Technical data

VHF/AM RADIO FSG 2T
3 Installation
20 FAV_D10048 June 2014
continuous Receiver acoustic noise without strange or rhythmic characteristic is
audible.
b) In Receive Mode, cw (clockwise) rotate / adjust the dot marking of the SQ knob on the
dot marked on front panel.
Verify, whether Receiver sensitivity on all channels complies with technical data
(make sensitivity tests covering the whole frequency range).
At almost full ccw and full cw position, the Squelch threshold shall be within
approximately 0.5 µV / -113 dBm and 5 µV/ -93 dBm / 50 Ohms (vary signal
generator output level).
c) Connect a 50 Ohm Wattmeter and a 20 dB or 30 dB throughline RF attenuator pad.
Key the transmitter and check RF output level (approximately 5 W carrier).
d) For Amplified / Standard Carbon Microphone(s) adjust the audio generator to
1,000 Hz and apply signal via decoupling capacitor to the Standard Carbon MIC
input. With 80 mV to 100 mV rms input, the transmitter shall achieve more than 70%
AM (depends on MIC sensitivity setting). Increase AF input to 500 mV rms, observe
modulation envelope, no overmodulation shall occur, depth of modulation must
remain less than 95%.
e) For Dynamic Microphone(s) adjust the audio generator to 1,000 Hz and apply signal
via attenuator to the Dynamic MIC input. With some 0.5 mV to 3 mV rms input, the
transmitter shall achieve more than 70% AM (depends on MIC sensitivity setting).
Increase AF input to 15 mV rms and observe modulation envelope. No over-
modulation shall occur; depth of modulation must remain less than 95% AM.
NOTE Proper modulation input level setting is indicated, when the (time delayed)
control LED on the front panel just changes from red (too low modulation
level) to yellow (appropriate modulation level setting).
3.3.1 Particular Remarks to FSG 2T Transmitter Modulation
Highly demanding, specific requirements shall be comprehensively considered as
follows:
1. Voice modulation with its typical dynamic peaks (fast and large level changes) shall
modulate the transmitter with peak AM depth of not more than some 85%.
2. Factory setting of the very specific FSG 2T voice processor results in a remarkable
AVERAGE of approximately 80% AM depth with voice and Sine modulation!
Thus, optimized usage of the RF carrier is achieved.
3. Do not change this setting, otherwise the stringent (25 kHz) Transmitter RF Emission
Spectrum Mask is no longer maintained.
4. The FSG 2T incorporates a special VOICE PROCESSOR, which is matched best to
meet the requirements of the particular environmental noise level situation.
a) This ensures an always loud and clear transmitter modulation, under consideration
of specific test requirements.
b) Even under these very specific conditions, fulfillment of the critical, highly
demanding RF Emission Spectrum Mask is achieved.