Rare SEG-15D HF SSB radio with black front panel East Germany

This is a very rare version of the portable HF SSB transceiver SEG-15D, having a BLACK front panel instead of the more common white panel version. The SEG-15D transceiver was designed and manufactured in the former East Germany by VEB Funkwerk Koepenick, RFT which was based in East Berlin. The radio was used by the Stasi (East German secret police) as well as the East German military. It is an excellent design. It is fully digitally synthesized deriving all frequencies from a single 10MHz master TCXO. It has two excellent mechanical filters (at 200 kHz center frequency), one for USB, one for LSB. Output power is 20 watts or 5 watts. It runs from 24V DC or 127/220V AC using the snap-on AC PSU. It has a built-in manual antenna tuner to tune a whip antenna when using it mobile, or the radio can be used stationary by means of a 50 ohm BNC RF connector for an external HF antenna. In the latter case the antenna tuner is actually used as RF pre-post selector, to optimize the receiver large signal handling. The digital PLL synthesizer is built-up with TTL chips (made by Tesla which was based in the former Czechoslovakia). These East Block made TTL chips were actually reverse engineered from the well known 74XX TTL series from Texas Instruments. The radio is an up-converting design using 28.2 MHz as the first IF, 200kHz as the second. As you can see in the video, the SEG-15D works very well. The radio has an excellent modulation quality and a superb AGC action for the receiver. The receiver uses a diode ringmixer in the first IF and as a result it stands its ground in the overcrowded 7MHz band at night - not a trace of overloading. To top it all off, it is VERY well built. Considering the fact that this radio was designed in the early Seventies, it is clear to me that East German transceiver design capabilities were on par with the West in those days. RFT Funkwerk Koepenick (where this radio was made) was auctioned off after the wall came down in 1990 and East Germany was annexed by the West. The new owners closed it for reasons of eliminating unwanted competition, killing about 5000 jobs in the process.

[Radiogenes]

Very clean reception! Nice looking rig✌️

[jimmyharris]

I owned several of them and modified them with the filter unit of the SEG 100 to use the 300 Hz mechanical CW filter for Digital Modes...
Also modified the diode mixer with modern diodes... as well as the Audio Frequency passband...
And extended the frequency range up to 14, 5 MHz for 20 meters DX...

[MadMax-jpxg]

Hello, I am looking for a schematic diagram of the SEG15D radio station. Regards Marcin

[MrRadioRover]

A hand full of Cubans use them still daily.