Spojovací prostředky, PVOS, zbraně, taktika... aneb neucelené a nekoordinované čtení o technice ČSLA

Spojovací prostředky, PVOS, zbraně, taktika... aneb neucelené a nekoordinované čtení o technice nejen ČSLA

Czech, English, German or even other languages You will find over here depends to information source availability...

Sunday, February 27, 2011

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


  1. Thanks for starting this blog, Petr. Great job! I'm always interested in this type of equipment. Here is the photo of my RM 31-M-a station as set up in my shack: http://ws19ops.com/Radios/Czech%20RM-31Ma.JPG . I love to use the station and it's on the air at least twice a week!

  2. Hello,

    thank You for comment. I know about You and Your beautiful setup. You are maybe only one who is actively using RM31-M-a coded name Trinec on the air. I will try to post more articles in english but be patient as it will take time.

    I hope we will have chance to make QSO using Your Trinec and my RM31-a coded name SuperTana setups on 80m band. It must be during good condition as the power output is only 6W on my side.

    Good luck,

    73 - Petr, OK1RP

  3. Hi Petr.

    I have one of this keys in use with my ham radio.
    It is fantastically well made. The feeling is outstanding. Solid and with superb quality. Will last for many many years of use and abuse.
    Mine has a 4 lead connector. As you mentioned 2 are only active when transmitting and 2 when receiving (lever up).
    The leads have different thickness so the key can only be inserted one way in the transmitter.

    The operating knob has got a very pleasant shape for the fingers and it sits at the right height on the desk. You can transmit for hours and not feeling tired.

    Thanks for sharing this info. I have learned a lot about my RM-31 CW/Morse key from this blog. This key and the Baumuster T1 are my favorite CW Keys.

    73 - Rob, YS1RS

    1. Hello Rob,

      thank You for Your information about the RM-31 pump key. I am sending the big congratulation for your key. You are really lucky as the 4-plugs version of the key comes to be a really hard to find on the flea markets...

      It is great way how to switching the TX/RX of any TRX simply by key itself without necessity of the PTT foot switch or so.

      More often the 2-plugs version can be reachable where the only TX pins are used. It was used in RM31-M-a or RM31-M-s-p radio setups coded name Trinec where the RS-41 transmitter has been keyed separately.

      Enjoy this blog my friend.

      73 - Petr, OK1RP

  4. Does the pivot point rest inside some small ball bearings or in a bushing of some sort? I just ordered one of these from the Czech Republic and wondered how long it will last. Everyone seems to like the feel of it (4.9 star average reviews on www.eham.net) and it looks to be better made than one I almost bought from Bulgaria (also a military key). Thanks!!!

  5. Hi,
    there are no ball bearings.
    Please look for the link here for details of the construction:
    73 - Petr, OK1RP

  6. Hello

    Im trying to buy these morse keýs
    Can enyone Help?
    Thank you For any Help


  7. I can try to help you. Please email me directly. indians at xsmail dot com

  8. I purchased a Czech military RM-31 straight key from W4KRN Karen, SKCC # 4495S,at the 2013 Dayton Hamvention for only $25.00 USD = 21.53 Euros = 551,53 CZK and absolutely love using it! I love the great feel of the key and best of all, because of the enclosure, I never have to clean the key contacts! It's my second most favorite straight key after my J.H. Bunnell CJB26003A Navy Flameproof I purchased from J.H. Bunnell Co.Telegraph Apparatus in Kings Park, NY (NOS)=New Old Stock that is mounted on a 1/2 inch (1.27 Cm) thick steel base that was custom made for me, with the screw holes tapped and threaded) by W4CUX Bill Worley, SKCC # 5497T, before his tragic death on December 28, 2012 from pancreatic cancer. Thanks for writing this very informative article about the RM-31! Mine has the later 2 prong plug on it. Very 73 from KU4GW Cliff, SKCC # 652C.