Re: [Elecraft] OT: math question

2005-03-31 Thread AD5MA
And while we're on the subject... the correct unit is dB, not dBm.

Remember that dB is a relative term. In the case of amplifier gain, this is
relative. The unit dBm is an absolute unit relative to 1 milliWatt. When the
amplifier is finally built, it will have 50 dBm of output power (assuming it
is driven with enough input signal) and will have 13 dB of gain.

Al.

- Original Message - 
From: S55M [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; elecraft@mailman.qth.net
Sent: Wednesday, March 30, 2005 12:41 PM
Subject: Re: [Elecraft] OT: math question


 dBm's

 Just remember this (no maths:))) :
 Every 3dB increase is power multiplied by 2 times (1W to 2W is 30dBm to
 33dBm)
 So 1W+3dB (1x2=2) is 2W+3dB (2x2=4)4W+3dB(4x2=8)8W and so on.
 Every 10dB increase is power multiplied by 10 (1W to 10W is 30dBm to 40dBm
 100W to 1KW is 50 dBm to 60 dBm the easy one HI)
 And dont care abt digits on calcullator (try to see 0,5dB on Your S-meter
or
 ask someone on the band to change the power from 100W to 50W or from 10W
to
 5W (3dB) You will see practically no difference.
 Why dBm? Because dBm is power related to 1mW=0dBm .

 S55M-Adi


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RE: [Elecraft] OT: math question

2005-03-30 Thread W3FPR - Don Wilhelm
dB = 10 log (P2/P1)
For your example of 5 watts to 100 watts, is an increase of 13.01029996 dB -
pardon the rounding but that is all the digits my calculator shows :).

73,
Don W3FPR

 -Original Message-

 How would one calculate the amplifier gain (in dB) required to go
 from one
 power level to another?  For example from 5W to 100W.

 K3UJ


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Re: [Elecraft] OT: math question

2005-03-30 Thread S55M
dBm's

Just remember this (no maths:))) :
Every 3dB increase is power multiplied by 2 times (1W to 2W is 30dBm to
33dBm)
So 1W+3dB (1x2=2) is 2W+3dB (2x2=4)4W+3dB(4x2=8)8W and so on.
Every 10dB increase is power multiplied by 10 (1W to 10W is 30dBm to 40dBm
100W to 1KW is 50 dBm to 60 dBm the easy one HI)
And dont care abt digits on calcullator (try to see 0,5dB on Your S-meter or
ask someone on the band to change the power from 100W to 50W or from 10W to
5W (3dB) You will see practically no difference.
Why dBm? Because dBm is power related to 1mW=0dBm .

S55M-Adi


- Original Message - 
From: W3FPR - Don Wilhelm [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; elecraft@mailman.qth.net
Sent: Wednesday, March 30, 2005 8:23 PM
Subject: RE: [Elecraft] OT: math question


 dB = 10 log (P2/P1)
 For your example of 5 watts to 100 watts, is an increase of 13.01029996
dB -
 pardon the rounding but that is all the digits my calculator shows :).

 73,
 Don W3FPR

  -Original Message-
 
  How would one calculate the amplifier gain (in dB) required to go
  from one
  power level to another?  For example from 5W to 100W.
 
  K3UJ


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Re: [Elecraft] OT: math question

2005-03-30 Thread K6TFZ
 
In a message dated 3/30/2005 10:02:44 AM Pacific Standard Time,  
[EMAIL PROTECTED] writes:

How  would one calculate the amplifier gain (in dB) required to go from one   
power level to another?  For example from 5W to 100W.   



