[evlatests] total power detector

[Barry Clark]

> From: Travis Newton <tnewton at aoc.nrao.edu>
> 
> Question 2.
> for the 1-2 GHz output operating at a nominal -37 dBm, what is the 
> desired bottom end reading? -37 centered and -46 for the bottom,
> -28 for the top? more top heavy?
>
> Question 3.
> and the same question applies to the 2-4 GHz output operating at
> at a nominal -25 dBm
> -29 centered, -34 bottom, -16 top?

Top and bottom are set by quite different considerations.  The room at the
top is set by wanting to follow the sun if there is a big, rapid, flare.
I don't understand solar needs very well, but I suspect the answer from a
solar astronomer would be a request for lots of headroom.  On the other
hand, I don't know how seriously to take that request; it would be used, in 
the best case, a couple dozen times per 11 year solar cycle.  And I wouldn't
support this sort of thing at all if FASR is built.

The room at the bottom is set by the need for diagnosing problems with the
module.  Probably three dB would be enough for scientific purposes.  If you 
think, for diagnostic reasons, you need to distinguish between a 'low gain' 
state and a 'broken' state, you should grab as much of the range as needed 
to do so.

> Question 1. Is this enough range?

Personally, I'm inclined to answer 'yes'.  However, there might be those 
who would argue that it should work across the whole headroom, which is
specified to be 20 db above nominal.

> The same detector chip is anticipated to be used for the RF input
> detector.  There is currently not enough hardware to make a
> similar test at the input., in progress

I do not know of a scientific need for this detector.  It is needed only
for diagnostic reasons.  Your ballcourt.