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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

CB linear amplifier type



 
 
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  #1  
Old September 9th 06, 06:19 AM posted to sci.electronics.repair
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Posts: 1
Default CB linear amplifier type

I know it's illegal to use an amplifier on a CB radio. I am just
trying to find out this information.

CB is the 11 meter band. With amplifiers being illegal to use on a
CB, it seems that advertising and selling 11 meter amplifiers could
tend to get someone in trouble. However, I was listening to a guy on
the CB and he said he was a trucker and was using a 10 meter
amplifier. I tend not to believe what I hear on the CB but this guy
was definately running some sort of power amp, because he was burying
my needle for many miles, and going opposite directions.

Is it possible to use a 10 meter amp on a CB? Does it need
modifications? (what?), or not?

One other thing. I understand that increasing a 4watt CB to say 10
watts is actually an insignificant gain, but going to 40 watts doubles
the power. How can a 10X increase only double the power? Wouldn't it
be 10 times as much? I dont understand this.
Just curious....

Thanks

Paul
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  #2  
Old September 9th 06, 03:31 PM posted to sci.electronics.repair
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Posts: 1,274
Default CB linear amplifier type


wrote in message
...
I know it's illegal to use an amplifier on a CB radio. I am just
trying to find out this information.

CB is the 11 meter band. With amplifiers being illegal to use on a
CB, it seems that advertising and selling 11 meter amplifiers could
tend to get someone in trouble. However, I was listening to a guy on
the CB and he said he was a trucker and was using a 10 meter
amplifier. I tend not to believe what I hear on the CB but this guy
was definately running some sort of power amp, because he was burying
my needle for many miles, and going opposite directions.

Is it possible to use a 10 meter amp on a CB? Does it need
modifications? (what?), or not?

One other thing. I understand that increasing a 4watt CB to say 10
watts is actually an insignificant gain, but going to 40 watts doubles
the power. How can a 10X increase only double the power? Wouldn't it
be 10 times as much? I dont understand this.
Just curious....

Thanks

Paul


All below is for the US .

Yes, it is possiable to use the 10 meter amp on CB. They may hae to have a
minor retuning of some internal controls. With many broad band amps
circuits, even this is not needed. Only problem is that for the last 30 or
so years it is illegal to make (mass produce) a 10 meter amp that will work
with the low power (4 to 12 watts) the CB rig is legal for. Many illegal
amps are being made and sold. The FCC does not devote much manpower to
oversee enforcing the rules.

It is usually not much gain if not going to about 8 to10 times the power of
the origional signal. It is a 10 times gain if going from 4 watts output to
40 watts output.


Below is a portion of the rules for the 10 meter amps just for your
information.

@@@@@@@@@@@@@@@@

(b) To receive a grant of certification, the amplifier must not be capable
of operation on any frequency or frequencies between 24 MHz and 35 MHz. The
amplifier will be deemed incapable of such operation if it:


(1) Exhibits no more than 6 dB gain between 24 MHz and 26 MHz and between
28 MHz and 35 MHz. (This gain will be determined by the ratio of the input
RF driving signal (mean power measurement) to the mean RF output power of
the amplifier); and
(2) Exhibits no amplification (0 dB gain) between 26 MHz and 28 MHz.

(c) Certification may be denied when denial would prevent the use of these
amplifiers in services other than the amateur service. The following
features will result in dismissal or denial of an application for
certification:


(1) Any accessible wiring which, when altered, would permit operation of
the amplifier in a manner contrary to the FCC Rules;
(2) Circuit boards or similar circuitry to facilitate the addition of
components to change the amplifier's operating characteristics in a manner
contrary to the FCC Rules;

(3) Instructions for operation or modification of the amplifier in a
manner contrary to the FCC Rules;

(4) Any internal or external controls or adjustments to facilitate
operation of the amplifier in a manner contrary to the FCC Rules;

(5) Any internal RF sensing circuitry or any external switch, the purpose
of which is to place the amplifier in the transmit mode;

