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3 Using FRG-7 Digital
Once everything is connected, the radio can be turned on. Once again, make sure that you do
not come into contact with the mains voltage.
The display will start up with the logo and then show the frequency and S-meter.
Since the frequency counter has already been calibrated, this is immediately the correct
frequency.
This may differ slightly from the analogue display. Especially because you can move the
indication with the "dial" button. The frequency progression is also not exactly linear over the
entire range.
Because no offset for LSB and USB has yet been set, the MODE will not be visible on the display.
You can now start further adjusting and setting the digital readout.
3.1 S-meter adjustment
The analog S-meter has now been replaced by a digital S-meter. Because an analog S-meter has
a certain inertia, this has been incorporated into the digital version. The characteristic
of the AGC of the FRG-7 has also been included. As a result, the S-meter values will better
correspond to the correct voltages on the antenna input.
Adjusting the S-meter can be done in two ways. Using a strong signal from a broadcast
transmitter or using a signal generator.
3.1.1
Adjustment with a broadcast transmitter
Tune to a strong shortwave broadcasting station so that the analog S-meter reads at least S9.
Try to get the needle to S9 by turning the PRESELECTOR.
Now use a thin screwdriver to adjust the ten-turn potentiometer RV1 such that the digital S-
meter is at S9.
3.1.2 Adjustment with a signal generator
Connect a signal generator to the PL-259 connector. Set this around 15.5 MHz. Do not use
exactly 15 MHz or another whole frequency, because then a problem arises with the
harmonic of the generator in the FRG-7.
Set the signal to -73dBm (50.2uV @ 50 Ohm) without modulation. This is the signal strength
of S9 at an HF receiver.
Tune in to this in AM mode and peak the PRESELECTOR on this signal. The analog S-meter will
now also read approximately S9.
Now use a thin screwdriver to adjust the ten-turn potentiometer RV1 such that the digital S-
meter is at S9.
3.1.3 Replacing analog S-meter
If desired, the analog S-meter can be left in the FRG-7 and secured with a cable tie.
15
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