Car radios

This chapter on vintage vehicle sound systems was created and co-authored by Jaroslav, owner of a Škoda 1201 sedan (skoda1201@centrum.cz).

We present here the types, technical specifications, and installation methods for various car radios used in post-war Czech vehicles. These radios can be converted to Western VHF (thus increasing their practical use), or a modern radio can be built into the original housing.

How to Solve Opposite Polarity on Vehicle and Radio

Completely insulate the radio and antenna from the body, then simply connect the radio outputs in reverse. However, insulation is a three-quarter day job – there must be no short circuit.
Change the +/? polarity on the vehicle.
Use a radio with opposite or switchable polarity (such radios were manufactured in the past).

Overview of Car Radio Types

503BV, 513BV OMIKRON

Manufacturer: TESLA BRNO, n. p.
Wave ranges: 1; 187.5 to 577 m (1600 to 520 kHz)
Intermediate frequency: 468 kHz
Average sensitivity: 16 mV
Average bandwidth: 10 kHz
Output power: 1.1 W
Speaker: dynamic with permanent magnet, speaker diameter 160 mm, voice coil impedance 5 ?
Power supply: type 503BV from 6 V battery, type 513BV from 12 V battery (switchable)
Power consumption: approx. 21 W (when powered from 6 V battery, current is 3.4 A, from 12 V battery approx. 1.85 A)
Derived receiver for export: 2000BV
Wave ranges: 2; 187 to 577 m, 1000 to 2000 m

2101BV ORLÍK

Manufacturer: TESLA BRNO, n. p., TESLA PŘELOUČ, n. p.
Wave ranges: 5; 25 m band (12.5 to 11.9 MHz), 31 m (10.1 to 9.5 MHz), 41 and 49 m (7.45 to 5.8 MHz), 195 to 575 m (1539 to 521.7 kHz), 1000 to 2000 m (300 to 150 kHz)
Intermediate frequency: 452 kHz
Average sensitivity: 10 mV
Average bandwidth: 10 kHz
Output power: 2 W
Speaker: dynamic with permanent magnet, speaker diameter 160 mm (on baffle 17.5 × 19.5 cm), voice coil impedance 5 ?
Power supply: from 6 or 12 V battery
Power consumption: approx. 35 W

2103BV LUXUS

Manufacturer: TESLA KOLÍN, n. p.
Wave ranges: 2; 4.05 to 4.58 m (65.5 to 74 MHz), 187 to 571 m (525 to 1605 kHz)
Intermediate frequency: for amplitude modulated signals 468 kHz; for frequency modulated signals 10.7 MHz
Average sensitivity: medium waves 10 mV, very short waves (for signal-to-noise ratio 20 dB) 6 mV
Average bandwidth: 13 kHz
Output power: 2.5 W
Speaker: dynamic with permanent magnet, oval 200 × 150 mm, voice coil impedance 5 ?
Power supply: from 6 or 12 V battery
Power consumption: approx. 45 W

2007BV STANDARD

Manufacturer: TESLA KOLÍN, n. p.
Wave ranges: 1; 187 to 571.4 m (525 to 1605 kHz)
Intermediate frequency: 468 kHz
Average sensitivity: 10 mV
Average bandwidth: 13 kHz
Output power: 2.5 W
Speaker: electrodynamic with permanent magnet, oval 200 × 150 mm, voice coil impedance 5 ? (mounted on baffle dimensions 310 × 150 mm)
Power supply: from 6 or 12 V battery
Power consumption: approx. 43 W

2003BV "TURISTA"

I discovered that in addition to the LUXUS and STANDARD variants, this car radio should also have existed. STANDARD differs from the LUXUS receiver in that it lacks the VHF range (it has only medium waves with automatic tuning). TURISTA then lacks even automatic tuning and is tuned only using the appropriate knob (medium waves only). Connection points and other controls are identical for all three versions (at first glance, these car radios can apparently be distinguished only by the small inscription on the dial – LUXUS, STANDARD, TURISTA).

This means that TURISTA will have the same parameters as the STANDARD type, but will have slightly lower power consumption. I have not yet found this type in any available literature (let alone encountered it anywhere in reality), but it should exist since the manufacturer listed it in their materials, so we include it here to make the list complete. Otherwise, the 2003BV "TURISTA" is truly a mystery to me. In period literature for repairmen (at least in what I have available) there is no mention of it. It is possible that due to its similarity with the LUXUS type, separate documentation was not issued. But as with the STANDARD type, there should be at least a note in the LUXUS documentation about this variant.

2203BV OZVĚNA

Manufacturer: TESLA KOLÍN, n. p.
Wave ranges: 2; 4.05 to 4.58 m (65.5 to 74 MHz), 187 to 571.4 m (525 to 1605 kHz)
Intermediate frequency: for amplitude modulated signals 468 kHz; for frequency modulated signals 10.7 MHz
Average sensitivity: medium waves 10 mV, very short waves (for signal-to-noise ratio 26 dB) 6 mV
Average bandwidth: 13 kHz
Output power: 8 W
Speakers: 5 electrodynamic with permanent magnets, circular with diameter 160 mm, voice coil impedance 4 ?
Microphone: electrodynamic, reporter type
Power supply: from 24 V battery (negative pole of battery connected to vehicle chassis)
Power consumption: approx. 130 W

MINI (transistor car radio)

Manufacturer: TESLA, trading company in cooperation with Polish company ZAKŁADY RADIOWE im. M. KASPRZAKA, Warsaw
Wave ranges: 3; 48.4 to 50.4 m (6.2 to 5.94 MHz), 187 to 571.4 m (1605 to 525 kHz), 1053 to 2000 m (285 to 150 kHz)
Intermediate frequency: 465 kHz
Average sensitivity: short, medium and long waves 100 mV (for signal-to-noise ratio 20 dB)
Average selectivity: 28 dB for all wave ranges
Output power: 1.7 W
Speaker: oval, dimensions 100 × 160 mm, voice coil impedance 4 ?
Power supply: from 6 or 12 V battery (switchable polarity for positive or negative pole on chassis)
Power consumption: approx. 1.9 W (0.95 A at 12 V)