Category Archives: Events

Grand Junk Sale Thursday 22nd March

Next meeting is Thursday 22nd March and it’s the RADARC Grand Junk Sale – so it’s time for a shack spring clean! (Note to self…)

Please bring along any unwanted broadly tech based items in order to support the club. RF based junk is always very desirable.

Venue: Woodford Park, Woodley as usual. The auction will start 8pm sharp
so it’s best to arrive early (eg. 7:30pm) to have a look at the wares.

Please note a couple of things:

  • If you successfully bid on something, you’ll need to wait until the
    end to settle up.
  • If you bring junk along and it doesn’t sell then please be prepared to
    take it home with you. My car is full.

Also please read the rules available at
http://www.radarc.org/Files/2016/Rules%20for%20Junk%20Sale%20_2016-03-03_.pdf

If you have not been before – it’s a hoot. It is an auction run by the
club’s very own top auctioneers/jesters. Particularly with the lot I’ve
got lined up for you… Even if you don’t wish to buy, the evening is
always entertaining.

73

John
G4RDC

‘Death Rays: Fact or Fiction?’ by Peter Butcher, Thursday 8th March

Next RADARC meeting Thursday 8th March, Woodford Park Leisure Centre, Woodley.
Eyes down 8pm.

Peter Butcher returns to deliver the intriguingly titled talk ‘Death
Rays: Fact or Fiction?’

You may remember Peter is an excellent speaker from his talk on
Emergency Communications Planning.

Sayeth Peter:
“Ever since the first recorded death by electrocution of J.G.
Doppelmayer in Nuremburg in the year 1750, the Military have pursued all new scientific discoveries as a means of killing without warning; the so called ‘Death Ray’.

This talk traces the evolution of these ideas from Doppelmayre through to the present day and shows how the various scientific discoveries were followed up. Electricity, Lightning, X Rays, The Electromagnetic Spectrum, Engine Stopping Rays and Nuclear Physics were all explored. Gradually, as all were rejected, Military thinking changed, as the type of warfare changed and today we have developed ‘Weapons of Denial’ as opposed to mass destruction”.

Then, enjoy a nice cup of tea and a biscuit or two.

Look forward to seeing you there.

talk “Height Matters” by Mike Naylor G4CDF, 22nd February 2018 8:00pm

Height Matters – by Mike Naylor G4CDF on Thursday 22nd February 2018 at 8:00 PM – 10:30 PM Woodford Park Leisure Centre, Haddon Dr, Woodley, Reading RG5 4LY

During a recent shack tidy Mike G4CDF encountered many QSL cards from his student days. On looking though them Mike was surprised by what was achieved (mainly VHF/UHF I believe) using the presumably modest station set up at the time. This lead him to thinking about how the location it’s associated attributes affected communications.

No doubt with a splash of reminiscence and a good helping of nostalgia, this should be a very interesting talk, and I am sure we will all learn something including some details on to build a station that can regularly communicate over distances of several hundred kilometres, the effects of antenna size and height, and the effect of local terrain, power level and local noise levels.

We look forward to seeing you there.

[New year’s resolution diet busting refreshments will be served – G4RDC]

73

Simon, M0ZSU, RADARC

meeting Thursday 8th February: Noel Matthews‏ G8GTZ : The Portsdown Digital Amateur Television Project

On Thursday 8th February, we welcome back “Professional radio amateur” Noel Matthews‏ G8GTZ to tell us all about the Portsdown Digital Amateur Television project. You may recall his last talk on cubesats where they used magnets to orient the craft in orbit…we all liked that.

Venue: Woodford Park Leisure Centre, Haddon Drive, Woodley, RG5 4LY
Time: 8pm

So…continuing the theme of elegant engineering:

“The Portsdown DATV project provides an easy way to “get on air” with Digital ATV at relatively low cost. The Portsdown system enables amateur radio operators with little or no knowledge of Digital ATV to construct the hardware elements, load and configure the software and use the system to send live Digital ATV signals across town on their existing aerials. It includes the new Reduced Bandwidth modes and the ability to transmit to local repeaters using the more traditional 2 and 4 Msymbol DATV modes. Frequency coverage of 71 MHz, 146 MHz, 437 MHz and 23cms bands.”

Our very own Simon M0ZSU is also involved with the project and is
building one himself.

Noel and Brian Coleman G4NNS (who also gave us a talk on mapping
galaxies from your back garden using hydrogen line astronomy iirc!!) are now global super-stars after their appearance on Michael Portillo’s “Great British Railway Journeys” BBC programme using the Goonhilly 32m GHY6 dish for 3.4GHz and 5.6GHz EME operation.

Now RADARC members aren’t backward in coming forward so perhaps we can extract some stories about that too. There must be some.

If we ask nicely, Noel might also tell us about his web sdr which I find
very useful for monitoring:

http://farnham-sdr.com/

Tea/coffee/biscuits (many thereof) as usual.

