The Radio Amateur's Hand Book
A. Frederick Collins
- Before
- delving
- into
- the
- mysteries
- of
- receiving
- and
- sending
- messages
- without
- wires,
- a
- word
- as
- to
- the
- history
- of
- the
- art
- and
- its
- present
- day
- applications
- may
- be
- of
- service.
- While
- popular
- interest
- in
- the
- subject
- has
- gone
- forward
- by
- leaps
- and
- bounds
- within
- the
- last
- two
- or
- three
- years,
- it
- has
- been
- a
- matter
- of
- scientific
- experiment
- for
- more
- than
- a
- quarter
- of
- a
- century.
- The
- wireless
- telegraph
- was
- invented
- by
- William
- Marconi,
- at
- Bologna,
- Italy,
- in
- 1896,
- and
- in
- his
- first
- experiments
- he
- sent
- dot
- and
- dash
- signals
- to
- a
- distance
- of
- 200
- or
- 300
- feet.
- The
- wireless
- telephone
- was
- invented
- by
- the
- author
- of
- this
- book
- at
- Narberth,
- Penn.,
- in
- 1899,
- and
- in
- his
- first
- experiments
- the
- human
- voice
- was
- transmitted
- to
- a
- distance
- of
- three
- blocks.
- The
- first
- vital
- experiments
- that
- led
- up
- to
- the
- invention
- of
- the
- wireless
- telegraph
- were
- made
- by
- Heinrich
- Hertz,
- of
- Germany,
- in
- 1888
- when
- he
- showed
- that
- the
- spark
- of
- an
- induction
- coil
- set
- up
- electric
- oscillations
- in
- an
- open
- circuit,
- and
- that
- the
- energy
- of
- these
- waves
- was,
- in
- turn,
- sent
- out
- in
- the
- form
- of
- electric
- waves.
- He
- also
- showed
- how
- they
- could
- be
- received
- at
- a
- distance
- by
- means
- of
- a
- ring
- detector,
- which
- he
- called
- a resonator.
