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KL 203P install, first timer

now we come to SSB, according to manufacturer, is fitted with a 12 amp fuse, so its safe to say with headroom draws about 10 amp at full belt, 13.8v at 10 amp gives a dc input of 138w, allowing for an optimistic 70% efficiency (thats where your heat goes) your looking at 138 x 70% = 96.6w, even if it was 100% efficient, which it ain't or it wouldn't heat up your looking at 138w P.E.P maximum.
73 Jazz

I fully get the AM side, but help me wrap my head around the above (since a couple hours of research didn't help me as I hoped it would).

In SSB mode, @ 13.8V*10A= 138W is the maximum expected output @ 100% efficiency. 96.6w would be considered nominal.

For the sake of the argument let's assume a meter is accurate (I realize this is a weak spot).. if PEP output is in fact measured at 138W what is going on there? Is that just generating heat/distortion if above the 96.6W level?

Secondly base upon a max rated output of 200W*.707=141.4W it would seem possible to the layman, yet I know OHMS law doesn't lie.
 
Glad to hear you've had so many pm's of support,pity they ain't got the gonads to do it on an open forum, but I'm sure it makes you feel justified in your claims, but then Antron / Solarcon sell many many Antron A99's and those people think they are good antennas, so delusion is rife in cb world.

Nuff said, I don't think so !!!

You claim 1w swinging 8 - 14 which is between double and 3.5 times the Carrier / P.E.P 4:1 ratio that gives 100% modulation (the perfect modulation for a clean AM signal). Your suggesting a chronically overmodulated signal full of harmonics being amplified by a non linear amplifier is a good idea, it has little if any filtering too by the way.

For a 1w input ideal P.E.P would be 4w P.E.P

I suggest 2w Carrier swinging to 8w P.E.P a perfect input for that amp and you tell me I'm wrong, I bet you a spectrum analyser won't tell me I'm wrong.

You suggest we do it differently in the UK, I do anyway, I can't speak for everyone as Ancient Modulation is barely if ever used here on CB, but I started on a President AR7 back in 78, you may know it, it's a FCC certified radio, and a damn good one at that, my next radio was a 120 Ch Cobra 148 GTL DX,pb010ab followed days later by an export version Stalker 1X, you will probably have seen that in the states too, in 40 AM/SSB guise, we got 80 AM/FM/SSB.

So right away I've started on 3 first class radios, all with AM, All Uniden made, which we used regular up till nov 2nd 1981 when our Govt in its infinite wisdom decided to legalise 27.60125 - 27.99125, on FM or more accurately Phase Modulation.

I also used the 148 on UKFM as it slides easily to the -3.75 Khz offset our government chose as well as still using it on AM for a couple more years and SSB till I got busted with it in 83, basically I was a daft kid of 16 and was overdriving the amplifier with it and causing allsorts of interference, which brought the wolf to the door and me seeking how to prevent it happening again.

I've had many radios since, all export Uniden or Ranger clone Sideband radios with AM. With an unmeasureable amount of Amplifiers, too many for my memory to recall.


you also claim the same P.E.P figures for SSB.


30 years later, almost 31 and your trying to convince me 1w carrier/dead key, call it what you want. swinging 8-14w P.E.P is a better setup than a 2w carrier swinging 8w P.E.P signal

Its no secret 100% modulation is the cleanest and best signal to amplify for a clean output and its a well known fact a 4:1 carrier ratio to P.E.P is whats required to achieve that without distortion/harmonics. I'm sure by now Freecell would have a sore neck from nodding, cause despite his people handling he was a very smart guy. I'm sure a few others will be too and those that don't agree about what I'm about to type, don't pm me bullshit, say it out here in the open, I don't bite, much.

