John Welsh – Menu Map


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)
    Useful Filter For MF Listeners
    The Dimmer Switch
    Extreme Radiation
    Ionospheric Refraction
    Resistance Of The Water Main
    Wooden Construction
    Thoughts On The Moon
    Christmas Tree Lights
    Thoughts On The Mangentic Field In A Toroid


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