CZK - Lambda - IV (přijímač)

Lambda radio receiver - IV


The TESLA LAMBDA-IV receiver (4th in order with the factory designation type 550000) is a 13 + 1 tube superheterodyne with double mixing for the reception of amplitude modulated signals A 3, telegraph signals modulated by A 2 and unmodulated A1.


- Frequency range: 58 kHz - 35.4 MHz, i.e. 5.118 to 8.5 m, divided into 11 frequency bands, designated A - K .:
A) 58 - 170 kHz
B) 165 - 435 kHz
C) 520 - 1.630 kHz
D) 1.58 - 2.7 MHz
E) 2.6 - 4.5 MHz
F) 4.4 - 10.1 MHz
G) 9.9 - 15.1 MHz
H) 14.85 - 20.2 MHz
I) 19.8 - 25.3 MHz
J) 24.7 - 30.3 MHz
K) 29.7 - 35.4 MHz


The change of wavelengths is solved by a rotating drum (carousel) with coils, controlled by a knob on the front. At the same time, the drum scale, calibrated directly in frequencies, rotates with the carousel. When switching the individual ranges, the output from the receiver is also switched off in an electromechanical manner.


- To measure the signal strength, a measuring instrument is built-in, calibrated directly in steps with an international scale (S-meter).
The output of the receiver is adapted for the connection of a speaker, headphones and a 600 Ohm line. When you insert the headphone jack (jack), the speaker turns off automatically.


- Mains supply 220 V/50 Hz.
(If necessary, the receiver can be powered either from the entire 12 V battery using a TESLA 550970 rotary converter, or by heating from a 12 V battery and anode from the battery).
The power supply is a separate unit and is connected to the receiver with a cable.


The receiver is built into a metal case and its controls are, except for the voltage selector and zero setting for the S - meter, concentrated on the front.

The speaker is in a separate metal housing with respect to the adapted housing of the receiver.


Dimensions: 430 x 330 x 350 mm


Source: www.dx.cz;
Vladimír Jánský: 333 receivers

The receiver had relatively low sensitivity compared to other receivers of the time. For ship service, there was a version with a range including the 500 kHz neighbourhood. This frequency was used as an emergency telegraph frequency. In the case of this ship's version, the end of the range was shifted to 30,3 MHz.


Source own collection