Wattage/ no swing
Luke Smith
maybe swings to 16 or 17?
I have heard many people talk about 6 watts swinging to 19, but I
have never got a radio to do that.. (Any ideas??) Also, why would I
want a low deadkey then a lot of swing? What is the difference between
swinging to 16 watts or deadkeying at 16?? Isn't that the same thing?
Jumping Jack Flash
-> You would not want a 6 to 19 watt swing.Yours has a very high
deadkey
->which is good for blanking out all background noise.
-> Most people, including you who claim to have such high power
levels
->on a "regular non export type radio" really have 5-6 watts if
measured on
->a "REAL" meter such as a Bird.
A cobra 29 LTD and 80% of all CB's come with a 25 watt final? I wonder
why they put a 25 watt transistor in a circuit that is only suppose to
be 4 watts? And the only difference between the cobra and the exports
is that 25 watt final is also being driven by a 25 watt driver in the
exports and around 10 in the cobra's. So 5-6 watts is a joke then.
After a cb is turned up the final is drawing roughly 1 1/2 amps of
current. 12 /1.5 = 8, 1.5^2 8 = 18 watts. Which is roughly what a
cobra will do when you send a steady low bass tone comparable to the
human voice. It has a dead key of around 6. The older cobra's would do
more. The newer ones has a 250pf coupling cap to lower the power
getting from the driver to the final. Replace it with 33pf or a 68pf
in about any radio for a watt or two. Mainly don't worry about dead
key or swing just what the radio is doing with a constant low freq
tone...like ahhhhhh , make sure also that it's not being clipped like
when you turn up your cb or home stereo up full volume. That will
sound distorted or muffled. You can use a scope and check it or take a
small amp and set it on the bench. It will pick up the rf transmitted
from the cb and you'll get a pretty good ideal as to rather it sounds
muffled or not.
JHynd73790
elce
you talk to has far less.
Do many people also claim to have 150% to 200% modulation???
Richard J Jones
writes:
Sure, but no use consuming power if your not TXing
Tom Randolph
In article <315a2a38...@199.171.83.2>, mar...@rbdc.rbdc.com (Jumping Jack Flash) writes...
>After a cb is turned up the final is drawing roughly 1 1/2 amps of
>current. 12 /1.5 = 8, 1.5^2 8 = 18 watts. Which is roughly what a
12 volts x 1.5 amps = 18 watts
This is what you would get out, if your final was 100% efficient. CBs being
AM, they probably have a Class AB final, so max. efficiency is right around
50%. That means 9 watts maximum output. Some of the current drawn goes to
power other things besides the final, so let's call it 8 watts. That's a 3 dB
increase over legal power. It takes 6 dB (4x power) to make any difference
at the other end.
Why bother?
-Tom R. N1OOQ rand...@est.enet.dec.com
Jumping Jack Flash
->
->In article <315a2a38...@199.171.83.2>, mar...@rbdc.rbdc.com
(Jumping Jack Flash) writes...
->>After a cb is turned up the final is drawing roughly 1 1/2 amps of
->>current. 12 /1.5 = 8, 1.5^2 8 = 18 watts. Which is roughly what a
->
->12 volts x 1.5 amps = 18 watts
->This is what you would get out, if your final was 100% efficient.
CBs being
->AM, they probably have a Class AB final, so max. efficiency is right
around
->50%. That means 9 watts maximum output. Some of the current drawn
goes to
->power other things besides the final, so let's call it 8 watts.
That's a 3 dB
->increase over legal power. It takes 6 dB (4x power) to make any
difference
->at the other end.
->
->Why bother?
->
->-Tom R. N1OOQ rand...@est.enet.dec.com
Funny cause my RF wattmeter also says 18 watts?
Codys PC
this...
In article <96032717...@fatal.com>, luke....@fatal.com (Luke Smith)
writes:
>Is it good if I have turned my radio up to dead key @ 15 watts and it
>maybe swings to 16 or 17?
No, not really. Lots of others that are using adjacent channels can
probably hear you just fine - 2 or 3 channels down or up from the channel
you're using. Even though there is less of a swing - for headroom for
transmission of sideband information - you may sound more like you're on
FM - check your settings. Are you on AM?
