First rule of antennas, the more miserable the conditions during the install the better they work.
I'm not a big power guy but I would have thought that kind of wattage would be a bit much for a Firestick.
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FatBoy 6 Pill
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I'm not a big power guy but I would have thought that kind of wattage would be a bit much for a Firestick.
Wow...OK She works - lock n' load ok, don't mess with it - keep the SWR low on it and let her rip...
50 amps? 5' Firestik? Hmm, might need metal to metal antennas - Fiberglass (Fireglass) will cook at those wattage numbers...
Might want to re-check and if needed rebuild the electrical to handle 50 amps off the battery that thing will certainly need. New cables - positive and negative (clean up that ground lug on frame especially) Even Alternator too will help, but a newer battery upgrade - even more...No less that #6 AWG too, route to, on that puppy. Bolt that amp to the frame too - at least to the Dodge - it' needs all the help it can get...
You got something that will kick butt if done right...
50 amps? 5' Firestik? Hmm, might need metal to metal antennas - Fiberglass (Fireglass) will cook at those wattage numbers...
Might want to re-check and if needed rebuild the electrical to handle 50 amps off the battery that thing will certainly need. New cables - positive and negative (clean up that ground lug on frame especially) Even Alternator too will help, but a newer battery upgrade - even more...No less that #6 AWG too, route to, on that puppy. Bolt that amp to the frame too - at least to the Dodge - it' needs all the help it can get...
You got something that will kick butt if done right...
Q: How is it that you see 800-ish watts output from 50A supply @ 13.8v? That makes only 690 usable watts available. Not to mention that pills are only - what? - 60% efficient with power in?
As a guess, I would calculate nearly 100 amps/more to see that kind of power. True, the six 2879's are capable of 750 clean watts; but it will take more current (amps) than just 50.
When you mean 10w input into the amp? Do you mean dead key watts? Well a 275HP will still swing to full 85-100w @ 10w/deadkey and also draw another additional 15+ amps to operate on its own. Furthermore, those six pills only require only 60w peak to go to full 750w output. Mind you, I'm just talking about the datasheet numbers and allowing for feeding them 13.8v.
Or am I missing something?
Sorry for all of the questions . . .
As a guess, I would calculate nearly 100 amps/more to see that kind of power. True, the six 2879's are capable of 750 clean watts; but it will take more current (amps) than just 50.
When you mean 10w input into the amp? Do you mean dead key watts? Well a 275HP will still swing to full 85-100w @ 10w/deadkey and also draw another additional 15+ amps to operate on its own. Furthermore, those six pills only require only 60w peak to go to full 750w output. Mind you, I'm just talking about the datasheet numbers and allowing for feeding them 13.8v.
Or am I missing something?
Sorry for all of the questions . . .
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If anyone is missing something it is probably me. And thanks for the questions, I am still in the wrapping my head around this whole thing stage.
I don't know the formulas to figure watts and amps, I was going from what I was told while he was testing. Probably was 10w dead key swinging to 75w but I swear even then I thought the Magnum was only drawing 5-6 amps. Tested the Fatboy on a separate amp meter and it didn't seem to draw much more than 50, possibly 60 amps. He also could have been supplying up to 15v but I showed him my truck and estimated 13.2v but that is something I need to research and verify. Hopefully the system doesn't draw 100 or more amps than estimated, that would require more investment than I want to do right now for my truck. I think my alternator puts out 140 amps at cruising speed and was hoping to only require about half that for this system.
So are you saying according to the datasheet numbers, the 257HP/Fatboy combo should be able to swing the wattage numbers just not at the voltage and amperage I am estimating?
I don't know the formulas to figure watts and amps, I was going from what I was told while he was testing. Probably was 10w dead key swinging to 75w but I swear even then I thought the Magnum was only drawing 5-6 amps. Tested the Fatboy on a separate amp meter and it didn't seem to draw much more than 50, possibly 60 amps. He also could have been supplying up to 15v but I showed him my truck and estimated 13.2v but that is something I need to research and verify. Hopefully the system doesn't draw 100 or more amps than estimated, that would require more investment than I want to do right now for my truck. I think my alternator puts out 140 amps at cruising speed and was hoping to only require about half that for this system.
