In article <LEqJg.86630$Eh1.85684@tornado.ohiordc.rr.com>,
"Eric <nospam@nospam.noo>" wrote:

Yeah, guess funding would be the biggest obstacle.   I wonder if any 
"canidate locations" are in the path of Arecibo and if so, how much it would 

All of the Phoenix target list are, as far as I know, unless they have
enhanced it for the ATA.

cost to give Arecibo the capability to transmit at the water hole.  (Didn't 
Arecibo send a signal out once, but had to do it ~2.3 Ghz.?)

By some definitions of the waterhole, 2.3GHz is in the waterhole.
Transmitting within the narrow definition (around ~1.42GHz) is illegal
(to protect radio astronomers).  Note that project Phoenix does cover
a wide range of frequencies, which might even include 2.3GHz and even
SERENDIP covers frequencies on which transmission is allowed.  SETI@Home
uses just part of the SERENDIP data that is all in the protected band.
(If I remember correctly, the frequency of first detection in "Contact"
was actually pi * that of the Hydrogen hyperfine line, about 4.46GHz.)

Arecibo regularly transmits at both around 2.3GHz and around 470MHz as
it is used for planetary radar and atmospheric sounding.  When it is
transmitting Arecibo cannot be used for any reception which means that
there is no concept of parasitic active SETI.

Many of the 2.3GHz transmissions are CW radar and are detectable at
interstellar distances, but would present as one of detections, which
couldn't be verified.

Note that, although there is a popular idea that Arecibo is for SETI, it's
only ever had primary SETI usages in terms of single figure percentages,
and is probably down to about 1 or 2%.  SERENDIP and therefore SETI@Home
are parasitic SETI, they take advantage of being able to operate multiple
receivers simultaneously (especially when at different feed points)
to make SETI observations in whatever direction is pointed at as the
result of primary experiments - except when it is transmitting.