Davtrend Ltd. Model DRAE SSTV Television Transceiver.

A more recent entry into the SSTV field by the U.K. company Davtrend
has resulted in the manufacture of this SSTV scan converter. The unit
was designed initially as a receive only converter, but provision has
been made on the main circuit board for the installation of a transmit
boar  A certain amount of setting-up of the internal pre-set controls
has to be carried out to achieve correct results, but the
manufacturers point out clearly in their documentation which controls
to adjust and which not to touch. The overall operation of the
converter is quite acceptable and the quality of pictures received and
transmitted are comparable with other units having similar facilities.

The manufacturer’s specifications for the Drae SSTV receiver are:

* Receive and transmit 128 lines @ 8.5 seconds with 128 pixels per line.

* 16 level grey scale.

* SSTV input 100mV to 2V.

* Video input fast-scan 625 lines 1V peak-to-peak into 75 ohms.

* SSTV output FM modulation 1500 Hz to 2300 Hz. Sync pulse 1200 Hz.

* Video output 1V peak-to-peak into 75 ohms.

* UHF output on channel 35 into 75 ohms.

The converter also carries a microphone socket on the front panel
which allows for phone operation without having to disconnect the unit
from the transmitter. The input to the converter is switchable between
the radio receiver, a tape recorder or a fast-scan camera to allow
setting up focus etc. prior to transmission. The only transmit picture
source input is for a fast-scan camera (or video recorder), from which
the unit snatches a frame during each slow-scan frame pulse and
transmits it as SSTV. A "freeze frame" facility is also available
which allows the received picture to be displayed on the screen
without being overwritten by incoming video.

Davtrend Ltd, Sanderson Centre, Lees Lane, Gosport, Hampshire, P012
3UL. Telephone: 0705 520141.