A nearly full house heard Paul Hyde explain that it was more than 83 years since Paul Jansky began investigating the static which was proving problematic to transatlantic radio telephony in 1929.    Jansky had built a large receiving array to scan the skies in an attempt to find the source of the noise. Apart from static from thunderstorms there was an emission from the sky near the location of Sagittarius. Other astronomers couldn’t accept the finding, but in1940 another astronomer,  Grote Reber  ( W9GFZ) from Chicago published his findings from his 9 meter dish at 160MHz. Jansky and Reber went on to map the sky and the first survey was published in 1944. Radio Astronomy as we now know it was underway, except that findings made during ww2 were classified and many who worked in astronomy were put to work in Radar.

Paul detailed the work that continued during and after the war which improved reception and resolution. It was explained how several aerials could be used at once and the results joined in a Correlator, a powerful computer able to combine the signals into one output. More signal sources in space were found and investigated resulting in discoveries of  Pulsars, Blazars, Quasars and Radio Galaxies. Doppler Shift was discovered and how to make use of the Hydrogen lines on the spectrum.

Paul pointed out that as of 2003, Astronomers knew that in the Universe Dark Energy amounted to 73% and Dark Matter to about 22%, which leaves us knowing about the remaining 4%!

David, G8UOD reports that the Saturday visit to  Mullard Radio Astronomy Observatory went very well. We were given a brief history of the site from the war through to becoming a site for antennas to monitor the skies.

We were shown the museum, which is quite small, but had some interesting items from the early days, including part of the German radar equipment, which was initially used with some modifications.

We were shown several of the arrays, including the one mile and half mile antennas and the 4C array made of conventional structured antennas, only lots of them.

The last time we visited the site was back in 2003 and the long array of dishes on the old railway line have now been clustered as the technology now available enables the University to do the same job as the old. We visited the millimetre antennas which were being built the last time we visited.

Peter was a very good host and we all enjoyed ourselves, although some would have liked a bit more info on what the information received was used for, but Peter pointed out that he was an engineer and the academics at the university would have to be the ones to give that information.

The tour started about 11.00 and ended at 14.15.  I thanked Peter on behalf of the club.   All in all an enjoyable experience.

On the evening of the UK referendum, four members turned out for the Summer 2m DF hunt. Although it had rained during  the day, the evening looked to be better.  This year the ‘Fox’ was Paul, G1GSN who started transmissions at 20:00 but couldn’t be heard very well. After a few more tries the transmissions improved and the hunters were off. Of course, the winner would be the person who drove the shortest route to the fox and not the first to arrive.

Martin, M6SCI assisted by Ian, G3ORG found the fox after having driven only 4 miles! The final tally showed that David, G8UOD had driven 5 miles and Derek, M0DLM had driven 6.

It appears the initial problem with the transmissions was caused by the dense and very wet foliage where Paul had parked up opposite the Southill school.

The group retired to the Brewery Tap for discussions and a drink.

A General Discussion took place, mainly about the future of the club’s participation in 48 hour contests. David kept a ‘pro and ‘con’ tally on a white board. It did seem as though the ‘cons’ had won the evening, although the entire membership was not in attendance.

Don, G4LOO started his presentation by making certain every one knew the dates of the contest: 2 – 3 July.  We then looked over last year’s results to analyze the data band by band to highlight errors.  Don also showed our position in relation to others who entered the same sections. He then went on to outline our entry for this year. The equipment needed for each band was listed and discussed. Last but not least, the rota was passed for members to sign up as operators, selecting their time and band choice.

A good turn out heard Brian explain the need for a WW2 system to achieve greater accuracy in the Anti-aircraft systems. The equipment needed to track a moving aircraft was complicated by the typical shell time of ten to twenty seconds and the need to predict the movement of the target.

By 1940 various systems such as photo sensors, electrostatic or magnetic field sensors were tried buy found wanting. Fortunately, Three British men, Butement, Shire and Thomson of The Air Defence Experimental Establishment suggested a CW oscillator in the shell with a circuit that would measure the Doppler effect of a reflected signal from the target and trigger the explosive shell.

However, Britain did not have the resources to produce the fuze in sufficient numbers and the decision was taken to send the design to the USA as part of the ‘Tizard Mission’ since the USA had the industrial resources to exploit the military potential of the British research.

The system was used with very little modification and in combination with the SCR 584 ten centimetre tracking radar was considered the most important development in WW2 after the Atom Bomb.

We had an eclectic mix of subjects starting with two short videos that explained the rationale behind the planned Square Kilometre Array Radio Telescope being planned by a consortium of countries.  Whilst 10 member countries are the core of the SKA, around 100 organisations across about 20 countries have been participating in the design and development of the SKA and are now engaged in the detailed design of the telescope.

To quote The Guardian: The Square Kilometre Array (SKA) is a huge project designed to sweep away many of the current roadblocks to astronomical progress. These include searching for the first celestial objects to form in the universe, investigating whether we need to develop a new theory of gravity, and looking for the building blocks of life in space.

Another short video showed the Intrepid-DX Team and their journey and operations on South Sandwich Island. Amongst hundreds of penguins, the team set up antennas on the rocky ground soon to be covered with a deep layer of snow.  The total number of contacts made were 54,641 between January 18 to January 25.  Not shown was their QSY to South Georgia where they did it all again!

In order to get back to some warm weather, the next clip was about the 2009 DXpedition to Midway Island.  The emerald blue sea has to been seen to be believed. The pileups were as big as ever for a major DXpedition.

Ian  reporting on the top band fox hunt last night:

The fox was in its ‘hole’ on the edge of ‘Bellcote Meadow, Millennium Green Breathing Spaces’ This is a recreational area behind the houses down Purcell Way which is off the Clifton Road Shefford, slightly east of Hong Kong House Chinese takeaway.

We were found by a single hound in 34minutes (2034 BST) whose name tag read Alan G4PSO. The remaining hounds were found eventually by the fox where they were rehydrating themselves in the Brewery Tap.

Rig comprised Kenwood TS-480 25 watts to a centre loaded whip on a steel base plate and mat of chicken wire.

Ian, G3ORG (fox 1)  and Martin, M6CSI (fox 2)

Gareth, M5KVK  began by saying his talk would focus on US space probes starting in 1958 with the launch of the sub orbital Explorer satellite which resulted in the discovery of the Van Allen Belt. He then detailed each launch through the years and how each built on the knowledge learned from earlier flights. How the problem of a power supply was solved for use beyond the influence of the sun and how communications had to be improved to cope with the increased distances when images can be as large as 10Mb each, which explains why they take so long to be transmitted the almost five billion miles to earth!

On July 14 the telescopic camera on NASA’s New Horizons spacecraft took the highest resolution images ever obtained of the intricate pattern of “pits” across a section of Pluto’s prominent heart-shaped region, informally named Tombaugh Regio. The image is part of a sequence taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) as the spacecraft passed within 9,550 miles (15,400 kilometres) of Pluto’s surface, just 13 minutes before the time of closest approach.

The Hall was being used for local elections.