[amsat-bb] 70cm LNA

[Kevin Elliott]

Not wanting to use this with a transceiver, mostly just for my 70cm QFH with SDR for satnogs. Aware of any other 70cm and 2m LNAs that perform well for receive-only?

> On Aug 12, 2020, at 12:11 PM, W3AB/GEO via AMSAT-BB <amsat-bb at amsat.org> wrote:
> 
> 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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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
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> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb