Help me identifying signal is good or bad - Observation 11266470: UNISAT-6 (40012)

Satellites & Observations Observations
1

Regarding Observation 11266470 …

Hello Libre space community, this is one of my earliest observation since installation.

I installed UHF yagi antenna directing zenith, which is mainly designed for territorial TV broadcast.

The observation sees some horizontal lines but I cannot clear identify whether it’s noise or signal.

Currently I set gain to 37db (RTL-SDR V4) and successfully obsessed clear signals - such as ISS and KSM.

Can anyone help identify whether this signal is good or bad?

2

Good morning,
Is working, but…

  1. Try other sattellite, like LEDSAT, YOMOGI, VZLUSAT, DOSAAF-85.
  2. Let us know if you your configuration (coaxial lenght, coaxial type, if you are using LNA, etc.)
  3. I saw you are using the gain value 38 dB. Try to use exactly one of the following value: 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6. Lets use something like 29.7 to 40.2 (use the exact value, not rounded).
  4. The horizontal lines terestrial, not satellite.

Regards,
Cristian - YO4DFT

3

I tried to look to your observations history:

  1. The value for ppm usually is maximum 10 (+/-), not 100…
  2. Almost all receptions around 400 Mhz satellites are looking good.
  3. For 435-438 Mhz satellites it appear some perturbing terrestrial signals. Is any UHF hamradio repeater around you ? (10-40 km around). Posibil solution is to point the antenna to other direction (East or West, 15-30 degrees elevation) to see if signals disapear.

Cristian -YO4DFT

4

Thank you for answer.

I’ll check ppm value how to set the proper value, please note that this is my earliest observation and not tuned yet.
Since the antenna is installed in metropolitan area there are high change of HAM repeater nearby.

5

leave the ppm as is now, change the gain to 37.2 (not 37, or 38). We shall see after this.

6

CUTE-1 observation, gain=40.2
-good signal (vertical one), but still terestrial unwanted.
-you can start playing with ppm now, but dont use more than 3-4 units (+/- 3). Lets try ppm=-3
-next step, try other direction of antenna, if you have without obstruction to East or West.

7

Thank you,

Applied -3.520 ppm, of which value is calculated by following instruction:
https://wiki.satnogs.org/Adjusting_the_SatNOGS_Client#adjustment_using_observations

Also tilted my antenna around 30deg to East, I’ll update once I get CW signal.

8

fyi: ppm is integer only

9

I’ve applied to ppm=-3 now it seems much better.

Followings are some CW signals:
https://network.satnogs.org/observations/11275122/
https://network.satnogs.org/observations/11279700/

For the territorial signal around 430MHz there are some possible source of noise

  • Remote thermometer that uses 433MHz; I just unplugged it.
  • Construction site near my house (<1km); some chance that they installed radio repeater.

Rotating the antenna to the East reduces some noise but still not very clear.

10

By experience, I think the gain is too high. Setting it close to max usually results in much worse interference. Doing this by observations is a slow process thou… testing ~ 10, 20, 30, 40

Using a live spectrum and starting from the lowest and going to highest gain, you can first see the signals increase, then the noise floor starts to rise with noise and signals increase at the same rate, then the noise increases by itself and starts to become irregular and wonky.
Where exactly these occur depends on your setup and the RF environment.

Does the antenna have a built in amplifier ?
LNA/preamp at the antenna is for sure one of the better ways to improve the results.

11

The antenna does not have LNA yet. I ordered one but it would take some time to be shipped.
Thanks for your recommendation, I roughly followed following guide.
I’ll double check noise floor and proper gain setting.
https://wiki.satnogs.org/Omnidirectional_Station_How_To#Setting_the_gain

12

Most probably you also need a pass-band filter…
What kind of antenna are you using ?

Cristian - YO4DFT

13

I would suggest to use a SDR program like GQRX, SDR++, SDR# or similar and do some real time analyses of you RF environment, there is a lot of noise, rfi etc being received.