Inhaltsverzeichnis
P-711
Double frame antenna direction finder P-711/m, Marconi DFg 29; developed by Marconi England, Chelmsford, assembled by Marconi Schweiz, Bern / Hasler AG, Bern.
In 1949, the Marconi DFg29 double frame antenna direction finder was purchased as a supplement to the stationary Adcock direction finder systems, two systems were used on a Dodge WC off-road vehicle and three systems were installed for stationary use.
Technical data
- Frequency range: 2.5 - 12 MHz
Power supply
- Mains operation: 220 V
- Batteries: from 6 V vehicle battery via inverter
Dimensions
- Direction finding receiver 76 kg
Accessories
Station material
The Double frame antenna direction finder Marconi DFg29 consists of a base receiver unit with a double frame direction finding antenna mounted directly on top of it, a shield made of metal mesh was used to improve the direction finding accuracy.
The DF receiver is housed in a large metal cabinet; the RF preamplifier, the actual DF receiver, the frame antenna rotating unit and the dynamotor for battery operation are also housed in the same cabinet.
An unusual feature of the design of the direction finding receiver is that the antenna preamplifier (frequency coverage 2.5 - 12 MHz) and the receiver itself (frequency coverage 2.1 - 19 MHz) can be tuned separately, so the set has two frequency dials and two band range switches.
The direction finding receiver is suitable for CW and AM reception (A1, A2, A3), the modes are omnidirectional reception to monitor the signal, direction finding mode and selectable side detection.
As the size and weight are considered, the receiver (60 kg) and direction finding antenna (16 kg) allow still portable use and the whole system can be installed / removed from the vehicle without great effort.
The power supply can be run from 220 V mains or 6 V DC from the vehicle battery via an inverter.
Technical principle
Tube assembly
Development
The system developed by Marconi England was assembled by Hasler AG, Bern, the Swiss representative of Marconi.
Deployment
Of the five systems procured, two were vehicle mounted for mobile operation and three installed for fixed use. The systems came into service in 1949 and remained in use until 1970.