Drake VMM860 Fixed Channel Modulator

RF

Frequency Range:

601 through 860 MHz.

Frequency Selection:

Set at the factory to one of the following channels:
Cable Channels 87 through 135
or UHF TV Channels 36 through 69

Output Level:

+45dBmV minimum, typically adjustable from +30 to +45 dBmV

Output Impedance:

75 Ohms, return loss of 12 dB

A/V Ratio:

Audio Carrier -22 to -10 dB referenced to video carrier, adjustable

Frequency Stability:

± 5 kHz (Visual Carrier)

Intercarrier Frequency:

4.5 MHz

FCC Frequency Offsets:

All aeronautical channels are offset positive

Spurious Outputs:

-65 dBc, measured at -15 dB A/V ratio and with modulator output level of +45 dBmV

Broadband Noise:

-95 dBc (4MHz bandwidth, ±12MHz offset)

Video

Input Level for 87.5% modulation:

1 Vp-p ± 3 dB, manual gain adjustable with front panel control

Input Impedance:

75 Ohms, return loss of 18 dB minimum

Frequency Response:

20 Hz to 4.2 MHz, ± 1 dB

Video S/N:

65 dB luminance weighted

Differential Gain:

± 3% (10 to 90% APL)

Differential Phase:

± 3 degrees (10 to 90% APL)

Audio

Input Level for 25 kHz Peak Deviation:

140 mV minimum. Manual gain adjustment with front panel control

Input Impedance:

10K Ohms, unbalanced

Pre-emphasis:

75 µSeconds (Defeatable via internal jumper for BTSC baseband compatibility)

Frequency Response:

40 Hz to 15 kHz, ± 1 dB referenced to 75 µ Seconds pre-emphasis curve. (20 Hz to 100 kHz if pre-emphasis is defeated.)

Intercarrier Stability:

± 5 kHz, 0° to 50° Celsius (32° to 122° Fahrenheit)

Total Harmonic Distortion:

0.5% maximum

Hum and Noise:

-65 dB minimum, referenced to 25 kHz peak deviation

General

DC Power Input:

+12 VDC @ 150 to 220 mA, +5 VDC @ 75 to 100 mA

Operating Temperature:

0° to 50° Celsius (32° to 122° Fahrenheit), ambient.

Dimensions:

3.5 inches (89 mm) Height x 1 inch (25 mm) Width x 7.5 inches (191 mm) Depth

Weight:

10.7 ounces (0.30 kg.)