So are you saying according to the datasheet numbers, the 257HP/Fatboy combo should be able to swing the wattage numbers just not at the voltage and amperage I am estimating?
There's one thing I've always wondered about when estimating amp draw by output wattage, maybe this is a good place to ask for clarification.
When using the formula Volts x Amps = Wattage is the peak or average wattage the one we want to use? it seems intuitive to me that average is the number that would be applicable here but I often see others using the peak wattage, so what's the real deal?
When using the formula Volts x Amps = Wattage is the peak or average wattage the one we want to use? it seems intuitive to me that average is the number that would be applicable here but I often see others using the peak wattage, so what's the real deal?
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amps x voltage = watts
If you multiply the amount of amps in a power supply and its voltage, the result is wattage.
So plug in 50 amps times 13.8 volts and it comes to 690 watts.
But we must consider that transistors aren't 100% efficient when they use amperage to make RF power. In this case, it think it is only like 65% of the available power can be converted into RF power output.
SO, if we multiply 690 watts times 65%, we get 448 usable RF watts output from a 50 amp source.
Which is NOT enough for full 6 pill output.
Since you can expect 750 clean watts from the amp if it is driven with no more than 60 watts from your radio (10w per pill = 60w input power) amd it has enough amperage available to it, you will need almost 100 amps to feed the amp to get the full 750 watts out of it.
That is the math behind the physics that makes it work.
Just saying.
Your 257HP radio will require about 10-15 amps - in addition.
If you multiply the amount of amps in a power supply and its voltage, the result is wattage.
So plug in 50 amps times 13.8 volts and it comes to 690 watts.
But we must consider that transistors aren't 100% efficient when they use amperage to make RF power. In this case, it think it is only like 65% of the available power can be converted into RF power output.
SO, if we multiply 690 watts times 65%, we get 448 usable RF watts output from a 50 amp source.
Which is NOT enough for full 6 pill output.
Since you can expect 750 clean watts from the amp if it is driven with no more than 60 watts from your radio (10w per pill = 60w input power) amd it has enough amperage available to it, you will need almost 100 amps to feed the amp to get the full 750 watts out of it.
That is the math behind the physics that makes it work.
Just saying.
Your 257HP radio will require about 10-15 amps - in addition.
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I like PEP for RF and RMS for everything else but I'm not sure why. It seems that RMS would be good for RF too but maybe it doesn't represent the antenna as a load in the real world. I'm not sure.
690 watts peak or 690 watts average?
Added on edit: The question can be reworded as is the peak output wattage or the average output wattage of the amp in question the wattage that determines the load on the power supply?
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Good question.
That would be the peak watts that a 50A power supply would provide. But can we run a a 50A supply a 690 watts constantly - 'balls to the wall''?
No; not unless you want to overheat it and fry it. So we must use an even larger capacity power supply.
In the case of this six pill amp, he would need bout 130-150 amp power supply to stay cool - or a very large alternator with a dual battery setup in his car to be able to use it to full output. Otherwise, it won't go to full output.
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I see you posted while I was editing my previous post, I tried to clarify what I'm getting at.
It's more about what determines how much current the amp has to pull than the capability of the supply.
It's more about what determines how much current the amp has to pull than the capability of the supply.
Wow, ok!
You guys are getting this figured out - I figure if he can even run 300 watts as Possible P-2-P I would be happy with that?
Most alternators start to sag under loads like that and could wind up putting the car in the shop for a while.
Especially while the mechanic figures out how to sort out all the fusible links that failed and fix them so he can have his car back. Lets' not go into the possible damages the shared belt system off the harmonic balancer he could face if you drive amps that hard without some serious rework...
Since all we know is it's a Dodge - that's enough for me to flag down a set of jumper cables when things go wrong.
I just want the guy to have fun.
Not kill it...
You guys are getting this figured out - I figure if he can even run 300 watts as Possible P-2-P I would be happy with that?
Most alternators start to sag under loads like that and could wind up putting the car in the shop for a while.
