[amsat-bb] Re: FW: 25 watt Moonbounce

Edward Cole kl7uw at acsalaska.net
Wed Jan 30 20:41:19 PST 2008


Nor was I trying to trivialize Angus' accomplishment.  But I was 
curious what he used for antenna.
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I think what made the contact by Angus all the more remarkable was that it's
reported he was just using a single 7 element yagi in his attic so would suffer
additional attenuation from roof tiles.

73 Trevor M5AKA
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If the antenna was a 7-element yagi in his attic, as Trevor states, 
that was quite a accomplishment.  BTW I heard my first 2m-eme signal 
in 1997 on a 10-element satellite antenna (with only horizontal 
elements) using a ARR preamp.  It was one of the larger stations 
(K5GW) running CW.

I have found that the lower limit of EIRP is about 16 KW for two 
stations of equal size.  That can be one yagi (13 dBd) and about 500w 
or four yagis (19 dBd) and 125w and requires running JT65 (remember 
dBd = 2.15 dBi).  CW requires about 10-dB stronger signals as a rule.

Angus most likely worked one the super-big eme stations that are 
running lots of yagis.  That extra gain makes up for a low power 
single yagi station.  BTW my first 2-way eme QSO was with two yagis 
and 120w made with W5UN (32-yagis) on CW in 1998.  Dave has given a 
lot of small stations their first contact!

73 Ed - KL7UW

At 06:30 AM 1/30/2008, Les Listwa wrote:



>Regardless if this is a record or not, the PR is great for the Ham community
>in general. Also, his accomplishments and the PR hopefully will motivate
>some of those working the birds to download the WJST software and slew their
>modest antennas towards the moon.  Six months ago, on a whim I downloaded
>the WJST software, aimed my 20 element crossed yagi 2M satellite  antenna at
>the moon and heard W5UN and worked him. I was so excited and felt like a
>Novice making my first contact. Since then I have made over 100 contacts (
>although, I have slowly grown my antennas and power to do it). I happened to
>be on the air the day Angus made the contact. I could not hear him, but I
>heard the other station he was working.  He was luckily ( or smart enough)
>to pick one of the few days of the month when EME conditions were close to
>perfect and also picked up an additional 6 db of ground gain as he was
>working the moon on his Horizon.  He also was  compensating for Faraday
>rotation as he was switching between horizontal and Vertical elements
>through out the QSO.  Was it a record? It does not matter. It was an
>accomplishment! And hopefully it will serve as motivation for anyone with
>even a modest satellite station to aim for the moon.
>
>Les WB2SZR, Daniel W2DBL
>
>
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73,
Ed - KL7UW
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