(6) The incorporation of more gain in the amplifier than is necessary to
operate in the amateur service; for purposes of this paragraph, the
amplifier must:


(i) Not be capable of achieving designed output power when driven with
less than 50 W mean RF input power;
(ii) Not be capable of amplifying the input RF driving signal by more
than 15 dB, unless the amplifier has a designed transmitter power of less
than 1.5 kW (in such a case, gain must be reduced by the same number of dB
as the transmitter power relationship to 1.5 kW; This gain limitation is
determined by the ratio of the input RF driving signal to the RF output
power of the amplifier where both signals are expressed in peak envelope
power or mean power);


  #3  
Old September 9th 06, 06:53 PM posted to sci.electronics.repair
external usenet poster
 
Posts: 1,001
Default CB linear amplifier type

wrote:

I know it's illegal to use an amplifier on a CB radio. I am just
trying to find out this information.

CB is the 11 meter band. With amplifiers being illegal to use on a
CB, it seems that advertising and selling 11 meter amplifiers could
tend to get someone in trouble. However, I was listening to a guy on
the CB and he said he was a trucker and was using a 10 meter
amplifier. I tend not to believe what I hear on the CB but this guy
was definately running some sort of power amp, because he was burying
my needle for many miles, and going opposite directions.

Is it possible to use a 10 meter amp on a CB? Does it need
modifications? (what?), or not?

One other thing. I understand that increasing a 4watt CB to say 10
watts is actually an insignificant gain, but going to 40 watts doubles
the power. How can a 10X increase only double the power? Wouldn't it
be 10 times as much? I dont understand this.
Just curious....

Thanks

Paul

if memory serves, you need to increase your output power 4 times to
each time you want to double your output effect of something like
that.
this means that 4 to 10..12 watts does work nicely in the effect
how ever, to get a noticeable increase from there, you need 50 watts,
then 200, 800 etc...
-- as far as 10 meter amps working on 11 meters? that is true/../
most 10 meter amps are push pull xformer output types and get
very broad banded. they even go down much lower than 11 meters with
no retuning needed how ever, they tend to generate some harmonics
that can raise hell with commercial gear..


--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

  #4  
Old September 10th 06, 06:16 PM posted to sci.electronics.repair
external usenet poster
 
Posts: 6,358
Default CB linear amplifier type


"Jamie" t wrote in message
...
wrote:

I know it's illegal to use an amplifier on a CB radio. I am just
trying to find out this information.

CB is the 11 meter band. With amplifiers being illegal to use on a
CB, it seems that advertising and selling 11 meter amplifiers could
tend to get someone in trouble. However, I was listening to a guy on
the CB and he said he was a trucker and was using a 10 meter
amplifier. I tend not to believe what I hear on the CB but this guy
was definately running some sort of power amp, because he was burying
my needle for many miles, and going opposite directions. Is it possible
to use a 10 meter amp on a CB? Does it need
modifications? (what?), or not?

One other thing. I understand that increasing a 4watt CB to say 10
watts is actually an insignificant gain, but going to 40 watts doubles
the power. How can a 10X increase only double the power? Wouldn't it
be 10 times as much? I dont understand this.
Just curious....

Thanks

Paul

if memory serves, you need to increase your output power 4 times to
each time you want to double your output effect of something like
that.
this means that 4 to 10..12 watts does work nicely in the effect
how ever, to get a noticeable increase from there, you need 50 watts,
then 200, 800 etc...
-- as far as 10 meter amps working on 11 meters? that is true/../
most 10 meter amps are push pull xformer output types and get
very broad banded. they even go down much lower than 11 meters with
no retuning needed how ever, they tend to generate some harmonics
that can raise hell with commercial gear..


--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5


The Italians have made some really quite good 11 metre linears over the
years, offered quite legally for sale here in the UK, but illegal to
actually use ... work that one out ... Many of these are now used for 10
metre ham band working, ( which is legal for an appropriately licensed
person ) often requiring little or nothing doing to them to get reasonably
efficient amplification.

Arfa



 




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