I'd think if you did a cal for the typical hf range of freq (1.8Mhz to say 30Mhz) you'd likely be OK. The swr reading may be off a little but when tuning an antenna you're looking for the swr dip. The nanovna may show a different swr than actual. As long as you understand this going in I'd think you would be OK. It will be precise but not accurate.
