5
nat 01 and nat 02 operation
connections
The FM aerial input socket must be connected via 75ohm low-loss coaxial cable to a suitable roof-
mounted directional aerial.
aerial requirements
The tuner aerial should be mounted on the roof, clear of obstructions and also as high as possible.
Horizontally polarised aerials will respond to all UK broadcasts whilst partially rejecting police and taxi
transmissions, and are therefore recommended. Use of an aerial preamplifier will disturb the muting
operation of the tuner and may cause crossmodulation problems. Such preamplifiers should only be
used as a last resort.
In the UK, BBC and commercial radio broadcasts are usually radiated from different sites even though
the target areas of the services may be similar. This means that unless the transmitters are in almost
the same direction looking from your house, an aerial aligned on one transmitter will give less than
optimum performance on the other. In these circumstances you should fit an aerial rotator, or a less
directional aerial if appropriate. The more sensitive and directional the aerial you use, the less good
will be the reception in directions other than the one towards which the aerial is pointing. If you are
particularly interested in receiving a wide range of VHF transmissions an aerial rotator is a necessity.
Your dealer will be familiar with local conditions and will be able to advise you on which stations are
capable of being received satisfactorily.
The tuner’s audio output is adjustable both for level and channel balance. It is set to 400mV for the
nat 01 and 340mV for the nat 02, all at 100% modulation and should match almost any preamplifier
without difficulty. Preamplifier load should be more than 10K .
frequency display
The frequency display lights dimly until a station is received and tuned with sufficient accuracy. The
display will then brighten and the mute will lift, allowing you to hear the programme. Rock the tuning
knob slightly backwards and forwards to check that the tuning is set to the centre of the range over
which the station can be heard, or the station may slip off tune.
signal strength indicator
The signal strength indicator will increase in brightness as a broadcast frequency is approached.
stereo indicator
Programmes which are broadcast in stereo carry an inaudible pilot tone, which is used to light the
”stereo“ indicator. This lights on all stereo broadcasts except those which are extremely weak, when
mono operation will be enforced.
In circumstances of very weak reception, the signal indicator will light while the the stereo indicator
remains off, showing that the programme will be received in mono, because stereo reproduction would
be too noisy.
As the signal strength increases, so will the stereo effect, until the stereo strength indicator is lit as
brightly as the signal indicator. At this point full stereo separation will be reproduced.