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CB Hacks
Author: Frederick R. Vobbe, W8HDU
3rd Update: March 28, 2022
2nd Update: June 18, 2020 / Original: July 13, 2017
This page has been updated since there has been a change in the attitude of overseas radio manufacturers, especially the Chinese companies like QTY, Baofeng, Anytone, Leixen, Tidradio, Tosuny, Radioddity, and many other.
Most have become very unfriendly with hams and radio users and no longer supply schematics, or service manuals with their products. You can't buy them or download them. Before thinking about modifying any radio, be sure to have "in hand" the schematic, and if possible the alignment information! If you don't have this, you can not modify the radio. I realize you can get a radio cheap, but what good is cheap if you can't do any mods to it.
Those in the prepper and survivalist community are now boycotting Chinese manufacturers. This includes radios thought to be U.S. made, which are actually Asian made, and U.S. branded. As with any mod, you must have documentation in hand before starting any work!
This page deals with modifications and hacks made to Citizens Band radio equipment. It's written for the preppers and survivalists perspective of communications. Please note, I'm not suggesting you make any mods to a radio which violates the radio's certification by the Federal Communications Commission, Industry Canada, or other regulatory bodies. I'm explaining how some people do it.
Most were made to Chinese radios early in the process before proprietary designs were in fashion. I think the reason for their "openness" is the Chinese made radios can be used all over the world, and programmed for each country's unique band plan.
This quest started when I heard about mods being made by survivalists and preppers. In specific, mods shown on YouTube, and overseas video platforms. There is a community of "freebanders" who use various frequencies in operations, and also those who used these odd frequencies for personal communications, neighborhood/rural block-watch, patriot paramilitary operations, encrypted comms, and even transmission of slow-speed data by survivalists.
Some of the commonly modded radios of Chinese origin contain AM and FM operation. In the case of the QYT model CB-27, (a CB radio sold in Europe, Asia, and America), the mod to open frequencies is as simple as a wire cut and resetting the processor. FM use is just a button press.
The QYT CB radio is 4-watts, and if that's too small for you there are mods for higher power, or a "linear amplifier" can be added to the output of the radio to achieve higher power. In some pictures I saw a few repainted Chinese manufactured amplifiers. Note: F.C.C. Rules prohibits persons from using any device capable of amplification of RF power in the frequency bands between 26-29 MHz.
A sharp-eye prepper noted in the Russian/Ukrainian war, (2022), Ukraine forces were using FRS radios, as well as modded HF and VHF radios for military comms.
In one still-frame picture a Yaesu FT-857 can be seen with the frequency readout of 26.0025 LSB. In another picture a QYT CB-27 radio is seen under the dash of truck with the frequency 25.9955 FM. In a video the translator talks about secure communication and shows how an encrypted VHF transmission sounds using an ICOM IC-2100 mobile radio in a backpack with a whip antenna. Without the encryption device you can't understand a word. With the encryption device it's clear, secure communications!
At the end of this page I will talk about the antennas which can be used with these radios. While there are some stock antennas, requests from preppers and survivalists lean toward a more discrete, hidden antenna.
USES FOR SECURE COMMS
It is not hard to imagine why someone would want to operate out of band, or off the normal band plan. Suppose you're on CB Channel 19 in the U.S. First of all, you're competing for the airwaves with all the other motorists and truckers on the highway. But let's say you're wanting to go to your secret "bug out" location. How many people do you want listening to your transmissions? This is why a lot of people will use frequencies which are not normal. The need for secure, secret communications are necessary.
CB has 40 approved channels. But if the radio can be modified for other frequencies, that provides them with the use of the radio for hunting, logging, coordinating construction, or in convoy, without someone hearing them. A Freebander may operate on 26.540 MHz, which is below channel 1, and out of the band plan, and on an unassigned channel. This would give them a near-private channel to communicate on. According to one prepper, 26.540 MHz is used by people in Latin American, transmissions are in SSB or FM. Best guess is taxi drivers in a metro area. (any help in identifying use and location would be welcomed).
Another group has more sophisticated radios operating in FM mode, and DCS. DCS is a digital tone transmitted by the sender along with their communications. In one community, they have radios with DCS, and when someone notices a stranger in their area, or someone lurking around that they don't know, they transmit to inform friends. If nobody is transmitting, the radio is stone silent, even if someone is talking on the channel. But when the DCS tone is activated, it turns on the speaker alerting the rest of the community to an emergency or alert. It's a simplified warning system off public communication networks.
In 1977 there was a group of survivalists operating on 26.4150 MHz with Johnson Model 123 CB radios. Their existence was not known until an aging member of the group sold his radios, and related the story of their use in 1985. They used this frequency for coordinating regional patrols, welfare checks, organizing hunting and work parties, and logistics for acquiring and shipping goods.
