Bob G. ACØKC
Yes, that old Dow Key DK77 relay needs to go. The 401 series that Dave mentioned is nice, but several hundred dollars. Ouch! I doctored the relay before (picture) and after (picture), but like Dave says, it *IS* ancient. . .
Maybe I just need to find that “round tuit” and work on the PIN diode switch. Have diodes, need to build & test the quarter wave section, either lump components or a piece of coax.
The whole thing still needs a housing/chassis also (picture).
Top of the heat sink was actually sanded flat with an orbital sander after drilling & tapping it for the board and module to prevent cracking of the internal substrate. (picture)
I had to add a 6dB pad on the input (not shown in these photos,) using three chip resistors cut into the input trace on the left side.
Right now, that’s welding rod & rather warped scrap lumber. Works well enough that I think I’ll keep the design and do it right.
Do have six BX tower sections lying in the yard, but it’ll be a while before that’s up and operational. . .