---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Mon 04/23/07: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:27 PM - Re: GNS 430W Antenna Requirements (reichec) 2. 07:52 PM - Re: GNS 430W Antenna Requirements (Bob C.) 3. 08:59 PM - Re: GNS 430W Antenna Requirements (Wayne Sweet) ________________________________ Message 1 _____________________________________ Time: 07:27:24 PM PST US Subject: Avionics-List: Re: GNS 430W Antenna Requirements From: "reichec" The input signal to the 430w must be at a maximum XdB (some number) the antenna has a gain factor of like 25dB and therefore there must be some loss to get it down to XdB thus 13 feet.. I beleive the magic number at the reciever is 20dB signal strength but not sure. Got it? Charles Read this topic online here: http://forums.matronics.com/viewtopic.php?p=108788#108788 ________________________________ Message 2 _____________________________________ Time: 07:52:28 PM PST US From: "Bob C. " Subject: Re: Avionics-List: GNS 430W Antenna Requirements I doubt that it's to attenuate the signal as suggested? More like it's to avoid having the feedline (coax) be susceptible to picking interference (acting like an antenna) at certain frequencies? I wouldn't worry so much why but I'd follow there suggestions. Regards, Bob in SE Iowa RV-8 Finishing - Slowly On 3/9/07, bakerocb@cox.net wrote: > > 3/9/2007 > > Hello List Experts, It is fairly well documented that Garmin wants high > quality antenna cable (RGU 142 or 400) to be used for the GNS 430W and it > must be between 13 and 35 feet long. > > I can understand a maximum limit. I cannot understand the physics or > electronic principles behind the minimum length requirement. > > Can someone please educate me? Thanks. > > OC -- The best investment we can make is the effort to gather and understand > knowledge. > > ________________________________ Message 3 _____________________________________ Time: 08:59:22 PM PST US From: "Wayne Sweet" Subject: Re: Avionics-List: GNS 430W Antenna Requirements I have my GNS430W installed with the antenna mounted on the aft of the canopy (BUSHBY MustangII); the RG400 coax is about 8 feet in length. No noticeable difference from the same location prior to the WAAS update. BTW, I'm having a ball flying GPS approached with ILS like display. In fact the needles are much calmer than on a ILS approach, and no worry about false lobes. :-))) Only problem (small), from the approach plate can't tell if there will be an active GS till I get on the approach and get the LNAV+V indication. The GS comes active on the waypoint just outside the FAF. Wayne ----- Original Message ----- From: "Bob C. " Sent: Monday, April 23, 2007 7:51 PM Subject: Re: Avionics-List: GNS 430W Antenna Requirements > > I doubt that it's to attenuate the signal as suggested? More like > it's to avoid having the feedline (coax) be susceptible to picking > interference (acting like an antenna) at certain frequencies? I > wouldn't worry so much why but I'd follow there suggestions. > > Regards, > Bob in SE Iowa > RV-8 Finishing - Slowly > > On 3/9/07, bakerocb@cox.net wrote: >> >> 3/9/2007 >> >> Hello List Experts, It is fairly well documented that Garmin wants high >> quality antenna cable (RGU 142 or 400) to be used for the GNS 430W and it >> must be between 13 and 35 feet long. >> >> I can understand a maximum limit. I cannot understand the physics or >> electronic principles behind the minimum length requirement. >> >> Can someone please educate me? Thanks. >> >> OC -- The best investment we can make is the effort to gather and >> understand >> knowledge. >> >> >> >> >> >> > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message avionics-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Avionics-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/avionics-list Browse Digests http://www.matronics.com/digest/avionics-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.