Tx FREQUENCY & Rx CRYSTAL CHECKER
This accessory was designed for use in the club and competition scene. It is able to verify 35MHz FM transmitter frequencies to 1KHz accuracy. The Tx FREQUENCY CHECKER can also be used as 'Transmitter Control' in preparation for 'slots' during competitions. Most transmitters these days are well made and reliable, but the occasion does exist when a flyer uses the wrong channel pennant - we've all seen it. The frequency checker provides the ability to eliminate this 'phenomena'!
In addition to its use with the transmitter the checker is able to test the operation of the Rx crystal.. It is with these crystals that damage is more likely to occur due to their more hostile environment with knocks, vibration and the occasional heavy landing. The test is done by inserting the crystal into the socket on the side of the case and switching on. Both single and dual conversion crystals can be checked. On the back of the case is a chart giving the frequency number that should be displayed with each of the checkers function.
It is also possible for the crystal to be slightly off frequency from physical damage or even tarnished pins. Either way, the results from a faulty crystal can be serious. A 1KHz error with certain makes of sets is not a worry, but any more than this will reduce range and give rise to 'anti-social' problems.
The unit is not intended to be used as a monitor and indeed, cannot be used as such. Its operational range is only short . It works by giving a precise digital readout to 3 decimal places when brought into the close proximity of a transmitter to be checked. On the back of the case is a chart listing channel numbers and their frequencies.
The FREQUENCY CHECKER is housed in a calculator-type case with an on/off button at the side. Power is provided from a small 9 volt PP3 battery which can last for several months. The overall dimensions are only 80mm x 145mm so the unit can easily be carried in the pocket.
During the 1988 Nationals, one of these units was used extensively in TRANSMITTER CONTROL prior to entry for the events.
Another quality product from MAINLINK.
Reviewed Dec '89 RCM&E Counterpoint; BMFA 1st Newsletter; July '96 Aviation Modeller