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, linux.) When in python, copy the following:
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.
73,
Mike ab3ap
On 2/17/19 10:38 AM, James F. Boehner MD via Elecraft wrote:
I use the Alpha Delta Series. They have SO-239 and "N" connector
models, two position or four position. For the price difference, I
always get four position.
They are not only well built switches, but they do have surge
protection (gas) with a replaceable pill. Their best feature is the
very high isolation they offer:
30 MHz >60 dB 150 MHz >50 dB 450 MHz 50 dB
And dB Loss:
30 MHz 0.1 dB 150 MHz 0.15 dB 450 MHz 0.5 dB
So, I wish these could be remotable. However, they are the best
switches I've found for a reasonable price, and I have many of them
in my station.
Oh yes, on the outside of my house, I have polyphasers.
'73 de JIM N2ZZ
I do use a number of Daiwa 2-position coax switches for various
purposes. Any comments on coax switches?
Bill W2BLC K-Line
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