What kind of radio are you using, and how did you turn it up? Did you
[!GULP!] modify the radio for more modulation? If so, you've got it a
little TOO high! You're describing what some Hams call 'FM-ing', it's when
the RF output is overdriven and clips because the radios Final is being
driven beyond it's linear range and saturates and distorts, or clips - and
it sounds like you're on FM.
Modulation when it's measured on a meter - shows an average - and using
what you're telling us here on a wattmeter [if that] - there is only 2
watt increase - so either your radio is reducing carrier proportionately
downward to give headroom for the sideband information - or your radios'
clipping big time!
DRIVER=Pleading for help!
FINAL=Screaming, GET ME OUTTA' HERE!
> I have heard many people talk about 6 watts swinging to 19, but I
>have never got a radio to do that.. (Any ideas??) Also, why would I
>want a low deadkey then a lot of swing? What is the difference between
>swinging to 16 watts or deadkeying at 16?? Isn't that the same thing?
Why would you want to increase the intermodulation distortion from the
radio you're using? Too much forward swing, or modulation components -
create the same problem of bleedover and interference - what are you doing
to your radio? OUCH!
A final can take some punishment, but it sounds like you're not doing
something right. *<16>* Watts? What are you using to measure this? You
must be going through fuses, are you now up to 8 Amp Slo-Blow types? ;-)
The Driver delivers about 1/2 watt to the base of the Final - and the
Final can take an 8 Amp surge for SSB use. So with what you have done to
your radio - it won't last long at the current setting - especially on AM.
The Final can work up to 12 watts continuous with some headroom - but
even at that setting your still saturating the transistor.
Are you telling us the truth, or are you making this up?
... Even though your all alone, you can still get it off, with your
microphone ...
kevin D. tischler
do you know wat you are talking about ????
are you talking about a maxon,midland, or a cobra 19+?
if so on either account, ..... we understand....
if not, you are an idiot,
my 148 WILL do a HONEST 6~24+ with a 2 amp fuse.
it has done so since 1992.
PERIOD end of discussion.
this is 10000% truth
kevin D. tischler
>
> In article <315a2a38...@199.171.83.2>, mar...@rbdc.rbdc.com (Jumping Jack Flash) writes...
>
well, my 148 measures 6 watts swinging 26
does that make a differance?
Codys PC
stuck in it's buffers, after making a mad dash for home, with the modem
behind - in close pursuit...
In article <315D20...@interramp.com>, "kevin D. tischler"
<cd00...@interramp.com> writes:
>my 148 WILL do a HONEST 6~24+ with a 2 amp fuse.
>it has done so since 1992.
>PERIOD end of discussion.
>this is 10000% truth
Well, well, well...look at what the Modem trolled in...
Exaggeration? Perjury? Or Menopause?
Folks, you be the judge....
I know where I stand on this, and certainly not as an idiot. If you look
carefully at the fuse you are using - Cobra 148s' come with a 4 Amp 250
Volt fuse as standard equipment. [as in STOCK RADIO] I've got your
fuse...are you currently on any kind of mood altering drug? [see PROZAC,
also DRUNK, CANNABIS HEMP, BEER, ETOH, POSTAL CLERK]
You possibly could use a 2 Amp fuse, if it's rated at 250 Volts - and if
thats what you have then it is not original - and I highly doubt the
condition it is in to prove it. Let alone use the radio at it's full
potential now. [see ABILITY also USEAGE, OPERATION, OWNERS MANUAL]
Do you do 24 watts with a dead key carrier of 6 watts on SSB? [You're
kidding right?] OR are you referring to the 6 as being measured in
Milli-Watts max on AM and 24 on SSB? The latter I could believe more -
please clarify. [see DISSERTATION, also ESSAY, EXPLANATION]
If you are pulling our leg[s] [see APPENDAGES] You might want to shift the
decimal point on the percentage, over to the left a few digits [see MATH
also FORMULA] - You can transfer the extra zero [or two, three even] over
just behind the 2 of the Fuse rating [see AMPERES also WATTAGE, METER, FCC
PART 95} you're stating - I'm flexible enough.[see INCRIMINATE, GUILTY
also ACCUSED] Thank You. [see APPRECIATE also SMILE]
Rec.radio.cb, relys on its users to provide some means of control over the
context [see LEARN also READ, COMPREHEND]. Please do not draw attention
to yourself in the fashion you are portraying in this message - do us all
a favor and be a little more honest next time. [see TWIT also FLAMED;
IGNORED; BORING; WHO PEED ON YOUR CORNFLAKES THIS MORNING?]
