Midland 75822 | Channel Mod Work

Here’s a concise, technical write-up for the Midland 75822 channel modification, commonly performed to expand transmit/receive frequencies beyond the stock 40 CB channels.

Step 1: Disassemble the Radio

  1. Remove the battery pack and antenna.
  2. Remove the four screws on the back of the chassis.
  3. Carefully separate the front and back housing. You will see the main PCB (printed circuit board).
  4. Locate the PLL chip – a small (usually 16 or 18-pin) IC near the channel selector knob. Look for markings like "LC7137," "D8581," or "MC145106."

Summary

  • Mod difficulty: Moderate (requires opening the case and soldering/cutting a trace).
  • Result: Opens approx. 120 channels (26.515–27.405).
  • Drawback: Power output is reduced to roughly 0.5W–1W on "extra" channels.
  • Legality: Illegal to transmit on frequencies outside the standard 40 CB channels without a proper license (Ham) or if the radio is not type-accepted for those frequencies.

Modifying the Midland 75-822 can expand its standard 40-channel operation to 120 channels by adding extra bands

. These extra frequencies typically include a "Low" band (C) below Channel 1 and a "High" band (E) above Channel 40.

While these types of modifications are discussed in various hobbyist circles, it is important to consider the technical and legal implications: Technical Risks

Modifying the internal circuitry of a handheld radio involves working with small surface-mount components. Hardware Damage

: Improper soldering can easily bridge unintended contacts or damage sensitive integrated circuits, rendering the device inoperable. Warranty Voidance

: Opening the casing and altering the hardware typically voids any manufacturer warranty. Signal Interference

: Increasing power output or changing frequency bands without proper filtering can cause interference with other essential radio services. Regulatory and Legal Considerations

Radio frequencies are strictly regulated by national authorities, such as the FCC in the United States. Authorized Frequencies

: CB radios are designed to operate within a specific 40-channel range (26.965 MHz to 27.405 MHz). Operating outside these frequencies without a specific license is a violation of federal regulations. Power Limits midland 75822 channel mod

: Standard CB radios are legally capped at an output of 4 watts for AM and 12 watts for SSB. Modifying a radio to exceed these limits can result in significant fines and equipment seizure. Certified Equipment

: In many jurisdictions, it is illegal to use "non-type-accepted" or modified equipment on the Citizens Band.

For those looking to expand their radio capabilities legally, pursuing an Amateur Radio (Ham) license is a recommended path. This provides legal access to a much wider range of frequencies and higher power levels after passing a competency exam.

The Midland 75-822 Go to product viewer dialog for this item.

is a highly versatile handheld CB radio known for its "all-in-one" design that bridges the gap between portable and vehicle-mounted use. While it natively supports 40 standard CB channels and 10 NOAA weather channels, some users seek a channel modification to expand its capabilities. Understanding Regulatory Compliance

It is important to note that in many jurisdictions, including the United States, the Federal Communications Commission (FCC) strictly regulates Citizens Band (CB) radio equipment. Under FCC Part 95 rules, CB radios must be type-certified by the manufacturer to operate only on the 40 designated channels within the 27 MHz band.

Modifying a CB radio to operate on frequencies outside of these 40 channels or to increase power output beyond the 4-watt legal limit is considered a violation of federal law. Such modifications can result in interference with other radio services, leading to potential fines, equipment seizure, or legal action. Furthermore, any internal modifications to the circuit board will immediately void the manufacturer's warranty. Optimizing Performance Within Legal Limits

While expanding the channel count is not permitted, there are several safe and legal ways to improve the performance and range of the Midland 75-822

Antenna Upgrades: The range of a handheld CB radio is heavily dependent on the antenna. Replacing the stock "rubber duck" antenna with a high-quality telescoping antenna or connecting the unit to an external vehicle-mounted magnetic antenna can significantly increase transmission and reception distance. Here’s a concise, technical write-up for the Midland

Power Supply: Using the included mobile vehicle adapter allows the radio to draw power directly from the vehicle’s battery, ensuring consistent performance compared to using standard AA batteries.

Squelch and Gain Adjustments: Properly adjusting the squelch control helps filter out background static, allowing for clearer communication on active channels. Memory Channel Programming : The

allows for the storage of up to five frequently used channels. This is done by selecting the desired channel, pressing the "F" (Function) button, and then holding one of the memory (M1-M5) buttons until the setting is saved.

By focusing on these external improvements, users can maximize the utility of their device while remaining in compliance with radio communication regulations. Would there be interest in more information regarding antenna types or battery maintenance for handheld radios?

