Hello Dave, the Input-Bias-schematics is ok, the Output FET-IC-Switch is by switch ON over L16 ... of ground. This is not ok - Kondensator on switch-output - L16. Sorry my english.
vy 73 Gerd DM2CDB ----- Original Message ----- From: [EMAIL PROTECTED] To: [email protected] Sent: Friday, June 09, 2006 6:49 PM Subject: Re: [soft_radio] Re: [softrock40] SDXCVR Boards On 9 Jun 2006 at 8:20, Dr. Gerd Köster DM2CDB wrote: > > Hello Dan, > > the bpf-schematics is not ok. The hat a bypass for the bias-voltage to ground (L16, L17 ...). Sorry > my english. > > vy 73 Gerd, DM2CDB > I am not real sure what you are referring to. The 100uH chokes between pin 5 of the FST3251's and the 2.5V bias prevents the RF from being shunted to ground. The capacitor at the other end of the choke (C163 and C164) provide RF bypass for the bias supply. The caps in parallel with L16 and L17 are part of the 2-6MHz band pass filter and have nothing to do with the bias supply bypass. I am re-designing the PCB. Each of the 6 filters will support a 7 pole elliptical design. I will post the new layout and new schematic in a few days when they are completed. If you are looking at the layout posted, it is the old layout and does not include the biasing. Dave - WB6DHW [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor --------------------~--> Protect your PC from spy ware with award winning anti spy technology. It's free. http://us.click.yahoo.com/97bhrC/LGxNAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
