RF11M-2 (eng)

RF11 M-2 small VHF manpack transceiver (coded name Petr) used in CSLA

The RF11 M-2 was a very small and simple VHF manpack radioset dedicated for short range R/T wireless communication. It's part of design (T/R switching and PSU, features and some hardware (socket) was inspired by the German WW2 Klein-Funk-Sprechgerät d, Kl.Fu.Spr.d (Dorette) otherwise electrically it's more close design to Russian RSB. (thanks to Miro, OM3CU)

The set consisting of two main boxes: the transceiver and battery case both carried on the operator's belt. Model RF11 M/2 was a later version of the RF11 and RF11 M which both operates on 23-28MHz. All versions are virtually identical.

• Frequency range 48.5-51.5 MHz.
• Battery valves (miniature type 1S4).
• Power 1.5V LT and 120V HT.
• Modulation AM R/T.
• RF output more than 30mW.
• Super-regenerative receiver.
• 21 channels with 150kHz steps
  
• Throat microphone.
• 50MHz crystal for calibration, fitted in RF11 M/2-K.
• Manufactured in 60's
  

73 - Petr, OK1RP

Text copyright © Petr, OK1RP

Vertical antenna RM31 with capacitive hat

This vertical antenna was designed and used only for RM31-P version of the radioset.(portable/field version)

The antenna suite contained the MB31-5 khaki canvas quiver with 18pcs of pipes made from tempered steel + coper after the temper. The pipes was 530mm long each with inner/outer thread. Also the aluminium rosette tool for capacitive hat, set of ropes, insulator base and some other ancils was included.

According to actual needs or field conditions it was possible to assemble 2 types of the antennas:

1. Full vertical radiator - where all of the 18pcs pipes was assembled together with total of 8.6m height.

2. Shortened vertical radiator - where 12pcs of the pipes was assembled together to make 5.7m tall vertical and rest of the pipes (6pcs) was used to create the capacitive hat on the top of the antenna using the aluminium rosette part. This type of the vertical antenna has higher radiation pattern angle if needed.

The antennas was designed as fixed height vertical radiators and in both cases antennas was tuned/matched on the operating frequencies (2-5.995MHz) using the antenna matching unit RM31-3.

This tuner was able to tune also the shorter antennas like mobile whip mounted on the GAZ69 vehicles as same as the wire antennas like 2x7m NVIS dipole etc.


As my daddy observed this vertical antenna was not so popular between the radio operators in Army as the installation was not engaging primarily in the winter time. In their troop the antenna has been installed just two times to practise it and never again...

73 - Petr, OK1RP

Text copyright © Petr, OK1RP