Return-Path: Sender: (Marvin Kaye) To: lml Date: Mon, 25 Nov 2002 23:56:02 -0500 Message-ID: X-Original-Return-Path: Received: from mail.indian-creek.net ([209.176.40.9] verified) by logan.com (CommuniGate Pro SMTP 4.0.1) with ESMTP id 1887066 for lml@lancaironline.net; Mon, 25 Nov 2002 20:54:34 -0500 Received: from VAIO (sl17.du.indian-creek.net [209.176.40.33] toucan@78055.com) by mail.indian-creek.net with SMTP (IOA-IPAD 3.70a/96) id 5F30800 for ; Mon, 25 Nov 2002 19:54:42 -0600 X-Original-Message-ID: <004d01c294ee$c20acc10$2128b0d1@VAIO> From: "Jim Cameron" X-Original-To: "Lancair Mailing List" Subject: XPDR Antenna Problem X-Original-Date: Mon, 25 Nov 2002 19:54:26 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004A_01C294BC.75B00E70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 This is a multi-part message in MIME format. ------=_NextPart_000_004A_01C294BC.75B00E70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I have the same problem with my Bob Archer XPDR antenna, which in my = ES is mounted on the inside of the large inspection cover on the left = side of the empennage, just under the HStab. Typically, when I'm 20 or = 30 miles out and heading directly toward an APC radar, they'll call me = and complain they're not receiving my transponder. I've learned to ask = them to just hold on for a few miles, as it usually shows up when I get = closer. They usually grump and admit they do have my primary echo. A = couple of times I've had to do a 90-degree turn for ID -- they'll see = it, then sometimes not see it again when I turn back toward the radar = location. So far no problems with transmission to either side or to the = rear. I did talk to Bob Archer on the telephone about it. He seemed = mildly surprised I was getting any forward transmission at all, given = the amount of junk forward of the antenna location (spars, gear plates, = flap motors, pilots, panel, engine, etc.). The size and shape of Bob's = antenna being what they are, I can't think of another location for it = that would fix the problem. Probably the only way around it is to put = an external antenna on the belly, and build a ground plane inside with = copper foil tape, a la Jim Weir. So far it hasn't been enough of a = problem, often enough, to justify any action. If I flew a lot of legs = into congested areas, however, I guess I'd have to do it. Jim Cameron Lancair Super ES, N143ES ------=_NextPart_000_004A_01C294BC.75B00E70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

I have the same = problem with my=20 Bob Archer XPDR antenna, which in my ES is mounted on the inside of the = large=20 inspection cover on the left side of the empennage, just under the = HStab. =20 Typically, when I'm 20 or 30 miles out and heading directly toward an = APC radar,=20 they'll call me and complain they're not receiving my transponder. = I've=20 learned to ask them to just hold on for a few miles, as it usually shows = up when=20 I get closer. They usually grump and admit they do have my primary = echo. A couple of times I've had to do a 90-degree turn for ID -- = they'll=20 see it, then sometimes not see it again when I turn back toward the = radar=20 location. So far no problems with transmission to either side or = to the=20 rear.

I did talk to Bob = Archer on the=20 telephone about it. He seemed mildly surprised I was getting any = forward=20 transmission at all, given the amount of junk forward of the antenna = location=20 (spars, gear plates, flap motors, pilots, panel, engine, = etc.). The=20 size and shape of Bob's antenna being what they are, I can't think of = another=20 location for it that would fix the problem. Probably the only way = around=20 it is to put an external antenna on the belly, and build a ground plane = inside=20 with copper foil tape, a la Jim Weir. So far it hasn't been enough = of a=20 problem, often enough, to justify any action. If I flew a lot of = legs into=20 congested areas, however, I guess I'd have to do it.

Jim Cameron

Lancair Super ES, = N143ES

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