Now we'll get to the crunch, and do some figures:

Positive Modulation % = SQ RT of P.E.P - SQ RT of CARRIER in Watts / SQ RT OF CARRIER in Watts X 100 :

Lets start with an easy one 4w P.E.P and 1W Carrier

4W P.E.P (sq rt is 2w) 2w - 1w (1w is sq rt of 1w carrier) = 1W / 1W = 1X 100 = 100% MODULATION, simples.


now we'll do it my way and both your minimum and extreme, I'll round up to keep it tidy ;)

my 8W P.E.P and 2w carrier = sq rt 8w P.E.P = 2.82w - sq rt of 2w = 1.41 = 1.41w/ 1.41w = 1 x 100 = 100% modulation.


lets try your best case scenario, cause your worst is frightening,

8w P.E.P and 1w Carrier already established both of these sq rt's in above 2 examples so i'll leave all that out:

2.82w - 1w = 1.82w/1w = 1.82 x 100 or 182% modulation, that's your best case scenario going through an amp with no filtering of any significance.


now the worst case, dearie me: that would be 14w P.E.P and 1w carrier, in your words not mine:

SQ RT of 14w P.E.P = 3.74w now we know SQ RT of 1 is 1 so here goes :

3.74w - 1w = 2.74w/1w carrier = 2.74 x 100 = 274% modulation going through an amp that ain't the cleanest to start with.

now we come to SSB, according to manufacturer, is fitted with a 12 amp fuse, so its safe to say with headroom draws about 10 amp at full belt, 13.8v at 10 amp gives a dc input of 138w, allowing for an optimistic 70% efficiency (thats where your heat goes) your looking at 138 x 70% = 96.6w, even if it was 100% efficient, which it ain't or it wouldn't heat up your looking at 138w P.E.P maximum.

I reckon this amp has about 10db gain with those 4 transistors biased the way they are., so when your pals are hitting 20w input the amp can't sustain 200w output and fries.


your friend/s with 3w swinging 20w are actually putting less overmodulation / distortion through than you are, whats blowing their amps is too much drive, yours ain't blown yet but it will be spewing shite all over the place and soon will blow at that level of abuse, thats if you don't get a knock at the door from the FCC first for causing mayhem all over the spectrum.


your friend/s overmodulation level is 20w P.E.P and 3W carrier,

sq rt of 20w P.E.P is 4.47, sq rt of 3w carrier is 1.73w so

4.47w - 1.73w = 2.74w / 1.73w = 1.58 x 100 = 158% overmodulation, another splatter box.


Feel free to get your pm buddies to check my figures, and bare this in mind, no matter what power meter you use be it bird,lp100,dosy or any other, it can't differentiate power on the fundamental frequency to power outside it. Only tool that will do that is a spectrum analyser which will break up exactly where that power is going. I can tell you this much without looking at a spectrum analyser at 182% modulation and over it ain't all going on the fundamental frequency.

now I've had time to answer you:
NUFF SAID !!!!

P.S. we don't have that problem using FM/PM as its not amplitude modulated, but don't mean some of us don't know AM swing is bullshit and when amplified, filthy.

73 Jazz




Hey I was thinking of buying this amp, can you tell me what the modulation would be in this example? Thanks man.

http://www.worldwidedx.com/cb-radio-gear-swapshop/167107-sale-dss-amp-2-transistor.html



Here is a copy & paste in case it's gone.

Digital Sport Systems
2 TRANSISTOR AMP ( 2 TRW. transistors)
Preamp does NOT work
Low power input 1watt deadkey ...output 3 watt DK swing to 220
Hi power input 1 watt DK...output 40 watt DK swing to 240
Older amp it is biased AB for SSB .
Price ..$100 shipped to lower 48
Thanks for looking
 
I think you need to contact RCI, Magnum, Galaxy, Stryker, and Connex so they can hire you. Seems they all build lots of Export radio's that can achieve higher peak wattage levels from carrier levels of 2-8 watts. Some will swing 40-50 watts from say a 3 watt carrier. And they sound so bad on the air that lots of forum members here keep buying them every day.

I gues i'm gonna have to send all my radio's to you so you can tune em right since DTB, Custom CB, Sparky, Key CB, Bob's CB, and Bells CB tuned every one of them wrong. Dang.
 
