You might start out at 18.04 and try upgrading to see how things do, but if it worked for 18.04 chances are you'll be okay on 20.04.
Pay close attention to the chipsets listed and make sure you verify that the specific laptop you are purchasing has the supported chipsets listed.
I have made the mistake of buying a Dell 5579 laptop and it had a different network adapter chipset than the 5579 that was listed on the Ubuntu certification.
Some retailers don't make the chipset information available which can be a huge pain when trying to ID the correct hardware. The lesson learned is that not all 5579s will be fully compatible.
You will want to verify requirements that your SDR will need if you plan on connecting an SDR to the laptop. I wanted to use an Ettus USRP N200 with that 5579, but since the networking chipset wasn't compatible I had to resort to using an ethernet to USB dongle.
The USB dongle didn't play nice with the USRP (degraded performance) but it worked for the specific application.
You can also special order the laptop preloaded with Ubuntu directly from the manufacturer - it may take a little longer to get. I am not sure what version they are shipping with, you'll have to check.
I would try to go for an i7 and 16G RAM minimum. You'll want more cores/power/memory if you plan on compiling from source. For example; I'm currently using a Lenovo IdeaPad with an i3 and 8GB ram to run GRC and SDRs from, but not doing really heavy DSP. Runs smooth but starts to slow down a little if I'm recording IQ data and displaying Fosphor at the same time.
I hope that helps.
I’m looking to buy a linux laptop specifically for gnuradio with pybombs. Does anyone have specific hardware recommendations that work well or to avoid? Similarly, is it safe to use the most recent version of Ubuntu (20.04 LTS)? I’ve been mostly considering Dells because of their extensive ubuntu support.
Any feedback or advice is appreciated!