LNAs are good, but they also raise the noise power in the pass band, right? From my experience, too much amplification is a bad thing when seeking lower power RF signals. Why not consider better (industrial/lab quality) components at the RF front ends taking out the components supplied with the cheap dongles? Use the back end, but reengineer the front end. Those parts are probably the cheapest quality so if one could get a 0.5 or 1 dB increase .... and I learnt of a tip: older radio operators (WWII to 1960s) used tube front ends in RX boards for weak signal VHF. Amazing technology that should still be interesting. Narrow-Q but high dynamic range! Like an audio pre-amp with tube circuits.
Discussion and criticism welcome.
Samudra N3RDX
-----Original Message----- From: Armand SP3QFE [email protected] Sent: Monday, December 28, 2020 3:14 PM To: Mathison Ott [email protected] Cc: Andy Brian [email protected]; AMSAT-BB [email protected] Subject: [AMSAT-BB] Re: SSTV with SDR RTL2832
Hi,
I think that the LNA will boost both 144 and 145 MHz signals.
Armand
W dniu 2020-12-28 21:11, Mathison Ott napisał(a):
Hartwig 144-149mhz LNA solved my RFI problems with my SATNOGS station.
https://network.satnogs.org/stations/984/
73 KJ6DZB cm87
On Mon, Dec 28, 2020 at 9:35 AM Andy Brian [email protected] wrote:
Hi,
I received many pictures from ISS. I'm using RTL dongle 2832 with SDR# program and MMSSTV with virtual cable and Orbitron.I found many rainbow lines on pictures and I analysed that this is the case of transmission with APRS local stations around 5km away and 1mhz below my receiving. Anyone have experirence of good filtering or set the SDR# program to reduce the infulence from of transmitter which is far away from 145.8MHz but still in the 2MHz bandwidth of RTL2832?
BR Andy
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