I’ve ben an avid amateur satellite user for years - I have a pair of WIMO X-Quads on an AZ/AL rotator.
I’m planning to put together a Satnog down station - Have a Pi and SDR - Just deciding if I put up VHF or UHF first. Planning to get it working with an omni antenna, and then consider if I integrate with my AZ/AL antennas.
Another dummies question - how complicated is it on the software side to support 2 bands? It’s trivial with a diplexer on the antenna side for me.
Which is the more valuable band for the community? VHF or UHF?
First off, I hope you will get this station up and running (:
I’d say you find more action on UHF, even more if extending the range to ~401MHz.
I’m running a diplexer setup with VHF+UHF broadband and it works pretty well.
I even have a signal splitter to have one rtlsdr for satnogs and one for openwebrx.
Regarding the software side, setting up multiple band is the easy part, just add the frequency ranges you want to support.
I would suggest you get your Pi distribution, get docker on it, and proceed to install the dockerized satnogs client. The idea is to start with one station, let’s say omnidirectional UHF, which is busier and measure how much CPU is available in average. For a Pi 4 it should be free CPU capacity, so you can install a second station with a second sdr and a different antenna on the same Pi.
I have been running a couple of SATNoGs stations (1936 & 1946) for a few years now.
With my setup I am using 3 x RPi’s. One for UHF with a RTL-SDR, LNA, HPF (~400MHz) and Turnstile Antenna, one for VHF with a RTL-SDR, LNA, HPF (~133MHz+) and a Flowerpot Antenna and finally one for an Auto Scheduler. Having the 3 RPi’s makes the setup a bit simpler but you could do it on one RPi4 I guess.
For reliability I find with RPi’s that feeding them with POE is the most reliable method. For the newer RPi’s I use a POE Hat. For the older RPi’s I use an external POE device……note these external POE devices are not good enough for new RPi’s with a USB device plugged in (ie RTL-SDR).
I found the easiest way to provide POE was to use a TP-Link POE Switch. It also makes the cabling a bit neater.
One last reliability thing is I added a timer to the power for the POE switch. At midnight I turn the power to all devices off for one minute. This has the effect of resetting the whole system with overcomes the occasional lockup.
The Auto-Scheduler generates about 200+ passes per day. For the first year I used to vet these but I just could not keep up so now I just leave them un-vetted.
There is only one other SATNoGs station in Melbourne (1042 – VK3XN – VHF) so a UHF band is going to be most useful to the community in my view.
Just on antennas……I find with the turnstile antenna on UHF I only get about 4-6 decoded signals per day. More gain/sensitivity would be nice. I tried a 5 element yagi pointing straight up but that did not give any improvement. I have recently built an Asymmetric Turnstile Antenna (ATA) with an aim of getting better signals at lower angles. The ATA is easier to build than the QFH and supposedly almost as good. I will see how it goes.
The other thing to improve decodes that I have yet to try is to add the gr-satellite decoder module. I believe this gives more decodes.
