The greater the sensitivity a receiver has, the more RFI (radio frequency interference) it will pick up. It is therefore incumbent upon the design engineer to take steps to filter out unwanted interference. David Sorenson Duluth On Mon, 21 Jul 2008 09:20:11 -0400 "Bill" <bill@tapestrylink.com> writes: > Mike, > > > > Not being an EE (or anything close) I don't really understand what > RX/TX > "sensitivity" would have to do with a radio allowing noise > (inverter, > engine, or other) to interfere with RX/TX. I appreciate your input > on this > (seriously) but I think the larger issue goes to the ICOM POV - it's > always > somebody else's fault. The SH I installed is the Quantum GX 5500S. > I > believe the specs match up to the ICOM pretty well but again I'm no > EE. > Anyway, thanks for the input. If you are right that it's really a > sensitivity issue then I would argue that ICOM needs a better > understanding > of real-world installations. (Again, no connection to SH) > > > > Bill > _______________________________________________ > http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering > > To unsubscribe or modify your subscription options (get password, > change email address, etc) go to: > http://lists.samurai.com/mailman/options/trawlers-and-trawlering > > Trawlers & Trawlering and T&T are trademarks of Water World > Productions. Unauthorized use is prohibited. > > ____________________________________________________________ Click to get a free auto insurance quotes from top companies. http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3m2nsTiab1hZgNqQeXJyYIjisUtbG1jSPm2H4QYkWAFqFpYA/

First, I should say that I have received good support from Icom over the years that I have used them on the few occasions that IO have needed help. Second, the burden is on the inverter manufacturer to eliminate its RF interference. The last time that this was the subject on the List, Arild pointed-out that Xantrex/Heart was producing units with a cheaper copmponent that produced RFI. Another time, Jeffrey Siegle was having a problem with his Raymarine units and installed RFI, iron ferrite chokes on the wires (to include mikes) leading to those components - it worked. Those wires act as antennae picking-up RFI. The DC cables can also carry some types of RFI. You place the chokes as close to the item being protected as possible. Another tactic that I have used successfully is grounding the unit's chassis to Earth via a copper plate on the hull or a seacock (less effective.) Furuno usually furnishes a lug for this purpose. My ancient, Furuno commercial radar is interfered with by my Heart 2500 that came with the boat. Ron Rogers

Ron Rogers wrote: > Second, the burden is on the inverter manufacturer to eliminate its RF > interference. The last time that this was the subject on the List, Arild > pointed-out that Xantrex/Heart was producing units with a cheaper copmponent > that produced RFI. Another time, Jeffrey Siegle was having a problem with > his Raymarine units and installed RFI, iron ferrite chokes on the wires (to > include mikes) leading to those components - it worked. Those wires act as > antennae picking-up RFI. The DC cables can also carry some types of RFI. You > place the chokes as close to the item being protected as possible. REPLY It's not a case of using cheaper components, but of including or omiting filtering circuits. Tyhese filters cost money to include. Generally speaking sine wave inverters using high frequency switch mode are better filtered than MSW inverters. This equally true for any brand of inverter. To determine if the RFI is conducted by wires or being radiated, power the radio from a completely seperate and isolated battery. Its usually easier to supress the source of noise than to block out RFI in the receiver. Shielding the offending device can be done with copper mesh or foil shields and making suer the metallic case is grounded as Roger says. cheers Arild