U.S. M-209 Simulator
 

With all of the interest in Enigma and other cryptographic topics in the forum, I thought folks might be interested in a virtual "hands-on" experience that shows how the other half lived in World War II. In May 2013 the Maritime Radio Historical Society (MRHS) and the Military Radio Collectors Group (MRCG) joined forces to give interested parties an opportunity to copy a Morse code (CW) message which had been encoded using an M-209 Cipher Machine as used by U.S. forces in World War II and Korea. Listeners who had the good fortune to own an M-209 could use it to decode the message while those not so fortunate could use an M-209 simulator developed by Dirk Rijmenants to achieve the same end.

Although I was on the other side of the country during the event, I was able to successfully copy the Morse code message and use the M-209 Simulator to correctly decode the message transmitted by the MRHS. If you want to avoid spoilers and make an honest effort to decode the message, don't read the MRCG after-event action report or the comments in the following posts. Here is the MRHS announcement of the event:

http://archive.constantcontact.com/f...190830388.html

Mark Blair's announcement of the event is available here:

http://www.nf6x.net/2013/04/ksm-mrcg...pto-operation/

You will need the key table here to correctly set the internal pins and lugs:

http://www.nf6x.net/2013/03/a-collec...-key-table-fm/

You will need Mark's series of posts on how to use the M-209 in order to use the simulator:

http://www.nf6x.net/2013/03/practica...ine-chapter-1/

The M-209 Simulator is available here:

http://users.telenet.be/d.rijmenants/en/m209sim.htm

In order to successfully decode the message, you will have to follow all of the procedures actually used to adjust pins and lugs in the M-209 according to the proper key table, test your adjustments, determine the external message indicator, generate the internal message indicator from the external message indicator, etc. as described in Mark's tutorials. Simply feeding the encoded data from the Morse code transmission directly into the simulator will NOT work. I recommend reading through all of Mark's tutorials at least once to get your bearings on how to use the M-209 before attempting to use the simulator. Also, note that the simulator has clipboard and auto-typing features to make it easy to copy the M-209 output and eliminate some of the tedium of entering the encrypted text a single character at a time (i.e., you can copy and paste the whole encrypted message at once after you have removed spaces and linefeeds). Getting through the tutorials and getting the simulated M-209 in order will probably take 1.5-2 hours.

Here is the Morse code message as transmitted by the MRHS at 1800 UTC on 04 May 2013 on 16914.0 kHz (the encryped message text is in bold for clarity):
Once you correctly generate the deciphered message, you can use a search engine to see a photo of the original message.

The radioteletype (RTTY) message mentioned in the Morse code transmission was apparently only copyable in the immediate San Francisco area due to less-than-optimal propagation conditions, but at least one listener was able to copy and decode that message as well.

Good luck!

Welcome back!