Re: [amsat-bb] L band Uplink

["Edward R. Cole" <al7eb@xxxxxxxxxxxxx>]

>Message text written by John Heath
>>
>Hi Guys,
>
>Looking for some advice regarding  the L band uplink for AO-40.
>Will  12W at the antenna, and a 15dB gain RHCP Helical
>give me an adequate signal ?
>Would appreciate some guidance before I build it !!
>
>73 john G7HIA<
>--------------
>
>Hi, John:
>        Funny you should ask; a few weeks ago I asked a similar question
>and used the info, along with my own expereince, in a seminar I gave at the
>Dayton Hamvention.
>        Bottom line is that it will be adequate when conditions are good;
>i.e. less than 15 degrees off pointing and (hopefully) at less than apogee.
>If you speak CW, it will be a lot better yet. But, unless you have a high
>tolerance for weak signals, for armchair SSB ragchewing, it's 3db or so too
>light. 
>        But, as easy as a helix is to build, try it! Except make it about
>twice as long.
>        Have fun!
>
>73,
>Ed K9EK
>
>hummm.... maybe we also need a "Mode L: The Book"??

John, Ed:

Just to add my mode-L experience:  I ran 9.5w into a 45-elem loop yagi (20
dBi linear) to get about one s-unit above noise last fall.  AO-40
conditions may be a bit different now, but that translates to 950 w EiRP
and effectively half that correcting for polarity mismatch.  John states 12
x 30 = 360w dBic so that would be slightly less (I concur on getting more
watts or more gain).  I will say that my experience was that my 9.5w at the
anttena was marginal for good ssb copy...I want to try to get another 3 dB
of signal.

Well, as many know the 45-loop yagi is now a 20-something loop yagi after
the antenna crash.  I might have an offer of another 45 looper but am
giving some thought to trying to get my 8-foot dish operational on
1269/1296 MHz...that would be around 13w (after coax loss) to 28 dBic!

PS: Ed...I think you are correct...why not publish a capsule article for
the Journal?  I book would be a good goal, too!  BTW you gave a great talk
at Dayton!

Ed, AL7EB
sorry I was not in the window for the mode-VS test, but still sitting with
antennas lying on the roof.  May get a new roof-top mount constructed (by
FD???).  Trying to get my 2m-eme operational to try JT44 this
weekend...running out time...wish it would stop raining! :-)

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org