[Amps] Maximum RF output in practical application: 4-250A

[Joe Isabella]

White noise is definitely worst-case, and with max allowed ALC it makes an ugly spectral plot.  However, I'm not sure what you mean by "white noise with a peak-to-average ratio typical of voice...".  White noise will drive the rig from the lowest to highest audio freq it will pass, and beyond at an equal level.  Also, max ALC and max *rated* PEP aren't necessarily the same level, and would likely drastically change the measurement.  My rig, for example has substantial IMD products when driven into max ALC, but when driven with no ALC at ~90W, they are WAY down even with white noise.  I need to do this experiment again and get pictures of the analyzer -- when I did it last time, I just made notes.  I'll do that this week and post the results...

But I'm glad to hear that you would be willing to tolerate wider occupied BW, that logic has escaped a lot of folks, as well as the ARRL.  Honestly though, I doubt it would change anything even if the ARRL's proposal was implemented.  Those who operate a nasty station will probably continue to do so, and those that operate a clean 4k station will continue to do so.  I just wonder how many "BW Cops" will be created running around with their ProIIIs (or whatever) telling everyone they're "too wide" (hell, it already happens!!)...

Joe, N3JI


----- Original Message ----
From: Michael Tope <W4EF at dellroy.com>
To: Joe Isabella <n3ji at yahoo.com>; g3rzp at g3rzp.wanadoo.co.uk; Tom W8JI <w8ji at w8ji.com>; zdtech <zdtech at iprimus.com.au>; amps at contesting.com
Sent: Monday, July 3, 2006 12:29:56 PM
Subject: Re: [Amps] Maximum RF output in practical application: 4-250A

----- Original Message ----- 
From: Joe Isabella 

Okay, so how is that tested?  White noise?  Tones?  Voice?  Max power?  Max allowed ALC?  No ALC?

Come on Michael, there's no way that would be anything but arbitrary, as a lot of the ARRL's "measurements" already are.

Joe, N3JI

White noise with a peak-to-average ratio typical of voice 
transmission, processor on, maximum allowed ALC, and 
output power adjusted to maximum rated PEP output of 
transceiver. IMO, this would provide a good measure of 
whether the rig is capable of reasonably clean operation. 

BTW, I am not as concerned about signal bandwidth (3KHz 
vs 4 KHz vs 6KHz) as others appear to be. My concern is 
with spectral regrowth caused by IMD. In my mind, a guy 
running 2.6 KHz signal bandwidth with horibble IMD products 
stretching +/- 10 KHz of his center frequency is much more 
offensive than a guy running 4 KHz "Hi-Fi" bandwidth into a 
class A amplifier that has very low IMD products resembling 
a brick-wall spectral mask. IOW, I wouldn't have a problem 
stretching or offseting the mask to accommodate variations 
in the signal bandwidth. 

73, Mike W4EF..................................................
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