The formula is:  dB = 10 log (P2 / P1)
 
P2 / P1 = 100 / 5 = 20
 
log of 20 = 1.30103
 
10 times it = 13.0103
 
That's your answer: 13.0103 dB
 
Geoff, K6TFZ
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Re: [Elecraft] OT: math question

2005-03-30 Thread thom2
Im with Adi on this one..i.e NO MATH!.  Although I'm 100% certain Don is 
correct, my fingers came with *about* a 12.6 dB increase. (I never did 
understand those loggers)
Tom
WB2QDG
K2 1103

 -- Original message --
From: S55M [EMAIL PROTECTED]
 dBm's
 
 Just remember this (no maths:))) :
 Every 3dB increase is power multiplied by 2 times (1W to 2W is 30dBm to
 33dBm)
 So 1W+3dB (1x2=2) is 2W+3dB (2x2=4)4W+3dB(4x2=8)8W and so on.
 Every 10dB increase is power multiplied by 10 (1W to 10W is 30dBm to 40dBm
 100W to 1KW is 50 dBm to 60 dBm the easy one HI)
 And dont care abt digits on calcullator (try to see 0,5dB on Your S-meter or
 ask someone on the band to change the power from 100W to 50W or from 10W to
 5W (3dB) You will see practically no difference.
 Why dBm? Because dBm is power related to 1mW=0dBm .
 
 S55M-Adi
 
 
 - Original Message - 
 From: W3FPR - Don Wilhelm [EMAIL PROTECTED]
 To: [EMAIL PROTECTED]; elecraft@mailman.qth.net
 Sent: Wednesday, March 30, 2005 8:23 PM
 Subject: RE: [Elecraft] OT: math question
 
 
  dB = 10 log (P2/P1)
  For your example of 5 watts to 100 watts, is an increase of 13.01029996
 dB -
  pardon the rounding but that is all the digits my calculator shows :).
 
  73,
  Don W3FPR
 
   -Original Message-
  
   How would one calculate the amplifier gain (in dB) required to go
   from one
   power level to another?  For example from 5W to 100W.
  
   K3UJ
 
 
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Re: [Elecraft] OT: math question

2005-03-30 Thread Tom Hammond

At 12:01 PM 3/30/05, you wrote:

How would one calculate the amplifier gain (in dB) required to go from one
power level to another?  For example from 5W to 100W.


10 log(P2/P1) = 10 log(100/5) = 10 log(20) = 10 (1.30103) = 13.0103dB

An easy 'rule of thumb' way to get a good idea of such levels
is to remember that:

  a power INcrease of 2  = approx. +3dB change
  a power DEcrease of 2  = approx. -3dB change

  a power INcrease of 10 = +10dB
  a power DEcrease of 10 = -10dB

So, to go from 5W to 10W output, you have 3dB GAIN
to go from 10W to 100W, you have 10dB gain

Since dB's can be added, going from 5W to 100W = 3db + 10 dB = 13dB

Similarly, if you went from 2W to 800W...

  From 2W to 4W (first doubling of power) =  +3dB
  From 4W to 8W (2nd doubling of power)   =  +3dB
  From 8W to 800W (increase of 10X)   = +10dB
  ---
   Total power increase in dB = +16dB

73,

Tom Hammond   N0SS

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RE: [Elecraft] OT: math question

2005-03-30 Thread Dan Barker
I ran into a brain-teaser once, that had me baffled for hours (I won't say
how many). Finally, I called my sister, the Rocket Scientist (actually,
we're not _Rocket_ scientists - That's a quote from her husband) and asked
her.

She and Paul spent a few minutes on the problem, figured it out, but it was
such a trivial answer they threw it away. Since I'd spent so long on the
Question, I gave her about a week and then I called back. Luckily they'd not
taken out the trash, so she easily found their notes and read them to me.

I won't spoil it for you 'crafters.

Dan / WG4S / K2 #2456

Problem: An alley has a 20-foot ladder across it, in the left lower corner
and leaning on the right wall. There also is a 30-foot ladder, from the
right lower corner leaning on the left wall. The laders cross at 10 feet
high.

How wide is the alley?

Usual conventions: alley is all right angles, ladders have no thickness nor
bends, blah blah blah...

This should make some juices flow out there. Just simple geometry, or is it?


PS: Iteration is cheating. Sorry Issac.


snip
 the responses would be far more interesting than merely looking up the
answer
/snip

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Re: [Elecraft] OT: math question

2005-03-30 Thread S55M
Yes math is beautifull (callculating needed space for 3d antennas HI.
But google can spare some time and paper.

