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
