MT-MR PLATINUM. POINT TO POINT AURAL RADIO RELAY SYSTEM
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17.- Connect a Distortion Meter (or the same Audio Test Set, who is fitted with this instrument, adjusted to read
measure Harmonic Distortion) at Receiver's stereo baseband output (BNC connector). Connect Baseband Tone
Generator to stereo baseband input at transmitter, as before. Adjust it to produce 0 dBm signal level at frequencies
indicated in (18), sequentially.
18.- Perform an Harmonic Distortion test at 50Hz, 60 Hz, 400 Hz, 1 KHz, 5 KHz, 10KHz, 50 KHz & 100 KHz. Check
that Harmonic Distortion keeps below or assumes the values indicated in system's Technical Specifications. Log
these results.
19.- De-energize transmitter, receiver and instruments. Disassemble the test arrangement. Pack again transmitter
and receiver (take care not to change any setting in both equipments) and send it to the correspondent stations.
20.- To install Transmitter and Receiver at its respective stations, first install the antenna system: yagis, log-
periodics or parabolic antennas at both stations, each aiming to the opposite station; that is, transmitter antenna
located at the required height in the tower, aiming approximately to Receiver Station, and with transmission line
completely installed. Check system for VSWR and put it ready to connect. The same with Receiver Antenna
system, this aimed approximately to transmitter station. Check it also for VSWR, after installation is finished. Be
sure to protect all outdoors connectors with rubber & plastic tape, and silicon compound, avoiding any humidity
condensation or water penetration inside, at both stations.
21.- Mount transmitter into its correspondent rack, and make all definitive connections, including antenna system
(previously checked), AC & audio. The same for receiver equipment at receiving station.
22.- It's very convenient to have a private two-ways communication system present when dealing with these system
installations. A couple of CB or VHF (check it for interference) handie-talkies will work fine for this purpose. Four in
the same frequency are still better: two for outdoors (tower men) and two for indoors.
23.- Energize transmitter at Transmitter station. Energize receiver at Receiver station. Set transmitter for stereo
transmission (flat response, not pre-emphasized) and set receiver to the same condition. Connect a 1 KHz Test
Tone Generator to the transmitter's baseband input.
Adjust its level for 75 KHz deviation (100% modulation). Set transmitter at full 10 watts transmitted power. Check
reflected power to verify antenna conditions. Disable mute circuit at receiver. Read the value of received signal, if
any. If there is some signal present, 1 KHz test tone will be heard through the monitor speaker, and some
indication will be read in receiver's Display. This is the best case. Taking into account the type of antenna who is
installed at both sites (more or less narrow pattern), first loose horizontal locks and slowly move transmitter antenna
horizontally in both directions: left and rightwise, searching for a maximum indication in receiver's meter (taking care
not to confuse with the side lobes). Once maximum deflection is obtained, fasten antenna horizontal locks and
loose the vertical ones, then moving slowly antenna up and downwards, once maximum deflection is obtained
(hearing the tone all the time) at receiver's Display. Once transmitter antenna is properly oriented, unlock the
horizontal movement of receiving antenna and perform the same operation. At this point, is possible that receiver's
Display reading is quite high, and receiver can begin to saturate. If reading is approaching to this value, insert a line
attenuator to decrease this reading about 50% and then continue moving antenna, always looking for the maximum
point, first in horizontal, lock horizontal, then in vertical direction, locking vertical. Having both antenna systems
properly oriented, remove input attenuator from receiver's antenna input, reconnecting antenna and watching the
new reading at Receiver Display. This should show an appreciable increase in Received Field Strength. Continue
optimizing the orientation process until nominal signal value is reached, as calculated in introductory Chapter I in
this Manual. If it's not indeed, and obtained field strength value differs in more than ± 1 dB from theoretical value,