VOICE ENCRYPTION
There are devices which allow a persons voice to be encrypted in analog or digital, transmitted over the air, and de-encrypted by someone who has the encryption key. The simple form of "voice inversion" is enough to keep curious ears from listening to your transmissions. However, if you're trying to keep your transmissions away from the government or spy organizations, you'll need something much better than standard encryption.
For most private user communications an encryption system like Midian sells will work well. Those who use it, or the older Selectone ST-022 systems, the level of security is 99.5% secure.
One thing to be aware of... if you're using radios in encryption mode, and a friend tries to contact you with their radio which does not have encryption, you will not hear anything from your friend. Encryption attributes must match on all your radios. There is no margin to "ballpark" it. It is also important to understand that audio and logic levels are carefully set. With encryption, everything must match.
In a future article, I'll explain how a friend modified an ICOM IC-2100 2-meter ham radios for encryption, as well as other frequencies.
PACKET
A group in a rural area use radios connected to Packet TNC units and computer. This allows them to send a message like you would keyboard chat on the internet. You can also send small files, and pre-formatted text messages.
The message to the left was received at 10:22 Eastern time, Friday, April 10, 2020, on the frequency of 26.312500 MHz, narrow band FM. I just happened to catch this as I was monitoring for broadcast station RPU traffic on 26.31000 MHz. (Our local TV station uses 26.310 and 26.410 for sporadic transmissions to news crews in the field, from the crew at the TV station.)
It was apparently sent by one survivalist to another survivalist during the pandemic, so it's assumed that they made some kind of arrangement with a grocery store and dry goods store, and were asking other survivalists if they could get pick up something for them while they were getting their stuff.
The call signs are completely bogus, and you will note there are no names, or indication of where the message originated, or where they were going to pick up their groceries and dry goods.
Many messages like this will simply contain a tactical name, not identifying the person specifically. You would never know they were there unless you knew the method for transmitting, frequency, and just happened to catch them transmitting!
Another good catch was someone feeding news in a foreign language. This was discovered by setting up a Whistler model WS-1065 to scan 25.000 to 26.960 MHz, recording the "hits" I would get on the frequency. Later, a recorder was added to identify what was on the frequency. Oddly, the transmission started with a female voice, (in a foreign language saying), the name "Edmonton" three times, pausing, then another three times, pausing, then the data transmission started. At the end, and after the data transmission, there was an exchange between the female voice and an unidentified male voice, (weaker signal quality), and then nothing else was heard.
The picture to the right shows the message transmitted. It was later followed by two more transmissions, each starting with the female voice, data, and then closing voice exchange. All transmitted on the HF frequency of 13.7245 MHz.
Asking a friend who is into clandestine radio operations, it's his opinion that these transmissions are from someone either on the eastern seaboard, or possibly western Europe, sending news content to a community which has a vested interest in the content. And those with the interest, perhaps, live in Edmonton, Alberta, Canada. It could be a newspaper, radio broadcaster, webcaster, podcaster ... but someone may be getting a feed of content which is off the Internet and via secretive means.
Another use I've heard has been coordinating with others while driving on the highway.
The lead car/truck may inform others of police watching the road. Or they may be coordinating to pull over for fuel. Several times during the year, (since I live near Interstate 75), there will be these odd communications as our "snowbirds" come south before winter hits, and then back north around May when it's warmer up in Canada.
There is one guy, named "Reggie" who apparently drives a motor home with other members of the family driving other vehicles, and makes the trek north, and south each year. Once I heard him say, "Let's pull off here in Lima to Bob Evans and get breakfast". Had I been more curious, I could have drove over to Bob Evans, and because he and his party likely have antennas for their radios, it would have been easy to ID him. I'm not going to mention his frequency.
Back when the Dayton Hamvention was running every April/May, it was not unlikely to hear a handful of stations on frequencies from 24.500 to 24.890, 25.100 to 26.800, 27.500 to 27.995, and 29.725 up as high as 30.350 MHz.
A pre-arranged frequency, modulation, and operation name make things more secure. But still, never assume you have 100% security with your comms.
Keep your information you don't want others to know in your inner circle. The more people you tell, or blab on the air, the more chance you will have of being monitored or tracked.
RADIO CHOICES
Radios change year to year. You have to do your homework by reading forums, lists, and groups. What you need to look for is a radio which can be modified, and has a track record of mods that maintain integrity. Optionally, you can look for surplus radios at hamfests or swap-n-shops.
Recently a large number of Motorola business radios were at an Ohio flea market. They were Motorola Mitrek mobiles, TS1JJA4000DK, low band mobiles (30 - 41 MHz). I saw one fellow buy 11 of them for his survivalist organization. I have doubts that he had a license for operation, which is mostly occupied by business and some public service operations. But if they find an unused frequency, chances are they could stay on it for a long time without being discovered.
