Advertisement
For PNI 8
lixed station installations, ,12ndard
A coils and B
batteries
arc
normally suppli«I.
These large
batteries will give in
excess of 200 hours
of
s,rvicc.
A sp«ial
battery
cable is ,vaihblc for use with the"'
batrcries,
having
at one
end a
connector
which fits the
power
plug on
the
chassis and at the other
end
spade
lugs and l»ttery
plugs for
connection
to the
"A"
and
"B" batteries
respectively.
The
s,rvice life ratings which ha,•c been quoted above
for
the thr,e
different
types
of battery available with this e<juipmcnt
uc based
on
an assumed
continuous
discharsc
of
)
minutes transmit•}
minutes
receive.
Con.sideubJy
longc,
s,rvicc
life
will be rcali•«I if the discharge
conditions 2re lcs.,
stringent
than
those s1a1«1.
The transmitter
·,,ill
deliver
a carrier
power
output
of 2 to 2.S
watts 10 a
resistive
load, on any one of
three
crystal<onlroll«I fre<juencfcs bctw«n 3.0
a.•d
.6.0 megacydts.
This
carrier can be
keyed
for
C.W.
Op<fltion, or 100%
soecch
modulated
for
)bdiolclephone
operation.
On Radiotelephone
Oi"'ralion
the carrier is controlled by the
"press-to-talk"
switch
incorporated in the
microphc,ne,
the
transp,itter b,,ing turned off
and
the
rcccivcr tum«!
on
when
the "prc.ss-to-12lk'' button
is
released.
The receiver is
continu0tuly tunable over the .s.1mc
frequency
ringe
a.S
the
transmitter,
the
dial
being alibr,t«I directly
in
megacycles.
The
receiver
em•
ploy, six vmcuum tubes
in
a
superheterodyne circuit, providing
high
sensitivity,
selectivity. siJtnal
to noise
ratio.
and im.1ge
attenu.ition. Automatic
volume
control
is
us«! for
telephone
reception
but
IS
automatically
remov«I when the
receiver is
switch«! over
for the
receptio
n
of
C.W. signals.
TRANSMITTER-RECEIVER DESCRIP'I'ION
Rdcrence
should
be
made
to the
Oia,i:r,ms of
Connections contained
in
the
b'ack of
this
m1nu1I when reading
the
following
technical
description.
The
o,·cra.11 cabintt is constructed of aluminum, we:athtrproof constroction being
used
throu,thout.
The
transmitter
and
recdvtr
are
built on
a
common
chassis,
which
fits into
the upper compartment of the cabinet
where
it
is
secured by
screws thr0<1,1th the
top.of
the front
oanel and thcou~h
the
sides
of the
cabinet.
The lower
half of the cabinet provides accommodation foe the
portable
bottery
and
the
telegraph
key, and stowage
for the
whip antenna.
earphones
and micro-
phone when not
in
us,.
In
the
PNIB
the
loudspeaker is
also mounted
in
this compartment.
.
B21terv volt•~• is
supplied,
from one of
the
thrc,
tvpes
of battery 1lceady
described, through a
four conductor cable,
terminating in 1 locking
type plu,1t
connector
which fits
into a rectpt.acle
mounted in
2
ffJnge
under
the front
p1ntl
at
the centre of the
transmitter
receiver chassis, This
receptacle is
bbelled
"Power".
Another
simil,r
receptacle labelled
"Audio'' and
mounted
on.the
umc
Ran,lle as the ·
Power'·
receptacle. receives
the
plug from
the
microphone•
headset assemblv. Locat«I between these recepta<les, but towards the rear
of
the
chassis. is a small
jack which
rcccivts the plug on the
lead-in
from
the
rod
antenna.
2
I,
Advertisement