73

John
G4RDC

Meeting Thursday 25th January: “Magnetic Loop Antennas” by Rael Paster, M0RTP

Folks,

Our very own Rael Paster M0RTP will be with us next Thursday 25th January telling us all about the amazing things he’s done making and
using Magnetic Loop Antennas.

Venue: Woodford Park Sports Centre, Woodley, RG5 4LY
Time: 8pm

“Mag Loops” are physically small compared to a typical wire HF antenna. They can be of the order of a metre or so in diameter. If you’re stuck for space for antennas, this talk is for you. Fabrication materials include 28mm copper pipe so you’ll gain plumbing skills by having a go at building one.

For transmission, even with relatively low powers the currents and voltages circulating in the loop can become substantial so interesting
devices such as vacuum variable capacitors are useful for tuning.

The talk will include a description of the “mag loop
controller” (typically a small computing device or microcontroller such as an ‘arduino’ board) as this integral to ease of use as the loops need precise tuning.

Rael has used WSPR (Weak Signal Propagation Reporter) to great effect to map where he’s managed to radiate RF to – you’ll learn all about the possibilities there. (https://physics.princeton.edu/pulsar/k1jt/wspr.html)

All powered by tea and biscuits. Look forward to seeing you there.

73

John
G4RDC

The Great Construction Contest – 9th Nov, Woodford Park

The great construction contest is on again. It doesn’t matter that you haven’t painted it yet, or haven’t powered up the PA, or that you made it years ago and never entered it. It can still win if the members think it’s the best entry.

Big software projects using commercial rigs and USB gadgets are popular, pure metalwork and craftsmanship projects and ambitious or novel hardware ideas have all won in recent years and the selection depends on the judgement of ALL the members with the voting system designed to support the idea behind every entry.

A really good entry might get 4 points from loads of people, but your subtly cleverer idea may well get many more 3s and you’d win. Loads of people have only entered after persuasion and then won.

In any case, it’s great to show off what you do and to show the whole membership that we are a great club with loads of dynamic people ready to show our expertise.

Robin G4IWS

Sharp Resonance: A Low cost Audio filter from Screwfix; mag loop update

Tony Canning G2NF has an intriguing evening lined up for us next meeting:

Thursday 12th October, Woodford Park Leisure Centre, Woodley, 8pm

Some of you will remember his superb talk on ‘Tricks with Coax’.

He states:

“Given my interest in coax related stuff and various tricks, I have been
playing with an audio filter that can give the user with no IF 200Hz
filter a similar tool in a pile up, and like wise for the SSB operator
an audio notch filter. There is no eltrickery, smoke mirrors or power
supply involved. I think its a great resonance demo, as the relationship to coax filters and tuned circuits is uncanny.

Can be made from house hold items or from Wickes / Screwfix or BnQ etc.

This is not about Audio DSP but my simple efforts do appear to offer
comparable performance to some at a fraction of the price but much more fun building and learning.”

Continuing the theme of sharp resonance, I’m trying to twist G2DD’s arm (Loz) into bring along the coax based magnetic loop antenna he’s been working on as I know a few people would be interested in having a go at making something. Or indeed – if you have been working on one feel free to bring it along and tell us what you’ve been up to!

Refreshments to be served as usual with an increasingly wide selection of biscuits of variable age.

73

John
G4RDC

HF Digital Voice (HF-DV) communications by Dr. Alison Johnston, G8ROG

Dr. Alison Johnston G8ROG will be with us on Thursday 28th September to tell us all about the “high quality” voice communications now possible on HF.

Venue: Woodford Park Sports Centre, Woodley, 8pm, as usual.

Modern digital modulation techniques allow more information to be
exchanged in the few kilohertz of bandwidth we typically use on SSB, for example. This enables near-FM quality.

We will cover a bit of theory, the practicalities of interfacing the
necessary computing equipment (maybe even mobile phones???) with (HF) radios and there will be a demonstration using a couple of HF sets.

For me, HF DV is in the true spirit of amateur radio and is an exciting
development as the technology is open to all. If you wish to experiment with the software, you can. As far as I am aware it is not covered by any patents.

Refreshments to be served as usual.

A huge thankyou to Alison for supporting us. Her knowledge of radio is, shall we say, expansive to say the least, as you may be aware. So if you have related queries I’m sure she would be interested to hear them over a cup of tea.

Looking forward to seeing you there.

73

John
G4RDC

The events leading up to and including the Battle of Britain by Chris Wren MBE

Next meeting is on Thursday 14th September entitled “The events leading up to and including the Battle of Britain by Chris Wren MBE”.

Venue: Woodford Park, Woodley, 8pm.
Refreshments to be served as usual.

Chris is the curator of the WW2 underground bunker and museum at RAF Uxbridge built in 1939 some 60 feet below ground. He will introduce personalities of the time including Douglas Bader who had a flying accident not far from the our very own Woodford Park on the Woodley airfield and the most successful fighter squadron at the time.

Churchill visited the bunker during one confrontation and enquired what reserves we had – the answer was “none”.

I look forward to seeing you there to look back on those perilous times and be inspired by those incredibly brave men and women to who we owe so much.