I fully get the AM side, but help me wrap my head around the above (since a couple hours of research didn't help me as I hoped it would).

In SSB mode, @ 13.8V*10A= 138W is the maximum expected output @ 100% efficiency. 96.6w would be considered nominal.

For the sake of the argument let's assume a meter is accurate (I realize this is a weak spot).. if PEP output is in fact measured at 138W what is going on there? Is that just generating heat/distortion if above the 96.6W level?

Secondly base upon a max rated output of 200W*.707=141.4W it would seem possible to the layman, yet I know OHMS law doesn't lie.

Hi mate,

Firstly we came to the approx 70% by different means, your using the RMS value of.707 on a manufacturing claim and on a P.E.P output, RMS is the root mean square of the wave voltage not the P.E.P power.

My conservative 70% came from the way the amplifier is biased, and what bias class that is, 60-65% is probably a bit more accurate, the rest of the dc input is lost in heat via the heatsink.

The 12 amp fuse tells the main story, when fusing something you always allow a bit of headroom, or it would pop constant, if it shorts it will overcome that headroom and blow fast. I think its safe to assume 10 amps is nominal draw, and as P = I x V 10 x 13.8 amps is 138w Dc input, the 60-70% efficiency is typical for most cb amps, driving it the way I would I'd expect to see about 80 w or so AM P.E.P, or a 20w Deadkey from amp from 2w input,and closer to a hundred on SSB with slightly more drive as it has a far lighter duty cycle, still wouldn't push it to 20w, more like 8-12 P.E.P (Baring in mind the voice will rarely peak at 12 P.E.P and average about 8w P.E.P depending who's voice it is) won't last long at 20W Swing,

any extra power you see would come from overdriving with distort and would change amplifier bias as it struggled to cope, transistors may handle extra poswer a while, but that signal is filthy and a power meter can't tell that, just ain't worth it, no one will ever notice a few extra happy watts, except the saddo that watches a power meter all the time their transmitting, I'm sure theirs others here could give you an even more detailed explanation,

all I will say is RM and Zetagi of Italy are well known to have redifined what a watt is be it on their amps or meters, all their claims are exaggerated and prey on the ignorance of unsuspecting customers, on the Zetagi B300p they claim 400w SSB from two Motorola Mrf 455's be lucky to get 160 at any drive level, as they are 75w -80w transistors in parallel, reality bares this out, they have 2 x 10 amp fuses, so say 16 amp max draw, maybe a bit more, 16 x 13.x x 70% = 154.56w, far from the claimed 200w am/ 400w ssb, but right slap bang in the middle of the specsheet value of the transistors used together, and what people with good P.E.P power meters into a dummy load will find is the real output. Even best case scenario at 13.8v x 18 amps x 70% = only 173.88w max, as long as you know the real expectations of these amp they are worth buying, I have 2 KL203P's and expect 75-100w max either on SSB or FM/AM, the lower end on Am, and higher end on SSB with slightly more drive. I've had countless B300p's too, I never go bye level 4 on them, you get almost full power there anyway, even the output power knob is misleading, its actually an input attenuator.

But at end of the day people are free to believe what they want, don't mean they or I are right. That's for others to decide, its their gear. 73 Jazz

Its no different to the claimed 9.9Dbi gain of the A99, totally misleading and preying on the buyers lack of knowledge.

There is no such thing as RMS power, Average power is taken from RMS voltage measurements, if you think radio is confusing you should check out the outrageous claims made on hifi gear, where RMS power, Peak Music Power Output, Peak Output, Peak to Peak and all sorts of Total Harmonic Distortion figures and impedance mismatches are quoted to give appearance of more power, you give a 100w from a 4 ohms amp into 8 ohm speakers they won't deliver 100w, no different to the deception used in power, gain and many other technical claims in radio, they know 99.9999999 people out of a 100 won't know what they mean anyway.

