Re: SSTRAN final input power-Rich's Reply
> scroll down to near the bottom of the page to where
> transmitter efficiency is discussed.
...parts of which follow:
"I found that the Hamilton Rangemaster NWXAM-1000 Transmitter had the best input power to output power efficiency (90%) of any transmitter I tested . The typical output power for 100 Mw. input is 90 Mw. Most of the other transmitters I tested had an efficiency of less than 50%. ... A big advantage with the Rangemaster is that it uses traditional 'high level modulation' and actually develops 360 Mw. of output at 100% modulation."
_______________
Modulating _any_ AM transmitter 100% by a sine wave will increase the r-f power measured at its output connector by a factor of 1.5X (150%), no matter how the tx is modulated. Average power increase during normal program modulation is less than that, even.
If your "360 Mw." value above refers to peak power, that would indicate an average carrier output power of 90 mW. Peak power at 100% sinewave AM is 4X the average value of the unmodulated carrier. But again, that would apply to _all_ AM txs able to amplitude-modulate a constant carrier to +/-100%.
> With flea power part 15 transmitters, every milliwatt of
> actual output counts. The greater, the better.
To put this in better perspective, the difference in field strength produced by a given antenna over a given path changes by the square root of the change in applied power. So reducing the _output power_ by 1/2 reduces field strength by about 29%. Much greater effects on field strength can be achieved by reducing the RF resistance of the ground system (see my earlier post here on MW grounds).
//
> scroll down to near the bottom of the page to where
> transmitter efficiency is discussed.
...parts of which follow:
"I found that the Hamilton Rangemaster NWXAM-1000 Transmitter had the best input power to output power efficiency (90%) of any transmitter I tested . The typical output power for 100 Mw. input is 90 Mw. Most of the other transmitters I tested had an efficiency of less than 50%. ... A big advantage with the Rangemaster is that it uses traditional 'high level modulation' and actually develops 360 Mw. of output at 100% modulation."
_______________
Modulating _any_ AM transmitter 100% by a sine wave will increase the r-f power measured at its output connector by a factor of 1.5X (150%), no matter how the tx is modulated. Average power increase during normal program modulation is less than that, even.
If your "360 Mw." value above refers to peak power, that would indicate an average carrier output power of 90 mW. Peak power at 100% sinewave AM is 4X the average value of the unmodulated carrier. But again, that would apply to _all_ AM txs able to amplitude-modulate a constant carrier to +/-100%.
> With flea power part 15 transmitters, every milliwatt of
> actual output counts. The greater, the better.
To put this in better perspective, the difference in field strength produced by a given antenna over a given path changes by the square root of the change in applied power. So reducing the _output power_ by 1/2 reduces field strength by about 29%. Much greater effects on field strength can be achieved by reducing the RF resistance of the ground system (see my earlier post here on MW grounds).
//