RACAL TRANSMITTER DRIVE UNIT TYPE MA1720The RACAL MA1720 is a solid state ,Transmitter Drive Unit providing 289,999 frequency channels in 100c/s steps over the frequency range 1 to 29.9999 Mc's.The output frequency is derived by frequency synthesis from a highly stable crystal controlled 5Mc's reference sourse.Channel frequency is selected by 6 thumbwheel
switches which display the frequency in digital for;;no other tuning action is necessary."Locking-in" to the selected frequency is achieved in approximately 10 milliseconds;a front panel indicator illuminates when the MA1720 is in "lock",i.e.when the tuning sequence is completed.The output level of the unit may be preset from 25mW to 200mW;the output impedance is 50 ohms.
Two front panel jacks are provided for connection and monitoring of line inputs,connection of a microphone or contact closure keying.Line 1 jack is used for USB or LSB,press to talk,sidetone output and connection of an output from an associated receiver.Rear panel connectors provide connection for two 600ohm balanced inputs,a high impedance RTTY input,and telegraph keying.
Operational facilities,which are selected by front panel controls,are as follows;
LSB,USB,ISB,Key,AM,CW,RTTY(tone shift keying),RTTY Test(selects mark),VOX,PTT and Transmit.
To increase the flexibility of any system using the RACAL MA1720 Drive Unit,provision is made for muting an associated receiver and for control of antenna switching between the associated receiver and transmitter.The receiver output may be monitored at the drive unit and the drive unit sidetone fed to the receiver.
The drive unit is designed for rack mounting in a standard 19" rack.Power requirements are 100-125volts ac or 200-250 volts ac.
This most versatile and useful drive unit is in very good condition and is in working order.The manufacturers of this unit produce a very comprehensive manual for this transmitter driver.A copy of the handbook and associated circuit diagrams is included with this unit.A very good quality and highly recommended piece of equipment.The price of the Racal MA1720 is $1085 US Dollars which includes the cost of air freight to the USA.