I 've got te answer

I wonder first if dBW depended or not on the QRG below 30 MHz.
It doesn't (excepting that over 30 MHz there is less noise temperature and
often transverter in front of TX showing a 20 dB gain, and this figure is
thus till less).
In addition dBm and co are defined by IARU recommendations where I found all
equivalence dBm-S-point-dBW.

Thanks for your answers but I never imagine that at receive the true power
was so low. I add well a signal report and equivalent in dB or dBW but I
never really make this relation.

Thierry, ON4SKY


"Steve Nosko" wrote in message
...

"Thierry" to answer direct see http://www.astrosurf.com/lombry/post.htm
wrote in message ...
Hi,

A question about dBW and power at receive.
Among scales used in power measurement, there is the signal strength or
noise level estimation, also known as the "dB below W" (dBW or SDBW).
Its
relation is dBW = 10 Log P, where P is the power expressed in watt :
That means that 100 W is 20 dBW into 50 ohms.

But usually, in propagation program (VOACAP, etc), the power strength at
receive expressed in dBW is far below such values. I read somewhere the
next
equivalences :
- (minus) 93 ~ S9+10, -103 = S9, -127 = S5, -151 = S1.

With -93 dBW for a S9+10 signal at receive, that 'd mean that the power
'd
be only P(W) = 10^ (dBW/10) = 0.7 watt ?
IMHO this power is much to low... What is wrong in this relations (or
in
my
interpretation) ?
Thanks in advance
Thierry, ON4SKY
http://www.astrosurf.com/lombry



As others pointed out, your calculation is wrong and that .7 W is way too
large for received power. We receive powers in the -123 dBm (-153 dBW)
range easily and that's ok

However, it is not clear from your post just what you want to
do/ask/learn.
What is your number too low for? What are you wanting?
--
Steve N, K,9;d, c. i My email has no u's.