Much of my time during this COVID-19 isolation has been spent debugging a novel HF/VHF channel simulator and then using it to characterize performance of the different Winlink digital modes across a range of conditions. One conclusion is that VARA HF and VARA FM (the registered versions) work really well and at a much lower cost than a PACTOR modem. This report just got published on the Winlink website:
Tom N5TW