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Written by: Maintenance Guy

Category: Feature Articles

Published: 09 February 2020

Hits: 2510

• WebSDR
• Software Defined Radio
• SDR

Intoduction

WebSDR (Software Defined Radio receivers) connected to the internet via a server permit a number of simultaneous connections allowing listeners to independently tune any frequency within the band offered and hear the signals via their own computer audio output (speaker).

These Web SDR's are established and operated by individual amateur radio operators, radio clubs and universities around the world.

Each website offers similar features to operate the WebSDR, firstly an introduction to the sponsor and their installation, followed by a spectrum or waterfall display for the band selected in the various selection boxes.
The type of modulation and filter bandwidth can also be selected to suit the signals you wish to monitor.

The use of HTML5 allows the WebSDR's audio stream to play directly via your compatible browser (Chrome, Edge, Opera and Firefox.) All of these enable full access to any of the WebSDR's in the list below without resorting to the installation of any additional software.

So lets get started - here is a selection of WebSDRs in the UK. You will notice they offer a range of different bands to monitor. The first is Hack Green - Great for monitoring the Sunday morning MSARS 80m club net!

N.B. If there is no audio make sure that you have opened up the WebSDR in one of the browsers above.

iPad Users: Click 'IOS audio start' which you will find on the RH side at top of the waterfall next to HTML5 button.

 

Web SDR Name	Location	Bands Covered	Link
Hack Green HF	Nantwich, Cheshire	160m; 80m; 60m; 40m; 20m; 17m.	http://hackgreensdr.org:8901
Hack Green VHF UHF	Nantwich, Cheshire	70cm 2m 4m + (10m)	http://hackgreensdr.org:8902
Southampton Wireless Society	Farnham	LF 2m 70cm 3cm + Follow the ISS, Funcube-1 and High Altitude Balloon Transmissions on the Satellite Tracking Map	http://farnham-sdr.com
University of Twente	Enschede, Netherlands	0-29MHz continuous - Includes WSPR and Chirp Receivers. Full instructions on their site.	http://websdr.ewi.utwente.nl:8901
General list of sites	Over 100 SDR's	For the latest list click:	http://websdr.org

 

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Written by: Maintenance Guy

Category: Feature Articles

Published: 31 January 2019

Hits: 970

• Tony
• G3XQM

Built during the late 19th Century, Park Crescent in Brighton consists of 48 Grade II listed Regency houses.

Three of these building were replaced after the Second World War because of bomb damage, and another was the scene of one of Brighton's notorious "Trunk Murders" of the 1930s.

Park Crescent encircles a private garden which was formerly a pleasure ground and cricket pitch; home to the Brighton Cricket Club which later became The Sussex CCC.

Over time many of these houses had been converted into flats, and it was indeed at Flat 3, 17 Park Crescent that I spent my early life growing up.

Flat 3 is in fact on the top floor, with picturesque views of the private garden and beyond, from the lounge and what was my bedroom.

The roof of these buildings is in the form of a double apex style. Imagine an ‘M’ shaped roof where there is a walkable channel in the middle, not only over number 17 Park Crescent but many of the adjoining properties as well - useful I found out later for stringing up a long wire!

In fact this 12 year old child found that by carefully repositioning the hall cupboard and clambering on top of it aided by a pair of steps, I could gain access to the loft via a trap door high up in the wall. A further trap door in the loft gave access to the roof and onto the walkable channel – what a discovery!

My first communications receiver was an ex-government ‘Canadian 52 set’ made by the Canadian Marconi company and sold to me by GWM Radio in Worthing who specialised in ex-government communication equipment.

This covered a frequency range of 1.75-16.0MHz CW and AM.

There were many shops similar to GWM Radio around in the 60’s. The most popular ones were in London’s Lisle Street (Soho) and Tottenham Court Road. The pages of Practical Wireless would be full of adverts from many of these outlets every month.

I was still at school at the time and had saved up my pocket money all year for this receiver. It eventually arrived, packed in a large wooden crate and was waiting for me when I returned home.

The crate had been placed just inside the main entrance hall of the building.