It should be outlawed and a standard of power used across the board be it Average or P.E.P (makes no difference as you can easily work out one from the other, without swing mods and using pure 100% modulation) so people can fairly guage things, but that would reveal the truth about the electronics industry and they ain't gonna do that although a few companies are honest, especially the more upmarket ones, that honesty is what keeps them top of the pile.
 
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I think you need to contact RCI, Magnum, Galaxy, Stryker, and Connex so they can hire you. Seems they all build lots of Export radio's that can achieve higher peak wattage levels from carrier levels of 2-8 watts. Some will swing 40-50 watts from say a 3 watt carrier. And they sound so bad on the air that lots of forum members here keep buying them every day.

I gues i'm gonna have to send all my radio's to you so you can tune em right since DTB, Custom CB, Sparky, Key CB, Bob's CB, and Bells CB tuned every one of them wrong. Dang.

Whatever !!

Galaxy and Connex are both made by RCI by the way, and techs generally do what dumb people ask them, They might not sound bad to you, they do to me, I wouldn't do your radios for all the money in the world cause you wouldn't appreciate it,

I notice Kenwood,Yaesu and Icom are all doing these brilliant selling points too,

have you ever actually read a service manual?

I also notice you omitted the biggest and best CB/Export radio manufacturer of all, Uniden, wonder why they ain't doing it, maybe because they like being number 1 ????

Your preaching to the unconvertable, nothing you say will convince me your right and I don't see these huge crowds of PM'ers coming in to back you up, wonder why ???? Maybe they are scared of being proved wrong too, 3 swinging 40 or 50, lmfao, I gave you the formula, get a calculator and do the square roots and see what percentage modulation that is,

I'll give you a hand, the answer is 308 % positive modulation for a 3 x 50 swing, now if you can't hear that distortion I'd be visiting an ear specialist.

Your list of techs is impressive, did you ask them to do that to your radios or did they do it of their own free will? I've seen DTB post on here a number of times, he comes across as a lot more conscientious than what your suggesting.
 
Hi mate,
The 12 amp fuse tells the main story, when fusing something you always allow a bit of headroom, or it would pop constant, if it shorts it will overcome that headroom and blow fast. I think its safe to assume 10 amps is nominal draw, and as P = I x V 10 x 13.8 amps is 138w Dc input, the 60-70% efficiency is typical for most cb amps, driving it the way I would I'd expect to see about 80 w or so AM P.E.P, or a 20w Deadkey from amp from 2w input,and closer to a hundred on SSB with slightly more drive as it has a far lighter duty cycle, still wouldn't push it to 20w, more like 8-12 P.E.P (Baring in mind the voice will rarely peak at 12 P.E.P and average about 8w P.E.P depending who's voice it is) won't last long at 20W Swing,

any extra power you see would come from overdriving with distort and would change amplifier bias as it struggled to cope, transistors may handle extra poswer a while, but that signal is filthy and a power meter can't tell that, just ain't worth it, no one will ever notice a few extra happy watts,

Thanks for taking the time. Funny, regarding the .707, I wasn't thinking RMS, but 70%, but crosswired. Though X*.707 is pretty close to 70%.

So at the end of the day, for SSB, and simply as a general rule of thumb, it can be safe to say that one would be best served to target SSB PEP at the calculated 70% number derived by Ohms law in an an attempt to provide the cleanest modulation/signal.

13.8v*10a =138w
138w*70% = 96.6w (PEP)

So xx PEP out at transciever = 96.6 PEP out at amp.
I know in my case the KL-203P is indeed pulling 10a using a 1kz tone.
At 14w PEP/1khz tone output shows 120w
At 14w normal voice it hovers around 100w

Perhaps I will drop it down to 12w PEP based on this discussion. I actually have the 12w figure, just not at my current location.

Thanks, again.
 
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Thanks for taking the time. Funny, regarding the .707, I wasn't thinking RMS, but 70%, but crosswired. Though X*.707 is pretty close to 70%.

So at the end of the day, for SSB, and simply as a general rule of thumb, it can be safe to say that one would be best served to target SSB PEP at the calculated 70% number derived by Ohms law in an an attempt to provide the cleanest modulation/signal.

