Category Archives: Talks

Events, Talks, Uncategorized

meeting 14th February – TELL US WHAT YOU’RE UP TO!

14th Feb Woodford Park meeting is a chance for us to catch up on the
various projects/activities we’re up to – in particular any follow ups
to the Great Construction Contest but not limited to that.

If you’d like a short (5 minute or so) slot let me know.

Doesn’t have to be stuff – could be contest updates or how RADARC
contributes comms to events like 3 towers etc.

Also – what would you like to see and I’ll try and arrange?

We can take contributions on the fly on the evening if need be.

  • Min G0JMS will kindly bring along a RigExpert HF to VHF SWR meter (Digital display) RigExpert to show you and VHF to UHF swr power meter (Cheap unit) which includes frequency. He will also do a brief demo of Yaesu Fusion – Wires X technology RF paths permitting.

If necessary, I’ll bore you for a few minutes before the bottles and
tomatoes start flying:

  • Geostationary satellite project – es hail 2. Mike G4CDF (and possibly others???) is making the running on this one but I will present on his behalf a very short overview. iirc it’s 2.4GHz up and 10GHz down. tx/rx is based on an SDR transceiver (lime sdr mini).
  • Adventures with FT8 internals and taxi radios (generating FT8 tones by pulling a carrier around) – update. TBH anything that generates a stable carrier and can be pulled a bit maybe down to 1Hz resolution looks like it might work – eg. voltage controlled oscillator.
  • cheap RTL-SDR dongles (£15 delivered). Mine does work but probably better to get the real ones rather than fakes like mine.
  • short gnuradio demo (maybe)

We’ll have the ICOM IC7300 out for people to have a play with and the spectrum analyser.

Tea, coffee and biscuits will be in plentiful supply all evening.

Looking forward to hearing from you.

73

John

G4RDC

Equipment, Talks

meeting 10th Jan – Equipment + Alignment evening, Spectrum analyser Intro

Folks,

Happy RADARC New Year to you!

Next meeting is Thursday 10th January, Woodford Park, Woodley.

Eyes down 8pm.

This time it’s the club equipment that’s the star of the show with the new Rigol spectrum analyser and the Icom IC7300 transceiver “Top of the Bill”. However Ray G3SCZ will also give a short introduction to the spectrum analyser and what it’s capable of. Many thanks to Ray for that.

It will be less formal than ‘normal’ talk evenings. This is more a chance for you to play with stuff – and have a natter, of course.

Also note the “humble support acts” are very capable (antenna analysers etc.). If you haven’t used one and you enjoy messing with antennas do come along.

This is a great opportunity to see how test equipment can make your life much easier and what radio equipment we have that’s ready to use.

Bring along any filters you may need aligned, also attenuators and dummy loads to find out what they’re really doing, and antennas within reason. Alignment evenings reborn!

On show will be:

  • Icom IC7300 transceiver
  • Rigol Spectrum Analyser + tracking generator + VSWR attachment
  • MFJ259 + MFJ269 Antenna Analysers
  • FT100D HF Rig
  • Marconi radio test set (combination of sig gen + spec analyser iirc
    donated by Mick G8ZWN. Need to get to know this better.)
  • FL2100Z linear – even if we just admire the glassware on it. Needs bringing up on a variac.
  • FT757GT transceiver
  • Advantest 1GHz spectrum analyser

+more, will keep you updated.

This will also be a good opportunity to discuss what our next equipment purchase should be. One obvious thing I’d say is missing is a decent, modern (i.e. small, light, capable) RF signal generator. Others:

  • 10MHz GPS locked frequency source
  • Decent Frequency counter i.e. accurate and wide range.

Would be good to chat about what makes sense to purchase as a club and what not.

Tea, coffee, biscuits will be in plentiful supply – perhaps a bit
earlier than usual. But only for humans/our membership. A valve linear at full throttle drinking a cup of tea doesn’t bear thinking about! As ever, keep your meetings ideas coming. If you mentioned something to me before and I’ve not done anything about it, please nag me.

Season’s greetings all,

73

John
G4RDC

(Hopefully you can read this. I’m battling the new ‘wordpress’ interface as you may be able to tell.)

Events, Talks, UHF, VHF

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

Events, SHF, Talks, UHF, VHF

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

Events, Talks

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

Events, Talks

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

DIY, Events, Member stories, News, Talks

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

Events, News, Talks

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

Events, Talks

In-depth DMR talk by Denis G0OLX and Colin G4EML

Denis Stanton G0OLX and Colin Durbridge G4EML will be with us on Thursday 22nd June for an in-depth look at DMR or “Digital Mobile
Radio” (so sayeth wikipedia). These two chaps are acclaimed experts in the field (at least by Ian G8NXJ so that must be right). Find out all
about colour codes, code plugs and time slots. Rig prices are becoming affordable making this relatively new area of our hobby quite accessible.

Venue: Woodford Park, Woodley, 8pm.

Refreshments to be served as usual.

Events, News, Talks

Signals Analysis of MH370

We have a special meeting forthcoming on 8th June (election day).

Venue: Palmer Building, Reading University, Lecture Theatre 109.

Use Shinfield Road entrance to campus. Post Code RG6 6UR.

Alan Schuster Bruce from Inmarsat will give a talk entitled “Signals
Analysis of MH370”.

He will talk about the innovative methods used in the analysis of
satellite radio signals from Malaysian Airlines MH370 to determine its flight path.

The disappearance of flight MH370 just over three years ago, you may recall, was an event of global significance. I personally was proud to see a UK company immediately leading the world in science and technology with heroic efforts to explain what happened. And particularly to see radio communications being “front and centre”.

It is a real privilege for us to be able to host this meeting.

It’s fine to bring guests but please let me know if you intend to do so
and how many.

Parking permits are not required on site. The closest car park to Palmer is Car Park 4.  Please see Whiteknights campus map and keys 2016 (1)

73

John
G4RDC