Flat 1, the ground floor flat was occupied by an elderly gentleman and his wife. He couldn’t help noticing when this large consignment arrived, and was inquisitive and enquired what it was.

With great enthusiasm I somehow managed to open the crate, removed the straw and there it was! “A short wave radio receiver” I replied to the gentleman – I may have called him Sir – but then again probably not – especially after what happened over the following weeks.

Having climbed three flights of stairs (managing to avoid tripping over Smokey the cat who belonged to flat two) and undoubtedly stopping for an oxygen break, I and my new acquisition eventually made it to the shack (bedroom).

What was I going to do for an aerial? Now 14years of age, I probably didn’t have much knowledge of amateur radio aerials and anyway I was more interested in general short wave listening.

I recalled how I had previously gained access to the loft, and so that was where my very first radio aerial was to be strung up – attached to the rafters at each end, eventually being threaded though a pin hole in the corner of my bedroom ceiling and down to the radio.

Now at this time TV reception was very poor in the low lying areas of Brighton. VHF 405 line TV only being available from the Rowridge (Isle of Wight) or London transmitters. TV reception in Flat 1 apparently was awful – so the elderly gentleman told me and much worse since that ‘box’ arrived!

“You must be transmitting” he said angrily. Repeatedly telling him it was only a receiver and did not have the ability to transmit fell on deaf ears. I’m afraid, my poor old mum got it in the ear. Anyway he must have sorted out whatever was causing his TV problem as he eventually stopped making any comments.

I enjoyed my first experience listening to the short wave bands very much, and soon wanted more – a better receiver and a decent aerial to go with it.

My interest in the amateur bands began shortly after I started attending Brighton Technical College in Richmond Terrace – just a short distance from home.

I was studying radio and TV servicing and was sent there by my employer Scotts Radio one day a week for five years. Scotts Radio was an independent dealer who had a number of high street shops with their service department in London Road close to Preston Circus – another short walk from home.

They say you remember the best teachers at school; well we had two great ones at college; Ron Bravery G3SKI and Richard Canning G6YJ. Some of you will remember and indeed may have been taught by Richard as he used to also teach the Radio Amateurs Examination courses (RAE).

Richard (known to us as Fred Canning) was a keen CW operator, lived with his wife in Burgess Hill, and for a few years later in his life, taught the RAE at Marle Place Burgess Hill. I can recall his Bungalow in Windmill Drive with long garden and antenna to match.

Richard and Ron had set up an amateur radio station in the basement of Brighton Technical College, and as students we would be given demonstrations of the station.

The station consisted of a KW Viceroy HF Transmitter (100Watts out) and a KW77 receiver. The antenna was a 132ft centre fed Zepp installed between the college and the brewery. All modes were catered for (CW-AM-SSB) although AM was still the most popular (1966 era).

The ‘transceiver’ as we know it today had not arrived on the scene as yet. Separates were the order of the day. Having tuned the receiver into an amateur station’s CQ call, you would then adjust the transmitter to net onto the receiver’s frequency; this by means of very low level RF signal.

Those of us studying radio and TV serving were encouraged to attend the RAE course for a useful form of revision. This would be one evening a week over the academic year.

Now here’s the crack: Richard Canning was such an entertaining lecturer that most of us didn’t just sit the course for one year, but three instead! – Now there’s evening entertainment!

Indeed some of us took the radio amateurs exam in year two for the hell of it, and still came back for more. It wasn’t that we were swats – far from it.

To lighten the evenings lecture especially when the subject matter became dull, Richard would have us rolling about laughing as he re-told stories from the time when he was employed by the Welsh Electricity Board and all the high voltages he had to deal with, and the things that went wrong – although I suspect they had a meaning for us.

There was great rivalry between Richard and Ron with regards to amateur radio stations worked on the air. Indeed both of them wanted to be the first to show off their latest collection of QSL cards.

Working at the Scott’s Radio service department gave me access to a huge number of components – fantastic for the prolific constructor that I was to become. Indeed my service manager Robert Harding was very supportive – after all I could only gain experience which hopefully would benefit the company.

