I generally do DBs in my head. Just remember with power 3 db=2X, 6db-4X,
7DB=5X and 10 db=10X. It scales from there. Every 10 db is a factor of 10. 60
db is a factor of one million. Just divide 1500 by a million.
For voltage the scale doubles so 20 db is 10X, 6 db is 2X, etc.
Sent from my
On 2/17/19 4:32 PM, Andy Durbin wrote:
"
from math import *
w2dbm = lambda x: 10 * log10(x/10) + 30
dbm2w = lambda x: 10 ** ((x-30)/10)
iso = lambda pwr_W, iso_dB: dbm2w(w2dbm(pwr_W) - iso_dB)
and now something like
>>> iso(1500, 60)
0.001500
tells you that 1500 W with 60 dB isolation leaks
Thanks for the math stuff! 'Specially that last line. Good to know.
Also, some emails asked where I get/what is a slip on PL259. Go here:
https://www.rfparts.com/rfp530.html
May be others, but that is where I got my newest ones.
Bill W2BLC K-Line
"
from math import *
w2dbm = lambda x: 10 * log10(x/10) + 30
dbm2w = lambda x: 10 ** ((x-30)/10)
iso = lambda pwr_W, iso_dB: dbm2w(w2dbm(pwr_W) - iso_dB)
and now something like
>>> iso(1500, 60)
0.001500
tells you that 1500 W with 60 dB isolation leaks 1.5 mW to the other port."
Does dividing
At work (RF lab), dBm power units let a feeble-minded engineer :-) use
plus/minus rather than times/divide with Watts for calculations.
For isolation and other calculations in the ham shack where Watts are
used, a few python one-liners useful. (Python is free and runs on
Windows, Mac,
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