[amsat-bb] 70cm LNA

[W3AB/GEO]

Very nice Zach.

⁣___
Sent from my two way wrist watch
73 de W3AB/GEO​

On Aug 12, 2020, 11:45, at 11:45, Zach Metzinger via AMSAT-BB <amsat-bb at amsat.org> wrote:
>On 08/11/20 21:47, Zach Metzinger via AMSAT-BB wrote:
>> Success! The SAW filter eliminated the offending cell-tower sources.
>> The noise floor barely moves when the preamp is switched in, while
>> the desired beacon signal increases significantly.
>The 3-D printed passive Lindenblad + homebrew LNA, driving 75' of 
>look-alike-LMR400 is working well for receiving RS-44 now. The LMR400
>is 
>optional, as there is plenty of gain from the MAX2640 LNA, but was used
>
>to keep losses down when transmitting on this antenna.
>
>I can reliably copy the RS-44 beacon about 8 degrees above the horizon,
>
>and SSB is quite readable at about 20 degrees.
>
>A horizon-to-horizon pass recording is located here:
>
>http://www.n0zgo.net/oscar/rs44_12082020_1802.mp3
>
>(The good stuff starts at about 7 minutes into the recording. I chase 
>the beacon at the end in CW mode, and it disappears at 5 degrees
>elevation.)
>
>A FT-847 was used for reception, but a cheap SDR dongle would probably 
>work just as well for a lost-cost entry into 70cm downlink capability 
>(as required for the GOLF satellites).
>
>Now to wire it up for automatic Doppler correction and we're in
>business.
>
>73,
>
>--- Zach
>N0ZGO
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