Are you the same person that posted the original message?
Let's see...Original headers as follows...
From: luke....@fatal.com (Luke Smith)
Newsgroups: rec.radio.cb
Subject: Wattage/ no swing
Date: Thu, 28 Mar 1996 01:04:44 GMT
Message-ID: <96032717...@fatal.com>
Organization: FATAL ERROR |(916)365-7456/6104 | Redding, Ca.
Distribution: world
Ok, what did you post it as...
From: "kevin D. tischler" <cd00...@interramp.com>
Newsgroups: rec.radio.cb
Subject: Re: Wattage/ no swing
Date: Sat, 30 Mar 1996 04:54:05 -0700
Organization: PSI Public Usenet Link
Lines: 68
Message-ID: <315D20...@interramp.com>
References: <96032717...@fatal.com>
<4jikk5$o...@newsbf02.news.aol.com>
NNTP-Posting-Host: ip48.ft.worth.tx.interramp.com
Hmmm...funny, this doesn't seem to be the right person to be responding
like this to a message I sent to Luke Smith. Are you responding for him?
Are you using the radio he was talking about? I don't remember him telling
us that he has a Cobra 148, or what kind of radio he was using - it was
never mentioned in the original message.
I did ask him for some information, and thank you for supplying yours,
however it does not suit our present needs.
Are you looking to start an arguement? You'd better look elsewhere...
:+> Andy <+:
Tom Randolph
In article <315D1F...@interramp.com>, "kevin D. tischler" <cd00...@interramp.com> writes...
>well, my 148 measures 6 watts swinging 26
>does that make a differance?
Yah, if all 26 watts are going out on the channel you're tuned to, which I
doubt. You said in another post that you're running off of a 2 amp fuse.
2 amps x 12 volts = 24 watts maximum unless someone has repealed the laws of
physics. Even at the ~13.8 volts coming out of a car's alternator regulator,
you're talking about a radio that's 94% efficient, which doesn't exist for
less than thousands of $.
What are you measuring with, a power meter? Those are calibrated for sine
waves, and easily fooled if you're putting out a flat-topped, distorted
signal.
-Tom R. N1OOQ rand...@est.enet.dec.com
bill harris
>have never got a radio to do that.. (Any ideas??) Also, why would I
>want a low deadkey then a lot of swing? What is the difference between
>swinging to 16 watts or deadkeying at 16?? Isn't that the same thing?
be very little swing noticed on an output meter or watt meter. With high-level
modulation the output power is controlled by the amount of modulation.
With key down and no modulation you get a steady carrier, when modulation
is present the carrier is varied with the audio wave form. As the audio wave form
goes positive, the carrier is increased according to the strength of the audio
wave form until the audio wave form reaches it's peak. Then as the wave form
starts in a negative direction the carrier is reduced and when the audio
wave form crosses the zero level the carrier is back at it's key down level.
Now as the audio wave form goes minus the carrier is reduced below it's
key down level until the audio wave form reaches it's negative peak. Then
as the wave form heads back towards a positive direction the carrier increases
and so on and so on for the entire speech process. For 100% modulation
the modulator must be capable of delivering audio power equal to one-half
of the final rf stage. It take 5 watts of audio to 100% modulate a 10 watt
carrier. At 100% modulation, on the negative peaks the audio wave form
will just cause the carrier to be reduced to zero output. If the negative
peaks of the audio wave form are two strong, as in over-modulation, the
rf carrier will be driven beyond cutoff . This sharp cut off of the carrier
causes distortion and produces a large number of harmonics of the
audio frequency, thus you have a lousy sounding signal and one that
occupies a very broad bandwidth, ie., lots of splatter on the band.
On the positive peaks the same occurs as the rf final can just deliver so
much output and if the modulation tries to drive it further it just can't deliver
and so the positive peaks are also flat-topped.
