X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 02 Apr 2010 14:06:28 -0400 Message-ID: X-Original-Return-Path: Received: from imr-db02.mx.aol.com ([205.188.91.96] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4193439 for lml@lancaironline.net; Fri, 02 Apr 2010 11:32:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.91.96; envelope-from=YoSamuel@aol.com Received: from imo-da04.mx.aol.com (imo-da04.mx.aol.com [205.188.169.202]) by imr-db02.mx.aol.com (8.14.1/8.14.1) with ESMTP id o32FVPlh015305 for ; Fri, 2 Apr 2010 11:31:25 -0400 Received: from YoSamuel@aol.com by imo-da04.mx.aol.com (mail_out_v42.9.) id q.ca2.6946c668 (37231) for ; Fri, 2 Apr 2010 11:31:23 -0400 (EDT) Received: from magic-d19.mail.aol.com (magic-d19.mail.aol.com [172.19.155.135]) by cia-ma06.mx.aol.com (v127_r1.2) with ESMTP id MAILCIAMA068-916f4bb60dcb25d; Fri, 02 Apr 2010 11:31:23 -0400 From: YoSamuel@aol.com X-Original-Message-ID: <18650.197416c9.38e767cb@aol.com> X-Original-Date: Fri, 2 Apr 2010 11:31:23 EDT Subject: Re: [LML] Re: GPS reception issue X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_18650.197416c9.38e767cb_boundary" X-Mailer: AOL 9.1 sub 5009 X-AOL-ORIG-IP: 76.21.67.141 X-AOL-IP: 172.19.155.135 X-Spam-Flag:NO X-AOL-SENDER: YoSamuel@aol.com --part1_18650.197416c9.38e767cb_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en IV so more carbon fiber blockage issues. The Garmin 430 antenna is in at= =20 the base of the vertical stabilizer, all e-glass above. It works all the= =20 time. My Chelton antenna is mounted under the instrument panel glare shiel= d. =20 It loses signal periodically. It too will be located in the same spot as= the =20 Garmin antenna. =20 Dave. =20 =20 In a message dated 4/2/2010 8:08:31 A.M. Pacific Daylight Time, =20 rpastusek@htii.com writes: =20 Keith,=20 The GPS signal is very weak, and easily blocked/jammed. To avoid such=20 issues, I mounted my GPS antennae (2) on the top of the fuselage, behind= the=20 door (IV-P, but the concept is the same on any aircraft). It needs to =E2= =80=9Csee=E2=80=9D=20 a large part of the sky at all times, and the area it needs is dependent= on=20 the sight line to several satellites, all in different positions at any= =20 time. Consider relocating your antenna as a good fix for the sight line= =20 issue.=20 Two other considerations: Use RG400 or better cable to connect the antenn= a=20 to the unit=E2=80=A6or the originally supplied cable if you have it. RG58= is not=20 good enough, nor will =E2=80=9CTV hookup cable=E2=80=9D do the job. Also,= CAREFULLY check=20 the antenna gain against the requirements of your unit, and that you are= =20 using the correct (active or passive) antenna for your GPS. All of these= are=20 potential =E2=80=9Cgottchas,=E2=80=9D but when you finally get it working= reliably, it=E2=80=99s a=20 thing of beauty!=20 Good luck,=20 Bob=20 The signal reception on my Garmin 420 is really dodgy. We've tested the= =20 unit on a bench and it worked great. We've swapped the antenna, no chang= e.=20 We swapped the antenna cable, it actually got quite a bit worse (the old= =20 one had intermittent issues, the new one is dodgy, nearly full time.) If I route the cable 'just so', I can make it work fairly well on the=20 ground with the canopy open, but it tends to go to hell when I close the= =20 canopy. =20 If I unscrew and lift the glare shield about 1/2" - 1", the reception is= =20 great. The GPS antenna is attached to the top of the glare shield on the= =20 co-pilot side. I'm going to get some help from a shop in debugging this...but it seems= to=20 me that part of the canopy is either causing interference within the=20 antenna cable, or the antenna itself. Has anyone experienced anything like this before? This is in a 360. Keith --part1_18650.197416c9.38e767cb_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en <= FONT id=3Drole_document color=3D#000000 size=3D2 face=3DArial>
IV so more carbon fiber blockage issues. The Garmin 430 ant= enna=20 is in at the base of the vertical stabilizer, all e-glass above. It works= all=20 the time. My Chelton antenna is mounted under the instrument panel glare= shield.=20 It loses signal periodically. It too will be located in the same spot as= the=20 Garmin antenna.
 
Dave.
 
In a message dated 4/2/2010 8:08:31 A.M. Pacific Daylight Time,=20 rpastusek@htii.com writes:

Keith,

 

The=20 GPS signal is very weak, and easily blocked/jammed. To avoid such issues= , I=20 mounted my GPS antennae (2) on the top of the fuselage, behind the door= (IV-P,=20 but the concept is the same on any aircraft). It needs to =E2=80=9Csee= =E2=80=9D a large part=20 of the sky at all times, and the area it needs is dependent on the sight= line=20 to several satellites, all in different positions at any time. Consider= =20 relocating your antenna as a good fix for the sight line=20 issue.

 

Two=20 other considerations: Use RG400 or better cable to connect the antenna= to the=20 unit=E2=80=A6or the originally supplied cable if you have it. RG58 is no= t good enough,=20 nor will =E2=80=9CTV hookup cable=E2=80=9D do the job. Also, CAREFULLY= check the antenna gain=20 against the requirements of your unit, and that you are using the correc= t=20 (active or passive) antenna for your GPS. All of these are potential=20 =E2=80=9Cgottchas,=E2=80=9D but when you finally get it working reliably= , it=E2=80=99s a thing of=20 beauty!

 

Good=20 luck,


Bob

 

 

 

The signal reception on my Garmin 420 is really=20 dodgy.  We've tested the unit on a bench and it worked great. = We've=20 swapped the antenna, no change. We swapped the antenna cable, it actuall= y got=20 quite a bit worse (the old one had intermittent issues, the new one is= dodgy,=20 nearly full time.)

If I route the cable 'just so', I can make it= work=20 fairly well on the ground with the canopy open, but it tends to go to he= ll=20 when I close the canopy. 

If I unscrew and lift the glare= shield=20 about 1/2" - 1", the reception is great.  The GPS antenna is attach= ed to=20 the top of the glare shield on the co-pilot side.

I'm going to ge= t some=20 help from a shop in debugging this...but it seems to me that part of the= =20 canopy is either causing interference within the antenna cable, or the= antenna=20 itself.

Has anyone experienced anything like this before? This is= in a=20 360.

Keith

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