The John Welsh Collection


A Short History Of Radio
Earliest Times
Late 19th Early 20th Century
Early Last Century
Did Marconi really hear those Transatlantic signals?
The Tuned Spark Transmitter
The Coming of the Diode
The Triode, the start of modern electronics

Historic Electronics
Tesla Etcetera (Part 1)
Tesla Etcetera (Part 2)
Tesla Etcetera (Part 3)
Tesla Etcetera (Part 4)
The Thermionic Diode
The Triode Valve
The Klystron
The Klystron – Addendum
The Magnetron
The Magnetron Addendum

Analogies of Electricity Part 1
Analogies of Electricity Part 2
Scale: Some Numbers
A Crystal Set
The Electron
Wire Baluns (Part 1)
Wire Baluns (Part 2
Transmitter Impedance
The ‘Q’ of a Tuned Circuit
The Phase Locked Loop
The dbs
Units Of Measurement
Lead Acid Batteries
The Microphone
Thoughts on the Magnetic Field in a Toroid

The Transistor
The Semiconductor Diode
Capacitors (Part 1)
Capacitors (Part 2)
Ferriteless Toroids
The Thyristor

Aerial Gain
The Dipole
Low Frequency Aerials
Shortend Dipole – pt1
Shortend Dipole – pt2
Low Frequency Aerials
Off Centre Fed Aerials
Aerials for Circular Polorisation
Loading Of Aerials
Traps In Aerials
Wave Polorisation (Part 1)
Wave Polorisation (Part 2)
Aerials and their Q
Monopoles and Earth Image
Radiation From A Wire

Aerial Feeders
Coax – Does Size Matter?
Coax Calculations
Coax Impedance – Power
Coax Impedance – Loss
Skin Effect
Standing Waves (Part 1)
Standing Waves (Part 2)
Transmission Lines

Earth Image
The Measurement Of Earth Resisitance
The Importance Of A Good Earth At Low Frequencies
Monopoles and Earth Image

Are You Getting Out? The Sniffer Box
The Evolution Of Morse Code In Radio Science
Slow Morse (Part 1)
QRSS – Noise (Part 2)
Back To QRSS – (Part 3)
Q Codes

Atmospheric Attenuation
Impedance Of Free Space (Part 1)
Impedance Of Free Space (Part 2)
Impedance Of Free Space (Part 3)
Impedance Of Free Space (Part 4)

TX Factor – 10 years and 30 Episodes.

TX Factor is marking its ten-year anniversary by launching its 30th episode. It looks at how radio technology has advanced since Marconi conducted some of his early transmissions. The episode includes the first of a two-part feature on operating via the QO-100 geostationary satellite with a look at the hardware and software needed to achieve ... Read more

The RSGB’s National Radio Centre will be operating special event callsign GB2DAY to commemorate the 80th anniversary of the D-Day landings during World War Two. The station will be active between the 6th and 9th of June. In addition, volunteers will be hosting the special demonstration station GB1SOE on Saturday the 15th of June. Don’t ... Read more

DXpedition to Scotland

Guisborough and District Amateur Radio Club is organising a mini DXpedition to Scotland, on the Isle of Lewis from the 22nd to the 29th of September. The team has a couple of spaces left and is welcoming amateurs from other clubs who would like to join in. For more information email

International Museums Weekend

A reminder now that International Museums Weekend will be taking place on the third and fourth weekends in June. This year, those weekends are the 15th and 16th, and the 22nd and 23rd of June. Special event stations will be operating from a wide variety of museums from many different countries. To read more about ... Read more

The UK Six Meter Group Summer Marathon

The activity is open to all amateur radio operators worldwide and membership of the Group is not required.The objective is to work as many four-digit grid squares as possible between the 4th of May and the 4th of August on the 6m band.Logs can be submitted until the 18th of August 2024. You can find out more at ... Read more

145 Alive – upcoming

The next in the series of the popular 145 Alive events, to promote the use of 145MHz FM, is coming up on Saturday the 11th of May, from 1pm to 3pm. The event and the supporting Facebook Group was started by Tim, G5TM and from the start of 2024 has been organised by Mark, M0XICand John, M0XJA. The last successful ... Read more

Blue Ham Exercise

The RAF Air Cadets are pleased to announce that they are running the ever-popular Blue Ham Radio Communications Exercise in June on the 60m band. The exercise will take place between the 17th and 21st of June. Subject to your licence conditions, the Blue Ham team hopes that you can put some time aside to ... Read more

Mills On The Air

Mills on the Air Weekend 2024 is coming up on Saturday the 11th and Sunday the 12th of May. The event takes place across the UK every May with more than 300 windmills and watermills usually taking part. For more information, to register, and to view a list of registered stations, visit

SOS Radio Week

SOS Radio Week is an annual event that takes place throughout the month of May to celebrate the work of the volunteers from the Royal National Lifeboat Institution, Independent Lifeboats and National Coastwatch Stations around the British Isles. Members of these organisations save many people between them who are in danger along and around the ... Read more

International Marconi Day

International Marconi Day will take place on Saturday the 27th of April. Once again, the Cornish Radio Amateur Club is organising and running the event. Lots of amateur radio stations will be operating from sites that Marconi operated from or had a personal connection with. For more information, and to view a list of the ... Read more
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