Even though the carrier is increasing and decreasing with modulation,
the average output remains the same and that is what output and
watt-meter read, average (unless they are peak reading). So the
output meter should swing very little either side of the rated
output.
You can get more than 100% modulation on positive peaks if the
rf final can handle it, but this take special modulator circuitry to keep
the negative peaks from driving the final to beyond cutoff.
So if you tweak a radio that normally puts out 5 watts to 20 watts,
then something must be done to the audio section to increase the
audio to at least 10 watts or you will not get 100% modulation.
At 100% modulation, at the positive peak of the audio wave , the
carrier output is four times the unmodulated carrier power. That is
why a 5 watt radio has a 20 watt final, so it can safely handly the
peaks. If you peak the radio for higher un-modulated carrier, then
you are really stressing the final on modulation peaks, assuming
100% modulation.
So these yahoos who adjust their radios to get all that swing and
claim they are getting 200% modulation are just fooling themselves
and causing a lot of interference with a lousy sounding signal.
The problem is that those who don't know better equate a widly
swinging output meter with lots of power.
Fasttrak
I couldn't have said it any better!!!!!!!!!!!
Vern Faulkner
: and causing a lot of interference with a lousy sounding signal.
: The problem is that those who don't know better equate a widly
: swinging output meter with lots of power.
Oh, don't spoil it for the darlings. You'll take all the fun out of the game
for those chaps who feel that power is everything. Just get that 4W model
pumped up to 20W output (Kewl, man) and everything is fine. That way, (man)
we can forget about things like having the right length of coax (Whaddya
mean, length? Its only six feet from my radio to mah antenna. Ma cuzzin done
put it up,....) and having quality coax as well. (Ma cuzzin had somma diz stuff lyin' around
from a couple years back, just sittin' in the back yard doin' nothing all
winter).... forget antenna dynamics - or ground planes, or having a good
antenna. (Shewt, I done got 20 Whuts... an iffn' that ain't enuff, I'll get
one-a dem echomikes. They shur is kewl....)
Codys PC
harris) writes:
>So these yahoos who adjust their radios to get all that swing and
>claim they are getting 200% modulation are just fooling themselves
>and causing a lot of interference with a lousy sounding signal.
>The problem is that those who don't know better equate a widly
>swinging output meter with lots of power.
Nice Job! Mind if I keep the post around to help answer a few questions?
;-) You broke it down into much simpler terms then that which I could have
done.
There is also another factor of developing the amount of audio needed -
the increased distortion components [THD] from the audio chip being driven
to the limit from audio input from the Mic amp can cause the harmonics and
clipping distortion to appear at the RF output and then cause the spurious
emmissions that create TVI and also EMI in telephones - and the 200%
readings on wattmeters. The RF coils can only saturate so much before they
lose their ability to attenuate the unwanted components in the RF section.
... Zen follower to the Hot Dog vendor...
"Make me one with everything!"
sbo...@radix.net
>> be very little swing noticed on an output meter or watt meter. With high-level
What you're saying then is that we should peak the radio then adjust
the modulation so the metter's needle just STARTS to swing and then
back it off just a little and we'll be better off?
George Warner
>> be very little swing noticed on an output meter or watt meter. With high-level
(Rest of message deleted for brevity)
On the contrary, an amplitude modulated signal outputs more power when modulated.
At 100% modulation, the power output is 50% greater than the carrier power alone.
Thus, a radio with a 4 watt carrier outputs 6 watts when 100% modulated.
George
Tom Randolph
In article <315b82b8....@199.171.83.2>, mar...@rbdc.rbdc.com (Jumping Jack Flash) writes...
>Funny cause my RF wattmeter also says 18 watts?
Wattmeters are calibrated for sine waves. Most of the cheap ones rectify the
signal, filter out the AC, measure the voltage, and assume a sine wave power
into 50 ohms based on the voltage measured. It isn't real tough to get one of
these to read anything you want if you put in some distorted, non-sine signal.
All you need to do is get your radio to put out a signal that peaks at some
high voltage that the meter assumes is due to high power. Look at your
waveform on an oscilloscope - if it's not a clean sine wave, a wattmeter is
meaningless.