13.8v*10a =138w
138w*70% = 96.6w (PEP)

So xx PEP out at transciever = 96.6 PEP out at amp.
I know in my case the KL-203P is indeed pulling 10a using a 1kz tone.
At 14w PEP/1khz tone output shows 120w
At 14w normal voice it hovers around 100w

Perhaps I will drop it down to 12w PEP based on this discussion. I actually have the 12w figure, just not at my current location.

Thanks, again.

Your Welcome,

12w or less P.E.P will give a cleaner signal ;)
For the RMS value of Peak voltage you would use the formula 1/sq rt of 2 = 1/1.41 = .707 that's it rounded to 3 decimal places/digits after the point. The formula is only for true sine waves ;)

Generally SSB P.E.P is measured using two non harmonically related tones of the same amplitude, I.e 1 Khz and 1.9 Khz or 1Khz and 2.4 Khz, input at the same time, google SSB Two Tone test.

The main point I'm trying to make here is if you put a heavily overmodulated signal through a linear amplifier, (few cb amps are truly linear) it ain't going to come out the other end clean, because your amplifying a filthy signal to start with.

I'm beginning to think that 9C1 Drivers PM's are Phantom Messages, cause their ain't a lot of them showing up here to argue his case, his only argument is based on the fact lots of people do it so by default they must be right.

If anyone out there has this amp and a spectrum analyser and a radio capable of 1w swinging 8w P.E.P can you post the spectrum analysis of that signal please, I wish I had the money to buy one and the technical stupidity to do that mod just to show you what the output signal looks like, would scare the shit out you.

Then do it with a 2w swinging 8w signal, the difference will equally astound you.

His whole argument works on the same premise thousands of people buy A99's so by default they must be good antennas, in both cases the masses are WRONG and been duped into accepting bullshit and hype as FACT.

Any textbook you read will tell you a 4:1 ratio is what is required for perfect 100% modulation of an AM carrier signal, Freecall has argued this case on here so many times I've lost count, but I'm sure those with good memories will verify that. As soon as you start increasing that ratio you lose linearity and the end result is distortion amd harmonic content at the output.

You can't put a filthy signal into a linear amplifier and expect a clean signal out, all you get is a larger dirty signal, more prone to causing interference, Am swing mods are pure bullshit, many radio stations run aysymetric output signals, which sound louder but contain distortion, albeit there's is barely perceptible and a trade off, but when you start going above 150% positive modulation its starting to get really dirty.

Using speech compression, mp3 compression or wma compression all give similar trade offs, The more you compress the dirtier the signal purity, I'm not saying it can't be done and sound "acceptable" but it definately doesn't sound good and when you approach 180% and above it is very noticeable unless your tone deaf. It is also very tiresome to listen too, try pushing a hifi into distortion and see how long you can bare it, or listen to a radio that's setup properly as opposed to one heavily overmodulated and tell me both are as comfortable to listen too. A 12w P.E.P input signal will be cleaner than a 14w P.E.P one, The reason most sensible manufacturers techs set radios for 4w AM/FM and 12w P.E.P SSB is 4w 100% modulated gives 2 x 1w sidebands, or a total of 6w average power,or 16w P.E.P. SSB has an approximate 50% duty cycle compared to a 100% modulated AM signal, therefore SSB can use double the power with the same or actually slightly less load on the PA. The 2sc1969/2312 etc all are rated around 16w P.E.P which is why when people turn up the carrier or modulation they end up blowing the power amplifier, if Uniden could get away with 16w P.E.P on export radios they would as their is no laws to stop them as those type radios are illegal in every country in the world anyway and an extra 4w would be a principle selling point, they choose not to, not because the output can't take it, but because it is so borderline they would end up with non stop repairs, although 16w P.E.P is the AM 100% modulation power level, no-one constantly talks at 100% modulation so the load on the PA is similar too SSB at 12w P.E.P., the end result is longevity of the final and a cleaner signal,

