New station for Amsterdam island!

Hello.

I have a friend who is going 6 months/1years on the island of amsterdam (india ocean).

I would like to give him an omnidirectional station link to satnogs.

For now here is the config envisaged:

QFH antenna 430mhz DIY.
+
LNA4All (standard)
+
LNA4All (standard, optional)
+
RTL-SDR v3
+
Raspberry pi3b +

  • rj45 / official alim5v

Everything except the antenna will be in a waterproof case.

On this island apart from a satellite connection there is nothing (no FM, no mobile network and no wifi).

So I would like to know that it is the average flow required for a satnogs station ?

If the project is concluded I intend to continue my connection with the French Polar Institute to take this station to the Concordia base (Dome C).

What do you think ?
Advice on the material chosen? (be careful it leaves on October 28th so not a lot of time).

Why not VHF? Because we can only bring a lot of stuff and a VHF antenna takes a lot more space than a UHF.

4 Likes

I think your setup looks fine.
The only thing I would add is a spare - prebuilt - SD card for the Pi.

This post here has a lot of information on how much data is used by a typical station

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+1 on the above (@thebaldgeek I’ve changed a little the link to point to the one that pierros analyse the bandwidth)

If the bandwidth above seems to be too much, we can probably decrease it by either schedule less observations or maybe cutting the audio and leave only waterfall and data which need less bandwidth (at least until we move to the waterfall-data instead of waterfall-image that we currently send).

2 Likes

Super that’s exactly what I was looking for

on my new list a add 2 micro sdcard and 1 usb key with etcher and prebuild image.
Is it possible to feed the 2 LNA4ALL with the 5v GPIO raspberry?
Or does it need a dedicated 5v power supply?

Yes.
Go to the LNA4ALL website; http://lna4all.blogspot.com/
Scroll down and look at the mods for the different power supply options.
I did the external 5v option (place the zero ohm jumper) and then took a USB lead and cut the end off.
One end plugs into one of the Pi USB ports, the other is soldered on the LNA4ALL.
It works just fine.

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do you think it would be possible to deactivate the download of the sound actualy ?

my contact said it has 100ko/s for upload rate.

ok nice ! it’s a good LNA !

As far as I know there isn’t any option right now for diactivated, so there two options, either implement this option or install it as it is and perfor locally at the installation the necessary changes.

I’m not sure if we will make it to have this option ready in the October, so probably we would need to go on with the second option.

Just to be sure, is the problem the internet speed (bandwidth rate) or the total volume of data (specific GB limit). In the first case, 100kb/s should be ok for the audio too, in the second case indeed we will need to limit the uploaded data.

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My two cents for this project:

  • Firstly: Super exciting opportunity and thank you for contributing!
  • For such a location (with limited serviceability) I would go for more rugged setup with proven components.
  • We are preparing an updated version of the reference no-rotator ground station (with intention of that being a kit). Check the BOM here and some pictures of how this looks. I would advise going for such a solution.
  • For such an extreme location we (LSF) might be able to help with procuring some parts and setup (and special software requirements). Please reachout to pierros@ libre dot space or reply here to figure out how we help more.

Cheers!

3 Likes

Thanks for support.
Unfortunately no budget will not allow to leave on such an advanced config.
The budget is currently in the 400euros.

I think to change the 2 LNA4ALL by the amp ZX60-12LN +.

The antenna will be outside but the electronics will be inside to test a realistic configuration for the south pole (-60/-80°C)

I do not plan to use on the raspberry pi 4 because it requires active cooling which is not allowed to the pole because of the production of static electricity from the ventilator and very low humidity.
In addition to the rtl-sdr, the rpi3b + is powerful enough.

In our configuration no need for filter because we will install the station in an area far from civilization

It is the antenna of this station that I intend to use :
https://network.satnogs.org/stations/923/

Hello. After further investigation I know we will have the right to only 220kbits/s (27.5ko/s) sends.

So I think I have to deactivate the sending of the sound to stay in resonable use of bandwidth (we are not all alone on it).