What make GB7MH tick

Previous posts have shown the details of the now famous flagtenna that radiates the signal from GB7MH. Malcolm G3NZP has now provided some photographs of the repeater equipment cabinet



... and of the 3G router that is providing the connection to the Internet.



Stewart/G3YSX

Happy Birthday Sir Isaac Newton

As Google have just reminded me that it is Sir Isaac Newton's Birthday with an apple bouncing Google Doodle, I thought that I would remind readers that he had another career after his time as Mathematician, Physicist and Alchemist. He was Master of the Royal Mint. There is a very good book, part biography, part detective story that I am just finishing reading and which I would recommend to others: Newton and the Counterfeiter by Thomas Levenson. Also it's worth looking at the author's video on the the Amazon site.

For those club members who don't have time to read the book, it was a Radio4 book of the week and I am sure the audio is still out there in the webverse.

Stewart/G3YSX

The G4JNT 500KHz Beacon

Andy, G4JNT, has produced an interesting writeup of his 500KHz beacon project. This can be found at http://www.g4jnt.com/500kHz_beacon.pdf

Stewart/G3YSX

Web SDR

A number of us are familiar with the webSDR at University of Twente. This is a multi-user SDR that runs on 80m, 40m and 20m. This has now been expanded to a world wide network. This program is a beta test, but the authors say that when these beta tests are successful, the software will be made available publicly on this site. That is very exciting news indeed.

Stewart/G3YSX


PS for a short time only one of the receivers is currently set up for 0..20KHz (it was set up for the Christmas Eve SAQ transmission on 17KHz), so if you have ever wondered what it's like down there, now is a good time to find out.

CARC Shack Familiarisation Wed 23 Dec

A very Merry Christmas to all readers of the CARC blog. As part of the work being conducted in the CARC shack and up on the tower we thought it would be a good idea to keep members up to speed on the changes. Therefore we propose a hands on session in the shack this Wednesday evening.

To start things off we plan to have a introduction for new members or a revision for existing members on the operation of the HF station. We'll be looking at the basics including operation of the FT1000MP, the role of the computer for logging and SteppIR antenna control. We'll also have a segment looking at how to tune the amplifier.

As there are still a few changes that need to be made, this will be a good chance to take on board suggestions for the future.

In the first place we'll concentrate on the simple modes, SSB and CW. In future sessions we'll look at the wide range of data modes which the shack can operate, also the VHF and UHF side of the shack.

I look forward to seeing you all there from 7.30pm onwards.

73
Mike
G0KAD

CARC Oscilloscope Evening Wednesday 26th August

Following on from the success of previous CARC member-participating events, such as the RF power meter, Morse key and receiver evenings it was decided to devote an evening to that great and trusty friend of scientists, electronics engineers and amateur radio enthusiasts, the oscilloscope.

This magical piece of equipment comes in many forms and guises, from simple low budget models costing less than £200 through to high-end top of the range laboratory models, which will set you back thousands. In between of course is a vast range of oscilloscopes to satisfy all types of requirements. These are prices for new equipment. Most amateurs make do with second hand scopes to meet their budget and typical applications.

So what does an oscilloscope actually do? Well, for a start it has a calibrated screen (graticule) or display, (older models used a CRT, modern ones are LCD or LED) on which you can measure frequency, time and shape of a waveform. If it has more than one channel, and four channels are quite common, it will measure a number of waveforms at the same time so that you can for example compare input and output waveforms to and from an amplifier. It is an extremely useful piece of test equipment for signal tracing and faultfinding.

The oscilloscope permits signal voltages to be viewed, usually as a two-dimensional graph of one or more electrical potential differences in the vertical (y) axis plotted as a function of time or of some other voltage in the horizontal (x) axis. Whilst a scope displays voltage on its vertical axis, any other quantity that can be converted to a voltage can also be displayed. Some more advanced scopes are designed as a main frame with space to fit additional modules or sub-units such as RF and AF spectrum analyser.

The scopes on display on the club evening varied in age and specification and included products manufactured by Tektronix, Philips, Fluke, Gould Advance, Hameg, Hewlet Packard and not forgetting a very nice miniature scope designed some years ago for commercial manufacture by Adrian Wood G3VJM.

The evening was well attended, and with plenty of models on display for people to play with, (see photos below), plus some additional boxes such as function generators and signal generators to provide input voltages and waveforms.

John Longhurst G3VLH



Welcome to Ray M0RXJ and Janet 2E0JXR who stopped by for the evening



A nice Tektronics 465B



Adrian G3VJM with a scope that he designed as one of his first jobs as a young engineer



Richard G4ANN and Peter G3LEG checking out a nice storage scope



The Philips PM3240 - a popular scope in its day



Adding a spectrum analyzer to scope makes a useful piece of test equipment

Annual General Meeting Agenda : Wednesday 27th January 2010

Notice is hereby given that the Annual General Meeting of the Crawley Amateur Radio Club will be held on Wednesday 27th January 2010 at 20.00. The meeting will be held in the Clubhouse, Hut 18, Tilgate Forest Recreational Centre, Crawley.

The Agenda for the meeting is as follows:

1. Apologies for Absence

2. To approve the minutes of the Annual General Meeting held on the 30th January 2008.

3. To discuss any Matters Arising.

4. To receive the Chairman’s Report for the year ending 31st December 2008.


5. To receive the Audited Balance Sheet and Accounts for the year ending 31st December 2008, together with the Hon. Treasurer’s Report and to pass a resolution adopting the Accounts.
A copy of the Audited Balance Sheet and Accounts for the year ending 31st December 2008 will be available at the meeting


6. To pass a resolution fixing the subscriptions for the year ending 31st December 2009.

7. To elect for the year ending the 31st December 2009:

1. The Chairman
2. The Vice Chairman
3. The Hon. Secretary
4. The Hon. Treasurer
5. The Hon. Newsletter Editor
6. Up to five Committee Members

8. Any Other Business

BY ORDER of the Committee

Malcolm Harman (G3NZP)
Hon. Secretary

Note : All paid-up members for 2009 are entitled to attend and to vote at the meeting and to nominate Officers and Committee Members.