VKN8
Short
history of the Metropolitan Fire brigade Medium Wave Radio
system Melbourne Victoria Australia - By Lionel VK3NM/VK6DC
VKN8
was the callsign used by the Metropolitan Fire Brigade dispatching
fire trucks to
various
jobs on approx 1620 Khz at the top end of the AM broadcast band with replies
from
the
fire trucks back to base on about 83 Mhz FM.
The
station operated with a power output of about 1000 watts into a loaded
" T " vertical
with
a ground plane on top of the Eastern Hill fire station just east of Melbourne
CBD a
quarter
wave ground plane was mounted on one of the poles for reception of replies
on
83 Mhz from the fire trucks.
A
carrier with some power supply hum was transmitted continuously 24 hours
a day with
a
beep every 30 seconds and sometimes when you hear the base operator giving
out
jobs
you could hear the fire truck replying due to leak through from the VHF
receiver
on
to the MF carrier.
In
the evenings VKN8 could be received interstate and I have heard the station
in New
Zealand
, It was very rich in harmonics with the 2nd heard many miles from the
station.
On
Sunday mornings VKN8 conducted radio checks with all the fire trucks usually
with
Henry VK3EN as the operator conducting the tests, Henry designed and maintained
the
station for many years up his retirement, Henry is now a silent key after
many years
being
very active on 160 metres AM.
Because
of the frequency used VKN8 could be received on any AM radio including
car
radios and many years before Victoria Police also used MF before moving
to VHF
and
VKN8 closed down on MF in 1972 and are now on UHF.
Photo
of Henry at the controls of VKN8