:)
http://home.att.net/~numericana/answer/algebra.htm#quartic


- Original Message - 
From: Dan Barker [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; Elecraft elecraft@mailman.qth.net
Sent: Wednesday, March 30, 2005 10:22 PM
Subject: RE: [Elecraft] OT: math question


 I ran into a brain-teaser once, that had me baffled for hours (I won't say
 how many). Finally, I called my sister, the Rocket Scientist (actually,
 we're not _Rocket_ scientists - That's a quote from her husband) and
asked
 her.

 She and Paul spent a few minutes on the problem, figured it out, but it
was
 such a trivial answer they threw it away. Since I'd spent so long on the
 Question, I gave her about a week and then I called back. Luckily they'd
not
 taken out the trash, so she easily found their notes and read them to me.

 I won't spoil it for you 'crafters.

 Dan / WG4S / K2 #2456

 Problem: An alley has a 20-foot ladder across it, in the left lower corner
 and leaning on the right wall. There also is a 30-foot ladder, from the
 right lower corner leaning on the left wall. The laders cross at 10 feet
 high.

 How wide is the alley?

 Usual conventions: alley is all right angles, ladders have no thickness
nor
 bends, blah blah blah...

 This should make some juices flow out there. Just simple geometry, or is
it?


 PS: Iteration is cheating. Sorry Issac.


 snip
  the responses would be far more interesting than merely looking up the
 answer
 /snip

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Re: [Elecraft] OT: math question

2005-03-30 Thread AD5MA
I always like to ask... Is this a trick question?

The way the problem is worded (and if I understand your geometry correctly)
implies an infinite number of solutions as long as the 20 foot ladder can
span the alley. Therefore, the width is anything less than or equal to 20
feet.

Al.

- Original Message - 
From: Dan Barker [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; Elecraft elecraft@mailman.qth.net
Sent: Wednesday, March 30, 2005 2:22 PM
Subject: RE: [Elecraft] OT: math question


 I ran into a brain-teaser once, that had me baffled for hours (I won't say
 how many). Finally, I called my sister, the Rocket Scientist (actually,
 we're not _Rocket_ scientists - That's a quote from her husband) and
asked
 her.

 She and Paul spent a few minutes on the problem, figured it out, but it
was
 such a trivial answer they threw it away. Since I'd spent so long on the
 Question, I gave her about a week and then I called back. Luckily they'd
not
 taken out the trash, so she easily found their notes and read them to me.

 I won't spoil it for you 'crafters.

 Dan / WG4S / K2 #2456

 Problem: An alley has a 20-foot ladder across it, in the left lower corner
 and leaning on the right wall. There also is a 30-foot ladder, from the
 right lower corner leaning on the left wall. The laders cross at 10 feet
 high.

 How wide is the alley?

 Usual conventions: alley is all right angles, ladders have no thickness
nor
 bends, blah blah blah...

 This should make some juices flow out there. Just simple geometry, or is
it?


 PS: Iteration is cheating. Sorry Issac.


 snip
  the responses would be far more interesting than merely looking up the
 answer
 /snip

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RE: [Elecraft] OT: math question

2005-03-30 Thread James C. Hall, MD
Hmmm ... never seen square root as O with dot-dot on top.

Jamie
WB4YDL

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of S55M
Sent: Wednesday, March 30, 2005 2:47 PM
To: Elecraft
Subject: Re: [Elecraft] OT: math question

Yes math is beautifull (callculating needed space for 3d antennas HI.
But google can spare some time and paper.

:)
http://home.att.net/~numericana/answer/algebra.htm#quartic


- Original Message - 
From: Dan Barker [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; Elecraft elecraft@mailman.qth.net
Sent: Wednesday, March 30, 2005 10:22 PM
Subject: RE: [Elecraft] OT: math question


 I ran into a brain-teaser once, that had me baffled for hours (I won't say
 how many). Finally, I called my sister, the Rocket Scientist (actually,
 we're not _Rocket_ scientists - That's a quote from her husband) and
asked
 her.

 She and Paul spent a few minutes on the problem, figured it out, but it
was
 such a trivial answer they threw it away. Since I'd spent so long on the
 Question, I gave her about a week and then I called back. Luckily they'd
not
 taken out the trash, so she easily found their notes and read them to me.

