cheap HF sdr transmitter without filters and PA:
https://osmocom.org/projects/osmo-fl2k/wiki
https://ipon.hu/webshop/product/gembird_usb_3.0_vga_d_sub_atalakito_fekete_15cm_ab_u3m_vgaf_01/1644596
one can order transmitter filter kits and PA kits from China...
to be continued, hopefully