Re: [amsat-bb] OK NOW WHAT? re: a040

[Bruce Nolte N3LSY <brucenol@xxxxxxx>]

jim hertel wrote:

>   I have AO40 going,  running the bbq dish and aidc down converter,  I
>hear my self and have made some contacts...  but  ...   The signal
>strength coming into the shack has something to be desired S1 to S3 the
>MB is S3 at  most times.  Do I need to put a preamplifier between the
>antenna and down converter?  Or do I need one after the down converter
>to the shack?  I have allot of noise now but will this increase the
>noise floor?  Also running RG6 to the shack (100 ft).   Also would it
>make any difference if I mounted the bbq dish horiz. or vert?
>rig is ft847 tx/rx.
>straining to hear,
>Jim Hertel
>N6KMR@arrl.net
>
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>  
>
The AIDC D/C should have plenty of gain, and if you were to put in a 
preamp, it would DEFINITLY be between the antenna and the downconverter. 
Here are a  couple of other factors to consider: Trees are DEATH to 
microwave signals, don't even try to work through them if they are in 
leaf, and don't expect much when they are bare.   Another factor is the 
Squint Angle, which is the angle that the satellite's downlink antenna 
is pointing away from your station. Over about 20 degrees squint, the 
received strength of the signal drops considerably. NOVA has a nice 
display of this information. Also, make sure there is no water in any of 
the connectors, particularly on the 2.4 Ghz side. This will kill signals 
quickly as well. RG-6 should be adequate for your downlink coax, with 
about 4 dB of attentuation (1 S unit). The attentuation will not 
appreciably affect the Signal to Noise Ratio, which is determined at the 
downconverter. Hope this helps.

73 ,

Bruce N3LSY

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