 I won't spoil it for you 'crafters.

 Dan / WG4S / K2 #2456

 Problem: An alley has a 20-foot ladder across it, in the left lower corner
 and leaning on the right wall. There also is a 30-foot ladder, from the
 right lower corner leaning on the left wall. The laders cross at 10 feet
 high.

 How wide is the alley?

 Usual conventions: alley is all right angles, ladders have no thickness
nor
 bends, blah blah blah...

 This should make some juices flow out there. Just simple geometry, or is
it?


 PS: Iteration is cheating. Sorry Issac.


 snip
  the responses would be far more interesting than merely looking up the
 answer
 /snip

 ___
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Re: [Elecraft] OT: math question

2005-03-30 Thread Andrea Borgia

James C. Hall, MD wrote:


Hmmm ... never seen square root as O with dot-dot on top.


Right, they should have printed it as dah-dah-dah-dit ;-P
Sorry, couldn't resist this one 8-)

B73,
Andrea.

--
Homepage: http://andrea.borgia.bo.it /Amateur radio: IZ4FHT
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RE: [Elecraft] OT: math question

2005-03-30 Thread Charles Mabbott
I like simple, 10Db gain will go from 5 to 50Watts; 3Db more will double 50
to 100 Watts.  Approximately 13 Db

-- 
73
Chuck AA8VS
www.aa8vs.org/aa8vs
FP #113  MI-QRP #1212  SOC #445 
Firebird #2117  TSARC #3952
 
 
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, March 30, 2005 1:02 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] OT: math question

How would one calculate the amplifier gain (in dB) required to go from one  
power level to another?  For example from 5W to 100W.  
 
K3UJ
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Re: [Elecraft] OT: math question

2005-03-30 Thread David A.Belsley

I'll go with an alley of zero width.

best wishes,

dave belsley, w1euy


On Mar 30, 2005, at 3:22 PM, Dan Barker wrote:

I ran into a brain-teaser once, that had me baffled for hours (I won't 
say
how many). Finally, I called my sister, the Rocket Scientist 
(actually,
we're not _Rocket_ scientists - That's a quote from her husband) and 
asked

her.

She and Paul spent a few minutes on the problem, figured it out, but 
it was
such a trivial answer they threw it away. Since I'd spent so long on 
the
Question, I gave her about a week and then I called back. Luckily 
they'd not
taken out the trash, so she easily found their notes and read them to 
me.


I won't spoil it for you 'crafters.

Dan / WG4S / K2 #2456

Problem: An alley has a 20-foot ladder across it, in the left lower 
corner

and leaning on the right wall. There also is a 30-foot ladder, from the
right lower corner leaning on the left wall. The laders cross at 10 
feet

high.

How wide is the alley?

Usual conventions: alley is all right angles, ladders have no 
thickness nor

bends, blah blah blah...

This should make some juices flow out there. Just simple geometry, or 
is it?



PS: Iteration is cheating. Sorry Issac.


snip
 the responses would be far more interesting than merely looking up 
the

answer
/snip

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Re: [Elecraft] OT: math question

2005-03-30 Thread Able2fly
 
 
That can't be right. Drawing it (roughly) on paper shows it to be around 13  
feet wide, give or take a foot or so. But coming up with a precise equation  
takes more math skills than high school left me with...
 
Bill  K3UJ
 

 

In a message dated 3/30/2005 4:51:20 P.M. Eastern Standard Time,  
[EMAIL PROTECTED] writes:

I'll go  with an alley of zero width.

best wishes,

dave belsley,  w1euy

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Re: [Elecraft] OT: math question

2005-03-30 Thread Tom Hammond

Hi Frank:

Thanks pal... guess I got a bit ahead of myself there!

Of course, you're completely correct! Should have been 26db, instead of 16dB!