The Midland 75822 is a 30-watt, 22-channel GMRS (General Mobile Radio Service) mobile radio. It is not designed to be modified for additional channels because its frequency range is locked to GMRS/FRS bands by hardware and firmware.

However, there are two common interpretations of a "channel mod" for this model:

Step 2: Identify the Diode Matrix

Near the PLL chip, you should see a small grid of diodes or empty solder pads labeled something like "CH1, CH2, CH4, CH8" – these are binary weighting pins (1, 2, 4, 8). There may also be a "Band A/B" pad.

  • CB Channels 1-40 use a specific combination of these pins grounded (via diodes) to a common bus.
  • To get extra channels, you need to change which pins are connected.

Step-by-Step: The Classic 3-Switch Mod (PLL Based)

This mod targets the PLL 02A or equivalent chip (often an LC7137 or D8581 in Midland units). We will be manipulating the "binary" inputs to the PLL.

Write-Up: Midland 75822 Channel Expansion (FCC “Freeband” Mod)

Objective
Enable access to frequencies above and below the standard 40 CB channels (26.965–27.405 MHz), including amateur 10m, “freeband,” and sometimes export frequencies (e.g., 25–28 MHz) depending on the specific PLL chip used in the 75822. Step 1: Disassemble the Radio

Background
The Midland 75822 (a variant of the 75-822 chassis) uses a Phase-Locked Loop (PLL) frequency synthesizer. By changing the binary code applied to the PLL’s programming pins, you can select channels outside the normal 40-channel range. The most common method involves installing a toggle switch or rotary switch to add or remove binary logic high/low states.

Tools & Parts

  • Small flathead and Phillips screwdrivers
  • Soldering iron (25–40W) + rosin-core solder
  • Wire cutters/strippers
  • SPDT or DPDT toggle switch (or 6-position rotary switch for band selection)
  • 2–3 ft of insulated hookup wire (24–26 AWG)
  • Multimeter (continuity check)

Procedure

  1. Disassemble – Remove case screws and separate front from rear chassis carefully. Unplug speaker wires if attached.
  2. Locate PLL IC – Look for a 16- or 18-pin chip labeled MC145106, LC7131, or similar. The 75822 often uses an LC7131 or LMX2301 derivative.
  3. Identify programming pins – For LC7131: pins 6–12 (binary code for N-divider). You will manipulate pins 10, 11, 12 (least significant bits).
  4. Cut traces / lift pins – Lift pin 12 (or cut PCB trace to it). This removes the factory channel logic.
  5. Wire the switch
    • Connect pin 12 to center pole of a SPDT switch.
    • Connect one throw to +5V (logic high).
    • Connect the other throw to ground (logic low).
      This adds ±8 channels above/below the normal range.
  6. Optional full band rotary – Use a 6-position switch to apply different binary combinations (e.g., 000 to 101) to pins 10–12, giving 6 bands × 40 channels.
  7. Reassemble – Check for shorts, mount the switch in a spare knockout hole on the case.
  8. Test – Power on with a dummy load. Use a frequency counter to verify new channel positions.

Typical Results

| Switch Position | Frequency Range (approx) |
|----------------|--------------------------|
| Normal (mid) | 26.965 – 27.405 MHz (40ch) |
| Low position | 26.515 – 26.955 MHz (“low band”) |
| High position | 27.415 – 27.855 MHz (“high band” / freeband) |

Some mods also enable 25.615–28.305 MHz with a different diode matrix.

Warnings

  • FCC violation – Transmitting outside CB frequencies (26.965–27.405 MHz) is illegal without an amateur license.
  • PLL unlock – Some frequencies may cause the PLL to lose lock; avoid dead spots.
  • Alignment – Output power and receive sensitivity may degrade far from the intended range.
  • Reverse polarity – Ensure no shorts between +5V and ground.

Tips

  • Use a frequency counter during setup.
  • Mark switch positions clearly on the case.
  • For AM-only use, avoid SSB-only bands if your 75822 lacks SSB.

Step 3: Cutting the Traces

On the PCB, locate pins 11, 12, 13, and 14 of the PLL chip. These are the Binary Data inputs (often called "Binary A, B, C, D").

  • Pin 13 (Binary A)
  • Pin 12 (Binary B)
  • Pin 11 (Binary C)
  • Pin 14 (Binary D - Not always used)

Using an X-Acto knife, carefully cut the PCB trace leading to pins 11, 12, and 13. This disconnects them from the radio’s channel switch. (Do not cut pin 14 unless your schematic says so).