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)

Churches On The Air

On Saturday the 13th, lots of amateur radio stations will be on the air to take part in the Churches and Chapels on the Air event, also known as CHOTA. The event will take place from 10am to 4pm. Although stations will be working on a variety of bands and modes, most operating will take ... Read more

Blue Ham Event

Engaging with the amateur radio community on the UK MOD 5MHz (Shared) Band. Blue Ham is back over the weekend 18-19 October 2025. RAFAC stations will be active 0800 to 1700 UTC each day. Blue Ham exercises provide a platform to further develop Cadet radio operator skill and confidence by engaging with the Amateur radio community ... Read more

Milton Keynes Rally

On Sunday the 24th the Milton Keynes Amateur Radio Society Rally is taking place at Heron’s Lodge Guide Activity Centre, Bradwell Road, Loughton Lodge, Milton Keynes. Free on-site parking, catering and disabled facilities will be available. The entrance fee is £3. The doors open to the public from 9am. For more information visit mkars.org.uk/mkrally

Essex CW Bootcamp

The next Essex CW Bootcamp will take place on Saturday 18th October 2025. It will be held again at the 3rd Witham Scout and Guide HQ, Powers Hall End, Witham, Essex CM8 2HE. I know our members all live in different parts of the world, but, who knows, you may be near-by on that date! ... Read more

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
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