(Louis Meulstee’s web site)
Return
In 1947 performance and technical requirements for the Ra120 series of VHF FM manpack
sets were specified. The tender for development and production was won by Svenska
Radio Aktiebolaget (SRA). The first trial models were tested in 1948. After considerable
mechanical and electrical modifications to the original design, the first production
sets were tried in mid-1949. Both Ra120 and Ra122 were normally carried as a single
load manpack, although later a dedicated vehicle version (Ra121) was produced, based
on the Ra120 and Ra122. A still later produced manpack version, known as Ra121B,
was similar to the earlier Ra120 and Ra122 but with a different frequency range.
The manpack version was powered by a 7.2V accumulator which was carried in a separate
battery box, attached to the
Front panel view of Ra120 transmitter-receiver unit. It is believed that this particular
set was of an early production.
Radio station Ra121 was developed for use in vehicles. It was based on the Ra120
and Ra122, having a different enclosure and a separate power supply unit.
Next page
|
Model
|
Frequency range
|
RF Output
|
Use
|
Channels
|
|
Ra120
|
34.11-41.69 MHz
|
0.7/3W
|
Manpack
|
77
|
|
Ra121
|
39.6-48 MHz
|
3W
|
Vehicle
|
85
|
|
Ra121B
|
39.6-48 MHz
|
0.6/3W
|
Manpack
|
85
|
|
Ra122
|
47-57 MHz
|
0.6/3W
|
Manpack
|
101
|
bottom of the set. High tension was obtained from an internally fitted vibrator power
pack.
The working range on 3W high-power mode, using the standard 3.25M aerial was about
13kM, and about 6kM with a short 1.25M aerial.
For static use, or when fitted in a vehicle, a 50 Ohm So259 socket was provided
for connecting the set to an external aerial. A special transistorised power unit,
introduced in the early 1960s, allowed the Ra120 series of manpacks to be operated
from 12V or 24V DC.
The Ra120 series had 100kHz channel spacing and could inter-operate with other manpack
sets which were used in the Swedish Army at the time, for example Ra100, Ra105 and
Ra130.
Radio stations Ra120, Ra121, Ra121B and Ra122
Front panel view of transmitter-receiver Ra122. Click to enlarge.
Ra122 in operational use (canvas front panel cover detached) showing the basic accessories.
Click to enlarge.
Accessories for the Ra120 series. Click to enlarge.
Ra120 series manpack station ready for transport.
Protective cover for Ra 120 series. Click to enlarge.
Transmitter-receiver Ra121B was identical to the Ra120 and Ra122, with the exception
of the frequency range.