Some of my early home brew can be seen in this picture, including the 4’ long bench at the end of the bed.

Entering the room from behind the curtain is the 600 Ohm feeder of the 132’ end fed Zepp aerial. By the age of eighteen, I had plucked up enough courage (and foolhardiness) not only to climb up onto our roof, but to climb over three other roof tops as well! The antenna I made using 14SWG hard drawn enamelled copper wire. The feeder spacers I made by cutting up lengths of EGA tubing (electrical conduit). The 132’ was fixed at both ends using porcelain insulators with short lengths of supporting wire attached to facia boards.

The Zepp feeder connects to a home brew ATU located on the shelf. Main components within it were the large tapped coil wound around a former constructed using a couple of strips of Paxolin board glued at right angles to each other to form an ‘X’ cross section. The wire was wound over the ends of the X.

Two reasonable wide spaced tuning capacitors were used probably in the value of 150pf – 250pF. The small meter I seem to remember was just used to sniff the RF and was not actually an SWR bridge, although I did construct one at a later stage.

Many of the unusual components were readily available from ex-government radio shops in Brighton such as Arthur Sallis in North Road and Hay & Sons in Trafalgar Street.

The antenna worked like magic proving in one lesson that height (we were three storeys up) was as important as resonant length.

Next to the ATU is the six valve oscilloscope built using a 3” ex-government radar tube. Used mainly for checking on modulation depth of the AM carrier while transmitting.

I seemed to have spent an awful lot of time cutting up aluminium, and I have lost count of how many valve bases I cut out with drills, round and half round files – no fancy valve base cutters at this shack!

Sitting on the bench left, is the first transmitter that I built. It is a 5 band HF 80m-10m 50 watt output AM rig based on the design by F.G Rayer G3OGR in Practical wireless - worked a treat especially with that aerial.

Sitting above it, is a Top Band AM/CW transmitter. Now I have to publically own up here how I practiced a bit of deceit…..

The ‘Codar AT5’ was a popular Top Band (1.8MHz - 2.0MHz) and 80m AM/CW transmitter. This was available to purchase from a shop in Southwick.

I rang them and said I had purchased one of their Codar AT5 transmitters and that it had now developed a fault, and would they kindly send me a circuit diagram so I could fix a repair – something like that.

What kind people – from that circuit diagram, three of us went on to build a copy of that rig. I leave the names of the other two out of this article to save any embarrassment.

On the RH side sitting on the bench is a second hand commercial KW77 all mode receiver – the same model that I saw a year earlier in use in the basement radio shack of the Technical College. SSB was starting to become popular.

Finally sitting on top of the KW77 is a general coverage transistorised receiver – never did work very well (deaf) for some reason so would have been dismantled – the parts used for some other project.

The flat in Park Crescent also saw the construction of Hi-Fi amplifiers – some of you will remember the popular Mullard 5-10 design (5 valve 10 watt output). I constructed two of these on one chassis, built a pair of speaker enclosures, fitted them out with woofers and tweeters – Voilà - Stereo – Herb Alpert – eat your heart out!

While all this was going on in the 60’s the backdrop was ‘Off shore radio ships with the likes of Radio London and Radio Caroline broadcasting pop music usually 24hrs a day from the North sea.

This caught the public’s imagination and was a great hit. Up until then the only station to broadcast pop music was Radio Luxembourg, although that was really only receivable in the evening which tended to fade in and out.

The BBC only broadcast pop a few hours a week on their ‘Light Programme’

August 1967 saw the marine offences bill outlaw the pirates. Shortly after that Radio 1 started broadcasting to fill the hole left by the radio ships. In my opion radio has never been the same since.

Tony G3XQM

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Written by: Maintenance Guy

Category: Feature Articles

Published: 31 January 2018

Hits: 728

• G4ZCS
• Getting Started in Amateur Radio
• Introduction
• Beginners
• Ham Radio

This short article will tell you how to go about getting involved in this magical technical hobby

Whether you have used no radio at all, operated CB, been a professional radio operator in the services, or just read about it, amateur radio can be for you. The hobby has many facets, technical design, construction, operation, or just for a social, it can be what you want.

