Hi,
I am learning to use a new propagation predicting program,
called ACE-HF (see, http://home.att.net/~acehf/da1.htm ).
Program uses the VOACAP prediction "engine".
One of the predicted parameters is the rcvd signal strength
at a DX station selected about the globe vs. my xmit output
power, my antenna sort, and the rcv antenna type. However,
the signal is given in dB microvolts, dBuv ! I don't speak that
well, hi. So, I did the following arithmetic attempting to
translate that figure into dBm, and from there into S units,
as follows (this is what I would like you to check for
correctness/error):
1 uv standing across a 50 ohm resistor, dissipates a power
of 2 X 10 to the minus 14 watts, or -107 dBm.
So 0.5uv would be -113 dBm. Then 0.1uv, or -10dBuv is
equal to -127 dBm ? So 10 microvolts, or +10 dBuv is -87 dBm ?
That's very nearly an S6 signal (at S9 equals a 50uv signal, and
6dB delta per S unit change).
Or a 10X's change in dBuv causes a 20 dB change in dBm.
dBm is of interest to me, since my RX-340 S meter is
calibrated in dBm, down to -140 dBm and up to +80 dBm !
Been a long time since I did such figuring, hi.
73, Jim KH7M
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