Hello, recently I reactivated my SatNOGS station #4205. Sometimes it getting this fluctuating horizontal line on the waterfall. I then troubleshoot by connecting it to the laptop and it appears it has unstable fluctuating noise floor.
For testing, I compare some observation with my other station (#3852).
#3852: VHF QFH that has resonance on UHF + RTL SDR V4 + TV Amp
#4205: 8 el UHF Yagi with the rotator inactive (pointed static to the North at 30 degree elevation) + RTL SDR V3 + SatNOGS diplexer + TV Amp
So yeah, mostly almost exact setup except SDR and antenna.
From what I read from the forum here and elsewhere, some say it was caused by a gain being set too high, but I already lowered the gain with similar results (or end up almost barely getting any signal). My area is rather quiet suburban, no high power transmitter nearby. I noticed that its happens most of the time on UHF amateur band, around 400 MHz often result clean waterfall.
OK I was having the same kinds of issues, mainly caused by phone charger type plugs and also a cheap ethernet hub. I do note that you seem to be using an omni antenna, there are not great for satellites, I assume a vertical / white stick type? You can hear the satellite quite clearly, from experience, you can hear lots of people trying to make contact through it, but the break are the satellite is spinning and your antenna only captures the signal at certain points. gain settings look OK. To get better coverage, you could use an egg beater type antenna (2 loops) still a compromise, and if you have a way of getting outside with the laptop / rtl and attaching it to a X yaggi type antenna and “tracking” the satellite with your hand (point antenna) will will see a huge difference in signal / reception. LMK if you need any help or want to chat. Cheers James M0JFP
I had a similar type of interference on my eggbeater antenna. I went and fiddled with it (yeah, thats the scientific term), and noticed the fitting was crimped too tight.
I must had “fiddled” it to a less compromising position, because I’m getting clear (well, clearer) copy now.
Next task is to replace that poorly crimped fitting.
yes I have an omni antenna which is QFH VHF. It’s been on since last year and I have no issues actually with that, the one that has issues is my other (newer) station that has a directional Yagi antenna permanently pointed North. It kept getting line interference like the image I attached, but the omnidirectional does not has the same issue (I scheduled exact same pass on both station to compare to each other).
Well, one thing I haven’t check was the power supply. What power supply do you recommend for powering up the Raspberry? I use Mini360 step down from 12 to 5.1v connected directly to the 5v rail as using most phone chargers and usb, I always getting low voltage warning on the Raspberry Pi.