Students on the courses run by The Mid Sussex Amateur Radio Society cover the age range from 10 to 80 and with a wide range of abilities (and disabilities as well), all have passed!

Many of the finest operators do not have full licences (more later) or, have they been on the air man and boy for 50 years, some have only just started. It all depends on what you want to do and how much time you want to spend doing it.

Getting started

Many people start as Short Wave Listeners, “SWL”s for short. Listening to the airwaves for interesting conversations, watching weather satellite maps appearing on the computer screen or listening to strange noises or Morse code (more later).

Anyone can do this, all you need is a radio with the world shortwave bands on it and a book or magazine with the frequencies, or channels, listed to help you on your way.

When you think you are ready to join in and start transmitting there are two ways to do it.

First is to buy a CB radio and just join in. Amateurs consider this to be a little restricting as you have only one band, limited channels, and can suffer considerable levels of interference. Or second, work for an amateur radio transmitting licence.

This entails taking in the first instance a short multi choice examination. Many radio clubs like ours run courses and help you get this first licence. It is called “The Foundation Licence” and allows you to transmit on the amateur bands with some restrictions.

You will be issued with a “callsign” unique to you in the world, currently in the series M7AAA to M7ZZZ.

Most courses consist of a two day weekend and culminate with the examination where you will be given the result within a few minutes. After applying for a licence you can be on the air within a week or so.

The course covers many subjects that are of interest to the newcomer and the old hands alike. A short session of using Morse code, the famous code of dots and dashes that most know of including S-O-S for emergency and the more recent mobile phone code S-M-S a text message has arrived for you. “Dot Dot Dot, Dash Dash, Dot Dot Dot”

You also get to operate a VHF short range radio and a long range HF short wave radio. Don’t worry we will explain what VHF and HF means!

Progressing on

Having passed the first exam, most people apply for a licence and start using the airwaves while they study for the second level exam.

Having a licence allows you to talk to like minded people all over the world, but especially those local to you who can, and usually will, help you learn your way about the hobby. It is not unusual to hear a “school class” being taken on some bands.

One of the best ways to enjoy the hobby is to join your local club, like ours. There you can attend technical lectures, join in with social activities, and use the club’s radio equipment.

The next level up is the Intermediate level, and is primarily designed to help you learn some of the technical “stuff” and let you actually construct a working circuit.

If you pass this intermediate exam you are allowed more on- air privileges and are permitted to build and modify all sorts of radio equipment for use on the air.

Finally you can, if you wish, progress to the “Full”, or Advance licence. This teaches you much of the theory of radio and allows you to teach others, run club stations and operate at sea and from most other countries of the world using maximum power!

Conclusion

So what to do first? Come along to the club on a club evening, or contact one of the officers in the contact us section. Buy and read one or more of the radio magazines on sale in newsagents or invest in a small radio and start listening to see what it is all about, then when you are ready, contact us to make a start. You will really enjoy this hobby for a lifetime.

My name is Chris and my call sign is G4ZCS, listen out for me sometime.

Chris Saunders G4ZCS

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Written by: Maintenance Guy

Category: Feature Articles

Published: 15 February 2017

Hits: 778

• WSJT-X
• Amateur Radio
• Digital Modes
• G3YTU
• RTTY
• WSPR
• Olivia
• PSK31

Getting Started

With digital modes you can work other amateur radio stations throughout the world with transmitter powers of 10 Watts or less using simple wire antennas.

You need an HF transceiver, antenna, computer and interface unit with suitable cables and software for your chosen mode(s). If you have a transceiver with a computer control interface, you may be able to connect it to the computer so that you can read and control the frequency directly. The interface unit serves to match the signal levels of the audio and isolate the Push to Talk (PTT) connection between the radio and the computer. If the transceiver has the Voice-Operated Switch (VOX) feature you may be able to use this instead of the PTT in which case you only need to connect the transmit and receive audio to the computer.

