RM KL 203P Questions

[DevilDog66]

Okay, here it goes....I am about to pull the trigger on an Italy RM KL 203P and was advised to tune my radio down to 2 watts and the amp will do 20w pep on SSB. however, I see on the specs of the 203p that it will do 100 watts with 10 watts of input. Why can't I leave my radio at the 5 1/2 that it is doing since it was peaked and tuned? The tech says it swings to about 6 1/2w, therefore I should be able to get out say 55-65 watts? Someone please HEEELP!

[1206FL]

First of all AM and SSB are 2 different modes of operation. AM requires a carrier, which with those amps can be anywhere from .25-2 watts dead key on AM and swinging to about 4-5 watts max. On SSB 12 watts should be fine for input to the radio. If your radio is doing 20 watts on SSB, that may be a bit much for the kl203. There is no carrier on SSB, just power when you modulate or inject a tone. If the radio has been "peaked and tuned" it is probably going to be too mug for the KL203. They don't require much input at all, and make sure your vswr readings are good as well. But mainly get the dead key set down and the pep wattage brought back down to about 6-8 watts pep. That is about all the amp needs for AM. Again, for SSB stock radio with 12 watts will work, if you can lower the power down a tad it might help with heat. And add a fan to the amp as well.

[silvereagle1]

Like he said...
2 watts DK with around 8-12 swing on AM will be good
10-12 on SSB will give clean sound.

I run my 503 with just a little under 2watts on AM and swing around 10-12 watts.
SSB I pep around 10 -12 watts into the 503 and I've never had a bad audio report and the heat sink stays cool for the most part. Been running it for over 2 years now with no problems. Had a fellow CBRT member tell me I was going to blow the amp up. Actually argued the point. Wish he was still on here so I could tell him he was wrong. cheers:

[DevilDog66]

Thanks for the info fellas. I went ahead and got the KL 203P. I figured if I ever get an SSB radio I'll have an amp capable of SSB, but for right now its going to be used only on AM. It also has the pre-amp option which I figured will be usefull to pull in those distant signals or when I'm out on the interstate in BFE! I do have another question though, can I hook up the wires for the power to a 2 hole cig plug adapter so I can move the radio and amp from car to car?

[silvereagle1]

I wouldn't plug it into a lighter socket. Lighter socket not designed for the amperage the amp will draw. I'd run 10 gauge to the battery. You can try the socket just to see but I don't think you'll get enough juice for the amps full potential. I'm not sure what size wires are on the backside of that power socket or what size fuse is in the fuse box for it either. I'd say the wire is smaller than you need. I believe the 203 draws 10 -12 amps.

[Deleted User 14541]

The 2 watt deadkey thing gets thrown around a lot. Most of the time it's close enough and is a good starting point. I'd still put a meter between the amp and antenna to see what's coming out of the amp. Running a big deadkey on AM makes heat and those little amps have a small heatsink. They rate it at 200 pep max so if it does 150 pep watts I'd run the deadkey out of the amp around 30 watts. Maybe less if it runs too hot.

Is the radio the midland you have on your profile? If it is I'm not familiar with them but what kind of watt meter was your tech using? The numbers you've posted sound like average wattage not PEP (peak envelope power). I can't imagine it keying 5 watts and swinging 6 pep. You would have very little audio and sound terrible.

[DevilDog66]

The 2 watt deadkey thing gets thrown around a lot. Most of the time it's close enough and is a good starting point. I'd still put a meter between the amp and antenna to see what's coming out of the amp. Running a big deadkey on AM makes heat and those little amps have a small heatsink. They rate it at 200 pep max so if it does 150 pep watts I'd run the deadkey out of the amp around 30 watts. Maybe less if it runs too hot.

Is the radio the midland you have on your profile? If it is I'm not familiar with them but what kind of watt meter was your tech using? The numbers you've posted sound like average wattage not PEP (peak envelope power). I can't imagine it keying 5 watts and swinging 6 pep. You would have very little audio and sound terrible.

I'm not sure what kind of meter he was running, but I bet he probably meant average wattage. I agree with you, if it was swinging to 6 I would sound horrible. I haven't had anybody tell me that when I get radio checks. I also run a Cobra power mic set on 8. The radio 1001LWX is there compact version with WX channels.