Many Ranger RCI single final radios were set at 10/20w most likely not at the factory to try to compete with president radios using a 40/50w Mrf 477 Transistor which was very rugged (will tolerate 10:1 vswr) and was only ever run at 50% or less of its potential as the surrounding circuits couldn't handle it at full drive, so next time you read thee words Lincoln High Power vwersion, that's the technical term for a shopkeeper who screwed the Alc up to please power hungry customers and blissfully unaware of the damage it will do,Uniden/President would have set them to run at full Bhuna if it was feasable without damage, distortion and harmonics which is why 9C1 Driver didn't mention them, conveniently.

Bare in mind also all the ones he did mention ripped off their PB010AB board for their exports as Shioda Ranger RCI's lawyer will tell you because they were never copyrighted,They also ripped off the PC999 Grant modulator section for their dual final radios and added it into the PB010AB boards or whatever each company mentioned renamed them as, ept3600 etc.

When Uniden moved to the Philippines they brought out a much Rarer PB010AC board and did copyright it, how do I know? because I've got 2 of those as well and are marked Uniden copyright 1991 and Made in Philippines. The brand name was President Richard. Not many of them being cloned ;)

For all you phantom PM'ers out there, come on, prove me wrong and support your pal, I know I would if it was my pal and I thought he was right :)
 
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I was playing with couple of kl203 in the past. 130-140W PEP SSB is the most you can get with clean signal on the scope. Cooling fan is needed.
Great posts jazzinger, but further than the wall you cannot go :)
Mike
 
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Glad to hear you've had so many pm's of support,pity they ain't got the gonads to do it on an open forum, but I'm sure it makes you feel justified in your claims, but then Antron / Solarcon sell many many Antron A99's and those people think they are good antennas, so delusion is rife in cb world.

Nuff said, I don't think so !!!

You claim 1w swinging 8 - 14 which is between double and 3.5 times the Carrier / P.E.P 4:1 ratio that gives 100% modulation (the perfect modulation for a clean AM signal). Your suggesting a chronically overmodulated signal full of harmonics being amplified by a non linear amplifier is a good idea, it has little if any filtering too by the way.

For a 1w input ideal P.E.P would be 4w P.E.P

I suggest 2w Carrier swinging to 8w P.E.P a perfect input for that amp and you tell me I'm wrong, I bet you a spectrum analyser won't tell me I'm wrong.

You suggest we do it differently in the UK, I do anyway, I can't speak for everyone as Ancient Modulation is barely if ever used here on CB, but I started on a President AR7 back in 78, you may know it, it's a FCC certified radio, and a damn good one at that, my next radio was a 120 Ch Cobra 148 GTL DX,pb010ab followed days later by an export version Stalker 1X, you will probably have seen that in the states too, in 40 AM/SSB guise, we got 80 AM/FM/SSB.

So right away I've started on 3 first class radios, all with AM, All Uniden made, which we used regular up till nov 2nd 1981 when our Govt in its infinite wisdom decided to legalise 27.60125 - 27.99125, on FM or more accurately Phase Modulation.

I also used the 148 on UKFM as it slides easily to the -3.75 Khz offset our government chose as well as still using it on AM for a couple more years and SSB till I got busted with it in 83, basically I was a daft kid of 16 and was overdriving the amplifier with it and causing allsorts of interference, which brought the wolf to the door and me seeking how to prevent it happening again.

I've had many radios since, all export Uniden or Ranger clone Sideband radios with AM. With an unmeasureable amount of Amplifiers, too many for my memory to recall.


you also claim the same P.E.P figures for SSB.


30 years later, almost 31 and your trying to convince me 1w carrier/dead key, call it what you want. swinging 8-14w P.E.P is a better setup than a 2w carrier swinging 8w P.E.P signal

Its no secret 100% modulation is the cleanest and best signal to amplify for a clean output and its a well known fact a 4:1 carrier ratio to P.E.P is whats required to achieve that without distortion/harmonics. I'm sure by now Freecell would have a sore neck from nodding, cause despite his people handling he was a very smart guy. I'm sure a few others will be too and those that don't agree about what I'm about to type, don't pm me bullshit, say it out here in the open, I don't bite, much.