HF radios can be opened up as well, and in Europe there seems to be a lot of conversations in the 3 MHz band, between land stations, and also maritime stations. With the conflicts in Cuba starting, some conversations were noted in the 8, and 11 MHz band between Cuba and the U.S.
ANTENNA CHOICES
I'll start by saying that the physics and the science of antennas has not changed since radio was invented. Any metal object can be a CB antenna. However, unless it is engineered properly, it will not radiate efficiently.
A good example of this explanation is the difference between a CB antenna which is short 32" fiberglass pole on a vehicle, and the typical 108" stainless steel whip. For CB radio work the 108" whip will always outperform because it's ability to radiate a signal on the horizontal plane is much more efficient than the 32" pole, by as much as 5dB! The 108" whip is electrically 1/4-wavelengh long, and thus presents a 50-ohm load to the radio, and the max radiation leaving between horizon line to 30-degrees. The 32" antenna will radiate up into the air even at 70 to 90-degrees. Who are you talking to up there?
Grounding is as important as the antenna. An antenna without a good ground usually can not be matched. The bigger issue is that an ungrounded antenna, (if it matches), acts more like a dummy load. The radiation is spewing in all directions, rather than on the horizontal plane, which is where you need it to go.
Base CB antennas should also be electrically grounded to prevent a lightning strike from following your coax back into your home. Mobile antennas need to be grounded to the fender or chassis, but to keep electrical noise in check you should also use braided strap between body sections and chassis. Do not assume the bolts that hold your vehicle together are sufficient. On my 2019 Silverado the difference between no straps, to strap grounding, was nearly 3 S-Units!!
When buying a base antenna, there are two choices to make. An omni-directional antenna, or a directional "beam" antenna. An "omni" receives in all directions. A beam is designed to focus on a specific direction, while ignoring other directions. If you are setting up an antenna for a community of preppers or survivalists, you want an omni antenna.
A third choice is a simple dipole. However there are nulls in the signal in two directions. If this is not a concern, then it's always a nice option. See Antenna 001: Simple Dipole. This antenna can be made with scrap wire, a cheap balun, and painted camo, army drab to blend in with the background.
No matter which use you have, always buy an antenna which is suited for the environment of use. I've seen cheap basee beams fold up and break under the weight of 1/8" of ice, or snap in half with winds greater than 45 mph. Likewise, I've seen cheap fiberglass antennas snap off vehicles, or fail electrically, due to the air pressure moving/flexing the antenna during driving. (Low tree limbs are usually the death of cheap antennas). One last warning about mobile antennas; watch out for parking garages!
BEING SECURE
The more you transmit, the odds are you will be noticed. You should maintain radio silence unless it's necessary. And when necessary, be brief, discrete, to the point, and sign off.
Mobile operation is less risky because it's hard to triangulate a mobile (moving) source, but they can track your direction of travel if you give out enough hints on your travels. And if they get close enough, an antenna on your vehicle makes you the prime suspect.
Never give up specific information. Names, intersections, cellphone numbers, locations such as State or Interstate highway intersections, your destination, places where you'll stop to eat or rest; all these are hints to your path of travel. And if you volunteer any phone numbers, or personal names, you've doxed yourself. If you give out your cell phone number, potentially, any law enforcement authority can now track you by your phone.
Don't bring attention to yourself by mentioning sketchy behavior, illegal activities, how much money or ammo you are carrying, or swearing like a rapper. Basically, don't attract attention to yourself.
Try not to speak excited, alarmed, or in distress. When other people hear someone excited or distressed, they will pay more attention to the conversation.
Propagation is where a signal can skip for thousands of miles. CBers use it all the time for talking to people in other states, and other countries. Just because you're a quarter mile apart on the highway in Michigan, doesn't mean someone is listening in Southern California. Always assume you're being monitored unless you use a high quality speech scrambler.
It's always best to use nicknames, handles, or tactical call signs. Real names can implicate you. Any information which is not coded in some way is information which can be used to identify you, your actions, or location.
If possible, disconnect your antenna when park at night. Antennas bring interest to thieves, but also those who may wish to locate you. I have a whip antenna on my vehicle, and it takes 7 seconds to take out a wrench, take off the antenna, and toss it in the cap of the truck. If someone is looking for someone who was on the radio, they will be looking for an antenna. Don't be obvious.
If you have a base antenna, it's often hard to disguise. However, you would be surprised at how well your typical 5-color military camo blends an antenna into a background such as a woods. Also, you can paint antennas. Just don't paint over gaps, capacitors, etc.
HACKING A CB
Also see: CB Channels, CB Survivalist, 11 Meter Antennas