Palomar 225 Good amp.
Skid
match).
And I never expected it to put out 225WRMS. I don't think palomar ever says it
does. But yes 225 implies it. But then again everyone knows $39,999 for a
car is a lot less than $40,000. It is just a sales ploy.
You want to figure out your output watts:
Quit being so technical.
Measure the current and voltage on your kicker, and you got your wattage then
subtract the aproximate watts of heat your kicker produces. The heat is your
in-effecianty and losses in the amp and the wattage that is reflected.
If your amp runs cool (and note that this only applies to solid state amps)
then it probably is only disipating<10w so it isn't much to worry about.
If it takes 10 fans to keep it cool, you are heating the room, not
transmitting that wattage.
My 150W all leaves my house and works fine.
Skid
Professor
Skid wrote in message <6o1bvt$b27$1...@magnolia.pe.net>...
Reddog
Mine did it too! (200 on SSB)
tgi...@goodnet.com
Bill Eitner
>
> That I'd like to see... 150W RMS, no way!
I agree. Even when volted I don't think it could make it
to 150 true RMS watts on AM.
Maybe there's some confusion with the measuring techniques.
To measure true RMS (or average) wattage you have to drive
the amp in such a way to where there is no needle swing on
the meter with modulation. For example, I can take a 225
and set it to dead key at 120 watts. The problem is that
when modulation is added the meter reading (using a true
average-reading meter) will go down. I can set that same
225 for a dead key of 40 watts. When modulation is added
the meter reading will increase. The point where the meter
reading does not change at all when modulation is added is
the amp's true RMS output. No needle swing with modulation
indicates that the positive and negative modulation swings
are equal and opposite, and that the input signal is within
the linear part of the amp's transfer characteristic. In
other words, the amp isn't being overdriven. On a Bird, with
a VCC of 14 volts, the 225s true RMS output under these condi-
tions is about 60-65 watts. In general, the RMS output using
modern meters (like the Bird or Coaxial Dynamics) works out to
about 1/3 of the peak reading. Using the classic RF power
equation and a scope or spectrum analyzer to verify it, the
true RMS output is 1/4 of the peak reading.
This measurement technique was used in the old days. It's the
reason why the old amps had smaller face values than today's amps
even though they're basically the same inside. For example, the
old Escondido California-built Palomar TX-75s and TX-100s would
be called 225s or 250s (the TX-75) and 300s or 350s (the TX-100)
today.
In the old days most meters were average-reading as well. People
set up their transmitters to where there was no swing in either
direction with modulation and then did the math. They knew that
their transmitter's peak output was 3 times the RMS output when
there was no needle swing with modulation. Now, we have all these
half-assed, pseudo peak-reading meters, and few CBers really know
what their transmitter is doing. That's progress. ;-)
I hope this helps clear up some of the confusion.
> Skid wrote in message <6o1bvt$b27$1...@magnolia.pe.net>...
> >My Palomar 225 puts out 120-160 (average) with my radio. Runs cool (due to
> low
> >match).
--
----------------------------------------
\ /
___ | ___
A
/ | \
-=[Bill Eitner]=- III
III
III
_________III_________
Bill Eitner
>
> Mine did it too! (200 on SSB)
Divide that by 3 to get the AM RMS value using a modern meter
like the Bird or Coaxial Dynamics. Divide it by 4 to get the
AM RMS value using a scope, spectrum analyzer, or thermocouple
RF ammeter (the classic equation). Maximum SSB power is con-
sidered a peak reading--it's not the same as AM RMS.
Matthew
can handle?
Thanks
Mudpuppy
http://www.angelfire.com/wi/citizensband
Bill Eitner
>
> What the heck does "volted" mean?
It means running the amp with a significantly higher than
normal supply voltage.
> Is it at the maximum voltage the amp
> can handle?
It can be that or more in some cases.
> Thanks
>
> Mudpuppy
>
> http://www.angelfire.com/wi/citizensband
>
> Bill Eitner wrote:
> >
> > Professor wrote:
> > >
> > > That I'd like to see... 150W RMS, no way!
> >
> > I agree. Even when volted I don't think it could make it
> > to 150 true RMS watts on AM.
--
DB850
supply..
RadioDoc37
That amp is probably only 60-70% efficient and its probably drawing 20 amps.
20 amps x 12 volts =240 Watts
150 is leaving the shack
Hmmmmmm No amp is 100% efficient
Take care
Mike
rooster
RadioDoc37 wrote in message
<199807102231...@ladder01.news.aol.com>...
Sean
shows the 455 doing 70+ watts apiece easily in their conservatively rated
specs. Sean aka Bigfoot
Bill Eitner wrote in message <35A557...@earthlink.net>...
>Professor wrote:
>>
>> That I'd like to see... 150W RMS, no way!
