dB gain/loss

[Dingo]

I was just looking at the nearby nodes on the database and noticed that even close ones (within 2ks) have a Clear path loss of over 100dB

Then I noticed nodes 10kms away are only 130dB loss

Does this mean I am too far from even the closest ones (1 -2 ks)

Or can a proper arial overcome this amount of loss?

[xerxes]

The power received at the receiving end is a function of the transmit power minus the losses in the TX antenna cable, the Transmit antenna gain, the path length, the frequency, the receive antenna gain and the losses in the receive cable.

Rrx=Ptx-TXloss+Gtx+Grx-20*LOG(D)-20*LOG(F)-32.4
Where
Prx = the power at the receive antenna port in dBm (Don't forget to account for the receive cable loss to get the actual power into you receiver.
Ptx = Power out of the Transmitter in dBm
Gtx = Transmit antenna gain in dB
Grx = Receive antenna gain in dB
D = distance between the two antennas in m
F = Frequency in GHz ie 2.5GHz for this stuff
32.4 is a factor that accounts for the units of meters & dB etc.

The gain of a dish antenna can be estimated from its diameter.  It is approximately
G = 20*LOG(Dia)+20*LOG(Freq)+17.8
Where
G is in dB
Dia is the diameter of the antenna in m
Freq is the frequency in GHz
17.8 is a factor to get account for the units.
If your antenna is not round, just work out the equivalent area.

Hope this is vaguely useful