Hi Don, Thank you for replying directly to my post. I have no doubt that the precautions you've mentioned aren't without merit.
All I was trying to convey was that there is good chance the OPs Macintosh is well grounded as are most commercially assembled computers. I can recall several occasions when I was "bitten" in the shack by poorly grounded gear, including at our UN station, but none have actually involved the computers. Fortunately, most cases required simply preventing RF energy from traveling back to the shack via the coax shield. Others were more complex and needed proper bonding to earth ground via copper plumbing. In all instances however, no issues involved the CPU units themselves. You are correct though that safety is paramount, and if one finds that any piece in their shack is poorly grounded, common sense would compel them to rectify the situation post-haste. 73, James K2QI Sent via BlackBerry from T-Mobile -----Original Message----- From: Don Wilhelm <w3...@embarqmail.com> Date: Mon, 11 Apr 2011 23:40:12 To: <k2qi....@gmail.com> Reply-To: d...@w3fpr.com Cc: Phil Hystad<phys...@mac.com>; Rick Prather<k6limae...@gmail.com>; Elecraft Reflector<elecraft@mailman.qth.net> Subject: Re: [Elecraft] Mac Grounding James, Yes, the ground through the AC line cord is "possibly" OK, but may or may not ground a laptop to the AC mains ground - it all depends on the design of the computer and its power supply. It also depends on having the computer plugged into the same receptacle that the rest of the ham station equipment is using, and that any ham station ground rods are bonded back to the electrical utility ground system. That is not the situation for many ham stations, particularly the part about bonding the station ground rods to the Utility entrance ground. There are just too many "ifs" to say for certain whether a problem can exist or not. The claims of one Mac user do not mitigate the fact that there is a potential hazard just waiting to do its dirty work. Keep yourself safe. An entirely plastic computer may not pose a hazard, much as double insulated power tools protect the user without need for a ground, but there are just too many variables here - some talk of Macs with plastic cases, and others talk of Macs with exposed aluminum parts. Some may be OK, but others may not - it all depends... As I indicated, err on the side of caution and keep yourself safe. We do not need any silent keys added because of situations like this. 73, Don W3FPR On 4/11/2011 10:40 PM, k2qi....@gmail.com wrote: > Forgive me if I misunderstood Don's response, but normally a computer > regardless of make or model is grounded via the power supply negating any > need for additional measures. > > The above statement is only applicable if the home ground has been properly > facilitated. Of course, all bets are off if this is not the case. > > Apart from that, OS or computer make if grounded correctly should not pose > any threat in a station should the shack's earth ground fail. > > Please correct me if I'm wrong, but what Phil has described has been the norm > at 4U1UN for many years without fail; not by choice but due to wiring > restrictions and location the club has endured for many years. > > 73, > James K2QI > Sent via BlackBerry from T-Mobile > > -----Original Message----- > From: Don Wilhelm<w3...@embarqmail.com> > Sender: elecraft-boun...@mailman.qth.net > Date: Mon, 11 Apr 2011 22:27:12 > To: Phil Hystad<phys...@mac.com> > Reply-To: d...@w3fpr.com > Cc: Rick Prather<k6limae...@gmail.com>; elecraft<elecraft@mailman.qth.net> > Subject: Re: [Elecraft] Mac Grounding > > Phil, > > May I suggest that your operating situation is not the norm. There are > those using Macs who do need to know how to bond the computer ground > into their station ground system. Please do not discourage them just > because your operation does not need it. > > Even in your case, if a surge event does occur, there can be a personnel > danger if one part of your body is in contact with the computer, while > another part is in contact with a properly grounded piece of radio > equipment. It is more than just a noise creating situation, it is a > matter of your safety while in the radio shack. > > Having two pieces of equipment at different chassis potentials is not a > good thing. The differential may be small and tolerable under normal > conditions, but in the case of a surge event, that difference can be > huge, and even life threatening. While Jim Brown's documents > concentrate on noise created by small differences in ground potential, > there is another side of the story, and that is one of safety - not > under normal conditions, but during a surge event. > > 73, > Don W3FPR > > > > On 4/11/2011 10:11 PM, Phil Hystad wrote: >> I understand the technical reasons that people suggest for grounding but I >> do not see the need. I have no problems. If there are problems, they are >> invisible to me. By the way, my Signalink is connected to my Mac only when >> I am using it. The reason is that I usually use the Signalink from my >> laptop and not my iMac and most of the time I am not using the Signalink. I >> think I last did PSK31 about two weeks ago and that was the first time in >> several months. >> >> At least 90 percent of all my contacts are CW. I never use a computer in >> tandem with my radio work. I think that is a real hassle and it does not >> interest me. I do enter log information in my own home grown logging >> application but I do not interface the computers to the radio. The only >> reason I do that is when I need to do a K3 or P3 firmware upgrade and when I >> do PSK31 (both of these are relatively rare events). >> >> By the way, I do love ham radio but I am in front of my laptop (usually >> sitting on the couch here in my room) more then I am in front of my radios. >> Thus, my computers are situated for all my programming activities, not for >> radio work. >> >> phil >> >> >> On Apr 11, 2011, at 6:45 PM, Robert Harmon wrote: >> >>> I have two Mac laptop computers in the shack. An aluminum encased MacBook >>> Pro and a plastic cased MacBook. >>> Is their a way to ground these without drilling/clamping etc ? I >>> understand the need but I'm not very excited >>> about modifying my Macs to provide grounding. >>> >>> Bob >>> K6UJ >>> >>> >>> >>> >>> On Apr 11, 2011, at 6:37 PM, Rick Prather wrote: >>> >>>> I have the aluminum 24" and I use a screw clamp on the aluminum leg on the >>>> back. >>>> >>>> Definitely eliminated the potential difference I used to see from the Mac >>>> to the radio. >>>> >>>> As much as I love Mac's there is nothing inherently magic about them that >>>> disallows the need for proper grounding. >>>> >>>> Also, running a ground strap is not in any way going to alter the warranty. >>>> >>>> In Phil's case, even using the SignalLink (for whatever reason) does not >>>> preclude the possibility of needing the units bonded together. >>>> >>>> I wondered how long it would take K9YC to weigh in on this and I'm sure he >>>> can do a much better job of explaining the requirement. Taking a look at >>>> his tutorial is an excellent idea. >>>> >>>> Rick >>>> K6LE >>>> >>>> On 4/11/2011, at 5:53 , Ray Sills wrote: >>>> >>>>> Hi Rick: >>>>> >>>>> Where to you connect that ground strap? My iMac (17" Intel) is >>>>> totally encased in plastic! >>>>> >>>>> 73 de Ray >>>>> K2ULR >>>>> >>>> ______________________________________________________________ >>>> 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 >>> ______________________________________________________________ >>> 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 >> ______________________________________________________________ >> 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 >> > ______________________________________________________________ > 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 > ______________________________________________________________ > 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 > ______________________________________________________________ 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
