Cobra29 lx amps?

I have one with the built in rfx 75 on the back works good not sure if cb shops are still installing those or not I've seen those little blue kickers that are supposed to be 100 watts I think Italy RM maybe never used one but never heard any complaints about them

 

Yes the KL-203 (RM Italy) amps do work very well. But you will need to lower your DK to less than 2 watts.

 

Yuppers: what Big_M said.
I've got one in my Chrysler van that's paired with my Emperor 10 Meter multimode rig. The radio has a front panel power level pot, and I've got an external relay that switches the KL203 in or out of the circuit. I don't need the amp for SSB; it already puts out 25 watts, and when 10 meters is open, that's plenty of power. When I use the amp for AM or FM, for which the radio is rated at 10 watts, I lower the radio's output to 1 watt (I marked a place on the power pot) and the amp puts out between 80 - 85 watts.

As long as that amp sees a clean (as it's seen on a spectrum analyzer) input, the output is also clean. Any more than 1.5 watts (2 *absolute max*) input drives the finals in the amp into substantially non-linear operation, where they draw too much current to survive for long because of the heating.

That's been my experience here on my service bench, as well as that of lots of other technicians who post elsewhere.

Hope that helps.

73

 

There are a lot of other things besides terrain and power output that you'll find affect your range. Your antenna system has a greater effect upon your range than anything else you can do. 1,000 watts into a poor antenna with badly installed connectors, set over a Fibreglas® roof (or entire cab), will convert most of that energy into heat.
If you're lucky enough to find a channel that's vacant *and* the skip has died out (at least temporarily), and you've got a decent antenna mounted to a large surface of (ideally) sheet metal, you might expect to talk 20 miles or more with 100 watts. Remember, though, that having 100 watts output and a "just average" receiver, especially when trying to talk to another station that has a severely compromised station, will be an exercise in frustration.
At my base station, with a homebrew quarterwave groundplane with the tip at 30 feet, I can reliably talk to another 4-watt base station in the evenings, after the skip dies down, about 19 miles away. Being bases, however, we don't have all those typical vehicular noise sources handicapping our receivers, so it's easier for us to hear each other. And if someone inbetween our stations decides to key up a mobile with a reasonable antenna system and 100 watts to make some reference to his dainty underthings, he'll likely take us out.

Skip has several time periods that affect it: where we are in the 11-year sunspot cycle, then the time of year, and time of day. Also, you can count on being able to talk skip when it's dawn or dusk at your place to other places that are experiencing dawn or dusk; the so-called "gray line."

If you want to be able to hear if the "skip is running", just tune into channel 6, home of the "Superbowl". It has become, for lack of a better term, a gentlemen's agreement for the folks running power into the tens of thousands to hang out and brag to one another about why they're akin to RF Gods by transmitting senseless streams of gibberish. But even massive power like that is pretty useless when the skip has been turned off for the day by the laws of physics, and their ground wave might only get them 25 or 30 miles.

Trying to get heard on channel 6 during the day with even 100 watts is closely akin to flatulence in a cyclone. Within a couple of miles, you *might* be able to be heard by a local station (like under 10 miles; maybe less with mobiles and compromise antennas) over the noise boxes. And trying to boost your chances with a "CB grade" amp, with no input or output filtering (typical of solid state amps marketed towards CBrs) into the hundreds of watts will likely put a majority of your signal on several adjacent channels, up and down the channel list from what you've got dialed up, where it's essentially wasted, except for its ability to render useless many channels that you don't *think* you're transmitting on.

When the skip is running, 100 watts can make enough of a difference in getting through or not on a lightly-used channel, because you'll be a couple of S-units higher on their receiver than a barefoot CB.

I listen to 38 LSB sometimes, or at least Channel 6 long enough to see if the band is open. When it is, then the 10 Meter, 6 Meter, and maybe 12 Meter bands should be open. I use CB for a propagation beacon when I don't want to bother looking up the lists of low power beacons on the other bands to see where the bands are open to.

Sorry I don't have a more concrete answer for you. It's sorta like asking, "How long is a piece of string?" or "How much does a boat cost?" There will always be many variables over which you have no control. But if you optimize your antenna system, you'll be helping your receive ability as well as your transmit side. And remember that, if you're barely making it to the other end with 100 watts, and the other station is barefoot, he/she/it may get frustrated because he/she/it can hear you for a couple of miles after you can no longer hear him/her/it.

73

 

I know somebody near me. (you could send that mic along and get it fixed too.) The trouble with using recommended CB shops from people you don't know is they may not know a good technician when they see one. Their opinion may be based on just how well they were B.S'd. Getting your radio "tuned up" then asking strangers for a radio check is not reliable anymore either. So somebody may think their newly tuned up radio is right on when it isn't. I can't believe there is not a decent tech somewhere in your area. Hopefully somebody will chime in. On my Cobra I've had one of the switches converted to a hi/lo power switch for when I run a amp. Works out great.