[swaghauler]

Originally Posted by Homer

Pretty cool ideas!

Great ways to introduce some adventure hooks. Or a one off mission in support of or to counter a listening post.

Does anyone have a mechanic for COMSEC and radio security? Like a roll against Electronics or INT to use an SOI or put up a directional antenna? Or breaking simple substitution cipher?

I do add a cascade of technical skills referred to as "Operator Skills." This cascade includes EW/ECM Operator, Radar Operator, Radio/Comms Operator, Sonar Operator, Millwright, Powerplant Operator, and Industrial Operator (including sewer plant, water plant, injection molding machines, extruding machines, and industrial ovens/food processors). I include Wire Tapping as a Qualification of my Radio/Comms Operator Skill (for those who are confused, I have posted my house rules in ANTENA's thread on Homebrew in this forum).
I give 1 exp in Radio/Comms Operator to all Military Basic Training Skill lists so every soldier has at least Familiarization (Skill 0 + Attributes) and all of the above Operator Skills use the average of [INT+EDU] for their Characteristic bonus. This Skill includes the use/setup of Field Telephones as well as Radios (hence the Comms part).

During play, I only require that a Skill roll be made if EW (electronic warfare for the uninitiated) is in play. Otherwise, no roll is needed AFTER Comms have been established!

Establishing Comms:

This involves running wire and plugging in phones to a switchboard or setting up an antenna and tying it into a radio. It is a ROUTINE Task and on an OUTSTANDING Success, your Radio's range will be increased by 5% to 30% (1D6 X 5) because of good antenna emplacement. A failed roll will see a Radio's range DECREASED by 5% to 30% (1D6 X5) due to poor antenna placement or a bad connection. A CATASTROPHIC FAILURE means the radio won't transmit or receive after being set up. Alternately, on an OUTSTANDING Success, the PCs may designate that the antenna is instead, placed so as to make detection more difficult. Large antennas normally use the Vehicle Spotting Chart in my Observation & Spotting Rules as they are tall and straight and need an unobstructed line of sight to the horizon. However, on an OUTSTANDING Success, the PCs can use the Spotting Chart for a Man-Sized target instead. The reduced Detection Range alone (1,000m) makes this a good choice for an Outstanding Success.
Once the radio or phones are running, no more rolls need to be made for basic Radio transmissions.

Advanced Commo Tasks: Direction Finding Of A Transmission.

If you have a DIRECTIONAL ANTENNA, you may be able to determine the direction that a broadcast is coming from. This is an AVERAGE Task and requires that your directional antenna be able to be rotated in order to determine the direction of any transmissions. On an OUTSTANDING Success, the operator is also able to determine a rough RANGE in addition to a BEARING (direction) based on the received transmission's signal strength. It should be noted that this bearing is "cone-shaped" and can vary from as wide as 20% (10km on a 50km transmission) to as little as 5% (2.5km wide on the same 50km transmission) based on the quality of your Directional Antenna.

Advanced Commo Tasks: Triangulation.

If you have two or more radio operators with directional antennas in different physical locations, You may be able to TRIANGULATE a transmission. This is done by having each operator make a roll to Direction Find the transmission. This is an AVERAGE Task for two operators. Three Operators using Direction Finding from three differing points makes the Task ROUTINE and four Operators make the Task EASY. The transmission will be isolated to a "box" a number of kilometers square equal to 20% of its Range for two operators (ie a transmission at 50km will be located in a 10km box). The box size will be 10% of the Range for three Triangulators, and just 5% for four or more Triangulators. On an OUTSTANDING Success, Altitude will also be established for the transmitter (please note this will be the altitude of the ANTENNA, not the radio).

Decryption OF Transmissions:

This will require specialized computer gear and the difficulty will depend on the quality of your equipment and the type of encryption.

Scrambled Encryption: This simply involves rearranging the letters in words. It is the easiest method to break because you only need a key/guide.
It is a DIFFICULT test to decrypt.

Scrambled & Frequency Hopping: This system "skips" from frequency to frequency and can be very hard to decrypt because you must also determine the sequence of the frequency hopping before you can begin. Frequency Hopping alone is not completely useful (AVERAGE Task to decrypt) because a lot of modern radios can listen in on multiple transmissions (frequencies) at once. Thus recognizing the pattern is pretty straightforward. HOWEVER, with this method, not only do you have to record the pattern of frequencies, but the words are also scrambled and will have to be put back in order. Thus, this Encryption is a FORMIDABLE Task to break.

Digital Encryption: The holy grail of Encryption when it became common in NATOS "LINK" data-sharing systems (LINK 12 was the most common in the 90s). It uses "bits" or characters to represent EACH WORD or even LETTER in a communication. The initial systems used 4-bit, 6-bit, and 8-bit (the most common in the Cold War era) representations for each LETTER in the LINK system. This meant that a 100-letter phrase would need 800 characters to be decrypted and placed in a proper order to read that phrase. Modern systems now use 128-bit encryption PER LETTER! Thus you will need a computer and special software that can do MILLIONS of operations per second to decrypt Digital Encryption. Therefore this is an IMPOSSIBLE Task to perform.

That is just an overview of my Radio Ops/Comms rules. I hope that helps.

Swag.