Can this mod:
http://cbradiomagazine.com/March 2007/Cobra 29 LTD Super Modulation Modification.htm
Be done a 29LX?
http://cbradiomagazine.com/March 2007/Cobra 29 LTD Super Modulation Modification.htm
Be done a 29LX?
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Super Modulation Modification
- Thread starter RoadRanger
- Start date
Yes the LX is basically the same radio as LTD beyond the bezel and weather feature.
If you do the color code route, that resistor shown in the photo may be a bit too high ohmic - 100 ohms may wind up blowing the driver - the one that is fed by this "JP36" mod. It is from the predriver throwing RF at the base and if you use the 100 ohm (or any range in the area of 82 ohm on up) resistor - you run the risk of more power at the base than at the Collector and poof.
Just wanted to post this, for that is one of the top reasons people have a radio in for repair, the blown Driver from the power level "swing" that mod does.
The danger comes more from the heavy modulation ADDED to the Collector without enough DC bias to offset that level of Audio power - somethings gotta' give. And it's usually the Driver that surrenders. The 100uF is ok, but going to the extreme of 1000uF and squeezing it all in there - is not. Risk of shorts is higher for one...
May be better to do another type of mod that isn't so "fixed" when you want to run a station that let's you remove an amp and/or run straight to the antenna. The Variable power - may provide more flexibility to interface the radio to the amp and tailor the drive level. Especially when you want to run the radio stock at times, those instances, the JP36 mod would actually do more harm than good.
The danger comes more from the heavy modulation ADDED to the Collector without enough DC bias to offset that level of Audio power - somethings gotta' give. And it's usually the Driver that surrenders. The 100uF is ok, but going to the extreme of 1000uF and squeezing it all in there - is not. Risk of shorts is higher for one...
May be better to do another type of mod that isn't so "fixed" when you want to run a station that let's you remove an amp and/or run straight to the antenna. The Variable power - may provide more flexibility to interface the radio to the amp and tailor the drive level. Especially when you want to run the radio stock at times, those instances, the JP36 mod would actually do more harm than good.
I use a 75 ohm . and a 220uf cap. or I use the variable mod as shown in the link I left for you
http://www.cbtricks.com/radios/cobra/mods_&_info/graphics/Cobra_Uniden_Var_Pwr.pdf
http://www.cbtricks.com/radios/cobra/mods_&_info/graphics/Cobra_Uniden_Var_Pwr.pdf
In the past when I'd done these mods, I used a 1000uf cap instead of the smaller ones. Mostly because I had extras of that size. Then I would tune the audio for max CLEAN audio. A scope is the only real option here to see that. Then it was work that I could stand behind IMO.
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Another radio about to go onto the air with crappy audio. If people can't hear you it isn't because your audio isn't loud enough....