The John Welsh Collection

Introduction
Introduction

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

Principles
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

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

Aerials
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

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

Operating
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

Other
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)

Upcoming Special Events

Special event station GB1HAF will be active on Saturday the 16th of August in support of SSAFA, the Armed Forces Charity. Operators will be working on the 40m, 20m, 10m, 2m and 70cm bands using SSB and, possibly, data modes and CW. The East Midlands Electronics and Radio Group will be on the air to ... Read more

International Lighthouse and Lightship Weekend

International Lighthouse and Lightship Weekend will run from 00:01 UTC on Saturday the 16th to 24:00 UTC on Sunday the 17th of August. The event usually attracts more than 500 lighthouse entries located in over 40 countries. To register for the event, and view a list of participating stations, visit illw.net

Commercial satellites on 430 to 440MHz

The prospect of a USA constellation of 240 commercial satellites that would use 430 to 440MHz for wideband control and telemetry, has prompted an unprecedented response from the amateur radio community to a Federal Communications Commission, or FCC, consultation. FCC Proceeding 25-201 would see AST SpaceMobile utilise much of 430 to 440MHz for downlinks as ... Read more

Airfield Bunkers 2025

Amateur radio operators are invited to take part in a special operating event in August celebrating the rich history of the UK’s wartime and Cold War airfield bunkers. AFB25 – that’s Airfield Bunkers 2025 – is a nationwide activity taking place from Friday the 1st to Sunday the 31st of August. Organised by UK Bunkers ... Read more

Revalidate Your Licence

When was the last time you revalidated your licence? Ofcom notes that whilst it is a requirement to revalidate your licence every five years, it is recommended to do it annually. Put a reminder in your diary to revalidate your licence soon, as Ofcom has stated that it intends to implement phases two and three ... Read more

RSGB appoints Morse Advocate

RSGB Board Director Mark Jones, G0MGX is delighted to announce that Laura Robertson, MM7BFL has agreed to take on the volunteer role of the RSGB CW Champion. Laura will head up the RSGB’s Morse-related activities and become an advocate for the use of CW. In her role Laura will also help the Society to take ... Read more

Special Event Station

Look out for these three special event stations Special callsign HS30DXA is active until the 21st of June to commemorate the 30th anniversary of the Thailand DX Association. Look for activity on all HF bands and the amateur radio satellites. QSL via HS6MYW. The Amateur Radio Society of India, VU2ZH is celebrating the centenary of ... Read more

Calling All Nigels!

Are you called Nigel? If so, you can join other amateur Nigels who are making plans to operate a special event station at what is hoped to be the largest ever gathering of Nigels in the world. The event will run from the 20th to the 21st of September in Worcestershire. Details on how to ... Read more

British Inland Waterways on the Air

The British Inland Waterways on the Air event will take place between Saturday the 23rd and Monday the 25th of August. The event is open to amateurs who use canals, towpaths, rivers, lakes or reservoirs for work or recreation. Registration for the event is now open. To sign up, visit Nunsfield House Amateur Radio Group’s ... Read more

BunkerFest 2025

BunkerFest 2025 is taking place on the 14th and 15th of June. This exciting international festival will bring together amateur radio operators from over 13 national Bunkers on the Air schemes. For rules and activation details visit wwbota.org/bunkerfest25
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