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)

DARC Shortwave Broadcast

The weekly shortwave broadcast from the Deutsche Amateur Radio Club, or D.A.R.C as it is also known, will be aired from Woofferton in England for the first time from January 2025. The broadcast will be made from an existing BBC broadcasting complex that is operated by the subsidiary company Encompass Media, where there is a ... Read more

145 Alive

The next in the series of 145 Alive events is taking place on Sunday the 26th of January 2025. The organisers are looking for volunteer Net Controllers to help cover as many Maidenhead squares in the UK as possible. Whether you’ve been a Net Controller before or not, the team would love to hear from ... Read more

SAQ – Grimeton Radio

The historic VLF transmitter at Grimeton Radio Station in Sweden is celebrating one hundred years since it was put into commercial operation. The unique Alexanderson alternator operates using callsign SAQ. To mark the centenary a special transmission will take place at 1000UTC on Sunday 1 December using CW on 17.2kHz. The event will be livestreamed ... Read more

YOTA Month

With just two weeks to go until Youngsters on the Air Month, operating slots for GB24YOTA are fast filling up. The special call sign will be active throughout December and is a fantastic opportunity to get youngsters active on the amateur bands. Whether you are part of a school, university, youth group, a club or ... Read more

RSGB Contest Club second World Wide Award event

The RSGB Contest Club is excited to announce that the second World Wide Award event will be taking place in January 2025 and it is looking for volunteers to take part. Last year’s event included 28 RSGB members who made in excess of 109,000 contacts. The Society’s Contest Club has confirmed there are currently special ... Read more

SSTV from the ISS

Amateur Radio on the International Space Station, also known as ARISS, will be conducting Slow Scan TV operations from the International Space Station between the 11th and 18th of November. There will be 12 images to catch during the week-long experiment, which will be on the theme of the 40th anniversary of amateur radio in ... Read more

VARC Satellite group

The VARC Satellite group have been making big strides to completing the system up at the cabin. They have been meeting regularly on a Wednesday evening and have installed a rotator with azimuth and elevation functionality. Ambrozy (M7MLU) made the first contact through the system steering the antenna manually. More recently they have aquired a ... Read more

Memorial Day QSO Party

The Memorial Day QSO Party is an activity providing participants with an opportunity to honour amateur radio operators who are now Silent Key. The event is being sponsored and managed by the First Class CW Operators’ Club and is open to all licensed amateurs. The eventbegins at 0900 UTC on the 1st of November 2024 ... Read more

CQ WW SSB

Up this weekend is the CQ WW SSB contest. Here at VARC we are inviting anyone from the club who would like to try an SSB contest for the first time to come along over the 48 hours of the 26th and 27th to try their hand. We will be holding an introductory day on ... Read more

Grid Radio App

grid.radio is a web application born out of the frustration that Rose, 2E0RXO and many others experienced during spontaneous, often unplanned, Parks on the Air activations. During busy moments, someone would inevitably ask for a Worked All Britain square or another reference that she wasn’t prepared for. There wasn’t a single, simple resource to quickly ... Read more
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