Now we'll get to the crunch, and do some figures:

Positive Modulation % = SQ RT of P.E.P - SQ RT of CARRIER in Watts / SQ RT OF CARRIER in Watts X 100 :

Lets start with an easy one 4w P.E.P and 1W Carrier

4W P.E.P (sq rt is 2w) 2w - 1w (1w is sq rt of 1w carrier) = 1W / 1W = 1X 100 = 100% MODULATION, simples.


now we'll do it my way and both your minimum and extreme, I'll round up to keep it tidy ;)

my 8W P.E.P and 2w carrier = sq rt 8w P.E.P = 2.82w - sq rt of 2w = 1.41 = 1.41w/ 1.41w = 1 x 100 = 100% modulation.


lets try your best case scenario, cause your worst is frightening,

8w P.E.P and 1w Carrier already established both of these sq rt's in above 2 examples so i'll leave all that out:

2.82w - 1w = 1.82w/1w = 1.82 x 100 or 182% modulation, that's your best case scenario going through an amp with no filtering of any significance.


now the worst case, dearie me: that would be 14w P.E.P and 1w carrier, in your words not mine:

SQ RT of 14w P.E.P = 3.74w now we know SQ RT of 1 is 1 so here goes :

3.74w - 1w = 2.74w/1w carrier = 2.74 x 100 = 274% modulation going through an amp that ain't the cleanest to start with.

now we come to SSB, according to manufacturer, is fitted with a 12 amp fuse, so its safe to say with headroom draws about 10 amp at full belt, 13.8v at 10 amp gives a dc input of 138w, allowing for an optimistic 70% efficiency (thats where your heat goes) your looking at 138 x 70% = 96.6w, even if it was 100% efficient, which it ain't or it wouldn't heat up your looking at 138w P.E.P maximum.

I reckon this amp has about 10db gain with those 4 transistors biased the way they are., so when your pals are hitting 20w input the amp can't sustain 200w output and fries.


your friend/s with 3w swinging 20w are actually putting less overmodulation / distortion through than you are, whats blowing their amps is too much drive, yours ain't blown yet but it will be spewing shite all over the place and soon will blow at that level of abuse, thats if you don't get a knock at the door from the FCC first for causing mayhem all over the spectrum.


your friend/s overmodulation level is 20w P.E.P and 3W carrier,

sq rt of 20w P.E.P is 4.47, sq rt of 3w carrier is 1.73w so

4.47w - 1.73w = 2.74w / 1.73w = 1.58 x 100 = 158% overmodulation, another splatter box.


Feel free to get your pm buddies to check my figures, and bare this in mind, no matter what power meter you use be it bird,lp100,dosy or any other, it can't differentiate power on the fundamental frequency to power outside it. Only tool that will do that is a spectrum analyser which will break up exactly where that power is going. I can tell you this much without looking at a spectrum analyser at 182% modulation and over it ain't all going on the fundamental frequency.

now I've had time to answer you:
NUFF SAID !!!!

P.S. we don't have that problem using FM/PM as its not amplitude modulated, but don't mean some of us don't know AM swing is bullshit and when amplified, filthy.

73 Jazz

iagree with ya completely!! now im not great at math but is it also safe to say,am modulation is same to 4 times the dk output. my example 4 watt dk /16 watt pep
if im wrong guess i better get a calalator
 
Just like to throw a bit into the mix:

RM Amps.... Radcom did a review on one of the "300W" RM amps and came to the conclusion that once you drove it over, as I recall, around 150W the signal became as dirty as hell.

TX Power: You're far better off generating 300W or so clean signal than a 500W dirty one. 200W more sounds impressive but its not even one S point on most meters or half a S point on a Collins calibrated one to the other station. So there's no point overdriving the amp to try and squeeze every last drop out of it.