Especially while the mechanic figures out how to sort out all the fusible links that failed and fix them so he can have his car back. Lets' not go into the possible damages the shared belt system off the harmonic balancer he could face if you drive amps that hard without some serious rework...
Since all we know is it's a Dodge - that's enough for me to flag down a set of jumper cables when things go wrong.
I just want the guy to have fun.
Not kill it...
Even if 50A would run it I still wouldn't try to pull that on a stock charging system, I'm not recommending that he run it as is. I'm just trying to get some clarification on a question I've had for some time now.
I hear a lot about how this big a power supply can't support this many watts out yet people do it all the time, but if you use the V x A = W formula and consider the result average watts instead of peak a lot of the wattage claims you hear about seem to make a little more sense.
So in a nutshell: Assuming 100% efficiency (Yes I know that won't happen in the real world) if I have an amp that puts out lets say 100 watts average and 200 watts peak do I need a power supply capable of supplying 100 watts or one that supplies 200 watts?
Added on edit: Magnum PI I would understand if you feel this tangent is an unwanted hijack and I'll go away if you want me to, I only asked my original question here because I felt the answer would be relevant to your situation.
I hear a lot about how this big a power supply can't support this many watts out yet people do it all the time, but if you use the V x A = W formula and consider the result average watts instead of peak a lot of the wattage claims you hear about seem to make a little more sense.
So in a nutshell: Assuming 100% efficiency (Yes I know that won't happen in the real world) if I have an amp that puts out lets say 100 watts average and 200 watts peak do I need a power supply capable of supplying 100 watts or one that supplies 200 watts?
Added on edit: Magnum PI I would understand if you feel this tangent is an unwanted hijack and I'll go away if you want me to, I only asked my original question here because I felt the answer would be relevant to your situation.
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Yes, that's the whole thing. I've seen people buy a simple TS 500 and then try running in an Import 4 cylinder with less lung capacity than that of a milk jug - not much there to begin with and you want to do what? With that?
It just lends credence to some vehicles to obtain some performance, have overrides when the vehicle is under heavy load and WOT with A/C - they drop AC and force a downshift to obtain RPM to hopefully get the pistons enough inertia to overcome the loss in ventilation the load places on the system.
Pretty much the same thing when it comes to efficiency - you can shear off a 5 cent dog clutch and elongate it's keyway to where the repair bill costs more than the car is now worth.
In that mess - it takes out, the timing system (belt or chain) the charging system, power steering and A/C - and we haven't even touched on the newer technology sensor driven electric motor system the replaces some of the drive belt systems.
All because some one wanted to get full power out of it - which to me is unreasonable.
I tell people if it works, don't fix it.
It just lends credence to some vehicles to obtain some performance, have overrides when the vehicle is under heavy load and WOT with A/C - they drop AC and force a downshift to obtain RPM to hopefully get the pistons enough inertia to overcome the loss in ventilation the load places on the system.
Pretty much the same thing when it comes to efficiency - you can shear off a 5 cent dog clutch and elongate it's keyway to where the repair bill costs more than the car is now worth.
In that mess - it takes out, the timing system (belt or chain) the charging system, power steering and A/C - and we haven't even touched on the newer technology sensor driven electric motor system the replaces some of the drive belt systems.
All because some one wanted to get full power out of it - which to me is unreasonable.
I tell people if it works, don't fix it.
In the real world, you cannot get something for nothing. No free lunch - right? One can only get so much out if only so much is put in. There has to be an equal exchange. A thousand watts from a 50 amp supply just ain't happening.
But as far as all of the finer details - that someone that knows a lot more about this that I do can say - but I do understand numbers - can answer these questions.
If you ask me, I would have to say that if an amp is capable of making 500w; then it would need a supply that would be able to carry that load - plus some breathing space so it doesn't overheat and go kerflewee. The amp won't; but the power supply will give out at some point of abuse. The amp just won't be able to do its designed power limit.
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Average or peak?
I'm not looking for a free lunch. I understand what you are saying and I know the math, The only question I asked is when doing all these calculations you describe do we use the peak output or the average output of the amp in question and why. I haven't seen an answer to that question.
I think it would be best if I accept that I'm not going to get any answer, I'm done here. Sorry for the hijack Magnum PI.
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