Having fully purple waterfall on my GS's observation


#1

Hello everybody,
I set up my first ground station named “Troy-1 GS” (has ID 905). I have done 5 observations but they all have a fully purple waterfall.

I think that the reason is the LNA that I am using but couldn’t be sure. Have you ever experienced this situation? What could be the problem?

Here is my ground station’s inside:


#2

Hello @denizmenekay tried it only with the antenna and sdr to see if this is the problem.check the satnogs-client (https://wiki.satnogs.org/Omnidirectional_Station_How_To) for settings .


#3

Thanks for your reply! That is what I am planning to do, but I am not close to the GS right now. Just wondered if anybody had this before. Maybe the reason is somewhere else.

I will check that website, thanks again!


#4

These are how signals look like in different situations:

The upper signal is only using rtl-sdr, other one has sdr, filter, and lna together:

In this picture, upper signal is sdr, filter, and lna together again and other one has both sdr and signal:


#5

Looks like the LNA might be overdriving the SDR. In the second screen shot, did you change the gain settings?

EDIT, generally you want to get the LNA close to the antenna, not close to the SDR as you have it.
Yes, it makes mounting more tricky, but it works the way it should, amplifying the signal rather than amplifying everything. (Including noise).


#6

Yep you were right, I just removed the LNA and everything works good. I may find a better place for LNA in the future as you say. Signals that I receive are good altough there is no LNA. Probably my antenna is adequate for powerful satellites. So far so good :slight_smile:

Thanks for your reply.