[MDYoungblood]

Dropping the DK will let that little amp live a longer life and the amount of watts that are lost is insignificant on the receiving end. If your using it behind the Midland you shouldn't have a problem, that is a single final radio like the Bearcat 880/980, don't have a tremendous amount of swing anyway.
I would not use the cigarette lighter socket, the circuit is really not designed for a continuous draw of amperage and you'll probably pick up loads of noise from it. Straight to the battery is always best, install a fuse at the battery positive lead before it goes through the firewall for safety.

3's

Greg

[DevilDog66]

MD thats a big rog! Man, I can't tell you how much I appreciate all the info on my amp questions! CBRT slays it!

[Scholar]

I just received a KL 203P and installed it in my truck. Tuned my Bearcat 980SSB down to 1.5 watts dead key before putting everything together. I had already ran #10 wire from the battery to a power block for the radio so it was a simple matter of hooking the KL 203P into the power block. Works great and I am even talking skip with it.

[theglide]

I have the same setup, 980SSB, KL-203P. When I lowered my AM deadkey under 2, the onboard diagnostics failed so I turned it back to 3. I don't use the amp for AM anyways. Lowered the SSB a bit though. Works good. Good sounding combo. I have a D104 handheld mic so I leave the radio mic gain at 2 and mic volume on mic at 4 when using the amp for a clean, clear sound. Great setup at a real good price! Ireland heard me the other day from my home in Florida. Too much traffic to converse.

[DevilDog66]

Just posting an update.....got my KL 203P on Friday. Looks great! All blue with blue buttons. I think this is the latest model of the 203, most pics I've seen have red buttons with a blue or red case/heat sinks. Anyway, I'll have to wait till Wednesday to get to the local DX shop to have it installed. I think I'll have him put a quick disconnect power cord on it so I can move it from vehicle to vehicle.

[silvereagle1]

Quick disconnects are the way to go. I have my radios on a rack and have quick connects on everything.

[MDYoungblood]

Quick disconnects are the way to go. I have my radios on a rack and have quick connects on everything.

I like Anderson Powerpole connectors, once you use them you'll never use anything else, the initial cost is the crimping tool but it will last forever.

3's

Greg

[Thumpor]

Guys I have a question. I have a bearcat 880 and I can't figure out how to tun down the dead key. I can only get it down to 4 watts, how do you turn it down to 2 watts for the kl 203p. I am new to working on radios, iv'e been talking on them for years but recently startrd trying to learn to work on my own. thank you

[295 antenna]

Check you tube
I believe I've seen something there

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Found this [Please login or register to view this link]

[MDYoungblood]

The 880 is a single final radio and turning it below 3 watts dead key starts other problems like the automatic SWR meter will no longer function, the modulation suffers, and there is the possibility it shortens the life of the radio.
The little RM-203 isn't much of an amplifier but it will live at 3 watts input if you give it breaks in use, if it is mounted to where you can touch the heatsink, if it feels hot, stop using it. A better choice is the RM-503 or comparable.

3's

Greg

[Mentor3006]

So what is the consensus on driving the KL203P with a 100% stock case never been opened AM/SSB radio so assume 4w AM and 12w SSB? The form factor for this amp is perfect for my application, and I don't need 300w to get my point across. So the KL503HD seems like overkill that from a size factor causes its own set of problems. Just not sure since the manual says 10 AM/FM/SSB if that means 10W PEP that SSB is supposed to be limited by the factory to... Or am I going to let the magic smoke out of this if I don't have the radio turned down for it?

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My question has been answered by Youtube... I know what I must do now.

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Been watching a ton of youtube videos on this amp, more than a few folks doing great with them driving em with a box stock radio. So I did a thing, and well, we will see for sure if this is enough push, should be...

[Mentor3006]

I noticed a poster here posed the question about hooking up to the Cig lighter socket. MOST vehicle 12v lighter sockets are 20 amp circuits running 10ga wire, but it wouldn't hurt to check your specific vehicle(s).

Per RM Italy specs the amp is fitted with a 12amp fuse, and is rated at a 10 amp input current. So yes, even if your 12v socket is a power port and not a cigar lighter socket, it should be 15 amps and more than enough to push the amp, but do NOT run both the amp and radio on the same circuit!