Inhaltsverzeichnis
Multi-channel adaptor MK-1
Multi-channel adaptor MK-1, company designation ZT 11c; manufactured by Brown Boveri.
Around 1946/49, Brown Boveri developed the MK-1 multi-channel adaptor, which could simultaneously operate two wideband (voice) and two narrowband (morse code, teletype) channels, to use a single microwave connection for the simultaneous transmission of several calls or teletype signals.
The MK-1 was used with the TLD (SE-213) decimeter wave station.
Technical data
- Principle: multi-channel adaptor, frequency multiplex
- Operation modes: two wideband channels (telephony), two narrowband channels (telegraphy / telex)
- Frequency range: transmission of telephony channels 0.3 - 3 kHz and telex channels 1.4 - 1.6 kHz
Power supply
- From the TLD mains power supply: Anode voltage 320 Volt and heaters voltage 12.7 Volt.
Dimensions
- Multi-channel unit MK-1/A: 364 x 439 x 256 mm, 35.4 kg
- MK-1/Z call unit: 364 x 439 x 256 mm, 23.6 kg
Accessories
Operation
The MK-1 multi-channel system comes in three chests and is supplied with power from the TLD power supply.
The actual Multichannel unit MK-1/A (the multiplexer) contains four channel units and a measuring unit; the system has a modular structure. The set contains from the left the two telephony units TF1 and TF2, the measuring unit to do control measurements on the modules and the telegraphy / teletype units TG3 and TG4.
The call unit MK-1/Z is used for call signal forwarding on the two telephony channels TF1 and TF2; no call forwarding is provided or possible for the narrowband telegraphy channels. The call forwarding unit MK-1/Z contains the two call units RF1 and RF2 and the call generator RG.
The box contains two canvas bags, each with a keying unit, a morse key and a pair of headphones; each keying unit is powered by two 4 V batteries in a compartment on the bottom of the set, one of which actually powers the keying unit and the second is a reserve battery.
The speech channels are transmitted above and below the two carrier frequencies 12 and 18 kHz:
| Channel 1 | Channel 2 | Channel 3 | Channel 4 | |
| Carrier frequency | 12 kHz | 18 kHz | 12 kHz | 18 kHz |
| Modulation frequency | 300 - 3000 Hz | 300 - 3000 Hz | 1.4 - 1.6 kHz | 1.4 - 1.6 kHz |
| Transmitted sideband | 9 - 11.7 kHz | 15 - 17 kHz | 13.4 - 13.6 kHz | 19.4 - 19.6 kHz |
Technical principle
Multi-channel adaptor using frequency-division multiplex technology for the transmission of two speech and two telegraphy or teletype channels.
Tube configuration
Development
The system was developed together with the SE-213 (TLD) from Brown Boveri in 1942/45 and ordered in 1946 only in the quite small number of 26 (or 22 according to the „Dokumentation Funkstationen“) sets at CHF 14'250 each. Because of the lack of multi-channel adaptors, the TLD as not beeing considered as useful in many situations and by many tactical commanders.
Delivery of the sets was delayed until 1950 and they were liquidated around 1961.
Deployment
The sets were used in the Fk Kp and Fl Uem Kp for radio relay connections together with the TLD. As the sets were ordered in insufficiently small quantities, the TLD connections could not play its advantages and the system was only used for point-to-point connections in rare occasions.
