Bill I'd like to add a few things to what Don has said. Fortunately the electronics in your HVAC system is fairly simply and easily shielded. However when susceptibly problems occur with Japanese designs it can be very difficult to get them to respond. Let's hope you don't have to go there.
What concerns me more is the noise/interference generated by some high SEER HVAC systems. These systems achieve variable speed by using variable frequency inverter driven motors. These can be a pain in two ways. First they radiate noise that can extend well above 160M. Second, they can induce harmonics on the powerlines. Line filters similar that what your kilowatt amps use are needed between the HVAC system and the 240vac power lines. Some of the HVAC systems have the filters built in and others don't. Let's hope they have done their homework and cleaned up their systems. With your system operating in the AC mode you will want to scan 160M for noise or hash. You may want to check 80M too if 160M is dirty. Don't take acceptance of the system until it is proven clean. 73, Fred, AE6QL -----Original Message----- >From: Don Wilhelm <w3...@embarqmail.com> >Sent: Aug 14, 2014 4:54 PM, >To: W2BLC <w2...@nycap.rr.com>, elecraft@mailman.qth.net >Subject: Re: [Elecraft] OT Antenna location concern > >Bill, > >All products are required to withstand RF susceptibility levels. So if >you encounter "strange happenings" with your HVAC system due to RF, the >supplier is bound to take corrective action. >Some may not understand, and some may not even know of the requirements, >so at worst case, you may have to get the FCC involved for resolution. >The most published FCC class B information regards radiation from the >device(s), but there is also regulations regarding susceptibility from >radiation from licensed services. The fact that you addressed the RF >interference situation with the installer should go a long way (document >that conversation for yourself with dates and names), and for a >reputable company should be as good as a written statement (I am no >lawyer, but it makes sense to me). > >73, >Don W3FPR > >On 8/14/2014 4:20 PM, W2BLC wrote: >> I recently installed a Mitsubishi mini-split system and now have an >> antenna concern. I am about to install a new dipole that will pass >> within ten feet of one of the interior units (that would be measured >> through the wall). I already know that the system has produced no >> interference to any reception - however, I am concerned about how >> being close to a transmitting antenna will effect or not effect the >> unit/system. The antenna's location will meet safe human exposure >> limits for the bands/power used - 160/75/40. >> >> I am assured by the installer that RF is not a problem and not to be >> concerned - of course that is not in writing. Attempts to email and >> call Mitsubishi have not been informative. Hence my question: >> >> Has anyone had difficulties with the control systems of their HVAC >> systems caused by RF from a nearby transmitting antenna? I run the >> KPA500 all the time - so consider this a 600 Watt station. >> > >______________________________________________________________ >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 fptowns...@earthlink.net ______________________________________________________________ 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
