On Fri, Jan 19, 2018 at 3:38 AM, Colin Buckup via Groups.Io <rotbaron77@...> wrote:
Hello gang,
Continuing my quest to complete the multi-band 5W Tx/Rx project, I just got my latest batch of kits in the mail. Included was the Relay Board revision 5 which now has as "normal" the option of always?having 1 LPF in the circuit. That works great for the TX side (LPF's). But not so for the RX side since you can't serialize BPF's...
Canvassing the web site and the previous discussions it seems that the Assembly Instructions for Revision 5, although making reference to the jumper configuration when using the relay board for BPF switching, never show the correct jumper setting for it and leave it open as? "published in another document". I could not find this document anywhere on the site... did I miss anything?
Looking at the circuit diagram it seems that if I want to use the 5 relays to switch 5 different BPF's, the output side of position 1 is ALWAYS connected to the center pin of the SMA coax connector. That would mean that if I configure the jumpers as NOT always having pos 1 in series and would as an example select any other position (say relay 4) and since the relay in position 1 is not energized (grounding the output of the BPF) that this would pull the SMA center pin to ground.
Do I need to perform a slight surgery on the board to prevent that? Anyone with previous experience in this? Rev 4 was easier since the RFin and RFout lines were always clear of the non-energized relays.
Hans, any ideas? does that jumper config doc exists somewhere and did I miss it?
