Peter King VARC is now running two remote radios from our cabin site. They are both using the ‘Remotehams’ software and seem to be running very well. If you have not used our remote before then why not take a look. To operate the stations you will need to be a member of VARC and your call … Read more
Earlier this week, Ofcom released a document titled “Updating the amateur radio licensing framework”. The document states that amateur radio licences will be changing in 2024 and provides details of the changes that are planned. These include adjustments to the overall licensing framework and rules in a number of areas including callsigns, technical parameters, and … Read more
The UK Six Metre Group Winter Marathon is underway. The objective is to work as many four-digit grid squares as possible, between 0000UTC on the 1st of December 2023 and 2359UTC on the 31st January 2024, on the 6m band. Logs can be submitted until 12 February 2024. For more information visit uksmg.org
Youngsters on the Air month has now begun. Callsign GB23YOTA is active for the duration of the month, with a range of groups, clubs and individuals having reserved operating slots. It will be on the air between 8am and 5pm. Sandringham School will be active on Wednesday the 6th of December between 8am and 4pm, as … Read more
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
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
Rhombic for 6m One thing I have fancied playing with for a long time is the Rhombic antenna. It has a very good directional gain and in principal is easy to construct. The problem is that on HF a Rhombic is extremely large. Even on 6m the antenna is pretty big! My idea for the … Read more
Back In “radio science”, ‘Q’ stands for Quality factor. In a simple resonant or tuned circuit, (and indeed also in a single inductor or capacitor), Q is conveniently summarised as “the component’s reactance divided by the component’s resistance”. The higher the Q, the lower the loss in the component’s resistance. (In most tuned circuits it … Read more
AB INITIO Back Puzzling facts As we approach the festive season of Christmas crackers, games and puzzles, it was thought once again that it would be appropriate to divert to something “Scientific” rather than strictly “Amateur Radio”. Everybody knows that the tides on the sea are due to the “pull of the moon”, but a … Read more
