[Moon-net] 10 Ghz EME from Cincinnati, Ohio, USA

[powis family]

Mike, Jim,

Congratulations on getting to this stage!  It's great to hear that you are 
comfortably receiving your own echoes - shouldn't be too long now before we 
hear about the first two-way QSO then...?

Best 73 & Gd DX!
Dave, G4HUP / ND8P
----- Original Message ----- 
From: <mmurphy at triumph-eng.com>
To: <moon-net at list-serv.davidv.net>
Sent: Friday, March 30, 2007 5:58 AM
Subject: [Moon-net] 10 Ghz EME from Cincinnati, Ohio, USA


> Gentlemen...
>
> On March 30th, around 01:30 GMT, Jim, N8ECI and myself were finally able 
> to receive our own echos
> at the old Voice of America shortwave transmitting site located just north 
> of Cincinnati, Ohio.
> The echos were about 10 db above the noise as seen on Spectran (thanks 
> I2PHD!) and we heard the
> signals by ear as well...
>
> The station consists of a 24 ft (7.2 meter) commercial dish (F/D = .3) 
> with Cassegrain optics and
> corrugated horn feed.  Six feet of 3/4 inch copper pipe acts a circular 
> waveguide from the feed
> horn, making an abrupt transition to rectangular guide at a waveguide 
> switch.  The receive chain
> consists of a transition feeding a DB6NT pre-amp (0.6 db NF), followed by 
> an RG-405 jumper and a
> Down East Microwave two-stage preamp.  The signal then enters a Down East 
> Microwave transverter in
> which it is heterodyned down to two meters where it is received on an old 
> Icom IC-251A.  Audio is
> sent to a PC running Spectran.  A G4NNS noise indicator (built by G4HUP 
> and N8ECI) provides a
> signal that aids in trimming antenna pointing using moon noise.
>
> Transmitted signals begin in the IC-251A, are heterodyned up to 10 kMc in 
> the Down East
> transverter. Then the signal is amplified in a 10 mW to two watt Down East 
> amp that feeds a two to
> eight watt Down East amplifier.  From there the transmitted signal hits a 
> transition at the
> waveguide switch, finally heading up the water pipe and out the horn to 
> the sub-reflector.
> Currently we are limited to 7.5 watts output power, and the transmit chain 
> has not been
> optimized.   A sequencer won at the '04 EME conference in New Jersey 
> controls all switched sub-
> components.
>
> The dish and mount was built by Vertex/RSI in '90, and it was removed from 
> service and abandoned
> in position in '94 when the short wave station closed.  VOA personnel 
> removed various components,
> including the drive motors and control system that moved the dish. 
> Actuation is now provided by
> three-phase motors and computer controlled, variable frequency drives via 
> pointing data generated
> by the W9IP tracking program "Nova".  Jim, N8ECI, wrote software to 
> control antenna pointing.
>
> Unfortunately, the mount is a degenerate alt-az system that can only point 
> between 120 and 240
> degrees azimuth.  This severely limits our moon visibility, especially at 
> high northerly
> declinations.  The EME station is located near 39.10 degrees north 
> lattitude and 84.51 degrees west
> longitude. Station call is "WC8VOA"...
>
> Photos and additional details can be seen at www.wc8voa.org
>
> Not sure of our schedule possibilities at this time, but we are somewhat 
> flexible and can try when
> we can see the moon with our limited azimuth window.
>
> Thanks to many, including G4HUP, I2PHD, W5LUA, W1GHZ, WA3ZKR, the 
> Engineering Department at
> Vertex/RSI in Kilgore, Texas as well as all the great EME men who came 
> before.  Guys like W2IMU,
> W8JK and the other pioneers around the world have been a great 
> inspiration...
>
> The moon looks different to me tonight!!!
>
> 73...
>
> Mike Murphy
> KA8ABR
>
>
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