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
The antenna consists of: 1:1 Balun Lengths of copper brake pipe approximately 1m long pipe and secured into grooves in a length of wood. “Stingers” which can be moved to adjust the length and secured with grub screws. It is secured to the mast with a stainless steel clamp.
Years ago I bought a commercial but cheap HB9CV antenna for 6m. I think in terms of dB per gram of beam aluminium, these antennas are top-notch and great for /P. (I have had a lot of success with good DX with my 2m version.) However, rushing a first activation (contest) a few weeks after … Read more
Every year Verulam Amateur Radio Club holds an Antenna ‘Shootout’ Contest. The idea is to get as many club members as possible building their own antennas and then competing against others to see who’s antenna performs the best. Over the years we have had loads of really interesting submissions, from massive quads to tin-foil and … Read more
The VARC Lockdown Challenge was to make a 6m antenna from materials found at the home QTH. No sneaking off to local suppliers or mail ordering! A rummage through my garage found the following: Plastic rectangular-section conduit, two telescopic Band 1 TV antennas, SO239 socket, ‘U’ bolts and miscellaneous bits of wood. Unfortunately, no useful … Read more
I’m entering the Verulam Amateur Radio Club aerial contest 2020. I’ve built a Delta loop with bits stored at the back of the house. Items used are plastic electrical conduit and drain pipe, coax cable and wire. Wire length is approx 6 metres, the conduit is 2 metres long. The matching coax is approx 1 … 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
Hello everyone, I am sure, like me, you have been following the news and government reports surrounding the coronavirus. While the risk to the general population is still perceived to be low, we need to consider the safety of our members, especially as some of us are likely to be in a high-risk category. Over … 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
The Club’s ‘fox hunt’ is an annual event held on a club night. This year it was Peter (G0OIKs) turn to be the fox. The way the club organises this event is for the fox to find a spot within a few miles of St Albans where a station is set up. Every few minutes … Read more