APRS use on high frequencies is not anything new, but we have seen a rapid re-birth thanks to the use of VARA HF. Here are some essentials to get started.
First, you need an HF radio that can connect to your computer. There are a variety of ways to do this and it all depends on your radio. I use a Yaesu FTdx-1200 with a Yaesu SCU-17 USB interface in my home station. For mobile, I use an old Yaesu FT-900 and USB soundcard connected to an inexpensive miniPC.
Secondly you need to install some sort of APRS Client software on your computer. I have PinPoint, YAAC, UIView and APRSIS32 all installed on my computer. I still haven’t even tried UIView, and it is, as I understand it, completely unsupported these days. The other three still have active support and regular updates. Of the three, I prefer APRSIS32 as it has the most features. Some might argue too many features and it sports a pretty hefty learning curve. Most VaraHF APRS stations are using PinPoint for their APRS needs.
Finally, you need the VaraHF software modem. VaraHF is a weak signal modulation, that packs information into many channels with your transmission. This effectively reduces the the transmission time of an APRS packet. These packets are decodable down to around -20db. It is available for use as a an unlimited free trial, with some limitations, or as paid, licensed software. VaraHF is great for Winlink email use too, and VaraAC is awesome for weak signal chatting.