[amsat-bb] 70cm LNA

[Pedro Converso]

Nice recording and information, TKS ! for sharing.

As an alternative, http://amsat.org.ar/pass.exe concurrent with HDSDR
could automatic handle & control Doppler on any generic SDR for RS-44
or any other sat.

73, lu7abf, Pedro

,On 8/12/20, 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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