Cobra cam 89 frequency mod?

[Robotto]

I have a Cobra cam 89. It has 23 channels. I am trying to talk on channel 28-40. Is there any way that I can modify the unit to work on these channels? If I lose the lower channels it.is all good. Thank you in advance for your time.

[Bozo]

Model 89_064349.png

I have a Cobra cam 89. It has 23 channels. I am trying to talk on channel 28-40. Is there any way that I can modify the unit to work on these channels? If I lose the lower channels it.is all good. Thank you in advance for your time.

Hey @Robotto,

Welcome to the forum and great to see you on here!

The Cobra Cam 89 is a classic rig — solid build and nice audio. Since it only covers the original 23 FCC channels, getting it to transmit on channels 28–40 (which are part of the modern 40-channel band) would require a modification to the PLL (Phase Locked Loop) circuit.

Depending on the PLL chip used (likely a uPD858 or similar), you might be able to expand or shift the frequency range with crystal swaps or a channel mod kit. However, this is not a beginner-level mod — it often involves removing or replacing crystals, cutting traces, and adding switches or jumpers.

If you're okay losing the lower channels and just want the higher ones, a crystal swap might get you close to 28–40. But the exact steps will depend on the board and PLL chip inside your unit.

A few tips:

• Check the PLL chip number on the board to know what's possible.
• Search for a SAMS Photofact or service manual for the Cobra Cam 89 to get a schematic.
• Consider finding a mod guide for your specific model or similar radios.
• Be cautious — transmitting on unauthorized frequencies or making unshielded mods can cause interference and get you in hot water with the FCC.

If you’re not comfortable with board-level mods, sometimes it’s easier (and safer) to pick up a used 40-channel radio that already has those channels available.

Hope this helps, and keep us posted on your project!

73s,
Bozo

[Robotto]

Thank you much

[MDYoungblood]

Here is an old Secret CB file, hope it will download.

secret_cb_vol_14_pg45_46 Cobra Cam89 mod.pdf

3's

Greg

[Bozo]

I have a Cobra cam 89. It has 23 channels. I am trying to talk on channel 28-40. Is there any way that I can modify the unit to work on these channels? If I lose the lower channels it.is all good. Thank you in advance for your time.

Hey @Robotto

Thanks for posting!

The Cobra CAM 89 is a cool piece of CB history, but since it’s a 23-channel radio, it was made before the FCC expanded the CB band to 40 channels in 1977. Unfortunately, there’s no simple mod to add channels 28–40 without serious internal work.

That said, some folks have swapped out the channel selector crystal or added channel kits back in the day, but those parts are rare and the modification requires experience with alignment and tuning. It's not as easy as soldering in a jumper wire or turning a dial. And unless you're familiar with working on radios and have the test equipment, I wouldn’t recommend attempting it yourself.

Honestly, if you're mainly trying to talk on the higher channels, it might be easier (and cheaper in the long run) to pick up a used 40-channel CB like a Cobra 29 or Uniden 68. You’ll get full coverage and better performance out of the box.

Still, if you're set on keeping the CAM 89 for the nostalgia or as a project, I can help dig up old schematics or mod guides—just let me know.

73s and good luck with your setup!