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From allegra!ulysses!dptg!att!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!news.acns.nwu.edu!network.ucsd.edu!news-mail-gateway Wed Oct 28 18:15:16 EST 1992 Article: 27119 of rec.radio.amateur.misc Path: allegra!ulysses!dptg!att!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!news.acns.nwu.edu!network.ucsd.edu!news-mail-gateway From: WFAUST@NOMVS.LSUMC.EDU (Wm. Bryant Faust, IV) Newsgroups: rec.radio.amateur.misc Subject: Re: Info-Hams Digest V92 #1117 Date: 28 Oct 1992 08:04:23 -0800 Organization: UCSD Usenet Gateway Lines: 23 Sender: daemon@ucsd.edu (The Devil Himself) Message-ID: <9210281604.AA23582@ucsd.edu> NNTP-Posting-Host: ucsd.edu > > Or you can use an extra pole on the dip switch for a tone on/off switch > and use the freed-up on/off switch as a band change. Look at the > schematic of the synthesizer and the thumbwheels real carefully. It's > not difficult to add 140-144 and 148-149.995 to the basic radio (it's > shipped from the factory with the Mhz switch 4-bit (as in 8421 binary values) > hard-wired on, and the 8-bit hardwired off. A couple of trace cuts and > jumpers will restore the lost functionality - but it's not a job for the > timid or those without a fine tip in their Weller Solder Station (tm)). Then > look at the schematic again and realize that there's a pin near the > 1mhz pin that is marked 10mhz (unlabeled on some schematics...) that is > hard-wired off... Duplicate the decoupling resistor/capacitor and hook it > to the freed-up on/off switch and you now have a 140-149mhz radio in one > position and a 150-159mhz radio in the other position... > > I don't know if a similar synthesizer mod will work on a 3AT or a 4AT - as > I don't have one and have not seen a 3AT or 4AT schematic. It does, my 4AT covers 450 and 460 via this type of a mod. Total bandwith of the transmitter is about 20 MHz. Bryant, N5GWF wfaust@nomvs.lsumc.edu 
