Carriacou Diary: Jonathan Hare

Day 9 — Weather

The w(h)eather or not challenge

Felt disappointed and even slightly confused about the challenge from the start. Even if we can make the equipment in 1-2 days what good are only 1-2 days of observations? This needed some talking about and I don't think it ever happened properly — it's probably the only challenge where I felt things were not feasible from the start. So what did they actually want?

Mike and I started to design and make up some of the various bits and pieces that a weather station might use. Barometer, hydrometer, wind speed device, rain gauge, thermometer etc.

I started on the barometer. Made up a U tube with water and used it to show Kate that the air pressure is due to the weight of air above our heads pressing down. So we go to the top of the lime factory and set the barometer and then go down to the sea and notice that the water level in the device has changed.

Now the density of air is about 1000 times less than water. So we need 1000 times less water height to balance the same mass of air. So by going 10m up (or down) in height the water barometer should change by 10m / 1000 = 0.01m = about 1cm, which it did - lovely piece of science. Can use this to measure the rough height of mountains etc.

Start on the wind speed / direction device. I spend too long trying to get the first design to work. The design works like this:

There is a flap that is attached to a wind vane. The vane makes sure the flap is always pointing into the wind. As the wind blows, it pushes the flap which by a string and lever mechanism moves a pointer fixed on the support pole. The problem which I wasted so much time on was how to get the pointer mechanism to move around with the rest of the gear and still work OK.

After several hours I drop this design for the more usual spinning half ball design. This worked very well (although the wind was sporadic and not good for testing it!) but how to get a scale or metre set up on it?

Day 10 — Weather

Spend too long today trying to get the wind speed dial to work on the anemometer. Lost hours making up all sort of cogs and wheels, slip rings and spring driven tension dials etc. Just could not make it work with bits I had at hand. I think the mixture of tiredness and excessive heat over the last two programmes is making us all slower.

Finally get the barometer, windspeed (and Angie's egg timer to count rotations), hydrometer, thermometer installed in the 'weather station' and start to make our first measurements. Do a spoof weather forecast with Mike B.

Watched Mike L and Ellen being filmed doing their bug experiment. It was a quiet shot so I could not go very near to hear what was happening — looked very interesting.

Kathy makes a wonderful microscope from a bead of glass. It was amazing what could be seen. She put in a mosquito and managed to get in focus the leg of the creature. I looked in and could only see a massive black hairy piece of wood — "No," says Kathy "that is the mosquito!". It must have had good magnification.

Kathy's Microscope

The tight spherical surface of a glass bead drop
Clear light directed and refracted to a spot
Insect leg, onion cell or salt crystal small
Using this device reveals them all
A skilful hand and curious mind
Amazement and wonder all the time.

Day 11 — Weather

Mike B and I do a few 'sound-overs' to explain the weather bits and pieces: chaos, predictions, modern computer set-ups etc. Mike makes a much better rain gauge device and we start to record these results.

David Shulman takes me and the crew up to Gun Point to film the wind speed device being calibrated or at least shown to be working (the wind at the lime factory is sporadic, the place being sheltered). Really windy here — the thing works great. This was one of the nicest moments of the shoot for me so far. It was a bit of calm 'windiness' during the hectic recording, I think because I got away from the factory for a moment.

On the way to Gun Point we had to travel along some narrow muddy tracks to the other side of the island, some of which are quite high up the hillside. On one of these tracks we came across a boy in a car almost toppling down the steep slope. Derek asked how old he was and he said he was 12 years old. It turned out that he had taken his dad's car out for a drive, had decided to turn round on the narrow track and had run off the road. We had arrived on the scene to this sweat-covered boy who had obviously been trying for a while to sort the problem out on his own. Luckily the four of us managed to right the car and his day was saved!

The day ends with Mike L going through the results of his Bug experiment. Really nice ending. Everyone seems to be mellowing out. Had a great evening at the Green Roof restaurant just down the coast from the hotel.

Day 12 — Rest Day

David, Mike L, Kathy, Angie and I go out to see Gun Point and also the mangrove swamp on the North of the island. I am very, very tired today. I even fall asleep in the mangrove swamp - which might be a world first for a human!

Get a dose of the blues this afternoon. Really don't want to go to the band tonight, even the beer didn't help or even taste any good!

Day 14 — Transmitter and Receiver

The human guess to the constitute of things,
Is that atoms form clusters, sometimes in rings,
Electrons are part of this complex world,
Their influence is all pervading, amazing to behold.

Around an electron is a field of electricity,
When it is moved it also creates magnetism, initially,
At a flick of a switch and in the wire,

At the speed of light too fast to conceive,
They travel through matter it's hard to believe,
And by changing their strength or even their vibration,
A word or news can be conveyed as information.

Marconi's dream and Maxwell's brilliance,
Has saved lives at sea, sometimes at an instance,
Inventions such as TV, radio and mobile phones -
Just a few examples that will continue to fill our homes.

Slept 11 hours last night! I think that accounts for the blues yesterday — I was exhausted.

