Say what? Sent on the TELUS Mobility network with BlackBerry -----Original Message----- From: "Vernon Densler" <m...@highwayusa.com>
Date: Sat, 18 Apr 2009 18:05:35 To: <Repeater-Builder@yahoogroups.com> Subject: RE: [Repeater-Builder] Re: MASTR II PTT With the simple echolink interace which has a NPN transistor doing the switching the voltage across the PTT line and ground is 7v when the com port is not active and 6.5v when it’s active. So I am only getting a ½ volt drop instead of a total short to ground. Is it because the transistor can’t pull it down far enough? Will a transistor with a higher power dissipation help? Thanks, Vern From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Vernon Densler Sent: Friday, April 17, 2009 6:54 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: MASTR II PTT OK. I am at my whit’s end here. The transistor won’t bring the PTT line down enough to trigger. The optoisolator won’t either. The mechanical relays can’t be latched by the com port. The SSR latches but won’t unlatch with DC. So do I run the SSR into an AC mechanical relay? Sounds like a serious Rube Goldberg way of doing it but it should work. There has to be another way though. It worked fine with the RC 1000 keying it so what does Ron have in that circuit that does the magic? Vern From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Ralph Mowery Sent: Friday, April 17, 2009 5:56 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: MASTR II PTT You probably overlooked the simple thing. The PTT line is DC and once the SCR fires it will latch. If you had AC then the voltage goes to zero and the SCR unlatches. --- On Fri, 4/17/09, Vernon Densler <m...@highwayusa.com> wrote: From: Vernon Densler <m...@highwayusa.com> Subject: RE: [Repeater-Builder] Re: MASTR II PTT To: Repeater-Builder@yahoogroups.com Date: Friday, April 17, 2009, 4:35 PM I got a Solid State Relay and the com port will trigger it. (same thing I use to control my Christmas lights from my computer). However for some reason the PTT won’t drop when the SSR shuts off. I know there is some voltage bleed on them but I can’t figure out why it would stay grounded afterwards. Any suggestions on that one?
