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Re: Great deal on a dish :)




>Hi,
>
>In case you don't read QST Ham Ads, I came across an interesting one on page
>150 of the September issue.  It is for a 60 foot disk with full drives in
>Colorado for $375K.  I wonder if that includes shipping?  On a slightly more
>serious note, it does say that 501-C3 organizations may contact them for
>consideration.
>
>
>Alan
>WA4SCA

This dish is several miles east of Pueblo, Colorado and is identical to the 
two on Table Mountain near Boulder.  As I recall they were built in the 
50's (Tom Clark has more detail).  An organization called the Deep Space 
Exploration Society had a lease on the Table Mountain dishes for a few 
years (they belong to NIST and are in a radio quite zone).  I was part of 
the team that rebuilt them and got them going again.  Among other 
contributors Junior De Castro (DOVE sponsor) donated an ICOM R-7000 
receiver for general use there.  They have been used to receive ATV from 
Edge of Space Sciences balloons in excess of 100 miles away, for radio 
astronomy, listen to the atmospheric sounder on 70cm that is a few miles 
away, and to receive a satellite or two.  I looked at the AO-10 passband a 
time or two with a spectrum analyzer; of course the passband noise was a 
few 10's of dB above the background noise.
We initially re-aligned the mechanical controls using sun noise.  Put a 
70cm feed at the focus with a preamp, SSB receiver in the building.  Had 
someone stand outside and yell in to the operator which way to go while 
observing the shadow of the feed on the dish.  Easy to tell when we hit the 
sun, the noise blew the receiver off the table.

Originally these were used for a tropo scatter study on VHF (yes, 
VHF).  Transmissions were from the Table Mountain end.  To fund some of the 
restoration work we sold off the 3 inch brass coax for scrap prices.

I did a talk on these at the Washington, D.C. AMSAT Symposium in 92.  See 
those proceedings page 191.  Page 194 has a table of gain and beam width 
for several bands.  Let's see, want to hear AO-40 really really well?  How 
about 50.7 dB gain at S band (beam width .5 degrees)?

I've not seen the one in southern Colorado but I'm told it is in excellent 
shape.  At one time we discussed the possibility of purchasing it and 
moving it to the Air Force Academy.  The problem is disassembling, moving 
and reassembling it would cost at least $1M.  It's just not worth it.  If a 
project came along that could use such a dish it would be much easier and 
less expensive to modernize one of the table mountain dishes than move the 
one that is advertised.

Having said that, these are built like battle ships.  All welded aluminum 
construction.  Very very rugged.  The Table Mountain pair sat for over 20 
years unused in the usual Boulder high wind, and were in quite good 
condition when we got the lease.  The hope was that some government or 
better, university, project would come along that had $100k or so to 
modernize one of them and put it to use for a year or so.  We had a design 
for full remote control via the Internet that would allow control and data 
transmission from anywhere.  Alas, no such project has come to light.

Jim
jim@coloradosatellite.com








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