I have a new linear, KL203P truck not running ,dead key 25Watts, truck running around 90 Watts, but either mode wen talking wattage backs up instead of going forward, anything I can do to correct problem?:?
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KL203P linear
- Thread starter Robert Cook Sr
- Start date
KL203 need constant supply voltage and 2W AM carrier and 12W SSB PEP.
Do it and come back with results.
Mike
Do it and come back with results.
Mike
radio putting out 1.5 watts dead key only Am radio but when talking backing up. SWR is less than 1.1.1 on steel whip
To measure power you must use dummy load and trusted meter. Measuring on antenna is never accurate.
Mike
Mike
Mr Cook...the KL203P is only rated for 100 watts max output. When you truck is turned off you’re only supplying 12 volts or less which isn’t sufficient. That’s why when the truck is running and generating 13.8 to 14.5 volts (roughly) you’re seeing more output. Since your driving it with 1.5 watts and seeing 90 watts. I’d say the amp is doing what it’s suppose to.
Regarding the watt meter backing up when you modulate here’s a couple of observations. Does your meter read PEP or only RMS. You need a peak reading meter that can capture the peaks of the modulated envelope wave as there are two peaks...a positive and a negative. It’s not unusual to see backwards modulating if your meter isn’t reading peaks. Honestly 10 watts short of seeing 100 is nothing. That amp is only specified for 100 watts output. When using just the radio does your meter show forward modulation (I.e. an increase in wattage). If not then you’re seeing exactly what you’re putting into the amp.
Brad
Regarding the watt meter backing up when you modulate here’s a couple of observations. Does your meter read PEP or only RMS. You need a peak reading meter that can capture the peaks of the modulated envelope wave as there are two peaks...a positive and a negative. It’s not unusual to see backwards modulating if your meter isn’t reading peaks. Honestly 10 watts short of seeing 100 is nothing. That amp is only specified for 100 watts output. When using just the radio does your meter show forward modulation (I.e. an increase in wattage). If not then you’re seeing exactly what you’re putting into the amp.
Brad
Backward swing. Not end-of-world. Some of my radios do that with a KL203 or -P model.
The following isn’t advice, per se, more that I think I recognize what you’re saying:
If you know (not guess) radio is 2.5W DK, you’re “okay”. Still better to use real advice above to round off safe operation.
If this is a big truck (semi tractor) the supplied CB fused circuit is either 10A or 15A. I’ve successfully run the amp plus low DK radio combo that way. But I’d advise a wiring upgrade (fused POS) to give some breathing room.
Now, depending on several factors and using a separate tuner (PEP Meter would be a better choice), I’ve seen from 50-90W with most radios I’ve used.
Look into “backward swing” as a search topic.
And a late WELCOME! to WWDX.
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Thanks for answers. I only get approx. 1.5 watts dead key with Nissan truck running giving me around 90 watts dead key only change is increase of voltage to Lenear.. I used CB 23 channel back in the 1970's Have equipment used until 1983 when I moved , seemed like I never had time to get back into CB until recently.. I just thought a 50 watt jump with just voltage increase wasn't normal. Years ago I used a Browning marks 111 SSB and am Mark3 am transmitter for years until my move to another state, also have Varmit 350 tube type let over also Popping fuses after 50 year rest. I read these forums to try to learn something from the big guys that know more than me. I had some schooling in the early 1970 's but transitors were just being used then.
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I used a PDC 600 meter and Delta meter to check ,got same reading on both meters
I have a 2 tube Elkin leaner that show a 40 watt swing using same meter 1 watt dead key a uniden 980 SSB
Welcome! What radio are you using with the 203? If the meter is swinging backwards, then you are overdriving the amp. If the amp dead keys 90w, then whatever the dead key on the radio is, it needs to be turned down.
Chris
Chris
I agree with ShadeTree. I have the same amp and my radio is set at 1.5w DK. With the amp on it will DK at 30w and swing to 140w or so. This is using a PEP watt meter. I would turn down the power until it DK’s around 25-30w amp on. You have no headroom so it’s swinging back.
It swings back with 1.5 watts into it and 25watts from Lenear with motor off my radio being new uniden pro 520XL only keys 1.5 watts with dummy load on meter a PDC600 I just checked my PDC meter, it has switch for pep and average, I'll run through more test tomorrow if not raining again
It seems strange that the dead key jumps up to 90w with the motor on. Maybe the mic is picking up the sound of the motor?
What condition is your battery in? It may not be holding proper voltage in a static state, it's possible to have less than 10.5 VDC. and your vehicle will still crank. That would explain why there's such a big difference in output from one state to the other. Agree with the backwards swing theory, providing you're getting ample voltage and current, it's possible both are starving, depending on your setup.