TC Problem Solving

If all else fails, read this!

As with all radio systems it is important that the ends of the aerials are kept away from earthed objects if maximum range is to be obtained.

The radio link is very robust, being crystal controlled and using a double conversion superhet receiver.

The Transmitter has a built in data slicer and the Receiver employs a phase locked loop detector and Schmidt trigger ensuring a consistent square wave output, free of noise and jitter. All this makes the system almost immune to noise and interference within its normal range. Even transmissions on the same frequency are completely rejected so long as their level is just 1 dB or less than the desired signal.

The system can only be used to transmit data, it cannot transmit analogue signals!

If problems are encountered with reception, make the following checks

Switch the Receiver on with the Transmitter unpowered.

Check the Receiver blue LED is good and bright showing the battery is OK.

Make sure that the red LED on the Receiver is NOT lit. If it lights permanently there is another transmission on the same frequency and you will encounter problems with interference, although this is highly unlikely! If the red LED flashes intermittently it is probably just interference, try moving the Receiver slightly until a position is found where the red LED is not lit.

Now power the Transmitter up and check the blue power LED on the side of the unit is brightly lit. The Transmitter does not need time code input to check the reception.

As you apply power, watch to see the red LED on the Receiver light, showing that carrier is being received.

Check the range by taking the Receiver away from the Transmitter and check that the red LED stays lit within the required range. Up to 500 metres line of sight should be obtained with good reliability.

How to check time code is coming out of the Receiver

It is easy to check time code is coming out of the Receiver by just touching a pair of cans on the BNC output on the side of the unit. Time code has a very distinctive "chirpy" sound - once you've heard it you will always recognise it. Or better still, plug the output into your mixer (line level) and have a listen.

Make sure the aerial is attached to the top of the unit (next to the LED's) and the time code output is taken from the socket on the side of the unit. I often get units back as appearing to be faulty because people try to take the time code out of the aerial socket!!!

Steady hiss like an off tune FM radio indicates no carrier is being received

Intermittent, dull, buzzy, crackly sound indicates carrier is received by no time code

Slightly varying chirpy sound indicates time code is being received (very distinctive sound)

Time code level problems

If you have ascertained that time code is coming out of the Receiver but the time code display has problems locking, it is possible that the level is too high or low.

This is adjustable by taking off the Receiver lid and using a small screwdriver to adjust the blue preset 2.2k adjuster near the battery compartment. NOTE THE POSITION OF THE ADJUSTER BEFORE MOVING IT. Try altering the adjuster whilst watching to see if the time code will lock. If it does, set it midway between the two points where lock is lost. The adjustment should not be at all critical.

The output is factory set to about 3.8 Volts but can be adjusted from 0 to +5 Volts. This will cope with just about any piece of equipment.

The time code levels are optimised for Betacam into the Transmitter (3.8 V) and Receiver (3.8 V). These levels will suit most equipment.

The Transmitter has a wide range that it will cope with from about 1 Volt to 6 Volts, which covers just about everything.

The Receiver will copy with most inputs - ie: Nagra, PortaDAT, Video playback machines - without adjustment. However, the level may need to be increased for some applications as described above, but with up to 5V drive this should be no problem.

If all else still fails, try a BNC cable in place of the radio link to check that the system is basically working before blaming "Black Box Video"!