The photos above show the RTTY hardware. The left photo shows, left to right, the Teletype model 15KSR printer (Signal Corp order number 14700-PH-49, serial number 793), the model 14 Transmitter Disbributor (tape reader), the loop patch boxes, and, on the right, the model 14 Typing Reperforator (Signal Corp. order number 3357-PHILA-52). The last two digits of the order number indicate the fiscal year of the order. Therefore, the printer was delivered in about 1949, and the typing reperf in about 1952. The middle photo shows the loop patch boxes. Each is a 4x4 electrical box with a blank cover. Four 1/4 inch Tip Ring Sleeve jacks are mounted on the blank covers. The jacks have a switch that shorts tip to ring when nothing is plugged in. The tip and ring connections are all wired in series. The box marked TU is connected to the Flesher TU-170 Terminal Unit. Any device plugged into one of the jacks on this box is inserted into the loop driven by the TU. The model 15KSR printer and 14TD are typically plugged into this loop. The other patch box is driven by a 152950 loop supply with series 2.2 k current limiting resistor seting the loop current to 60 mA. The right photo is the Flesher TU-170 Terminal Unit with a WAVE 2 scope on top as a tuning indicator.

When not being used for something else, the station is on the Green Keys autostart frequencies listed below.

Frequency Type Day (MHz) Night (MHz)Notes
Space14.083,7057.083,705Space is 170 Hz below Mark
US LSB14.086,0007.086,000Mark tone 2.125 kHz, Space 2.295 kHz
US LSB low tones14,085,1507,085,320HAL ST-6000 low tones. Mark 1.275 kHz, Space 1.445 kHz
Center14.083,7907.083,790Shift up 85 Hz for Mark, down 85 Hz for Space
Navy MMM LSB14.085,4907.085,490Mark tone 1.615 kHz, Space 1.785 kHz
Navy LF LSB14.084,7907.084,790Mark tone 915 Hz, Space 1085 Hz
Europe LSB14.085,8307.085,830Mark tone 1.955 kHz, Space 2.125 kHz

For 850 Hz shift, there is the Military Net on 7089 kHz center frequency, mark low. So 7088.575 mark, 7089.425 space. That is 7087 USB with 2000+/-425 tone as per military standard. The mark tone is 1.575 kHz, and the space tone 2.425 kHz. Note that the space tone frequency is above the mark tone frequency as is standard for 170 Hz shift. However, the RF mark frequency is below the space frequency, while standard amateur practice is for the RF space to be low (Low Space Makes Fine Teletype). This reversal (or, actually, lack of reversal) is accomplished by using USB. With typical 170 Hz shift amateur RTTY, we run LSB resulting in the frequency shift direction changing. For the Military Net, run USB. Your best bet for receiving would be with the receiver in "CW" mode, tuned to 7089 kHz, with IF BW of 1 kHz and BFO offset 2 kHz below the IF center freq, fast AGC. You could, of course, set up the receiver the same as the transmitter -- in USB mode with virtual carrier of 7087 kHz -- but this is not optimal. The 3 kHz IF BW is too wide and makes you vulnerable to adjacent channel interference (of which there's plenty) which will "capture" your AGC and disrupt copy. 0900 EST (1400 UTC) on Saturdays.