>
> I agree. Even when volted I don't think it could make it
> to 150 true RMS watts on AM.
>
Bill Eitner
power.
Skid wrote:
>
> My Palomar 225 puts out 120-160 (average) with my radio. Runs cool (due to low
> match).
> And I never expected it to put out 225WRMS. I don't think palomar ever says it
> does. But yes 225 implies it. But then again everyone knows $39,999 for a
> car is a lot less than $40,000. It is just a sales ploy.
>
> You want to figure out your output watts:
> Quit being so technical.
>
> Measure the current and voltage on your kicker, and you got your wattage then
> subtract the aproximate watts of heat your kicker produces. The heat is your
> in-effecianty and losses in the amp and the wattage that is reflected.
>
> If your amp runs cool (and note that this only applies to solid state amps)
> then it probably is only disipating<10w so it isn't much to worry about.
>
> If it takes 10 fans to keep it cool, you are heating the room, not
> transmitting that wattage.
>
> My 150W all leaves my house and works fine.
> Skid
--
Bill Eitner
power.
> >> >My Palomar 225 puts out 120-160 (average) with my radio. Runs cool (due
> to
> >> low
> >> >match).
> >
Bill Eitner
is 144 watts. Divide that by 50% and you'll get the amps RMS output.
144/2 = 72. This is wishful thinking. Most 225s RMS at 60 to 65 watts.
Bill Eitner
>
> 150 rms from two 455's or two 1446's can be achieved easily. even Motorola
> shows the 455 doing 70+ watts apiece easily in their conservatively rated
> specs. Sean aka Bigfoot
That's bullshit Sean. 455s and 1446s are PEP rated devices.
Two 455s make 120 PEP watts with low distortion. Two 1446s
make 140 watts with low distortion. You never understood
what I was trying to say.
LDD7777
225 but for the size and the price you can't bet it. 89.95 ,ab1,and driven
correctily clean.i use one for a driver for a large box and has held up well.i
use a modv and key at 1watt and let the audio take it up to 200 pep with clean
audio. my 2cents. 1200...................
Bill Eitner
I agree. The Blue Face 225 is a great little box.
Professor
lunacy.
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Professor
http://www.megsinet.com/bgriffey/docs/index
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Bill Eitner wrote in message <35A740...@earthlink.net>...
>You're the worst offender when it comes to not knowing how to measure
>power.
>
>Sean wrote:
>>
>> 150 rms from two 455's or two 1446's can be achieved easily. even
Motorola
>> shows the 455 doing 70+ watts apiece easily in their conservatively rated
>> specs. Sean aka Bigfoot
Professor
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Professor
http://www.megsinet.com/bgriffey/docs/index
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Bill Eitner wrote in message <35A743...@earthlink.net>...
>Palomar 225s only draw about 12 amps (MAX) on AM. 12VDC X 12 AMPS
>is 144 watts. Divide that by 50% and you'll get the amps RMS output.
>144/2 = 72. This is wishful thinking. Most 225s RMS at 60 to 65 watts.
>
>rooster wrote:
>>
>> sounds like it is working.
>>
>> RadioDoc37 wrote in message
>> <199807102231...@ladder01.news.aol.com>...
>> >Not all is leaving the house
>> >That amp is probably only 60-70% efficient and its probably drawing 20
>> amps.
>> >20 amps x 12 volts =240 Watts
>> >150 is leaving the shack
>> >Hmmmmmm No amp is 100% efficient
>> >
>> >Take care
>> >Mike
>
>
KCRHochbur
>Most 225s RMS at 60 to 65 watts.
I'm not a tech. But, I have noticed that (2) mrf455s will show about
100w.average reading with a considerable amount of back swing. When the power
is adjusted to the point of no swing (back or forward) it shows 40 to maybe
50w. at best, dependeing on the voltage. That's a Skipper 200. I would agree
with Bill. 60 to 65watts for the 225palomar.
kirk 908 GA.
ICECOLDNYC
kcrho...@aol.com (KCRHochbur) writes:
>I'm not a tech. But, I have noticed that (2) mrf455s will show about
>100w.average reading with a considerable amount of back swing. When the
>power
>is adjusted to the point of no swing (back or forward) it shows 40 to maybe
>50w. at best, dependeing on the voltage. That's a Skipper 200. I would agree
>with Bill. 60 to 65watts for the 225palomar.
This of course is at 12 volts right???
