My ground station is not very good. What do I do now?

SatNOGS
1

I have a DAT-75 and a big pole that used to be a TV antenna but that seems like a big undertaking right now. I was wondering if there is any way I can get my existing setup to work a bit better. Work out the issue with a smaller simpler setup before I get something bigger and more complicated.

I am using these things…

  • Nagoya UT-72
  • RTL-SDR Blog R820T2

I did the recommended steps of setting up ntp, adjusting for frequency drift and entering my coordinates with as much granularity as I could possibly get. I try to schedule with satellites that have a high success rate.

And most of my captures look empty.
https://network.satnogs.org/observations/493927/
https://network.satnogs.org/observations/493969/
https://network.satnogs.org/observations/493921/

I know of a few improvements I could make but I don’t know if they are small optimizations or my key to fixing things.

The coax from the antenna is long and ends with a long adapter. Then the long adapter goes to the sdr. I don’t know if it is too long or not. Here is a picture.

IMG_20190225_111142
IMG_20190225_1111423064×2504 2.04 MB

I have my setup indoors, but I heard that 400 Mhz didn’t have trouble with walls so I am not sure. I can’t really take the setup outdoors to test all that easily.

I have an LNA but it didn’t seem to help for satnogs and in gqrx it added a lot of noise everywhere. I am using it with the recommended voltage, and it is the most highly rated one on Amazon. I thought it had a better NF then my rtlsdr. When are you supposed to use an LNA and where in the circuit does it go? Is there anything else I should add? I was thinking of getting the FM bandstop but I want to know if it will help before I drop more money into that. I was pretty sure I heard FM terrestrial radio in the UHF band one time.

Thanks!

2

UHF will do worse indoors. It’s good for getting out of windows and doors, but not so much for actually going through walls (or ceilings and roofs). Can you get that antenna outside (coax through a window)? Also, try getting one of those SO-239 to SMA male adapters, so you can go straight from the antenna coax to the SDR, without using those pigtails.

3

Thanks for the fast response. I will try to get it out of the window and come back to you. :sweat_smile:

4

Hello, the LNA will only amplify what the antenna hears, so take it outside and try the LNA again, also consider the surrounding area. If you have lots of houses/buildings blocking your horizon then you will only be picking up sats that rise high in the sky. You can adjust what sats to schedule for in the dashboard using the minimum horizon. Only go for sats that you know have a good pass.

If you start getting adventurous consider building/purchasing a turnstile for UHF.

Good luck, don’t give in.

Carl