prcguy
Member
The path loss calculators are going to give you what you asked for which is loss in dB. Some calculators let you put in antenna gain or loss but you need one that also includes starting power at the transmitter and resulting power at the receiver in dBm, which is dB referenced to one milliwatt which is also 0dBm.
If you can't find a path loss calculator that lets you enter transmit power in watts or dBm then you can use this converter for watts to dBm, but you have to start with a power level at the transmitter to get power into the receiver in dBm. RF Power Conversion Calculator
So pick a power level to start with that you think the transmitting station would be using. Lets say its 50 watts just to get started and that calculates to 46.99dBm. Now we have something in dBm to start with and subtract that from your path loss example of 109.4dB but since that is a loss call it -109.4dB, so -109.4 of loss plus 46.99dBm of transmit power leaves you with -62.41dBm of signal present at the receive antenna and its the first time we have it in dBm because we started with something in dBm.
Now add the antenna gain minus feedline loss at the transmitter site. Lets use 6dBi of antenna gain minus 1.5dB of feedline loss which would reduce the transmit antenna gain to 4.5dBi. Add that 4.5dB to the calculated receive signal available at the antenna which would be -62.41dBm plus 4.5dB of antenna gain/feedline loss which is now -57.9dBm or a higher level at the receive antenna due to added transmit antenna gain with feedline loss.
Now add your receive antenna gain minus feedline loss at the receive end. You have a Remtronix antenna right on a handheld and I estimate that antenna to have about 2dBi of gain with no feedline loss in this case so add that to the receive level present at the antenna which now makes it the original -57.9dBm present at the antenna plus 2dBi Remtronix gain equal -55.91dBm into your scanner receiver.
Now replace that Remtronix with say an 11dBi gain Yagi with 2dB of feedline loss giving a net result of 9dBi receive gain. So going back to the original level present at the antenna which was -57.9dBm plus 9dBi antenna gain including feedline loss you would have -48.9dBm into your scanner receiver with the 11dBi Yagi, or 7dB more signal than what the Remtronix antenna provides, not counting the Yagi possible being higher on the roof and in the clear compared to the Remtronix inside your house with some loss through the walls.
The Pasternack path loss calculator appears to be free space as in space with no earth or buildings or trees involved, which is not realistic except for calculating signals from space. The other calculator that lets you choose a rural area might give a more realistic idea of levels between two points on earth but I don't know the difference between the Egli or Hata results or which one to use with my examples above.
Also, my examples are how my brain looks at things and there are other ways to add or subtract the info but the end result should be the same.
If you can't find a path loss calculator that lets you enter transmit power in watts or dBm then you can use this converter for watts to dBm, but you have to start with a power level at the transmitter to get power into the receiver in dBm. RF Power Conversion Calculator
So pick a power level to start with that you think the transmitting station would be using. Lets say its 50 watts just to get started and that calculates to 46.99dBm. Now we have something in dBm to start with and subtract that from your path loss example of 109.4dB but since that is a loss call it -109.4dB, so -109.4 of loss plus 46.99dBm of transmit power leaves you with -62.41dBm of signal present at the receive antenna and its the first time we have it in dBm because we started with something in dBm.
Now add the antenna gain minus feedline loss at the transmitter site. Lets use 6dBi of antenna gain minus 1.5dB of feedline loss which would reduce the transmit antenna gain to 4.5dBi. Add that 4.5dB to the calculated receive signal available at the antenna which would be -62.41dBm plus 4.5dB of antenna gain/feedline loss which is now -57.9dBm or a higher level at the receive antenna due to added transmit antenna gain with feedline loss.
Now add your receive antenna gain minus feedline loss at the receive end. You have a Remtronix antenna right on a handheld and I estimate that antenna to have about 2dBi of gain with no feedline loss in this case so add that to the receive level present at the antenna which now makes it the original -57.9dBm present at the antenna plus 2dBi Remtronix gain equal -55.91dBm into your scanner receiver.
Now replace that Remtronix with say an 11dBi gain Yagi with 2dB of feedline loss giving a net result of 9dBi receive gain. So going back to the original level present at the antenna which was -57.9dBm plus 9dBi antenna gain including feedline loss you would have -48.9dBm into your scanner receiver with the 11dBi Yagi, or 7dB more signal than what the Remtronix antenna provides, not counting the Yagi possible being higher on the roof and in the clear compared to the Remtronix inside your house with some loss through the walls.
The Pasternack path loss calculator appears to be free space as in space with no earth or buildings or trees involved, which is not realistic except for calculating signals from space. The other calculator that lets you choose a rural area might give a more realistic idea of levels between two points on earth but I don't know the difference between the Egli or Hata results or which one to use with my examples above.
Also, my examples are how my brain looks at things and there are other ways to add or subtract the info but the end result should be the same.
