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

RDM-61M (eng)

The RDM-61M/RDM-61 VHF transceiver (Ženíšek)

This transceiver was devoted to use in the field by commands and to replace wire telephones communication lines.

RDM-61M

Frequency: 235 - 260 MHz (2 switchable ranges)
Channels: 12 (each range)
Modes: F3 duplex
Sensitivity: 5uV
Power output: 100mW
Max. distance: up to 50km using 4el. yagi


Antennas: whip, 4el. yagi (yagi can be easily folded)
Power: pack SZ 6V / 40Ah
Operating time: 12 hours
Size: 120 x 205 x 135mm
Weight: 25kg (complete set in transport wooden box)


The wooden box consisting a lot of accessories including coaxial cables, microtelephones, long whip antenna parts, 2pcs of the battery packs, 8pcs poles mast and ropes set, test equipment unit, etc. This box was used just for set transportation. The station itself has been mounted into the commands vehicles or it was used in the field as portable VHF manpack radio.

The preview model was RDM-61 (Ženíšek) named after the author of the technology concept.

This radiostation includes 4 tubes working between 390 - 410 MHz. The transmitter and receiver has been tuned separatelly. The A3 mode was used on this radio.

73 - Petr, OK1RP

RM 31 (eng)

RM 31 (coded name Supertana) - General purpose field HF radio station used by CSLA in 60's

RM 31 is general purpose (universal) field HF radio station designed for different usage as follows:

RM 31-a > vehicle installation (automobilni)
RM 31-t > tank installation (tankova)
RM 31-p > infantry setup (pechotni)
RM 31-s > self propelled gun installation (samohybna dela)

RM 31-a as same as RM 31-p or RM 31-t and RM 31-s are equiped with heptal direct heating battery tubes 1H33, 1F33, 1L33 and 3L31 from TESLA. Also Hungary replacement Tungsram was used in some cases and they were direct copy of US tubes. The only final tube RL15A with coded name EV301 (original marking TESLA was 5L50) used in TX of this RM 31 radioset is different with 9pins glass B9G socket. It is pin compatible with pentode parts of the Germany RL4,8P15 tube.

The frequency coverage is 2000-5995kHz. There is 800 channels available with 5kHz steps and (+/-) 1.4 - 4kHz variable frequency offset.

Available modes are A1, A2, A3 with variable crystal CW filter 200Hz - 8kHz!
Power output: 1.5W/A3, 3W/A2 and 6W/A1 typicaly.

Powering the RM 31-p (used by infantry patrols)

PSU for RM 31 - field radio station

The RM 31-a (vehicle setup) was powered from battery packs thru double rotary converter ZD-31b. (maybe more correct english translation is "electromechanical vibrating transducer" connected to 12V batt cells) Frame of 2x6V cells packs 5NKN-45 was wired to 12V going to rotary converter which produced neccessary voltages for RM 31 station in RX/TX modes.

Also manual crank generator RM 31-1 was available for the RM 31-p (infantry) setup which produced 400V when TX was ON. In the RX mode it was powered from battery packs 4NKN-10 on the back of the "man nr.2" in the patrol thru vibra converter ZV 31. In this case the RM 31-p setup was operated by "3 men" in field operation.

(The article in Czech language is already posted)
http://greenradios.blogspot.com/2011/02/tana-liben-supertana-mana-trinec.html

(will be continued)

Text copyright © Petr, OK1RP

R-3 (eng)

Czech Army receiver R-3





















Czech Army receiver intended for using as backup receiver in field battle vehicle installation RM31-a + power amplifier Z-RM31 - coded name Sobota. This receiver has been used also by officers and high commands for surveillance of radio communication.

Ranges:
160 - 300 kHz,
480 - 900 kHz,
0,82 - 1,7 MHz,
1,64 - 3,4 MHz
3,38 - 7 MHz

Modes: A1, A2, A3

Antennas in set:
1,8 m long whip
13 m long wire

Powered: 5NKN10 (1x1.2V and 4.8V)

Size: 340x120x400 mm
Weight: 14,6 kg














More detailed description will come soon...

73 - Petr, OK1RP

Czech Army green radios on YouTube

Hello,

there are the Czech Army green radios and related video clips demonstration I found on YouTube. I am posting the links to them overe here. For more information You have to contact the owners of the video clips directly. All rights reserved to the authors of the clips signed below the clips on the Youtube.
(updated 11-Apr-2012)

R-4
R-3
RF-10 in UAZ-469
RM-31 hand key
V3S Praga fully equipped
RF-10 battery pack renovation
RF-10 in QSO with Clansman EVHF antenna
RF-10 in QSO using short whip
RM-31 hand key 4-plugs by YS1RS

Enjoy it!

73 - Petr, OK1RP

RM-31 Morse key - 1960 (eng)

RM-31 Morse hand key

This almost 60 year old CW key was made for the Czechoslovakia military (CSLA) radios. The first radio station where this key was used the RM 31 (Super Tana) was developed in 1952 so the key could be dated into 50's but commonly used and known is the key with later radiosets from 60's. This key is known as the RM-31 Telegraph Key (Telegrafni klic RM-31 in Czech language). These are the most pleasant hand keys to use and they are extremely well made.


They were used as the part of different versions RM 31 troops radiosets with coded name Super Tana (1952) or in later conteiner's version of RM 31-M-s-p radiosets with coded name Trinec (1964) and in many others in 60's years of course.


It has adjustments for tension and contact spacing and it has a very nice feel to it.


The keying arm moves upward into a second position for receiving (if all appropriate contacts are used like in RM 31 - Super Tana transceiver version). There are labels on the front edge of the enclosure for the up or non-keying position "Prijem" (receive) and the down or keying position "Vysilani" (transmit). This version of the key is using 4 plugs where twins are used for TX and another twins for RX separately. The TX/RX switching (PTT) was managed simply by pulling up the fingertip frame of the key as it is shown on the picture below.


The key with the original lead and original 2 plugs (which fit 4mm connectors) was used for example with separate transmitter RS-41 in RM 31-M-a installation on Tatra T-805 vehicle.


The key is made from bakelite and olive green painted steel. The key measures 150 x 65 x 50 mm (5 1/8 " x 2 1/2" x 2"). Weight is 470g (1.03 lbs).


Text copyright © Petr, OK1RP