73,

Tom

At 03:54 PM 3/30/05, you wrote:

Hi Tom,
Just a small correction to your 2W to 800W example:
From 2W to 4W (first doubling of power) =  +3dB
From 4W to 8W (2nd doubling of power) =  +3dB
From 8W to 80W (increase of 10X) = +10dB
From 80W to 800W (increase of 10X) = +10dB
Total = 3+3+10+10 = 26db

Best 73,
Frank - W6NEK

- Original Message - From: Tom Hammond [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; elecraft@mailman.qth.net
Sent: Wednesday, March 30, 2005 11:01 AM
Subject: Re: [Elecraft] OT: math question



At 12:01 PM 3/30/05, you wrote:

How would one calculate the amplifier gain (in dB) required to go from one
power level to another?  For example from 5W to 100W.


10 log(P2/P1) = 10 log(100/5) = 10 log(20) = 10 (1.30103) = 13.0103dB

An easy 'rule of thumb' way to get a good idea of such levels
is to remember that:

  a power INcrease of 2  = approx. +3dB change
  a power DEcrease of 2  = approx. -3dB change

  a power INcrease of 10 = +10dB
  a power DEcrease of 10 = -10dB

So, to go from 5W to 10W output, you have 3dB GAIN
to go from 10W to 100W, you have 10dB gain

Since dB's can be added, going from 5W to 100W = 3db + 10 dB = 13dB

Similarly, if you went from 2W to 800W...

  From 2W to 4W (first doubling of power) =  +3dB
  From 4W to 8W (2nd doubling of power)   =  +3dB
  From 8W to 800W (increase of 10X)   = +10dB
  ---
   Total power increase in dB = +16dB

73,

Tom Hammond   N0SS

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Re: [Elecraft] OT: math question

2005-03-30 Thread Larry Phipps


For convenience, Mini-Circuits has a nice printable conversion table at 
http://www.mini-circuits.com/dg03-110.pdf


Larry N8LP



Tom Hammond wrote:


At 12:01 PM 3/30/05, you wrote:

How would one calculate the amplifier gain (in dB) required to go 
from one

power level to another?  For example from 5W to 100W.



10 log(P2/P1) = 10 log(100/5) = 10 log(20) = 10 (1.30103) = 13.0103dB

An easy 'rule of thumb' way to get a good idea of such levels
is to remember that:

  a power INcrease of 2  = approx. +3dB change
  a power DEcrease of 2  = approx. -3dB change

  a power INcrease of 10 = +10dB
  a power DEcrease of 10 = -10dB

So, to go from 5W to 10W output, you have 3dB GAIN
to go from 10W to 100W, you have 10dB gain

Since dB's can be added, going from 5W to 100W = 3db + 10 dB = 13dB

Similarly, if you went from 2W to 800W...

  From 2W to 4W (first doubling of power) =  +3dB
  From 4W to 8W (2nd doubling of power)   =  +3dB
  From 8W to 800W (increase of 10X)   = +10dB
  ---
   Total power increase in dB = +16dB

73,

Tom Hammond   N0SS

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Re: [Elecraft] OT: math question

2005-03-30 Thread Thom R. Lacosta

On Wed, 30 Mar 2005, S55M wrote:


Yes math is beautifull (callculating needed space for 3d antennas HI.
But google can spare some time and paper.

:)
http://home.att.net/~numericana/answer/algebra.htm#quartic


ANd now I know why my daughters always hated math, and why I never passed the
test to get recruited by various federal agencies.

I(we) are dumb.

73
Thom
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Re: [Elecraft] OT: math question

2005-03-30 Thread David A.Belsley
Well, Bill, my first answer of zero feet width is, in fact, a correct 
answer, albeit rather degenerate.  It was an answer that came 
immediately to mind.  However, there is a nondegenerate answer, which 
is


approximately 12.3119 feet.

best wishes,

dave belsley, w1euy


That can't be right. Drawing it (roughly) on paper shows it to be 
around 13 feet wide, give or take a foot or so. But coming up with 
a precise equation takes more math skills than high school left me 
with...



Bill  K3UJ
 



In a message dated 3/30/2005 4:51:20 P.M. Eastern Standard Time, 
[EMAIL PROTECTED] writes:


I'll go with an alley of zero width.

best wishes,

dave belsley, w1euy___

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