X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 24 Oct 2007 19:05:36 -0400 Message-ID: X-Original-Return-Path: Received: from rwcrmhc13.comcast.net ([204.127.192.83] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2431403 for lml@lancaironline.net; Wed, 24 Oct 2007 18:07:36 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.192.83; envelope-from=rpastusek@htii.com Received: from dlhtpax009 (c-69-143-130-212.hsd1.va.comcast.net[69.143.130.212]) by comcast.net (rwcrmhc13) with SMTP id <20071024220657m1300bt3mde>; Wed, 24 Oct 2007 22:06:57 +0000 From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Re: GPS antennae X-Original-Date: Wed, 24 Oct 2007 18:06:45 -0400 X-Original-Message-ID: <015f01c8168a$31044340$930cc9c0$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0160_01C81668.A9F2A340" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcgWOMF5OlHOQnnWR/OL3gpu0Z4F8QAUCB5w Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_0160_01C81668.A9F2A340 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Dom writes: . on my recent transcontinental odyssey, pretty much over the GAFA, (if you don't know what the GAFA is, I'll explain it off LML), both my Garmin 295 and AvMap EK IV lost satellite signals intermittently every few seconds, while the KLN89B happily continued to receive all available satellites. This went on for some time. Dom, I have a Garmin 295 that's about as reliable and trustworthy as any piece of electronic equipment I own. Having said that, one of the radios in my Cherokee will definitely disrupt the signal on certain frequencies. It is so predictable on 119.3 (a primary approach control freq for our flying area) that I initially concluded that the GPS signal was being jammed in a specific geographic area-took me months to make the association to a change of ATC frequencies. The interesting thing is that radio #1 will jam the GPS if tuned to 119.3 every time, but radio #2 does not affect it. My suspicion is that there are some IF frequencies in the Narco radio that "walk on" the GPS signal-or perhaps internal circuitry in the GPS itself? Having "discovered" this, I have now taken to switching radios/frequencies any time I lose the GPS signal, and have thereby compiled a short list of frequencies, when tuned into the Narco, that interfere. I have discovered only one frequency on the King radio that interferes, and it's a different freq.go figure. In any case, you might give this some consideration. Bob Pastusek ------=_NextPart_000_0160_01C81668.A9F2A340 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Dom writes:

… on my recent transcontinental odyssey, pretty much over the GAFA, (if you = don’t know what the GAFA is, I’ll explain it off LML), both my Garmin = 295 and AvMap EK IV lost satellite signals intermittently every few seconds, = while the KLN89B happily continued to receive all available satellites. This went = on for some time.

 

Dom,

I have a Garmin 295 that’s about as reliable and trustworthy as any piece of electronic equipment I own. Having said = that, one of the radios in my Cherokee will definitely disrupt the signal on = certain frequencies. It is so predictable on 119.3 (a primary approach control = freq for our flying area) that I initially concluded that the GPS signal was = being jammed in a specific geographic area—took me months to make the association to a change of ATC frequencies. The interesting thing is = that radio #1 will jam the GPS if tuned to 119.3 every time, but radio #2 does not = affect it. My suspicion is that there are some IF frequencies in the Narco = radio that “walk on” the GPS signal—or perhaps internal circuitry in the GPS = itself? Having “discovered” this, I have now taken to switching radios/frequencies any time I lose the GPS signal, and have thereby = compiled a short list of frequencies, when tuned into the Narco, that interfere. I have = discovered only one frequency on the King radio that interferes, and it’s a = different freq…go figure. In any case, you might give this some = consideration.


Bob Pastusek

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