We continue to help bring newcomers into amateur radio and the club. In mind at the moment A) Calum M7??? – Calum is a student; I don’t yet have his callsign but he has our congratulations. B) Ivor M7EZM (Ivor lives in St Albans and again is recently licenced and has offered to do a … Read more
We desperately need to locate a new and more central venue for our more formal meeting/presentations/club projects. Several of us have spent quite some time hunting around but get little either little response from queries, expensive quotes in large (cold?) rooms etc. It would be great if someone could step up and push this forward … Read more
PREVIOUS MEETING A really big thanks to Matt G4IYT for a fascinating talk and demonstration of 3D printing with examples of amateur radio and other applications. 20 members and guests attended.
Wednesday 8th November saw 15 enthusiastic club members vist the RSGB’s visitor centre at Bletchley Park, the home of the code breakers. The club was treated to an insightful talk about the visitors centre and some of the history of the site. After splitting into two groups we took a tour of the exhibit hall … Read more
Two new pages have been added to the VARC website. 1. With many thanks to Peter G3UHN – in the operating section we now have a page giving details of how to program your radio for FM repeater operation. 2. With thanks to Bob G4PVB – we have a page dedicated to receiving the very … Read more
After an extended period of building maintenance, World Heritage Grimeton Radio Station has scheduled* SAQ to be on air on UN-Day, Tuesday October 24th 2023 at 17:00 CET (15:00 UTC), to send out a peace message to the whole world, using the 200kW Alexanderson alternator near Grimeton in Sweden from 1924, on 17.2 kHz CW. … Read more
In this ever growing website, we have now added a page dedicated to Slow Scan Television. You can find it by to to the webpage HERE!
Upcoming on the 28th of October is the 48 hour CQ WW SSB contest. We entered this one last for the first time in a long time last year and it proved to be a very good and enjoyable event. We are looking to set up and enter again this year, so if you are … Read more
For anyone that might be interested, there is an activity event on 2m happening on Saturday 30th September (’23) between 1:00 and 3:00pm. This is an organised activation consisiting of a series of nets that covers most of the UK. The nets are chaired so that stations can be quickly passed around to get as … Read more
We had quite a turn out for the working party this past weekend (3/9/23). As a result we have moved the repeater antennas off the pump up mast and mounted them on the VARC tower. The pump up mast has been moved to one side to allow room for work to begin on the shed … Read more
The ProblemMost general coverage receivers have adequate gain and you can hear the background atmospheric noise from the receiver’s bottom frequency limit of around 30 to 100 kHz up to their maximum frequency of 30 MHz: that is except for the “Medium Wave” range of 500 kHz to 1.620 MHz. The reason that most receivers … Read more
Recap on the ThyristorIn a previous article, I explained how a thyristor worked. This is a transistor-like device in which the current through it, (between anode and cathode), is controlled by the thyristor gate. However, unlike a transistor, the “through current” is not proportional to the gate current in a linear manner. Instead, the current … Read more
Electro-Magnetic radiation is not confined to broadcast, commercial and amateur bands, and figure 1 shows a significant portion of the electro-magnetic spectrum including the visible part. Particularly note the “fierce” logarithmic scales of frequency and wavelength. This is necessary to accommodate the huge range between “radio” waves and gamma rays in a single diagram. This … Read more
Some things can go faster than light, but not ‘material’ things. Three examples of these things are; the cutting point of scissors, the meeting point of lines as the lines go from crossing to parallel, and the phase of a wave. But these are imagined things, things in the mind. In the case of waves, … Read more
It would be no good removing the man-hole cover in the pavement and directly measuring the resistance between the metal pipes at either end of the plastic section, as these would be effectively shorted out by the surrounding earth, so I decided to simulate the real situation by measuring the resistance of a length of … Read more
Back In the hastily rearranged talk to the club on Tuesday, 21/11/06, Brian, G3YKB talked about many different methods of home construction of experimental or “one off” circuits. These included: conventional printed circuit board, strip board, “paddy board”, ugly bug, and others, and also how to make screened enclosures by soldering sheets of single sided … Read more
It has a similar layout to the alternators used for generating the country’s electricity supply, except that instead of having 6 poles for generating 3-phase 50Hz AC, it has 600 poles for generating single phase AC at 17,200Hz. It also rotates somewhat faster than the alternators supplying the national grid, and delivers 200 kW of … Read more
Back This is not really about amateur radio, but it is technical and it involves electricity. Have you ever got the Christmas Tree lights out from the box in which they had been carefully packed the previous year only to find that they no longer work? If so you will know that finding the offending … Read more
Back There has been some discussion on whether it is better to wind inductors as a torroid or as a solenoid on non magnetic material. Thoughts:-Magnetic lines of force add vectorially. They do not influence one another. Hence: The result of this is that the field near the centre of the solenoid is proportional to … Read more
AB INITIO PERFECTUS EST (or in plain English, this “From first principles” series is finished). This series of technical articles for the VARC Newsletter is now concluded. It has ranged over more than 3 decades and some 80 articles, although in the early days its publication in the VARC Newsletter was somewhat irregular. Its original … Read more
Back A dipole in free space, fed at its centre by a balanced feeder, can radiate all the RF power fed to it with no radiation from the feeder. Such a system is illustrated in figure 1. A dipole is a “resonant” aerial and its first “self resonance” is when its total length is approximately … Read more
The next VARC meeting will be at The Boot on Monday 17th of April. We welcome members and not members. You are cordially invited to join us for at The Boot on Monday 17th of April 2023. This is an excellent opportunity to connect with fellow club members, share your knowledge and your projects, and … Read more
My antenna is a 2m folded dipole designed by Dave Kimber, G8HQP. I followed his instructions like this: 2m Folded Dipole – a loft-mounted vertical folded dipole for the 144 – 146MHz band. Theory: A vertical antenna most appropriate for 2m. A fat dipole (therefore wideband) will have a lower feed impedance at resonance than a thin dipole … Read more
The annual VARC Antenna Shootout starts today and runs until the end of June. The theme for this year is ‘2-metre activity’ meaning that it can be any mode, any polarisation, and any power (within applicable licence restrictions of course). You can operate from any location but must use your own callsign and not the … Read more
Verulam Amateur Radio Club now has it’s remote station running from it’s site near Dunstable. This is running most HF bands and proving to be very successful. It is operating using the RemoteHams software, which is a free download from the Remote Hams website. Once downloaded you can search for VARC and access the radio. … Read more
Europe and the Falklands are seemingly the main activity on the 4 metres (70 MHz) band. America and Japan don’t have it so most big ham radio company manufacturers avoid it for the most part. (The Icom IC-7300 is the exception but only the European model.) VARC member Bob Houlston (GVPVB) sent an e-mail to Elecraft … Read more
SWLs may have a lot of fun monitoring the new FM voice repeater on the International Space Station. ‘I heard it on 21st May 2021 at 20:05 UTC for an 11-minute pass’, says VARC member Bob Houlston (G4PVB). ‘The Doppler effect is quite noticeable, so I tuned my receiver high to 437.810 MHz and gradually … Read more
In January, Ron White G6LTT, the club’s district representative spoke at the club’s virtual meeting. He was joined by Terry Baldwin G4UEM, also a representative. Ron described the changes now taking place, particularly with training and examinations which have moved online, including invigilation of exams, all of which can be booked and paid in the … Read more
VARC member Tim Price (G4YBU) took part in a radio interview on BBC Radio Surrey this morning discussing Summits on the Air (SOTA). Tim is one of the event organisers for SOTA. He was joined by RSGB Board Director Stewart Bryant (G3YSX).