RM and Zetagi are reknown for making crappy quality gear. Unfortunately in the UK most of the time its the only stuff that's both available and within most people's range of affordability. Not many CBers are going to spend £800 on a half decent 400-600W HF amp just to use it on 11m.

Jazzsinger is absolutely on the button with everything he's posted.
 
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Just like to throw a bit into the mix:

RM Amps.... Radcom did a review on one of the "300W" RM amps and came to the conclusion that once you drove it over, as I recall, around 150W the signal became as dirty as hell.

TX Power: You're far better off generating 300W or so clean signal than a 500W dirty one. 200W more sounds impressive but its not even one S point on most meters or half a S point on a Collins calibrated one to the other station. So there's no point overdriving the amp to try and squeeze every last drop out of it.

RM and Zetagi are reknown for making crappy quality gear. Unfortunately in the UK most of the time its the only stuff that's both available and within most people's range of affordability. Not many CBers are going to spend £800 on a half decent 400-600W HF amp just to use it on 11m.

Jazzsinger is absolutely on the button with everything he's posted.

i agree and just to add overdriving most amps will make them sound awful . just not RM amps
 
Just like to throw a bit into the mix:

RM Amps.... Radcom did a review on one of the "300W" RM amps and came to the conclusion that once you drove it over, as I recall, around 150W the signal became as dirty as hell.

TX Power: You're far better off generating 300W or so clean signal than a 500W dirty one. 200W more sounds impressive but its not even one S point on most meters or half a S point on a Collins calibrated one to the other station. So there's no point overdriving the amp to try and squeeze every last drop out of it.

RM and Zetagi are reknown for making crappy quality gear. Unfortunately in the UK most of the time its the only stuff that's both available and within most people's range of affordability. Not many CBers are going to spend £800 on a half decent 400-600W HF amp just to use it on 11m.

Jazzsinger is absolutely on the button with everything he's posted.

Your bang on Connor, 300 clean watts sounds much better than 500w that's happy or dirty watts. It won't even move a properly calibrated S meter half an S Point. You would need to go to 600w or 3Db gain to achieve a full .5 S Point, (The general accepted measure of an S Point is 6Db, on a Cb you could possibly move 3 s points some are that innacurate) Its dirty, sounds awful, affects other spectrum users and is very very selfish and inconsiderate, 2 Zetagi or RM watts roughly equal a real watt, they aren't bad amps when fed with a clean signal, add a low pass filter, with me usually a kenwood lf30a, and it will do the job well for the price,

I personally own 2 KL203P's and have had more B300p's than I care to remember along with B150, B153 and B30 along with a sweep tube EL519 Bv131, never have any of them done what they claim, the Mosfet ones might give a slightly higher efficiency than the BJT ones, I've not had a great amount of use out them and I never squeeze every watt anyway as I prefer longevity and courtesay to splattering all over others, but each to their own, as long as you realise what your buying is budget and needs carefull handling and preferably a low pass filter fitted its a good budget way of DX'ing and with a half decent radio and antenna will give any HF set a run for their money. Its all about the antenna anyway.

You don't need to spend a fortune to DX and sound good, all you need to do is invest it wisely, only time I ever got a bad audio report was battery running flat on Teardrop, those things eat fucking batteries and I was too lazy to wire it from the Jackson's 13.8v pin with a zener and resistor, always had a scredriver, spare battery and spare fuses for everything when I went out along wae a wee pocket multimeter to check for any faults,

Still waiting on all the PM supporters by the way ;) and still no answer why Kenwood,Icom,Yaesu,Elecraft,Uniden ain't all doing the super swing mods,

Nearly every one of them with the exception of Uniden uses some form of speech compression by the way and know it comes at the expense of signal purity so also add filtering after it before they feed it to the RF amplifier chain wonder why that is? Maybe just maybe because its best to put a CLEAN signal through a linear amplifier, especially if you want FCC certification.

P.S. The Radcom Conor referred to is the UK equivalent to your ARRL. They don't lie like manufacturers either ;)
 
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