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Wednesday, April 7, 2010

Urban Survival Skills – Communications Security 101 and Brevity Codes

The average Urban Survivalist using FRS/GMRS radios, like the various brands and models you buy from Wal-Mart, Target, etc., will need to develop communications protocols to ensure he/she and his/her survival group are using the radios in the most secure fashion possible.

Without some sort of communications security, the Urban Survival group risk providing potential threats with information that can be used against the Survival Group.

You, the Urban Survivalist, just may be more technical savvy than what we have to offer in this post. This is designed to help the Urban Survivalist adding common off the shelf FRS/GMRS radios to their Survival Gear and Equipment inventory and who do not have any idea of what communications security may mean.

Some of the FRS radios come with a voice scrambling mode using a form called voice inversion. This type of scrambling or Voice Inversion is easy to break using common voice inversion defeating SD type cards in handheld off the shelf frequency scanners. I understand that there is free software available on the internet that can be used in combination with computer sound cards to decode voice inversion.

So be aware that what you say on the radio will be easily picked up, decoded and understood by anybody who tries. There will be people who be able to determine a direction, from them to you, based on intercepting your signal. This can be accomplished using commercials radio direction finding equipment (called Signals Intelligence in the Military) or by skilled amateurs determining the direction of the strongest signal from your radios.

Simply, the Urban Survivalist needs to understand and use these precautions when using FRS radios.

Use Minimal Transmission Time. The longer you are on the air or transmitting the easier it is for someone to determine your direction and location, and, the longer you are transmitting, the more information you will be providing to eavesdroppers to exploit.

Protect Essential Information. Develop a list of information that you will never transmit or talk about on the radio. Some of these will be: Names – never names on the radio, instead use fictious names or code names; Locations – never send location, grid coordinates or any information that could be used to determine where you are; Assets – never talk about any assets you may have like people, food, vehicles, firearms,…anything!

Do Not Use Military Type lingo. We debated about this, but we think the easiest thing to do would be not to use military language as any eavesdroppers could determine you are a fairly well prepared Survival Group with Survival Gear, Equipment and Supplies but not too proficient to be able to hold onto to if the eavesdroppers attacked you. The flip side is that if you sounded too competent and well prepared then potential attackers may leave you alone. We think it’s better to try and stay under the radar screen.

Brevity codes are short words or phrases that have a longer meaning. Codes names are a replacement name for a location, person or thing that would not identify it.

A radio conversation that would transmit too much information may sound like this:
Person A: “House Security this is Security Patrol”
Person B: “Go ahead Recon Patrol”
Person A: “We finished with the Security Patrol and am heading back to your location, will be there in 15 minutes”
Person B: “Good copy Security Patrol”

Substitute some fictious names and some brevity codes and the sme conversation may sound like this:
Person A: “Hey James this is Charles”
Person B: “Go ahead Charlie”
Person A: “I got the house cleaned and mopped”
Person B: “Excellent”

House Cleaned means "Security Patrol finished". I’m cleaning the house means "still conducting the Security Patrol". Mopped may mean "I’m 15 minutes from re-entering the Survival Location". Excellent may mean "good copy".

We at will be doing some additional communications posts in the near future – please stay tuned, stay safe and get prepared.


  1. I recommend getting your Amateur radio license. you will learn a lot about communications. there are lots of clubs all around the country you can join with Amateur radio. Our club has 4 repeaters in the county. when disaster hits the cellphone will either be down or given priority to emergency management or jammed. Many times I able to communicate all over the country with a radio I built and antenna I built on only 15watts. Mores code isn't required anymore but its good to learn!

  2. Thank you this what I would do. but I would use the code 10 type of communictions first because it simple and next you can change what each code means for a different day or mission. I would also go with hand held ham radios and have a base unit for you base. also I would train each person in the use of the radios when on down time and before each mission set up what channels to be used that mission. Their are a lot of things you can do with hams. But one thing remember get ones that come with rechargeable battiers and that are able to use AA or AAA batteries also this way all you need is a solar panel and a small motorcycle battery to keep the charged. Also keep battery acid around just in case your motorcycle or car battery does die.