As an example, put a 10v peak square wave into a cheapo wattmeter. The actual
power of such a signal into a 50 ohm load is (10 x 10) / 50 = 2 watts. The
meter reads the 10v, assumes a sine wave, and tells you that it's measuring
1 watt!
-Tom R. N1OOQ rand...@est.enet.dec.com
Bill Nelson
: >> On a properly operating final stage using high-level am modulation, there should
: >> be very little swing noticed on an output meter or watt meter. With high-level
: (Rest of message deleted for brevity)
: What you're saying then is that we should peak the radio then adjust
: the modulation so the metter's needle just STARTS to swing and then
: back it off just a little and we'll be better off?
Yes and no. As another poster pointed out, it is possible to cause the
driver or modulator to clip, if turned too high.
The only proper way to peak a radio is using a scope with an rf probe.
Bill
Bill Nelson
: >> On a properly operating final stage using high-level am modulation, there should
: >> be very little swing noticed on an output meter or watt meter. With high-level
: (Rest of message deleted for brevity)
: On the contrary, an amplitude modulated signal outputs more power when modulated.
: At 100% modulation, the power output is 50% greater than the carrier power alone.
: Thus, a radio with a 4 watt carrier outputs 6 watts when 100% modulated.
Yes and no. The normal wattmeter only reads the voltage, and it reads rms not
peak voltage. With a symetrically modulated signal, the rms voltage changes
little, if at all, when the carrier is modulated. As such, the meter should
not do more than swing slightly upward.
Bill
George Harris
I believe you are no completly correct with your math. A properly
tuned radio which has a 4 watt carrier when modulated at 100%
could SWING(as they say) to 16 Watts without distortion. This
assumes that everything is tuned appropriatly. Remember the
Formula: ((Vp-p / 2.828)^2)/50
Have a fine Day!!!!!!!!
Really I insist!!!!!!!!
73,
another George
--
Don't do anything that I wouldn't, At least don't get CAUGHT!!!!
bill harris
>At 100% modulation, the power output is 50% greater than the carrier power alone.
>Thus, a radio with a 4 watt carrier outputs 6 watts when 100% modulated.
>
On the contrary, because the carrier is modulated upward and downward
with the speech wave form, the average power out is at about the same
level of the unmodulated carrier power. It may vary some depending upon
the speech waveform. Output and wattmeters, unless they are peak
reading, read average, so the output should show very little swing.
An output/wattmeter cannot respond fast enough to read the peaks and
valleys of the modulation, so give an average reading.
Look at the output of a properly operating radio on a wattmeter and on a
scope and you will see it plainly.
Bill
Tony Langdon
We'll return to bil...@spaceworks.com and All's
discussion of Wattage/ no swing
bi> Organization: SpaceWorks, Incorporated
>On the contrary, an amplitude modulated signal outputs more power when
bi> modulated. >At 100% modulation, the power output is 50% greater than
bi> the carrier power alone. >Thus, a radio with a 4 watt carrier outputs
bi> 6 watts when 100% modulated. >
>George
bi> On the contrary, because the carrier is modulated upward and downward
bi> with the speech wave form, the average power out is at about the same
bi> level of the unmodulated carrier power. It may vary some depending
bi> upon the speech waveform. Output and wattmeters, unless they are peak
bi> reading, read average, so the output should show very little swing.
bi> An output/wattmeter cannot respond fast enough to read the peaks and
bi> valleys of the modulation, so give an average reading.
bi> Look at the output of a properly operating radio on a wattmeter and on
bi> a scope and you will see it plainly.
George is right, as anyone who's done the maths behind modulation theory
will tell you. It can be proven that a 100% modulated AM signal does
in fact have 50% more (average) power than the unmodulated carrier.
However, you're also right in that this power increase doesn't show up
much on the power meters in a typical CB, for a couple of reasons.
These meters are very non-linear, so the increase to 6 watts will not
move the needle much. Also, 100% modulation typically applies only to
voice peaks, which are short lived, so the inertia of the meter movement
(assuming analogue meters) masks some of the increase.
Try measuring the output of a CB with a good power meter while
modulating it with a sinewave. You'll see the increase. :-)
... I'm Demtel of Borg. Sales resistance is futile.
--
| Fidonet: Tony Langdon 3:632/367.2
| Internet: tl...@freeway.DIALix.oz.au
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