Palomar 250 amp

Ok you got me beat ...

 

The instruction book that came with my KL203P specifies:

"Input power AM: 0.5-10 W;

Input power SSB: 1-20 W.

So, taking the factory's information at its word, I concluded that an untouched legal CB radio with a 4W maximum RF output is absolutely fine for input power to the amp. I further concluded that the radio I'm using is certainly OK to use out of the box with the amp because it actually produces about a measured 3W deadkey anyway; pretty typical for factory-fresh units.

However, after doing a lot of research, I found that some folks who proclaim to be very experienced users of the KL203P and at least one who claimed to be a government-contractor expert who experimented a lot with the the 203P, opine that a bit less wattage is better for the amp in terms of clarity and longevity. It was noted by several that the little amp can get very hot during long conversations, and that reducing the radio's RF output to the amp to one or two watts reduces this heat and thus is better for it. Necessary? No. A nice thing to do for the amp? Yes.

So, since I feel good when I'm being easy on equipment, I decided to get my radio's output going into the amp down to about a watt or so. I decided to do it by reducing the input voltage to the radio with the use of resistors. I used three cheap instruments to guide me: a voltmeter, an RF watt meter and an SWR meter. This whole bunch I had already on hand to keep track of how my equipment is doing, and altogether they set me back what, maybe forty bucks total? They ain't the best on the market, but me neither.

Through testing, I was able to see how much various voltage levels to my radio drop the radio's RF output wattage. I set a minimum of 12 volts to the radio as my target with the vehicle running, and I found that when plugged into my vehicle's electric system when running, a resistance of 1.06 ohms on the feed line to my radio reduces the voltage to an actual 12vdc. At that input level, the radio that I use with the 203P amp puts out about one watt RF, which is my target.

So that's how I be a little nicer to my 203P, and it's been working for me very nicely indeed for quite a while. At that radio input of about a watt, the amp produces about 60 watts on Channel 19, which is what I call my sweet spot. Although the amp is rated to output a maximum 100W AM (and 200W SSB), I see no need to push it to the limits with higher radio input wattage, as the additional communications benefits would marginal at best anyway.

BTY, I haven't found anyone else who uses my approach to reduce the ratio output via the use of reduced input voltage, and it's probably considered to be a stupid idea. But when I die, I want them to play the ole refrain, "I did It My Way." (Which, by the way, is probably what kills me.)

Addendum: voltage feeding the amplifier is at full vehicle system values, a nominal 14vdc.

 

Okay, earlier when I posted that if it works for you, it should work for the rest of us......well I wasn’t expecting the way you are doing it. Sounds like it would be easier for you to use your amp only while sitting at a truck stop with the motor turned off. LOL.

 

I used the amp quite a while with the 3W input from the factory radio, and it produced near the 100W spec IIRC.

As I noted in my treatise, I just wanted to be a little kinder to the amp. Necessary to do: of course not. Not much of what we do with these radios is necessary to do.

 

Just something to think about.....


All of these great techs retuning radios to make the amps work never heard of creating a pad to attenuate the signal into the amp so there is no tuning of the radio needed. I know this requires knowledge and a bit of simple math but come on ...

 

I had a Magnum predator for a while, it was pretty cool, run radio as a normal dual final radio or turn on the RFX and have 100 watts pep, I really dont know why other manufactures ( Ranger,Stryker) dont incorporate that unless Magnum had a patent.

 

No patent, I have one around here, not a bad radio.

 

Well the amp probably wont be an issue for long. Tuning the input is not to be nice to the amp, You have no understanding of radios how they work or how what you do affects other on the radio. Enjoy your splatter box, Run power in close proximity to other radios you can blow out the other guys stuff.

A dirty radio can and will take out the receive on adjacent channels especially in say a truckstop, or passing someone when you are using your amp.

 

Is this directed to me?

 

No