He who knows not and knows not he knows not,is a fool Shun him
He who knows not and knows he knows not,is simple Teach him
He who knows and knows not he knows,is asleep Awaken him
He who knows and knows that he knows,is wise Follow him
ICECOLDNYC
KCRHochbur
kirk
Sean
the Motorola RF Device Data book , DL110/D Rev. 8 ( the most current
available ) that you love to quote so much, the specs for the MRF 455 on
pages 2-462 and 2-463 specifically show the MRF 455 doing 80 watts apiece at
13.6 volts with 5 watts of drive applied. this is RMS mind you, not PEP.
when Motorola means PEP, they say it right in the specs. the specs for the
455 state "60 W, 30 MHz RF Power transistor NPN Silicon". on pages 2-440
through 2-443 of the same book, they list the specs for the MRF 421. it's
specs say "100 W (PEP), 30 MHZ RF Power Transistor NPN Silicon ". if you
noticed, they specifically stated PEP. if you look at all of the power
output graphs associated with the 421, they specifically state PEP in ALL of
the printed specs. anywhere they are talking about PEP, they print it right
in the specs and power graphs, like on pages 2-452 through 2-455 regarding
the MRF 429 transistor and on pages 2-448 through 2-451 regarding the MRF
426. NOWHERE do you see PEP listed in ANY of the specs or graphs listed for
either the MRF 454 or the MRF 455 transistors. even using the conservative
specs that Motorola chooses to publish in their own books, the MRF 455 is
listed at a total device dissipation of 175 watts at 55% efficiency. this
works out to 96.25 watts of output for each transistor, which Motorola
states will meet these specs under normal use and operation. the 454 is
rated for a total device dissipation of 250 watts with an efficiency of 50%,
making it capable of 125 watts of output according to Motorola's own specs.
coincidentally, i happened to have the opportunity to verify the output of a
(cheap) 2 pill 455 box today, even before i had a chance to read this. with
a 10 watt carrier into the box, it was doing 200 watts rms on the dot !!!
no, it wouldn't sound good like this or even last too long, but it will do
it. this was not even volted up either. i'm still following the old rule
of "back it up or pack it up". i've backed it up using the manufacturer's
own specs that anyone, even you Bill, can easily verify. i even saw it in
reality, even though i had no idea that it would directly relate to what you
posted here today. i guess it's time for you to pack it up. seeing as how
you titled me "the worst offender when it comes to not knowing how to
measure power" and i just STOMPED you using your own beloved reference book,
how smart does that make you feel ? if your going to throw rocks, you
should be prepared for the return fire. i don't use rocks though, it's more
like shells from a Howitzer. BABOOOOOOM !!! Direct Hit*** !!!! See
ya................... Sean aka Bigfoot
*** This also includes the Professor too, since he had added his comments
doubting my statements also. two birds with one stone..... aaaahhh....
howitzer.
.Bill Eitner wrote in message <35A745...@earthlink.net>...
>Sean wrote:
>>
>> 150 rms from two 455's or two 1446's can be achieved easily. even
Motorola
>> shows the 455 doing 70+ watts apiece easily in their conservatively rated
>> specs. Sean aka Bigfoot
>
> Two 455s make 120 PEP watts with low distortion. Two 1446s
> make 140 watts with low distortion. You never understood
> what I was trying to say.
>
KCRHochbur
> MRF 455 on
>pages 2-462 and 2-463 specifically show the MRF 455 doing 80 watts apiece at
>13.6 volts with 5 watts of drive applied. this is RMS
1. Does this mean that 5watts is the desired amount of drive?
> i happened to have the opportunity
to verify the output of a
>(cheap) 2 pill 455 box today, even before i had a chance to read this. with
>a 10 watt carrier into the box, it was doing 200 watts rms on the dot !!!
>no, it wouldn't sound good like this or even last too long, but it will do
It wouldn't sound good or last too long. 2. What should this 2-455
amplifier be run at, in order to sound good and last longer?
I'm not being smart. I have a two of these amps and was under the impression I
should not have much back swing. A 5 watt carrier gives about 110watts avrerage
reading and swingsback to about 50watts with added modulation. Maybe, I'm
not fully understanding RMS.
kirk 908 GA.
drg...@ziplink.net
wrote:
>You're the worst offender when it comes to not knowing how to measure
>power.
>
I really don't see what's wrong with a P225 doing 150W. It is not
impossible. Get a bird 43, put in the 200W slug of appropriate
frequency, key with the amp on high, with 14VDC going in, and crank
the drive up till you get to 150W. Done.
As far as the right way to run the amp in normal operation, it would
be foolish to run it that high- too much heat(at that, you could
probably fry bacon on the little heatsink), not very efficient for the
amount of drive put in, etc.... would sound like severe garbage on
AM..... Those boxes are good for about 60-75W for AM use, without
sounding too crappy.
-Mike
drg...@ziplink.net
wrote:
>Palomar 225s only draw about 12 amps (MAX) on AM. 12VDC X 12 AMPS
>is 144 watts. Divide that by 50% and you'll get the amps RMS output.
