to: PA3ESA

Good afternoon, Nico,

just read your message re above.
I have the smaller brother, the TRA 921 (2 - 8 MHz, synthesizer). In the
copy of the manual which I have there is also a section covering the TRA
922, which features a 49 channel crystal oscillator. In case it may help, I
will give you some details about that:

"Five channel oscillator circuits are fitted, and each is provided with ten
crystals (nine crystals in the case of oscillator No. 1), one of which is
selected by the 'digits' channel switch. One of the five oscillators is
activated by the 'tens' channel switch, thus bringing the selected
oscillator, with its selected crystal, into circuit. A clarifier provides
fine control of the channel oscillator frequency, and thus adjusts both the
transmit and receive frequencies.

A separate oscillator and amplifier is fitted to provide the 10.7 MHz
output. This output is muted when A.M. VOICE reception is used."

"CHANNEL CRYSTALS
A crystal is fitted for each of the required channels. The crystal frequency
required equals operating frequency plus 10.7 MHz, i.e. if Channel 3 is to
operate at 2.587 MHz, then a crystal of 13.287 MHz must be inserted in the
No. 3 Position."

This 49 channel crystal oscillator is called MA 923. Perhaps yours is
similar?

Best rgds.,
Peter, DC6BN+