Pushpit Rail Mounted VHF Antenna Suggestions

[Brian D]

What are you trying to express?

I see a 5X increase in power is a 7db increase, am I wrong

John, I am not sure of what you are trying to state. If you would explain to me your math then I might understand your thinking.

 

[JohnShannon]

All I was trying to say is that a 25W radio vs a 5W radio is 7db more power, the second point is that a 25W radio would transmit 2X the range vs a 5W radio (I suppose assuming the same antenna)

A factor of 5X in power in dB is 7db

So for example 1W is 0dbW and 5W is 7dbW and 25W is 14dbW

 

[jssailem]

They say. Beware of sailors bringing gifts. Or is that Greeks. I forget.

Maybe it is a “watched VHF does not transmit.” Or something like that.

 

[Brian D]

All I was trying to say is that a 25W radio vs a 5W radio is 7db more power, the second point is that a 25W radio would transmit 2X the range vs a 5W radio (I suppose assuming the same antenna)

A factor of 5X in power in dB is 7db

So for example 1W is 0dbW and 5W is 7dbW and 25W is 14dbW

OK, now I understand what you are saying. From 1W to 5W is indeed 5x. But from 5W to 25W is 5x in watts but not 5x in dBW. So there is where I was not understanding what you were trying to say. Then, throw on top of that 7dBm which was the sabot in the gears of my mind. dBm and dB are not interchangeable.

This is what happens when we start mixing units of measurements. It is like talking knots vs mph in wind speed. If we are going to talk watts then stick to watts. If we are going to talk dB then convert watts to dB and talk dB.

Thanks for your clarification.