A good turnout came to hear Donard, M0KRK tell of the history of under sea cables and the part James Graves played in their success. It appeared from the start that Donard knew more history of the man than expected, then he told how he was a descendant of James through his wife’s family. As a result, he had access to a very large pile of James’ technical papers.
Donard explained that in the early days of undersea cable, little was knows about the problems about to be faced. It was a completely different story from over land cables, A quick search will show there were many highly skilled and educated men working on the project, which in the end produced a result, overtaken only by the use of long range radio. Having said that, undersea fibre optic cables now carry gigabits of internet information around the clock
The evening started with an introduction to the Centre from Martyn G0GMB in the reception area. The Centre reception has been sympathetically designed to fit in with the main theme of Bletchley Park and the work done during the war. There are HRO, AR 88 and special SOE transmitters. Other items on display include letters to members of the VI from the RSS telling them what frequencies they need to monitor, so very much in keeping with the WW2 theme.
Tea, Coffee and biscuits were provided and served by Carmen so we were all refreshed ready for the tour.
As you work your way through the centre you are presented with different displays outlining the development of radio with images of inventors and scientist associated with radio as well as some of the equipment they would have used at that time.
After this corridor of history you have working displays on how some of the main principles of communications work. This area enables visitors to get hands on and experience some of the methods used in radio.
As you work your way round the centre you can not help hear the sounds from the GB3RS station, which uses several different pieces of equipment from some of the main manufacturers who have donated a lot of the systems.
The volunteer operators helping out this evening were Brian, Eric and Tony, who managed to answer most of the questions from our members on the equipment the modes used and the various screens showing where signals were coming from. There was some interest in the FT8 mode, which seemed to be receiving many signals from Europe and elsewhere.
Lots of the systems were computer controlled and everything was on large screen displays showing the grey line map of the world and locations of incoming signals. The station was very well set-up and we all managed to get a chance to see how some of the systems worked.
The evening ended with the club’s usual round of applause and thanks to all the volunteers for their hard work and for giving up their time for our visit.
Martyn said that the Centre relies on volunteers and if anybody was interested to contact the RSGB web site for information.
Last night’s presentation was all about CCTV security systems for use in both commercial and domestic situations.
John brought a selection cameras and storage systems which use the latest technology.
These systems include the use of Internet Protocol controlled cameras of various types enabling users to monitor their premises in colour with controllability enabling panning and zooming in on specific situations.
Other cameras use coaxial cabling, which relies on having a local power source, while the IP network provides power to the cameras up to 100 metres.
Normal monitors enable the images to be seen and computer based storage devices enable up to 15 terabyte of data to be stored.
Members had several questions relating to what effect there would be on radio systems and noise from powers sources.
The turnout for our Spring Junk Sale was very good, we even had visitors from other local clubs! However as always, the ‘quality’ of the junk was variable. This year we had a few too many books and magazines and not many ‘heavy pieces’ to take home. There were lots of bags of components but, as elsewhere in the hobby, they are not so much in demand anymore. Still, the evening was considered a success and a good chance to meet up and have a chat.
The meeting began at 20:00 with apologies for absences; there were none. The meeting followed the usual sequence without delay and Victor, G3JNB was asked to take the meeting for the election of officers and committee members who were returned unopposed.
The meeting ended with the presentation of cups and plaques:
Kit construction Martin, M0XMP received the DR. Little cup
Weekend Special Don, G4LOO received the G2DPQ cup
Club Support Don, G4LOO received the G3JKK shield
Best Talk by a member, Richard, G3NII received the G4CBI cup
The Bryan Bourne Quiz trophy was won by the ‘Brewery Tappers:
Don G4LOO, Brian G8GHR, Richard G3NII and Paul G8UIG (not present)
The evening began with a YouTube video by Randy, K7AGE who gave part one of his introduction to Arduino.
Martin then followed with an explanation of what he wanted to achieve and how he went about it.
On display was a large Mag-loop aerial and it was pointed out that tuning by hand wasn’t an option, not only because it’s not healthy to be near a transmitting loop, but that the tuning changes when the operator moves away from the aerial. Martin produced an ordinary TV remote handset and explained how he used the Arduino to decode the output from each button. That output was then used by the Arduino to control a stepper motor which turned the tuning capacitor and thereby achieved a degree of remote control. Martin explained the programming needed to achieve this outcome. However, he felt the tuning didn’t have the feedback necessary for fine tuning as he listened to the background noise rising and falling on his rig. He did admit to have previously tried using a servo to turn the tuning capacitor and felt that offered a better feel to achieve resonance since using a knob for tuning in place of the TV remote offered better feedback.
Martin felt that both methods had led to considerable scope for experimentation in mechanical and computer science.
This evening’s discussion was all about how members choose and maintain their antennas. A variety were talked about. Most members are using wires, either dipoles, doublets or untuned and tuned lengths, but there was one notable inclusion of two verticals which were home brewed by spiral winding wire around the vertical support and feeding above ground level and having sloping radials. This has proved to be a very successful arraignment for working real DX with low power.
For maintenance, various products were suggested for anti-corrosion connections and protection against moisture ingress.
Discussions continued through the tea break before members headed for home.