How do I turn down the power on my Cobra 29 ltd to 2 watts?

I run what you would call a splatter amp, it’s a class C. The coax is a few feet from my directv coax, and it doesn’t interfere with anything in the house at all. I run LMR 400 and a nice choke to keep the radiation from coming back with no counterpoise. I ran a class C box by the same builder in a 2013 Volvo. It didn’t interfere with a single thing in the truck, and wasn’t grounded except to the battery. The coax was right by the dash and didn’t interfere with the gauges, speakers, ecm, or anything electronic.

 

back in the 1970's I had a browning linear, I wish i knew where it was.

he is referring to bleed over on other channels.

A modulated microphone will do the same thing if it is set on high.

Even with a 4 watt radio transmitting on a Channel if your close to it you will get bleed over on the next channel.

The channels on a CB should have been farther apart.

 

About adjusting the radio's output: I've used a resistor to bring down the radio's feed voltage from the supply line to a nominal 12vdc when the truck's system running voltage is at 13.7vdc. This brings down my radio's output to less than 2 watts, which makes the amp happy. For me, it was easier and cheaper doing it this way than finding a trustworthy and competent technician to modify the radio in the "official" fashion.

 

I think I found the answer, and how to do it.

Cobra 29 LTD super modulation modification

 

Well the guy was nice enough to warn anyone that does this swing mod, that they will have a splatter box. Of course when it comes to amplifiers, you need a clean sounding radio. There’s an old saying trash in, trash out. In other words you don’t want to sound over modulated while trying to work DX. If people can’t understand you, then they will ignore you.

 

If you would like to do it the correct way, I would suggest this link.

http://www.cbtricks.com/radios/cobra/mods_&_info/graphics/Cobra_Uniden_Var_Pwr.pdf

If it were me, I would use that worthless delta tune knob (you would have to replace the pot I believe) instead of the rf gain knob to control the dead key. But that’s just my preference.

Also this guy does a good job explaining it.



Let us know how it works for you.

 

interesting.

he uses the same capacitor, and resistor.

 

Ya the basic parts should be the same, its been a long time since i watched that video. Using the tip120 transistor should give your radio a better/smother transition from lower to high power then just putting a resistor across the capacitor. I’ve never done this mod, but if i did i would just replace the delta tune pot with another rf gain pot. Mainly because i use my rf gain a lot.

 

Of course if your not comfortable with a soldering iron, i would recommend taking it to a cb shop like others have suggested. I thought i would share with you how the mod is done.

 

Back in the day, a guy in the Detroit area came up with that circuit, mentioned it to someone else who took credit for it.