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RM KL-203 and Repair

I'm using mine as a base setup. I'm putting 3 1/2 to 5 s-units on the guys who run base stations 25 miles away. Barefooted I'm 1 s-unit to them. Of conditions are noisy I'm in the mud. If I switched to a 5/8's wave ground plane or jacked my A99 antenna up another 10-20 feet I could do better.
 
9C1Driver said:
With a KL203 run it with an AM dead key of 1 watt and 10-18 peak watts. I would also suggest a fan. There are plenty who have probably run more into them but they don't last if you do.
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Thanks. I have turned my 959 down to a one watt deadkey with produces a 90ish watt swing and over 100 watts whistling. The guy who sold me the 203 keeps saying that it'll run on a 3 watt deadkey producing 200 watts pep. Anybody care to comment ?
 
My friend has a kl203 and he tells me it never gets hot???
He is seeing 30 watts dk and swinging 90
100 watts on side band....
 
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He must sandbag then. I've had 3 of these amps and would see similar numbers. They get HOT after a few minutes of ragchews. I always put a fan on them.
 
Lil'Yeshua said:
Thanks. I have turned my 959 down to a one watt deadkey with produces a 90ish watt swing and over 100 watts whistling. The guy who sold me the 203 keeps saying that it'll run on a 3 watt deadkey producing 200 watts pep. Anybody care to comment ?
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I've run the older red 203 amp for over 10 years. Still work like new. Keep the lower DK. And you and your 203 should be happy for years. People that I know who put more than 2 watts into their 203's killed them early.
 
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There was a guy over on eHam who did some testing with a 203 and a spectrum analyzer. The 203 is a fairly clean amp if you run it at about 70% it's rated output. More than that it's just another splatter box.
 
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Well,mine got fairly warm with my 959 doing 1 1/2 watt deadkey and using my Road Devil. It doesn't get as warm now at a 1 watt or less deadkey. I didn't use the dummy load this time but set VR18 through my MFJ-971. In other words VR18 is cranked all the way back. But that's okay. I also turned back VR16 to just over 100% modulation in order to have a cleaner audio. The KL203 is doing a 35 watt deadkey and swings to 90 watts. I now watch my modulation meter rather closely keeping the peaks touching 100%. That means keeping the RD's audio gain at a little less than halfway. My 959 really drives the 203. The 959 still swings 15-20 watts with the rf power pot turned all the way down.

Ratso,would it be beneficial for me to add the filter section to my 203? Yours has it,mine has the places for it but the components aren't there.
 
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Lil'Yeshua said:
Thanks. I have turned my 959 down to a one watt deadkey with produces a 90ish watt swing and over 100 watts whistling. The guy who sold me the 203 keeps saying that it'll run on a 3 watt deadkey producing 200 watts pep. Anybody care to comment ?
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A 1,2, or 3 watt dead key will have nothing to do with getting that amp to peak at 200 watts. It's the radio's peak drive or swing that will get you there.

I ran mine on SSB and at 20 watts PEP it would hit 200 watts but get warm fast. I added a fan and kept the peak input at about 12 watts, that was good for 100-120 watts.

I would not even try to get 200 watts from one because it won't last long that way. Won't last long on AM with a 3 watt dead key either.
 
9C1Driver said:
A 1,2, or 3 watt dead key will have nothing to do with getting that amp to peak at 200 watts. It's the radio's peak drive or swing that will get you there.

I ran mine on SSB and at 20 watts PEP it would hit 200 watts but get warm fast. I added a fan and kept the peak input at about 12 watts, that was good for 100-120 watts.

I would not even try to get 200 watts from one because it won't last long that way. Won't last long on AM with a 3 watt dead key either.
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Agreed. I'm happy with the 1 watt deadkey and the swing my 959 has. It don't have a swing kit installed either. At least the one's 25 miles away can hear me better in slightly noisy conditions.
 
9C1Driver said:
A 1,2, or 3 watt dead key will have nothing to do with getting that amp to peak at 200 watts. It's the radio's peak drive or swing that will get you there.

I ran mine on SSB and at 20 watts PEP it would hit 200 watts but get warm fast. I added a fan and kept the peak input at about 12 watts, that was good for 100-120 watts.

I would not even try to get 200 watts from one because it won't last long that way. Won't last long on AM with a 3 watt dead key either.
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I'm curious. What radio did you have driving the amp? It's obvious that my 959 doesn't produce those kind of PEP numbers unless I decide to have it modded to drive a 203 amp.
 
I use an RM KL203 (earlier red model) with my FT817, with 5W SSB I get around 80W, it doesn't get too hot either as I use it with my pedestrian mobile outfit. I also use a blue version with my Icom IC703 with 10W PEP SSB, now that bad boy gets hot pretty quick, if I was rag chewing all the time I'd definitely have a fan mounted on top.
 
Lil'Yeshua said:
I'm curious. What radio did you have driving the amp? It's obvious that my 959 doesn't produce those kind of PEP numbers unless I decide to have it modded to drive a 203 amp.
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One radio was an old orange display 2950, I could vary the SSB power from about 6 watts to 25 watts. On AM a 1 watt dead key would swing 12-14 watts. It had a very mild tune.
 

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