operators, with no experience of handling the kind of pile-up that a special event station can attract. To help them cope, a team of more‑experienced operators would establish an on-shore monitoring and logging station, and be prepared to step in and act as net controllers if the need arose.

With both ‘wet’ and ‘dry’ crews now training for the event, attention to technical matters became a priority. Our crew transport was to be a repurposed lifeboat – an ideal craft which had been designed for beach launch and recovery. Its spacious cabin had room for all our equipment, and gave us options for on-board radio operation if the weather turned inclement. It also had an MF/HF vertical antenna, which was easily tuned to 40m. The aluminium cabin roof necessitated outside antennas for 2m and 70cm too, so we set to work building a couple of marinised SlimJims that would replace redundant marine antennas.

The plan for disembarked operation was quite simple. Operation on 2m FM simplex, and on 70cm through GB3IW, was to be carried out with hand-held radios. The HF radio would sit on a picnic table, with a tuned vertical antenna. A length of copper pipe driven into the sand, and a short earth lead, would ensure this rig was connected to the world’s best ground plane. What could possibly go wrong?

Well first, we had to disembark. The lifeboat drew about 1m of water, which meant that as the boat settled onto the sand on the falling tide, we should still have 1m of water all around us. We should then have to wait for the tide to fall a further metre before we could get off the boat and onto the sand. There would then be a ‘feet‑dry’ period as the tide continued to fall to a low-water point, and then to rise back up to our level. As the sand flooded, we should have to re-board the lifeboat, and then wait for the tide to rise another metre before we could re-float and go home.

How long would all this take? How long might we get on the sand? And what should we do if one of our crew became ill or injured whilst the boat was aground? We needed a detailed picture of the tide, but tidal curves are only estimates; extrapolations of measured curves from a few standard ports. As we pondered this point our friends at the UK Hydrographic Office came up trumps, producing high-resolution tide curves for us, which covered our landing area for the few days when a possible tidal window existed. From these curves we could see immediately that our time on the sand might be nearly an hour, whilst the aground‑but‑flooded periods before and after could each be as much as an hour and a half; a total period of almost four hours when there would be no possibility getting the lifeboat under way.

We clearly needed a safety boat with a very shallow draught; something like a RHIB. Now where would we find one of those? “OK, I’ll get you a RHIB as well … and I suppose you’ll need a driver for it.” “Yes, please! …and the club can provide a crewman.”

When it comes to marginal beaches, the predicted height of the tide is only part of the story. The actual height of the tide is also influenced by barometric pressure, and by wind. We needed high barometric pressure, with a light and variable wind which tended to be easterly more than westerly; and we needed a reliable specialist to advise us when, or if, that was likely to occur during our very limited tidal windows. Enter Jim Bacon, G3YLA, retired television weather man and consummate expert on the interactions between weather and amateur radio. “I can give you the bigger picture,” explained Jim, “and I can probably do that a few days in advance. But you’ll need to look at local conditions for the detail.” Perfect!

One by-product of Covid restrictions, which made few headlines, was actually a minor relaxation of restrictions: The Ofcom requirement for special event stations to be publicly accessible was quietly suspended, and remains so even today. There was thus no regulatory barrier to a special‑event callsign, and an NoV for GB1BB – the first station on the Bramble Bank – was duly issued.

Now all we needed was advertising, to make sure GB1BB had some stations to work when (if) we got out there. A short video for the IOWRS website started the ball rolling. “We have two possible shots at this,” I told members, “the first around the actual equinox, 19-20 March, and the second at the back end of the Easter weekend; but we need to be ready to go in March if the weather is OK, because the weather at Easter might not be OK – and we won’t know that so far in advance.”

With a couple of draft texts prepared for future GB2RS broadcasts (nearer the time), I felt we had done just about everything we could possibly do to be as ready as possible for the Bramble Bank endeavour. Endeavour was – appropriately – also the name of our lifeboat.

Post-event

Was it all worth it? Well, judging from the smiling faces around our club, and the new members we are beginning to attract, the answer must surely be “Yes!”

GB1BB was never going to break any log book records, but our ‘dry crew’ recorded 119 QSOs with 94 different operators. We thought that was not too shabby for three Foundation licensees who had an operating window of just under an hour – and who managed their own pile‑ups with minimal intervention from those ashore. To be fair, our ‘dry crew’ had been warming up a queue of stations, all anxious to work GB1BB, for some time before the SES opened for business; and on 40m the queue had to be deftly QSY’d when our now-battered HF radio became stuck on one frequency.

We should like to say a big “Thank you!” to all our sponsors; and to all the stations who called in, whether or not they made it into the GB1BB log. We have produced a special QSL card, and all the QSL requests from confirmed contacts have been answered.

It was a fun thing to do, and we have some nice pictures for presentations to scout troops, schools, and any other interested parties.

Would we do it again? Certainly not! We’ve done that now. Next time it will be something else that is novel and interesting – and maybe just a tiny bit whacky. Whatever that turns out to be, details will be posted first here on IOWRS.org So, watch this space!