Re: [amsat-bb] Getting more gain without a solid dish....

[Jesse Morris <w4mvb@xxxxxxxx>]

Hi Al,
I too need some more gain for AO-40.  I was considering a system like you
described until I realized that the two Drake converters wont be on the
same frequency.  It work if you use two preamps providing you could come
up with a phase shifter and a  combiner.  The sad thing is that there is
only a maximum of 3 db available for two antennas and any losses in the
phase/combiner system would subtract from that.  I think we have to hope
that the wheels work and we bet the S1 transponder at apogee.

Good luck.

73's de Jess - W4MVB

On Tue, 24 Jul 2001 07:41:19 -0400 Al Lawler <alawler@us.oracle.com>
writes:
>
>
>  After my first night on ao-40,  I can see that
>despite not being the "poorest kid on the block"
>recieve-wise, I could definately do with some 
>more antenna gain.
>
>  My current setup is a 24dbi(linear) gain bbq
>dish with a DEM preamp and drake converter with
>the easy mods.
>
>  Using the Ao-40 spreadsheet, I see that the
>only thing I can really benifit from improving
>is the antenna itself.  (And possibly a few db 
>more preamp gain, but not much.)
>
>  Going to a solid dish with a helix feed isn't
>an option, due to wind/snow  resistance and weight
>considerations.
>
>  What I'm thinking of doing is to simply add
>a second BBQ dish, cross polarized with respect
>to the first one), with its own preamp/converter 
>(another dem/drake), then connecting the (144mhz)
>outputs of both drakes to the feedline via  a 2-meter
>"circular" phasing harness.  (I.e. the same
>harness used to get circular polarization out of
>2 yagi's.)  The idea is to be able to generate
>a circularly polarized antenna (with more capture
>area), without having to manufacture a precision
>phasing harness for 13cm.
>
>  Does anybody have any comments on how well this
>is likely to work?
>
>  -al
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