search

gut-space / satnogs

The goal of this project is to create a functional satellite ground station, able to receive VHF transmissions from NOAA sats and more!
https://aquarius.klub.com.pl
MIT License
9 stars 0 forks source link

Connection between antenna and RPi #7

Closed fivitti closed 4 years ago

fivitti commented 4 years ago

We need to decide where place the RPi and SDR. We have few options:

  1. On the roof, near the antenna
  2. In the laboratory, using long antenna cable
  3. SDR on the roof, RPi in the laboratory

On the roof

In this case we put the RPi and SDR on the roof, probably in waterproof box, near (or on) the antenna (far ~0,5 m). It should minimize the noises. But upgrade or manual reset of RPi is hard, because we cannot personally get on the roof. Other problem is communication with RPi. We don't know if we have Ethernet connection. If we don't have a possibility to connect to the network then we need plug the GSM modem to RPi. We know nothing about power supply on the roof too.

In the laboratory

Dr Siwicki says that exists the antenna cable from the roof to one laboratory on 7 level and we probably can use it. But this solution increase the noises. But we will to have a free access to our electronic components.

SDR on the roof, RPi in the laboratory

The noises occur when we work with analog signal. We have analog signal in antenna, between antenna and SDR and partially in SDR. SDR produces digital signal. We may put the antenna and SDR on the roof to convert signal to digital and next lossless transfer it to RPi in the laboratory. The main problem here is length of the cable. Some digital cables have limited length to few meters and it isn't enough. We don't know also if we have a possibility to install this cable.

To Do:

Originally posted in #5 by Sławek Figiel at 2019-10-03T20:26:40.911Z

fivitti commented 4 years ago

@slawek can this be closed?

Originally posted by Tomek Mrugalski at 2019-11-09T08:47:57.125Z

fivitti commented 4 years ago

LGTM.

Originally posted by Tomek Mrugalski at 2019-10-20T18:17:30.018Z

fivitti commented 4 years ago

assigned to @slawek

Originally posted by Tomek Mrugalski at 2019-10-20T18:17:35.644Z

fivitti commented 4 years ago

closed

Originally posted by Tomek Mrugalski at 2020-01-24T18:26:24.822Z

fivitti commented 4 years ago

changed the description

Originally posted by Tomek Mrugalski at 2019-10-20T18:16:52.580Z

fivitti commented 4 years ago

mentioned in issue #9

Originally posted by Sławek Figiel at 2019-10-13T16:15:47.861Z

fivitti commented 4 years ago

The list of satellites which operate on 137 MHz and has clockwise circular polarization.

Name Frequency Bandwidth Data type Orbit Observable in Gdansk
NOAA 15 DSB 137.35 / 137.77 MHz 46 kHz DSB Polar YES
NOAA 15 APT 137.62 MHz 38 kHz Meteo, graphics, analog
NOAA 18 DSB 137.35 / 137.77 MHz 46 kHz DSB Polar YES
NOAA 18 APT 137.9125 MHz 38 kHz Meteo, graphics, analog
NOAA 19 DSB 137.35 / 137.77 MHz 46 kHz DSB Polar YES
NOAA 19 APT 137.1 MHz 38 kHz Meteo, graphics, analog
Meteor N2 137.1 MHz 150 kHz Meteo, graphics, digital Polar YES
Meteor N2-2 137.9 MHz 150 kHz Meteo, graphics, digital Polar NO
Orbcomm FM13 Data YES
Orbcomm FM14 Data YES
Orbcomm FM15 Data YES
Orbcomm FM18 Data YES
Orbcomm FM19 Data YES
Orbcomm FM20 Data YES
Orbcomm FM113 Data YES

Orbcomm channels

Name Frequency Bandwidth
Orbcomm S-1 137.2000 MHz 25 kHz
Orbcomm S-2 137.2250 MHz 25 kHz
Orbcomm S-3 137.2500 MHz 25 kHz
Orbcomm S-4 137.4400 MHz 25 kHz
Orbcomm S-5 137.4600 MHz 25 kHz
Orbcomm S-6 137.6625 MHz 25 kHz
Orbcomm S-7 137.6875 MHz 25 kHz
Orbcomm S-8 137.7125 MHz 25 kHz
Orbcomm S-9 137.8000 MHz 25 kHz
Orbcomm S-10 137.2875 MHz 25 kHz
Orbcomm S-11 137.3125 MHz 25 kHz
Orbcomm S-12 137.5600 MHz 50 kHz
Orbcomm Gateway 137.2000 MHz 25 kHz

Average transit parameters 13.10.2019

Name Highest point altitude Highest point azimuth Average transit time Total transit time
NOAA 15 37° +- 27° 145° +- 112° 8:21 min +- 2:18 min 50:06 min
NOAA 18 30° +- 19° 116° +- 106° 7:17 min +- 4:09 min 36:23 min
NOAA 19 32° +- 18° 181° +- 128° 7:27 min +- 4:27 min 44:39 min
Meteor N2 38° +- 9° 152° +- 129° 9:51 min +- 35 sec 29:32 min

Originally posted by Sławek Figiel at 2019-10-12T18:58:46.720Z

fivitti commented 4 years ago

added ~5 label

Originally posted by Tomek Mrugalski at 2019-10-20T18:17:42.458Z

fivitti commented 4 years ago

My proposal:

Name NOAA 18
Frequency 137.9125 MHz
Polarization Circular right
Data type Graphic
Mean highest elevation 37 +- 18 degrees
Mean time of visibility 4 min +- 1 min 50 sec
Backup NOAA 15, Meteor

I don't found any good UHF satellite over Gdańsk. The best spacecraft to receive in UHF frequencies is IIS, but it isn't observable in Gdańsk. I found a few sats which transmit telemetry using UHF. Polish satellites as Swiatowid or Brite Lem and Heweliusz use UHF, but I don't found any information how we can receive the data.

I found also more satellites using VHF bands. Some useful links:

Originally posted by Sławek Figiel at 2019-10-10T17:21:16.292Z

fivitti commented 4 years ago

Currently the only sats that are using APT protocol are NOAA-15, NOAA-18 and NOAA-19. We've received many transmissions from all of them.

Originally posted by Tomek Mrugalski at 2020-01-24T18:26:24.286Z

fivitti commented 4 years ago

mentioned in issue #2

Originally posted by Sławek Figiel at 2019-10-10T17:30:25.486Z

fivitti commented 4 years ago

changed the description

Originally posted by Sławek Figiel at 2019-10-12T20:30:48.948Z