• Year
  • 1943/1944 ?
  • Category
  • Military Transceiver (TRX)
  • Radiomuseum.org ID
  • 319566

 Technical Specifications

  • Number of Tubes
  • 6
  • Main principle
  • Transceiver; ZF/IF 1500 kHz
  • Wave bands
  • Short Wave (SW only)
  • Power type and voltage
  • AC/DC-set / 120/220 or 12 Volt
  • Loudspeaker
  • - Is a Headphone or Earphone
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Suitcase Transmitter-Receiver BP4 - Polish Military Wireless Unit
  • Shape
  • Portable set > 8 inch (also usable without mains)
  • Dimensions (WHD)
  • 300 x 250 x 70 mm / 11.8 x 9.8 x 2.8 inch
  • Notes
  • The BP4 was designed and produced by Polski Wojskowy Warsztat Radiowy (Polish Military Wireless Unit) in Stanmore UK, in the same time as the A / AP series of clandestine radios, also under the direction and management of Tadeusz Heftman (chief constructor of PWWR and pre-war pioneer of radio amateur in Poland; call sign TPAX).

    The B or BP series were ordered by the General Staff of the Polish Army (Division II; in exile in the UK), and unlike the A / AP series, the B / BP series was intended for field use (larger antennas, higher power), mostly for use by the Polish Home Army (AK - Armia Krajowa) - resistance against Nazi occupiers, for internal/domestic communications. Radio has been ordered because of unavailability of that kind of radio equipment from other (UK) sources.

    There was two families of the B / BP series (similar like for A / AP-series of PWWR radios). One serie including B1, BP3 and BP5 was for lower frequencies from 2 to 8MHz, and the second family including B2 and BP4, was for wider frequency range from about 4 to about 16MHz. In that time the higher frequencies were considered as more suitable for long range communication - in this case intent was to keep link between Polish Home Army in occupied Poland and Polish government in excile in UK. After satisfying the most necessary needs of the Polish government in exile, these radios were also provided to the Allies (SOE and other special forces), in many cases in the trade exchange for other equipment for special operations.

    BP4 was clandestine transceiver with separate power supply to achieve higher output power than A/AP series also designed in the PWWR. Housing is the metal box with black wrinkle finish to resemble tool boxes. Front panel can be labelled in English or in Polish.
    Larger dimensions were the price for more transmitter power of the B / BP series in comparison to A / AP series. Therefore their usefulness for underground activities, especially in urban conditions, was lower.

    The design was based on electronic components available on the free market, which in practice meant the US market. This was due to the limited availability of electronic components manufactured by the British industry.

    Transmiter (quartz stabilized frequency) - oputput power about 50W or up to 70W with additional power source.
    Frequency range - 4 to 16MHz in two ranges 4 to 8 and 8 to 16MHz (similar as in the predecessor B2, where it was 3.5 to 15MHz).
    Transmitter tunning - maximum light of the bulb indicator.
    Receiver - superheterodyne.
    Key was build in on the front panel, but external key can be attached into dedicated socket.
    Antennas depending on the range of frequencies - 2 x 7m or 2 x 13m.
    Three variants of power supply available:
    -rectifier 120/220V AC
    -rotary converter 12V DC (500 and 250V)
    -rotary converter as above for transmitter plus additional rotary converter for receiver. For this variant of power supply, the output power of transmitter should be about 70W.


  • Net weight (2.2 lb = 1 kg)
  • 5 kg / 11 lb 0.2 oz (11.013 lb)
  • Mentioned in
  • -- Collector info (Sammler) (WftW Vol.4 - Clandestine Radio)
  • Literature/Schematics (1)
  • -- Collector info (Sammler) (https://www.cryptomuseum.com/spy/poland.htm)
  • Author
  • Model page created by Rafal Pietkiewicz. See "Data change" for further contributors.

 Collections | Museums | Literature


The model Suitcase Transmitter-Receiver is part of the collections of the following members.