Raspberry Pi 4B: Is 2 GB enough? #rsp1a


allen KC2KLC
 

I've been using an RSP1A connected to my Windows PC (primarily with SDR Console; not a fan of SDR Uno except for scanning) for a variety of purposes (including ADS-B, Inmarsat monitoring, shortwave pirate reception, etc.; hoping to reacquaint myself with weather satellite reception, which I'd done years ago on an analog receiver). Last March, for my birthday, I decided to get a Rasberry Pi to try building a portable setup, only to discover the global chip shortage rendered these unavailable. From what I've read, it seems I'd need a Raspberry 4 with 4 GB RAM for my purposes. A Raspberry 4B with 2 GB RAM is available in my area from a CraigsList user. He's asking $100, but I'm thinking of offering more like $50 - but first, I'd like to get this community's opinion on whether 2 GB RAM is too great a compromise, and if I would benefit greatly from waiting. Thanks!


David J Taylor
 

On 31/08/2022 02:14, allen KC2KLC wrote:
I've been using an RSP1A connected to my Windows PC (primarily with SDR Console; not a fan of SDR Uno except for scanning) for a variety of purposes (including ADS-B, Inmarsat monitoring, shortwave pirate reception, etc.; hoping to reacquaint myself with weather satellite reception, which I'd done years ago on an analog receiver). Last March, for my birthday, I decided to get a Rasberry Pi to try building a portable setup, only to discover the global chip shortage rendered these unavailable. From what I've read, it seems I'd need a Raspberry 4 with 4 GB RAM for my purposes. A Raspberry 4B with 2 GB RAM is available in my area from a CraigsList user. He's asking $100, but I'm thinking of offering more like $50 - but first, I'd like to get this community's opinion on whether 2 GB RAM is too great a compromise, and if I would benefit greatly from waiting. Thanks!
Allen,

I'm using an Raspberry Pi 3B which has 1 GB RAM and it's quite adequate. I use it with an RTL-SDR.COM dongle. Ideally I would use an Airspy HF+ discovery but as I have a filtered pre-amp noise factor of the dongle isn't a concern.

I'm using:
https://www.instructables.com/Raspberry-Pi-NOAA-Weather-Satellite-Receiver/

although there is a later version:
https://github.com/jekhokie/raspberry-noaa-v2

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@...
Twitter: @gm8arv


allen KC2KLC
 

Thanks David! Actually, I'd already bookmarked that link a while back, but I notice it calls for manually installing software. It's been many decades since I've used Unix, so I'm a bit concerned about the learning curve, but I'm willing to give it a go. I know there are images you can load onto an SD card for amateur radio applications; not sure if anything like that might be available for NOAA wx sats & other SDR projects.

It's encouraging that the RTL-SDR dongle runs on Pi 3 w/1 GB RAM, but I'm wondering if my RSP1A requires more in the way of processing power? Then again, maybe I'll buy a dongle and play with that instead - and leave the RSP1A in my radio rack (those dongles sure are affordable!).

allen


David J Taylor
 

On 31/08/2022 23:57, allen KC2KLC wrote:
Thanks David! Actually, I'd already bookmarked that link a while back, but I
notice it calls for manually installing software. It's been many decades since
I've used Unix, so I'm a bit concerned about the learning curve, but I'm
willing to give it a go. I know there are images you can load onto an SD card
for amateur radio applications; not sure if anything like that might be
available for NOAA wx sats & other SDR projects.

It's encouraging that the RTL-SDR dongle runs on Pi 3 w/1 GB RAM, but I'm
wondering if my RSP1A requires more in the way of processing power? Then again,
maybe I'll buy a dongle and play with that instead - and leave the RSP1A in my
radio rack (those dongles sure are affordable!).

allen
Allen,

Yes, some installation may be required, but it's typical of the Linux approach.
There are so many minor variations between all the different elements of
Linux and its programs that compiling from scratch can sometimes be the only
way to get things working! With your UNIX experience (like mine) just follow
the step-by-step instructions and I think you'll be OK.

I don't know of a complete ready-to-go image, but there may be one out there.

An RTL-SDR.COM dongle would be the best way to start, as that's what most
people use (and what I use here). The RSP may require extra software
installation, but it would likely be operated at a similar sample rate to the
dongle, so processing power may be little different. The RSP may have better
strong signal capability - if that matters in your part of the world. It does
here, and I needed extra filtering (pager TX on 153 MHz) even for an analog
receiver.

Here are the performance plots for my RPI-3B - not maxed out on memory or CPU.

https://www.satsignal.eu/mrtg/performance_raspi-13.php

It's running as an NTP server as well.

73,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@...
Twitter: @gm8arv


allen KC2KLC
 

I've read that a cooling fan was essential for Pi 4 (ambient heat sink doesn't cut it). Given that your Pi3 averages 50.7 C / 123 F and gets up to 56.9 C / 134 F, and assuming the Pi4 runs even hotter, I can see why! I think I'll put an offer on that Pi4, and if I get it for a good price, I'm all set for a nice indoor winter project :)


David J Taylor
 

On 02/09/2022 02:51, allen KC2KLC wrote:
I've read that a cooling fan was essential for Pi 4 (ambient heat sink doesn't cut it). Given that your Pi3 averages 50.7 C / 123 F and gets up to 56.9 C / 134 F, and assuming the Pi4 runs even hotter, I can see why! I think I'll put an offer on that Pi4, and if I get it for a good price, I'm all set for a nice indoor winter project :)
Allen,

It depends on your ambient temperature, but here none of my RPi4 have a fan. They run at about 50C which is fine by me. CPU usage for the APT reception application is low. If you have a need for a fan, I would suggest:

https://shop.pimoroni.com/products/fan-shim?variant=29210095812691

Mine is sitting on the bench in the shack (heated indoor room) and is fitted with a GPS HAT which will restrict the natural cooling. Again, 60C would not concern me at all. Others may have different views.

By far the best heatsinking comes from the Raspberry Pi 400, where the heatsink is built in, and is the width of the keyboard. I have a couple and would heartily recommend them. They have the USB connections required for a dongle etc. You can get the RPi in keyboard alone, or as a "kit" with mouse, power supply and so forth.


https://magpi.raspberrypi.com/articles/raspberry-pi-400-specifications-benchmarks-and-personal-computer-kit

https://www.raspberrypi.com/products/raspberry-pi-400-unit/

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@...
Twitter: @gm8arv