I was once a 2-way radio tech and have installed over 1000 business band radios (yes, over one thousand) in my 15 or so years career. One thing we, the companies I've worked for, was NEVER to run a dedicated ground wire to the battery. We used a short ground wire from the radio and the local vehicle chassis. From the 100W Motrac/Mastr II/SyntorX (and many others) all used the chassis as a return path. Only once did I have a problem. Once a Low band unit (39MHz) with a magnetic mount (NMO-40) came back because the excess ground wire was coiled into a nice inductor. (I installed that one). Caused all sorts of RFI in the broadcast radio etc. Just a data point on thousands and thousands of industrial, commercial and public safety radio installs out there doing it that way. Myron WVØHPrinted on Recycled Data -------- Original message --------From: Jim Brown <j...@audiosystemsgroup.com> Date: 9/12/2016 8:58 PM (GMT-07:00) To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KX3 vehicle mount OK. In the absence of learning something different, I agree with your analysis, Josh. One of the great things about sticking your neck out and saying what you think you know is that when you're wrong, folks will tell you about it. :)
Thanks! 73, Jim On Mon,9/12/2016 7:40 PM, Josh Fiden wrote: > How I understand it is that the sensor is measuring charge/discharge > current of the battery. > > The following assumes the radio is connected directly to the battery > terminal: > > Case 1. If the alternator is running, then current to the radio is > passing through the sensor which looks like charging current to the > battery. > > Case 2. If the alternator is not running, then the current to the > radio is discharging the battery, but not being registered by the sensor. > > If instead we connect the radio's negative supply to the chassis > ground side of the sensor, then the sensor can correctly measure when > the radio is discharging the battery. > > Caveat: my understanding of this is from the fount of all knowledge, > i.e. I read about it on the internet! If I got it wrong, someone > please correct. > > 73, > Josh W6XU > > On 9/12/2016 5:56 PM, Jim Brown wrote: >> Thanks Josh. >> >> To confuse the sensor, it seems to me that the sensor would need to >> be built into the battery lug, so that it was between where we could >> connect our 12V minus lead and the battery -- i.e., so that our >> current was going through it. I was assuming it was on the wire side >> of the battery lug. I haven't seen one of these things, so I must >> plead ignorance. >> >> Thanks and 73, Jim > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to j...@audiosystemsgroup.com > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to thelas...@gmail.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
