Question: Is it possible to install Bitcoin Core on Raspbian OS with just apt-get?

I tried adding the Bitcoin repo using:

```
sudo add-apt-repository ppa:bitcoin/bitcoin

```

and I get:

```
sudo add-apt-repository ppa:bitcoin/bitcoin
Traceback (most recent call last):
  File "/usr/bin/add-apt-repository", line 95, in <module>
    sp = SoftwareProperties(options=options)
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 109, in __init__
    self.reload_sourceslist()
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 599, in reload_sourceslist
    self.distro.get_sources(self.sourceslist)
  File "/usr/lib/python3/dist-packages/aptsources/distro.py", line 93, in get_sources
    (self.id, self.codename))
aptsources.distro.NoDistroTemplateException: Error: could not find a distribution template for Raspbian/buster

```

Answer: 
PPAs are generally specific to ubuntu and usually can't be used with other Debian derivatives like Raspbian. Raspbian specific packages are not available in the bitcoin PPA.

Furthermore, the `bitcoin/bitcoin` PPA is discontinued and no longer being updated. If you still want to use a PPA to install onto Ubuntu and Ubuntu derived OSes, you can use luke-jr's PPA: <https://launchpad.net/~luke-jr/+archive/ubuntu/bitcoincore>
I would just install it without using packages, for Raspbian I would recommend [RaspiBolt guide](https://stadicus.github.io/RaspiBolt/) (you can look at parts of it, if you aren't interested in LND, for example, ATM).