[Elecraft] Miles per Watt
Miles per Watt is nonsense data to impress people.because nothing happens in linear mode!!!So increasing or decreasing power by 10 times will not expand range by 10 times.. More you go to miliwatts better will be m/W calculated ratio. Adi ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] Miles per Watt
- Original Message - From: Pierre Desjardins [EMAIL PROTECTED] To: S55M [EMAIL PROTECTED] Sent: Friday, January 07, 2005 17:39 Subject: [Elecraft] Miles per Watt Miles per Watt is nonsense data to impress people.because nothing happens in linear mode!!! Not a linear behavior for sure... Lets say that a 500 mW signal at 7,4 mHz is received 4000 km away and that both antennas are half-waves dipoles. We could be tempted to say that an 1 watt signal would reach 8000 km in the same conditions. But according to the Friis transmission formula, the first 500 mW signal is reduced to 0,0096 microwatts at the received end, and the second one (1 watt) is a whooping 0,0048 microwatts! Still readable? Not sure... The inverse of the square of the distances is working there, hyperbolic, not linear. Twice the power, but the distance doubled, squared makes 4 and the fraction becomes 1/2. 72/73, de VE2PID KX1 # 442 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Miles per Watt
It's all in fun, miles, the simple math, the whole bit. As I pointed out on slashdot, it's a simpified model. Going to inverse squared is one step closer to the physics, but it's a slippery slope. You will want to measure the ERP in the direction used by the propagation path, factor in the antenna receiving gain sinilarly, use the IONCAP or that Australian ionosonde data to find the length of the actual propagation path and refraction angles (It's not like the radio signal goes on a great circle path! Perhaps the 3d straight-line distance through the Earth wold be better?), subtract our D layer attenuation, note the coding gain in dB -- surely there is some gain in QRSS at one hour -- and finally define an acceptable BER (bit error rate). In other words, you can make it as complicated as you want. Or as simple as 1000 miles per watt. DX can have a 1000kKM/watt award! Leigh. On Fri, 7 Jan 2005 12:40 pm, S55M wrote: Miles per Watt is nonsense data to impress people.because nothing happens in linear mode!!!So increasing or decreasing power by 10 times will not expand range by 10 times.. More you go to miliwatts better will be m/W calculated ratio. Adi ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
