User manual DRAKE DIGITAL 300VMFPLUS

[. . . ] When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over. 9 a. 14. Unplug the apparatus during lightning storms or when unused for long periods of time. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped. Table of Contents/Description/Specifications TABLE OF CONTENTS 3 2 2 3 3 4 Caution Statements Important Safety Instructions Table of Contents / General Description Specifications Front Panel Controls, Indicators, and Connections 5 6 7 8 9 Rear Panel Connections and Internal Jumper Installation Frequency Allocation Charts Service / If You Need To Call For Help Warranty DESCRIPTION The DRACOM 300VMF+ Video Modulator is a vestigial sideband heterodyne audio/video modulator that provides a modulated visual and aural RF carrier output on any single EIA standard channel from channel 2 through channel 78 plus channels 95 to 99. All aeronautical channels are offset positive with a tolerance of ±5 kHz as required by FCC rules. [. . . ] If test equipment is not available for such measurements, then adjust for proper picture contrast when viewed on a TV set (compare with known off-air broadcast picture quality). Rear Panel Description and Internal Jumper 5 VIDEO INPUT AUDIO INPUT R. OUTPUT 120V AC 60Hz 610W 600W MAX MADE IN TAIWAN R1 R2 R3 R4 R5 Figure 2 R1 - VIDEO INPUT Connector This is the baseband video input to the IF circuits. This input accepts baseband through 4. 2 MHz video at levels from 0. 7 Vp-p to 1. 5 Vp-p. R2 - AUDIO INPUT Connector This is an unbalanced audio input to the IF circuits. This input accepts 40 Hz through 15 kHz audio at a nominal level of 250 mV RMS (approximately -10 dBu). If a separate BTSC stereo encoder, such as the Drake MMTS20, is to be used with this modulator, this jack can input 40 Hz through over 50 kHz with flat response if internal jumper J8 is set to flat - see below) R3 - RF OUTPUT This is the modulator output. R4 - AC OUTLET Receptacle This is a power receptacle for other equipment and is rated at 600 W maximum; 120 V, 5 Amp. When the cable is connected to a properly wired AC power line outlet, this cable grounds the instrument cabinet. Do not defeat the safety purpose of the attached line cord plug. INTERNAL JUMPER SETTING - AUDIO RESPONSE Internal jumper J8 may be used to disable the 75 uSec pre-emphasis (normal setting). Flat response may be chosen if an external BTSC stereo signal is to be input to the modulator through the audio input jack. Remove the three screws holding the top cover of the chassis in place. After setting this jumper, reinstall the cover before returning power to the unit. NORMAL RESPONSE of 75 uSec = Jumper in the 1-2 position (shorting pins 1 and 2 of the J8 header). FLAT RESPONSE = Jumper in the 2-3 position (shorting pins 2 and 3 of header J8). Change to this setting when an external BTSC stereo encoder is used with the 300VMF+. 6 Installation The 'RF Output Level' and 'A/V Ratio' controls are used respectively to make these adjustments. If an output level of less than +43 dBmV is required, add an attenuator of the appropriate value to the modulator output. Example: For an output level of +35 dBmV, add a 12 dB attenuator pad to the modulator output and set the output level. RACK MOUNTING Adequate ventilation is very important in multichannel installations. Units should be spaced apart by at least one panel height wherever possible, and some air movement is advisable in enclosed rack cabinets. Excessive heat will shorten component life and modulator performance will be degraded without proper cooling. CONNECTIONS AND CONTROLS All connections to and from the 300VMF+ are made through the rear panel. Figure 4 shows a typical two channel installation using a typical satellite receiver as a signal source. Additional channels can be added by using additional 300VMF+ modulators and either multi-port combiners or combinations of two-port combiners. INSTALLATION NOTES Level adjustment provides optimum performance in multichannel installations. [. . . ] DRAKE COMPANY or the nearest authorized service facility, or ship the same in its original container or equivalent, fully insured and shipping charges prepaid. Correct maintenance, repair, and use are important to obtain proper performance from this product. DRAKE COMPANY determines is due to: (1) Improper maintenance or repair, including the installation of parts or accessories that do not conform to the quality and specifications of the original parts. All implied warranties, if any, including warranties of merchantability and fitness for a particular purpose, terminate one (1) year from the date of the original purchase. [. . . ]