Vernier tuning (+- 500 hz about each 1000 hz increment) allows the receiver to be continuously tuned over the frequency range.
The two major units of the radio set are:-
Receiver/Transmitter, Radio RT-622/GRC
Amplifier, Radio Frequency AM-3349/GRC 106
Accessories include the Radio Teletypewriter Modem MD-522A/GRC and the Radio Teletypewriters GRC-142/l22.
The units weigh around 50Kg.
The frequency stability is 5 parts in 10/8 in 24 hours.
The receiver IFs are as follows:
First .......... .... 20 or 30 Mhz
Second... ........ 2.85 Mhz
Third........ .... ..1.75 Mhz
The bandwidth is 3.2 K/cs, derived via a crystal filter.
The set is capable of SSB (upper) AM (compatible) CW and FSK/NSK with the modem.
There are two antennas used, a l5ft whip for mobile use and a doublet for fixed mobile applications.
The power output is 400w PEP on SSB and compatible AM and 200w average on CW and FSK. Receive sensitivity is less than .3 microvolt for 10db signal to noise.
The AF response is less than 2 db variation from 300 - 5 000 c/s. The power output is 2 watts into 600 ohms.
The unit operates from 27 vdc (+- 3v) and requires up to 60A on transmit.
The receiver uses around lA only at 24vdc.
The operating range is quoted at 50 miles on the whip and 1000 miles on the doublet antenna.
Versions available in Sydney, NSW, have come from ATTU, Richmond, from an auction in November 1995, and are generally in excellent condition.
© Ian O'Toole, 2009. Page created: 28/04/03 Last updated: 4/12/2009