Category Archives: Uncategorized

21 May 2015 – Development of VTOL Craft

The Harrier
The Harrier

The speaker for the evening was Alan Merriman who spoke of the development of Vertical Take Off and Landing aircraft from the flying bedstead through to the operational Harriers

Covered was engine development where the thrust to weight ratio became the idea for vertical lift.  The RAF became interested because of the fear that runways would be bombed and STOL and VTOL aircrafts could continue to be operational.  However, later development of the Tornado offered better load capacity and carried a navigator and all terrain radar.

Flying Beadstead, the Rolls-Royce Thrust-Measuring Rig (TMR), an experimental aircraft that was first flown on Aug. 2, 1954
Flying Beadstead, the Rolls-Royce Thrust-Measuring Rig (TMR), an experimental aircraft that was first flown on Aug. 2, 1954

 

14 May 2015 – Solar Panels by David, G8UOD

David admitted he wasn’t an expert on the subject, but knew there would be interest in the economies and perhaps, nearer to members hearts, the effects they can have on our hobby.  Firstly, he gave an insight into how they work and what they are made of. Then followed by explaining how they are used to efficiently create energy.  David detailed how solar panels are used in the domestic environment.  The cost effectiveness was explained, followed by small applications where they might be useful in amateur radio.

Most members are more familiar with the problems associated with them and David explained what can be done to overcome these issues. Particularly which standards should be sought and the consequences of not following them.

David's SME Inverter
David’s SMA Inverter

 

7 May 2015 – Election Day!

There is no club meeting this Thursday as the hall is being used for elections.      Next week, however, on the 14th of May, David, G8UOD will be telling about Solar Panels.

30 April 2015 – A Visit to Peterborough Radio

Shefford club member Steve Durham, M0DYR hosted a visit to Radio Peterborough to explain the ‘Hows and Whys’ of broadcast radio.

Radio Peterborough is a local community radio station based in Orton Malborne, Peterborough. They’ve been based in the city since 2010, with numerous successful restricted service licence broadcasts completed on 106.2FM. They continue to broadcast music on their website, just click the LISTEN LIVE button!   They want to become the local full time community radio station and have applied to Ofcom for the licence.

The station is a “not for profit” enterprise, and everyone who works for the station does so on a voluntary basis. Many of the city’s best known local radio broadcasters are on the airwaves to support the project. In addition many new voices trained by the station can also be heard presenting a range of programmes during the evenings and weekends. Radio Peterborough is always looking for volunteers to work both on air and behind the scenes – everyone is welcome to participate in this truly local community project.

Steve (right) explains studio operations
Steve (right) explains studio operations

19 April 2015 – Annual Club Lunch

Not quite as many members attended the Club Lunch this year, but those who came enjoyed the spring like day and the pleasant company!

Awards made were:

The Dr Little Cup to Paul Bradfield, G1GSN for the construction of a 4M antenna
The G4CBI Cup to Bryan Bourne, M0BIK the best presentation to the club by member.
The G3JKK Shield for Club Support to David Lloyd, G8UOD for his service to the club.
The Round Quize Trophy to Victor, G3JNB since he was a member of the team of 4 who won the Annual Club Quiz. (Team members were: Victor, G3JNB, Alan, G4PSO, Quentin, G0BVW and Bryan, M0BIK)

Other members who won, but who were not present were:
Paul Tewksbury who will receive the G8EMJ Shield for the Major Construction Project and Terry Rose, G4OXD who helped Bryan with the best presentation to the club by a club member.

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16 April 2015 – THE AGE OF SPARK WIRELESS BY BRIAN HAWES, G2KQ

Coherer        Morse Inker
Coherer                                                                                            Morse Inker

Brian started by explaining that many persons contributed to the inventions which led to the start of the wireless age. Mentioned were famous names, such as Clark Maxwell, Heinrich Hertz and Edouard Branly. It was Branly’s invention of the coherer that was used in all early detection of radio waves. In 1894 Prof. Oliver Lodge demonstrated reception of signals by wireless, a full year before Marconi. Unfortunately, he didn’t pursue the matter commercially as Marconi did.

Message communications of the time were by telegraph over cables and many people saw no need for anything different. However, the Navy could see the benefit of being able to communicate with ships once they had left harbour. Marconi focused his attention on that aspect and in 1901 the first high power transmitter was built at Poldhu in Cornwall. High power equipment was also fitted on ships being built at that time. However, the communications were not primarily for safety or nautical aspects, but for the convenience of passengers who wanted to send messages at 2 shillings and sixpence each, an eye watering £55. in today’s money!

After the Titanic disaster, authorities agreed that ships should carry wireless as a safety measure and provide a full time radio watch. 1910 to 1920 saw the end of spark transmissions, mainly due to the invention and use of the thermionic valve which allowed amplification of signals and ushered in the era of voice communications.

Brian had a display of working Morse tape inkers and coherers which members were invited to inspect and try out! Not the usual museum pieces under glass!

Brian demonstrating an inker
Brian demonstrating an inker

 

9 April 2-15 – Jim Bacon asks ‘Sporadic E, is it here yet?’

Jim, G3YLA
Jim, G3YLA

Speaking to a full house, Jim explained the weather related propagation modes most associated with VHF/UHF. By knowing the signs, an operator might pick the best time to be on the air. The main modes of propagation for the higher bands described by Jim were Sporadic E and Tropospheric Ducting and although weather related, the two modes have different properties. Being able to differentiate means the operator could possibly know what to expect and what results might be obtainable.

Various weather situations were explained and how they impact propagation. Jim pointed out that by listening for beacon signals one might know when paths are open and in which direction. Some discussion followed about the part the Jet Stream plays in controlling the weather and how the highs affected could propagate signals for long distances.

Jim then gave a brief look at modern forecasting methods and how a certain percentage of reliability is achieved, especially for businesses that could be affected by unexpected weather extremes.

 

26 March 2015 – Ken’s Keys

Ken's Keys

 

Referencing the CD by Prof. Tom Perera, W1TP, Telegraph Collectors Reference CD,  I was able to show various keys which I had used from my first days with CW.  Then followed with more details  about modern keys and keyers.  The subject of how to learn Morse followed starting with some recordings by the US Army Signal Corps. made during WWll.  These were from rather scratchy 78 rpm records. Although there are some 48 in the complete set, only small samples were played.  Some tips were given on how to best get started in learning and practicing the code.  Discussions followed when other members related their experiences and showed their keys.

19 March 2015 – Utility Listening, by Don, G4LOO

A typical SDR display
A typical SDR display

Don reminded members that his first talk about Utility Listening was back in 1990 when he described the Hoka Code 3 Data Mode Decoder. At that time there were about 37 or so different modes which are, for the most part, no longer used.
Since  that time, many of those who made the  transmissions have changed to satellite communications. However, now it is realized that satellites can be  vulnerable as well as costly. Slowly the authorities have been migrating back to HF communications. The use of complicated software negates some of the shortcomings of HF drop-outs and the overall result is still reliable and much cheaper. While still using satellites, having the HF communications means all the eggs aren’t in one basket.
Don demonstrated the free decoding software available and identified several transmissions using modern modes of modulation, although much of the results are encrypted.

Don's presentation
Don with SDR equipment