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Réglage du volume avec interrupteur et réglage de rétroaction (potentiomètres
Prises et connecteurs d'antenn
Poser les quatre douilles de raccordement. Le raccordement de terre rouge doit être monté sur le
bord supérieur, les trois douilles marron comme connexions d'antenne au-dessous. Entre le conden-
sateur variable et les potentiomètres se trouve le trou de 5 mm pour la LED. Le condensateur
variable et la LED sont ensuite soudés sur la platine et doivent par conséquent être démontés enco-
re une fois.
Disposition des éléments de command
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Calibrating the Scale
The printed frequency scale ranges from 3.5 MHz to 9.5 MHz. You must calibrate the receiver, to
ensure that the frequencies indicated are as accurate as possible. You need two radio stations, with
known frequency, on the lower and upper end of the range or a second radio for comparison.
Adjust the high frequency receiver first. Adjust the trimming capacitor, above C2 on the variable capac-
itor, with a screwdriver, until the transmission is located on the correct position on the scale. In gener-
al, the trimmer must be adjusted to the least capacity and thus the highest frequency. Then adjust to a
transmission in the lower range. Now, adjust the coil's ferrite screw core, until the scale is correct. The
frequency is lower, when the core is sunk deeper into the coil. Thus, the upper setting can move a bit.
So repeat the adjustment for the top of the range again.
CW and SSB
Morse station reception is at the lower end of the 80-m amateur radio band, starting from 3.5 MHZ.
Therefore, the feedback must be adjusted just above the oscillation field. The frequency you hear
corresponds to the distance between the transmitter frequency and the oscillation frequency of the
Audion. Use the feedback controller to fine-tune the frequency. Since the feedback is very smooth,
you can adjust a few kilohertz, without leaving the optimal sensitivity area. Avoid too powerful a feed-
back, since this decreases the sensitivity and the receiver becomes a small transmitter that can inter-
fere with neighbouring receivers. More CW stations can be found in the 40-m amateur radio band
starting from 7 MHz.
The usual voice mode in amateur radio is SSB (single sideband, SSB modulation). In order to receive
these stations, you must add a separate rack with the feedback turned up. Reception requires very
precise adjustment of the frequency, which is possible with the feedback controller as a fine tuner. If
you hear a typical Mickey Mouse voice, the frequency must be corrected slightly. With a little practise
it is possible to find the correct setting. SSB stations can be found mainly in the evening, in the 80-m
band between 3.6 MHz and 3.8 MHz, and in the 40-m band between 7 MHz and 7.2 MHz. You can
also find commercial SSB stations between the radio bands, e.g. the air weather service at 5.5 MHz.
There is still much more to discover with the feedback turned up. You can recognise telegraphs by
their lilting tone. The German Weather Service broadcasts weather fax images, at regular intervals,
at 3855 kHz, with 120 lines per minute. You hear a steady signal with two passes per second. There
are special devices and PC software for decoding these stations.
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