 

Digital Modes RTTY and PSK31

The digital modes RTTY and PSK31 are the easiest to begin with and enable you to have a QSO in plain language at a reasonable speed. RTTY has no error correction but PSK31 does, and can provide a good error free readout providing the signal is slightly above the noise level. For RTTY, start with the MMTTY software and check the AA5AU website which provides a lot of information on setting up the software. For PSK31 you can try MMVARI or DIGIPAN software.

The Fldigi software by W1HKJ incorporates RTTY, PSK31 and many other digital modes (except for the WSJT weak signal modes) and enables you to switch between modes quickly.

This software is installed on the MSARS computer in the radio shack.

 

Weak Signal Modes – WSJT, WSJT-X and WSPR

WSJT, WSJT-X and WSPR developed by Joe Taylor K1JT, are programs designed for weak-signal digital communications.

WSJT has digital protocols (JTMS, FSK441, ISCAT, JT6M, JT65 and JT4) optimized for Earth-Moon-Earth, Meteor Scatter, Ionospheric Scatter at VHF and UHF and also HF Skywave Propagation.

WSJT-X implements a new protocol JT9 optimized for the LF, MF and HF bands.

WSPR (Weak Signal Propagation Reporter) is designed for sending and receiving low power MF and HF signals to test propagation paths. WSPR Version 2.11 also includes a package ‘FMT’ which enables you to make accurate frequency measurements such as those used by participants in the ARRL Frequency Measuring Tests ‘Challenge’.

JT65-HF is a development of the WSJT program specifically for HF by Joe Large W6CQZ.

You need to use software such as ‘Dimension 4’ to synchronise your computer with an accurate clock so that the software decodes the messages accurately.

For most of these modes you are able to exchange signal report and callsign, not really a conversation by any means, but still a contact!

 

More Digital Modes

There are even more digital modes to try such as Olivia and FSQ once you have conquered the simpler modes if you want a challenge. There is also a software implementation of the HF digital voice algorithm called ‘FreeDV’. However, try the simpler modes first as they are more popular and you will find more stations on the air using them before experimenting with other more complex modes.

 

Sources and Suppliers

Radio to Computer Hardware Interface

ZLP Electronics: www.g4zlp.co.uk

Tigertronics SignaLink: www.tigertronics.com

G3LIV: www.g3liv.co.uk

Radioarena: radioarena.co.uk

WM2U: www.qsl.net/wm2u/interface.html

 

Digital Mode Application Software

MMTTY and MMVARI: hamsoft.ca

DIGIPAN: www.digipan.net

FLDIGI: www.w1hkj.com

WSJT WSJT-X and WSPR: physics.princeton.edu/pulsar/K1JT/index.html

JT65-HF: sourceforge.net/projects/jt65-hf

Olivia: www.oliviamode.com/index.htm

FSQ by ZL1BPU: www.qsl.net/zl1bpu/MFSK/FSQweb.htm

 

PC Clock Synchronisation Software

Dimension 4: www.thinkman.com/dimension4

UK National Physics Laboratory: www.npl.co.uk/science-technology/time-frequency/products-and-services/time/time-synchronisation-of-computers-to-utc(npl)

Meinberg NTP: www.meinbergglobal.com/english/sw/ntp.htm

 

Information

AA5AU Getting Started on RTTY: www.aa5au.com/rtty/getting-started-on-rtty

British Amateur Radio Teledata Group (BARTG): www.bartg.co.uk

ARRL: www.arrl.org/digital-data-modes

G4UCJ: hfradio.org.uk/html/digital_modes.html

WB8NUT: wb8nut.com/digital

Essex Ham: www.essexham.co.uk/how-to-get-started-with-data-modes

RTTY.COM: www.rtty.com/index.htm

 

Band plans and frequencies

RSGB: rsgb.org/main/operating/band-plans

HFLINK: http://hflink.com/bandplans

 

YouTube

K7AGE PSK31 videos: www.youtube.com/playlist?list=PL8D7C6EBD6E2081E2

 

Further reading

RTTY/PSK31 for Radio Amateurs By Roger Cooke G3LDI

Get on the Air with HF Digital By Steve Ford WB8IMY

Work the World with JT65 and JT9 by Steve Ford WB8IMY