Subject:TW4000 mod notes I just looked over schematics for the Kenwood TW-4000-A/T/W dual bander (yes, I'm actually doing the schematics I've received - but I have a couple of BIG boxes full, so be patient if yours is in there!), and it looks like a very good candidate for 9600 baud. Filters look good, although digitally optimized filters such as MuRata SFG-455D or SFH-455D would allow a tighter passband; and it uses a separate transmit oscillator common to both 144 and 430 MHz for generating FM. This uses a crystal, inductor, and varactor to produce nice, linear FM, and heterodynes up from there to the respective bands. This is exactly as I've described in my 9600 baud manual as the "ideal" 9600 rig. The "mods" I've come up with are: TXA:Tack a 6.8k resistor to the cathode of D-16 (junction of C125-R95-D16) RXA:Tack a 4.7k resistor to IC-1 pin 17 If the received eye pattern from a known good transmitter is jittery, try changing C-155 (associated with Q19) from .01 to something like .005 - .001. It also might be necessary to change C125 from .0022 to .001 if the transmit waveform is jittery. I've not tested this, so would appreciate feedback from anyone trying this. So far, I've received precious little in the way of feedback, so I have no idea whether these mods work or not. 73, Mike Curtis wd6ehr@k6ve.#soca.ca.usa.na  Amsterdam View Our Stats   CLICK FOR A FREE DOMAIN NAMES HTTP://WWW.YOURNAME.TK FOR YOUR OWN WEBSITE IF YOU CLICK HERE AND YOU CAN VOTE FOR OUR FREE WEBSITES IN THE TOP 100 LIST  WANT A TOP RANKING ? USE THE ULTIMATE SOFTWARE SUITE FOR WEB SITE PROMOTION  FreeWebSubmissions Submit Your Site To The Web's Top 50 Search Engines For Free THE ALEXA BANNER, THIS BANNER GIVES THE DALLY STATISTICS OF THIS FREE WEB SITE The World of Free Packet Radio Software Amsterdam The World Of Free Packet Radio Software Amsterdam The Netherlands |