Foldback Mk4 instr

863 MHz UHF Foldback (Mk 4) - FOLDBACK TRANSMITTER

DESCRIPTION

This high quality Transmitter works in the licence exempt 863 MHz band, for use with the Black Box Video Mk 4 Director's Foldback Receiver. The Transmitter has many innovative features all built into a slim line, robust diecast case.

The Transmitter is crystal controlled and set to 863.625 MHz. Three other compatible frequencies are available to special order.

The units is powered by a standard Hirose 4 pin power connector and runs on a nominal 12 volt supply.

Audio in to the unit is via a standard 6 pin Hirose connector at nominal line level

It is also helpful to note that the Mk 3 version is NOT compatible with either the Mk 4 or the Mk 1 versions, but it IS compatible with Mk 2 units.

INSTRUCTIONS FOR USE

Operation

Connect the supplied aerial to the BNC socket on the top of the Transmitter. Connect the audio inputs at line level to the 6 pin Hirose socket on the side of the Transmitter (a suitable 6 pin Hirose to Hirose lead is available from us if required). The Transmitter can be fed with stereo or two track audio and channels 1 and 2 will be monoed without combining the original signals.

Connect nominal 12 volt supply to one of the 4 pin Hirose sockets on the side of the Transmitter (Pins 1 + 4 - again a suitable lead is available from us if required). The two sockets are parallel and either can be used for power in or out.

The Transmitter will operate satisfactorily from voltages between 8 to 15 volts. Current consumption is 90mA. The cyan power LED will be bright at 12 volts and dim as battery voltages reduces.

Switch on the Transmitter with the toggle switch on the top of the unit. Apply some audio from the mixer and check the signal is being received on a Black Box Video Mk 4 863 MHz Foldback Receiver.

This new Mk 4 system uses a compander to achieve a signal to noise ratio of 90dB, absolutely no hiss!

Modulation Level

Input sensitivity for the Transmitter is set to line level but there is a modulation level control inside the Transmitter which gives about +/- 10dB adjustment. This is the blue preset on the circuit board.

Aerials

The supplied aerial was carefully selected to give good performance without being too long. We can optionally supply high gain longer aerials if required, which will improve both Transmitter and Receiver performance but are about twice as long.

863 MHz UHF Foldback (Mk 4) - FOLDBACK RECEIVER

DESCRIPTION

This high quality UHF FM Foldback Receiver works on the licence exempt frequency of 863 MHz.

It is a small lightweight unit designed to be used by Directors, PAs and anyone who needs to hear the sound mix on set. It receives high quality signals from the Black Box Video Mk 4 Transmitter.

The unit has a side mounted volume control, toggle on/off switch and a stereo minijack socket for headphones.

A cyan battery level LED and a red carrier OK LED.

The Foldback Receiver is powered by a PP3 type battery located in a quick change compartment.

Both Transmitter and Receiver are crystal controlled ensuring they don't drift off tune.

It is also helpful to note that the Mk 3 version is NOT compatible with either the Mk 4 or the Mk 1 versions, but it IS compatible with Mk 2 units.

INSTRUCTIONS FOR USE

Operation

Fit a PP3 type battery in the battery drawer. Fit the supplied aerial to the BNC connector on the top of the unit. Switch on with the top mounted toggle switch. The cyan LED should light brightly and the red carrier light come on when the Transmitter is powered up.

Adjust volume to required level with the side mounted control.

Replacement Parts

Most of the items that could get damaged in everyday use are plug-in replaceable. The volume control, minijack and LEDs all plug into the circuit board - no soldering required.

Battery Life

Battery life should be approximately 15 hours continuous use. The cyan power LED will start to dim when the battery needs replacing.

Troubleshooting

Because the frequency is in the upper part of the UHF band the maximum range is only obtained when the aerials are in line of sight of each other. A maximum range of about 100 metres should be achieved. This range will be considerably less inside buildings. Longer aerials are available which will improve performance at the expense of being less convenient. Raising the transmit aerial to a height of about 2 metres helps get the signal over people's heads and improves reception. The high sensitivity of the Receiver means that a power booster should not be required.

The system is crystal controlled so does not require any tuning.