>144/2 = 72. This is wishful thinking. Most 225s RMS at 60 to 65 watts.
>
Bill, It's also wishful thinking that most operators actually run the
darn things at the appropriate drive level! :) (Which would
result in the 60-65W you mention)
-Mike
drg...@ziplink.net
>> Bill Eitner <kd6...@earthlink.net> writes:
>
>>Most 225s RMS at 60 to 65 watts.
>
>
>I'm not a tech. But, I have noticed that (2) mrf455s will show about
>100w.average reading with a considerable amount of back swing. When the power
>is adjusted to the point of no swing (back or forward) it shows 40 to maybe
>50w. at best, dependeing on the voltage. That's a Skipper 200. I would agree
>with Bill. 60 to 65watts for the 225palomar.
>
> kirk 908 GA.
>
Kirk- I think people are under a misunderstanding here. The P225
will do 150W RMS, on AM. Won't sound good, but it's not impossible.
-Mike
drg...@ziplink.net
wrote:
>150 rms from two 455's or two 1446's can be achieved easily. even Motorola
>shows the 455 doing 70+ watts apiece easily in their conservatively rated
>specs. Sean aka Bigfoot
Sean- the 455 is rated for 60W. Of course the little curve thing
says otherwise. :)
I do believe it is possible to get the P225 to do 150W. However, I
would definitely not operate it at that power output(would sound
crappy except for FM) and given about 15 minutes keyed at that power,
the transistors would probably fry if there was no external cooling,
as the heatsink on this thing is like tiny.
-Mike
drg...@ziplink.net
<bgri...@megsinet.net> wrote:
>I agree... the power levels these guys come up with is nothing short of
>lunacy.
Hmm.... I only have the Yaesu YS-60... but im sure it doesnt lie
too badly.
I "RMS'ed" a Texas star DX350 @ 400W output, at a 14V
drive level.
According to the "books" and the spec sheets, this goes against
everything. RF parts claims 125W apiece for 2879s, Toshiba
claims 100W.....
The thing you guys appear to be forggetting here is that:
MOST BOZOS DONT RUN THEIR AMPS FOR THE RECCOMENDED
IMD REGION. So therefore the manufacturer's initial specifications
don't apply; take a look at the curve on the bottom of the spec
sheets and look further up it. Sure the IMD sucks, sure theyre
distorting, etc, etc.... but thats where a lot of people run the
amps. (sad but too true)
Sure, the "clean" output of the DX350 is about 250W on SSB......
possibly less... on AM things should be set at about
60W for a 4:1 peak to carrier, or 125W for a 2:1 peak to carrier.
-Mike
Professor
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Professor
http://www.megsinet.com/bgriffey/docs/index
Toll Free
you have been saying at the time. The 2879 will do over 100 watts a piece.
Remove the bias from your skywave, go Class C, and run teh supply voltage to
the collectors up. See just what a difference it makes in the total
saturated power output.
Don't post any kind of reply until done. If the VSWR goes up, you may have
to rewind the xformers and recap them to get the impedance / reactance down
to the appropriate levels for the higher Vcc.
--
Remember.... Technicians make it happen!
Toll Free
http://www.bigradios.com/tollfree
One of the Big Johnson Boys in the Dome!
Every woman likes a man with a great big Johnson!!!
Sean
probably run best with a radio producing a carrier level somewhere between
.75 and 3.5 watts, depending on model and design. even units off the same
production line will have variances and require different levels of drive.
you would have to play with your individual unit to find the best
combination. due to the differences in design and gain characteristics of
the individual transistors used, this should leave plenty of dynamic
headroom to sound very clean and punchy if it isn't overdriven into
saturation. this will (A) give excellent results for day to day usage (B)
let the amp run cleaner and cooler (C) let the amp deal with antenna
mismatches easier (D) increase the units life span. the closer that you get
to full output on just the carrier alone leaves less room for modulation,
makes the amp run hotter and also makes the amp "pickier" about swr. the
harder we push it, the better the antenna system has to be to keep damage
from happening to the amps circuitry and components. hope this helps clear
things up for you. Sean aka Bigfoot
.
KCRHochbur wrote in message
<199807121513...@ladder03.news.aol.com>...
>>Motorola RF Device Data book
>
>>pages 2-462 and 2-463 specifically show the MRF 455 doing 80 watts apiece
at
>>13.6 volts with 5 watts of drive applied. this is RMS
>
>
>
opportunity
>to verify the output of a
>>(cheap) 2 pill 455 box today, even before i had a chance to read this.
with
>>a 10 watt carrier into the box, it was doing 200 watts rms on the dot !!!
>>no, it wouldn't sound good like this or even last too long, but it will do
>
Professor
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Professor
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DB850 wrote in message <199807100348...@ladder03.news.aol.com>...
