The organizer/publisher of the AM Transmitter Challenge posted on his website today (13 May 2014), suggesting that his next test setup in this Challenge might use a "standard" buried ground rod, while adding resistance in that path to simulate LESS than an "optimum ground."
However the r-f ground path resistance via a connection to a single ground rod buried in the earth conductivity likely at the original Challenge test site already is MUCH MORE than is provided by an optimum ground.
If the goal of the Challenge includes comparing the performance of the systems tested when using optimum or even typical r-f grounds (say, ground connections with an r-f resistance of less than 40 ohms), then the next set(s) of tests in this Challenge should be designed to REDUCE the r-f ground resistance used in the original Challenge, rather than to increase it.
And whatever happened to your (Rich(F)'s) perfectly excellent suggestion of simply laying ground radials on the surface of the earth with no puncturing of dirt being necessary?
And whatever happened to their poo-pooing the idea of another challenge and concentrating instead on dummy load tests?
And what about the basic fact that by not responding to challenge by e-mail, SSTran effectively declined and indicated a non-verbal "No thank you."
How rude to force the AMT5000 into tests despite a rejection.
Doing another challenge amounts to admitting that the first one was a flop.
We're going around in circles. Pretty much everything that can be said about the Challenge has been said, both positive and negative.
I actually think it was a blessing in disguise that the AMT5000 showed poorly in the first Challenge because of issues in its setup and execution. And I'm glad that the Challenge guys were such b*ttheads about it, denying any and all responsibility. For it shone the spotlight on what might otherwise have slipped through the cracks, and it's gotten some highly intelligent people looking at the issue and why that might have occurred.
I have certainly learned a lot, although I can't say that about the Challenge guy. His ego is getting in the way of learning anything, and I don't think that anyone should count too much on unbiased test results forthcoming any time soon. And that's OK too, because I think that a sufficient number of inquisitive Part 15'ers are now interested enough to see what the AMT5000 can do when it is properly installed and tuned. Even a newbie might be tempted to throw down their supposed ignorance, do some additional research and try it out.
Criticism/doubt has been leveled by some (and supported by others) about whether or not the AMT5000 can be properly tuned into loads with unknown resistive loss in the r-f ground path, without using an oscilloscope.
But even if by misadjustment, the output power of the AMT5000 is reduced by 50% from its potential ~98 mW output power when perfectly adjusted into an acceptable load impedance, the change in radiated power due to the loss in the r-f ground path can be several times greater (see chart below).
For best performance of Part 15 AM systems, the installation/use of a low-loss r-f ground can be more important than on getting every last milliwatt of output power from the transmitter, no matter what the operating class of its final amplifier
How about closing this thread and moving on?
Thread closed.