RFX-75 add on to Cobra 29LX-- will it work on the CB jacks?

I had this exact same radio in my old pickup and I ran IIRC 12 or 10 ga wires to power it, Can't remember what my main fuse was but I want to say 20 amps? Got rid of that pickup and the radio won't fit in the new one so its going in my Pete, but first I'm going to run a new set of wires up to it, probably fused off the battery, of 12 or 10 ga, not sure if I'll try to use the factory jacks in the headliner or just poke my new wires through.

I don't like running too much power through too small of wire. In my younger and dumber days I did and had bad things happen to me.

My 2 cents.

 

I want to make sure I don't melt the wires!

 

Nearly every RFX-equipped CB has been tuned for strictly the highest possible RF output, and usually over 75% of that power above 5 watts has been spurs and harmonics. If it's got variable power output, turn it down to the minimum before you turn it on, make sure your antenna presents a decent load, and try talking on it. Increase the power to max and see if the fuse holds. Keep in mind, however, that merely increasing the fuse rating won't increase the current carrying capacity of the wires to the binding posts, so you might end up with a case where the wires melt down inside the dash to "protect the fuse". Not a good outcome.

Also you should expect that a "dirty" RFX install, putting out a substantial proportion of its output outside the CB band, will not be transferred efficiently to a CB antenna, so the antenna will reflect the out-of-band signals back to your SWR meter, *correctly* showing a horrible match. No amount of tuning on the antenna will make it broadbanded enough to radiate signals from 27 to 108 (or so) MHz.

If you're able, can you run separate, larger gauge wires from the "CB Power Posts" down to the junction block or wherever it picks up its power? I'd personally run a pair of 10 gauge leads through a length of black heat shrink (just don't shrink it, so it'll look natural) or wire loom to help conceal it from prying eyes. Put a 20-amp fuse someplace concealable near the battery (as close as you can get it to the battery) and then the right size fuse that's recommended for the radio, on the short power pigtail near the radio to protect the radio against shorts or just plain too much current draw cuz of magic screwdrivers "tuning and peaking" whatever they do inside the radio.

If it turns out to be too big a hassle to run the wires big enough to run the RFX at full-ish output, then you've gotta figure out whether it's worth having a radio that *could* put out more power than the average true CB radio, but with which you can't cuz of the vehicle's wiring and a receiver that was never really tuned properly (at 90% of "CB shops") to work as well in the CB band. If it's not worth the status symbol of having a 4 or 5 watt compromise radio that doesn't hear as well as a real CB, but looks cooler than heck on your dash, then just put in a trusty Cobra or Uniden or Rat Shack.

Kind of a matter of your budget and ability to find folks who can tune your RFX-equipped Cobra with more than just a relative RF output meter instead of spectrum analyzer.

But best of luck, and happy hunting.
73

 

I got a 29ltd home with an rfx 75...#### thing works awsome..Alot of people have asked to buy it cause of its clarity and out put..An rfx 75 will do more than 75-80 watts to,try 120 range....
As said above me some 10ga and a 20amp fuse good grounding(ground plane not electrical)and someone who can properly tune radio and ant and you will get out and sound good..

I actually had a guy ask me to leave my trk open so ge could uninstall my radio and reinstall in his trk lol..He begged me to sell it to him but nope,my head swelled with all the POWER!!!

LOL now its sittin home with 3 other cobras collecting dust...I saw a new radio and had to buy it...Stryker 955..
Now at home i got 4 cobras and two predator 10k and two k 40 ant....I gotta stop collecting this stuff..

 

I wouldn't run any amplified radio to anything but directly to the battery but that's me. I was told the HP40 didn't need to be either but I would. It's the amplified version of the General Lee.
I did have a cobra 29 with the rfx75. I opted to go with the General Lee and if I want more than the 50 watts it does PEP then I'll run it on low (2watts) thru a kicker. I wouldn't do the rfx75 again. They just don't hold up.
Again just my opinion. In any case, Be careful about continually running it on less than adequate power.

 

I agree about running direct to battery with fuseable link and thicker ga wire..
Dont know about the rfx being reliable though cause mine has been fine for almost a yr till i got my stryker..
Love to have a kicker for my stryker but i wanna learn more about what i got and get it right before i take on somethin new like a kicker..
All i know bout them so far is i need a 4 pill and its about a buck a watt..

 

Mine lasted about 2 years and quit transmitting. Not sure why. I'll open it up someday and find out. I've since heard the RFX can be problematic from several reputable techs. Some of which use them when requested by customers but don't necessarily think they are all that. I will say that 29 did a fine job with it tho. It got out good and the quality was still as good as the Cobras are known for. On the other hand I know some techs really push them so who knows.
I'm not sold on a kicker either but did have my General set up so as to have the power switch deadkey at 2 watts on low should I go that route. TBH I think the 50+PEP I get on high is sufficient tho and the quality is outstanding on this radio. I wish the Cobra 29 had the power and the the options the General does out of the box tho. The 29 is a good quality radio that receives and transmits well for what it is.

 

Well to be honest i have had like 5-6 techs workin on it sence i bought it,and every tec would say WTF did that guy do...Sence adding the rfx and haven it looked after by the last tec its been cats ###..
I have 4 cobras at home now and its gettin to be a bit much..Ill sell 3 of them but keep my oldest one..Its one i bought in the late 90's and been a perfect radio with nothin more than a echo board and if memory is right finals upgraded...Its been a long time sence i used that radio so im not sure anymore..That radio will never be sold or touched inside again..Its super clear sounding radio with a echo board and astatic mic..
The bt cobra sux cause of the mic quality and my lcd one is awsome to..Jesus maybe ill keepem all lol..

 

Mine had NW and weather and BT but I had a tech mod an RK56 for the 5 pin and add a button for it.