Kathy and I take on the transmitter challenge!! Have a really great creative day today as we had loads to do. Also the good day seemed to be the same for everyone as we all seem to be on top form. Manage on first day to make the basic transmitter and Kathy almost finished the receiver. The receiver will have two types of detector and so the design has taken a little longer. We are in the nice position to start testing the two together tomorrow.

Reggie came along last thing to pick us all up in the minibus. He had a medium-wave car receiver and so we turned it on. Could just about hear the transmitter buzzing away. I was a bit disappointed as I had expected much more of a signal. By the end of the day K and I were feeling knackered. We were both picking up bradawls and trying to use them as screwdrivers and generally going a bit fuzzy with all the efforts of the day.

Day 15 — Transmitter and Receiver

Another creative action packed day for the two of us. I make up a morse key to operate the transmitter. K and I set up the antenna and the transmitter and receiver on the sea front so that we can use the sea as a good connection to Earth. Razorblade detector did not seem to work but the coke did! K very happy.

By the end of the day we were in a position to try out the transmitter near to the receiver but even just ten feet between the antennas produced no result. It was near to the end of the day and as an experiment we tried out one of the three or four other alternative coils for the transmitter. The largest winding coil we found worked! So we dragged back the film crew and got them to film the first working test runs with the set-up. Great way to end the second day.

Big coil or small coil?

The transmitter we built was a spark gap transmitter. The small coils we used (i.e. using only about 100 turns of wire) made the greatest spark and so naturally we thought this would mean that it would be best for the transmitter. However, it seems that a spark is not enough — it needs to be a high-voltage spark. The smaller coils seem to produce a large spark but I would guess that it is a low-voltage, high-current spark. There's loads of power in this spark but it is mostly heat and light and it seems to have very little radio energy.

The larger coil produced a smaller spark but the coil produces a high-voltage back which makes the spark a high voltage spark. You can see that there is a difference in the colour, presumably because the high voltage breaks down the air to produce ozone and other gases that the lower voltages can't do. So the large coil won the day.

Day 16 — Transmitter and Receiver

The first half of today was quite stressful. Time seemed to be going away from us and the transmitter, antennas and receiver modifications and the tens of other things to do weren't getting finished. This was partly because other filming had to be done and we could not make too much noise and also because they needed to film our steps and results. A major reason was also because we were trying again and again to get the transmitter to work better — and failing.

K tried out a step-up-transformer using the buzzer coil as a primary and a much larger secondary coil around it to produce a step-up in voltage. But all our attempts failed to step up to any reasonable degree. We were having problems with the coupling efficiency between the coils and losing all our power! Instead of getting a step of x10 or x100 we were getting x2, which was basically useless. The sun beat down and we were getting tired. Thinking slows down and we all become less efficient. The challenge of sending a message over a distance seems far off.

We try out a much larger step-up coil having 1000 to 1 step-up. This worked much better but even this was having problems. We rigged up a simple spark gap and every so often we would get a decent spark but then minutes would go by with nothing. It began to dawn on us that the humidity was partly the problem. In some ways high humidity makes sparking easier but in this case it was causing very small sparks and losses in the air well before the voltage had time to build up to the level it could do. Consequently we were missing our potential.

We all stopped for lunch to have a break and think about what could be done. I started to think about what was happening in the spark. I would guess that the buzzer starts to spark immediately the connections separate and the screw comes away from the bending saw blade. In the first instance the gap is incredibly small, perhaps a millionth of a metre. So in this case even 1 volt across this gap would produce 10,0000V/m electric field and spark.

As the blade moves away a little more, the air is hot and electrified and passes current (due to the ions made in the initial spark) and this continues to spark as the gap increases. So it is possible to have a low voltage spark this way. Our thought was that it might be possible to add the high voltage produced by the step-up coil into the lower-voltage spark. In the end we found that we could use the vibrating saw blade not only to form the buzzer circuit but also to kick-start the high voltage spark into action. With another screw attached to the saw blade and the connections wired up carefully and in the correct way we got our high voltage spark gap transmitter to work!!

Kathy and I, Derek and John put up another large antenna for the transmitter and used the previous antenna for the receiver. They were fitted about 40m (44 yards) apart and they worked — just about. The signals were tiny in the earpiece and softer than the sound of the wind or the crashing of the waves.

The final scene

After the time signal has been sent by the two Mikes, Kathy sends me a secret morse code message, while I sit trying desperately to hear the morse above the background noise! I could not do it. I ask Kathy to send it faster. Suddenly it was much better. I hear Y .. , then Y. S, definitely an S at the end. Then I try perhaps three or four times to hear the middle letter. Sounds like a dot which is an E. Longer letters such as Y -.- - are in some ways easier to hear because you realise the first dot or dash has passed with the quiet succession of the others. E is therefore rather difficult. Kate ends up coming and saying "Jonathan, what else can it be?" I had been concentrating so hard I hadn't even thought about the word. Of course it was YES! This is really a high. I've been learning morse since Christmas and my first ever live test was done on TV!!

Paul tells me later that all the while this was going on the religious radio programme in the background of the radio reception was talking about circumcision and damnation!! I was concentrating so hard on the morse that I missed all this, otherwise I would not have kept a straight face!