Ultra Short Wave Radio Telephone - Eddystone Short Wave Manual

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EDDYSTONE SHORT WAVE MANUAL
ULTRA SHORT WAVE
RADIO TELEPHONE
This apparatus we. have called an Ultra
Short Wave radio telephone since it can be
used together with a similar equipment for
duplex telephony working over a distance of
several miles.
The actual range is governed
by circumstances such as the efficiency of the
aerial due to location and the character of
the intervening country.
To give examples which not only apply
to this apparatus, but to all low powered
ultra short wave equipment in general, the
following remarks arc offered as a guide :-
From hill top to hill top with intervening
lower lying land, 10 to 25 miles range.
From one aerial erected some 15 to 20 feet
high, clear of surrounding or screening objects
across flat wooded country, 5 to 10 miles.
Under the same circumstances, but with
aerials on the ground; 5 miles, or if with hilly
country in between, 2 to 5 miles.
In towns or cities with the aerials erected
20-25 feet high and unscreened, 3 to 5 miles.
With aerials at ground level, I mile to
2 miles.
View of combined Transmitter
and Receiver with handset ready
for Duplex working.
These figures are based on actual ex-
perience ;
greater ranges are sometimes
obtained, but they are not reliable.
This apparatus consists of two compact
individual units, the receiver and the trans-
mitter. Either of these can be built and used
separately.
The receiver is suitable for all
ultra short wave reception and both it and the
transmitter
fit
separately into the small
Eddystone metal cabinet No. 1033.. Altern-
atively the two units together fit into the larger
Eddystone metal cabinet No. 1034, as shown
in
the top photograph when they form a
complete equipment for portable use, yet call
be taken apart and used as transmitter and
receiver when required.
The combination of
the two separate
units is superior to the alternative transceiver
construction, where
the valves serve one
function for receiving and another
function
on transmit. In this case proper efficiency for
both functions is impossible.
Further, the
present arrangement permits of Duplex work-
ing since
frequency adjustments
of
both
receiver and transmitter can be
left set,
whereas the transceiver has a common tuning
circuit which must be switched and retuned
each time.