Mastr II Mobile.
From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Tuesday, October 06, 2009 11:34 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Strange Problem What radio? Mastr II mobile? Mastr II station? Hopefully I can find my manual, otherwise I'll need to look online. Chuck WB2EDV ----- Original Message ----- From: Vernon Densler <mailto:m...@highwayusa.com> To: Repeater-Builder@yahoogroups.com Sent: Tuesday, October 06, 2009 11:28 AM Subject: RE: [Repeater-Builder] Strange Problem Where might I find that bias line? Thanks, Vern KI4ONW From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Tuesday, October 06, 2009 11:09 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Strange Problem If you are not using a local microphone (I don't) my solution is to simply remove the bias to mic high and forget messing with a cap. Chuck WB2EDV ----- Original Message ----- From: Vernon Densler <mailto:m...@highwayusa.com> To: Repeater-Builder@yahoogroups.com Sent: Tuesday, October 06, 2009 10:46 AM Subject: RE: [Repeater-Builder] Strange Problem Sure don't have that cap on there and on my radio it's 9.7v on that mic line. Trying a blocking cap now to see if it fixes the issue. I will keep you posted. Thanks, Vern KI4ONW From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Doug Bade Sent: Tuesday, October 06, 2009 9:53 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Strange Problem Mastr II/ Exec II transmitters can have ~5vdc on mic high, this is the bias for the amplifier in a normal microphone. If you do not have a capacitor in series to the computer interface or the computer interface has a polarized cap that is in the wrong direction, strange things like this can happen. Verify DC potential on both sides of any interface components... as capacitors can work backwards for a while but eventually stop passing when incorrectly polarized... It is always better to use non polarized capacitors in this audio path but they do usually cost a little more and sometimes are harder to acquire... Doug KD8B
