X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 06 Nov 2013 07:31:58 -0500 Message-ID: X-Original-Return-Path: Received: from qmta02.westchester.pa.mail.comcast.net ([76.96.62.24] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTP id 6578505 for lml@lancaironline.net; Wed, 06 Nov 2013 06:56:17 -0500 Received-SPF: pass receiver=logan.com; client-ip=76.96.62.24; envelope-from=jmorgan1023@comcast.net Received: from omta05.westchester.pa.mail.comcast.net ([76.96.62.43]) by qmta02.westchester.pa.mail.comcast.net with comcast id mBvM1m0080vyq2s51BvhL3; Wed, 06 Nov 2013 11:55:41 +0000 Received: from [192.168.1.102] ([24.11.157.196]) by omta05.westchester.pa.mail.comcast.net with comcast id mBvh1m00B4EXR5U3RBvhgx; Wed, 06 Nov 2013 11:55:41 +0000 From: Jack Morgan Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: multipart/alternative; boundary="Apple-Mail=_82BF02FF-7A24-450D-87E6-357F293427D5" Subject: Carbon is a good ground plane X-Original-Date: Wed, 6 Nov 2013 06:55:40 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <1B578F5E-4C28-4F24-B787-63D5BD38C89B@comcast.net> X-Mailer: Apple Mail (2.1283) --Apple-Mail=_82BF02FF-7A24-450D-87E6-357F293427D5 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 I agree with Kevin. I also have no xpdr issues using the carbon as a = ground plane. The nav/com/xpdr/gps frequencies are plenty high to insure = good capacitive ground coupling to the carbon. The resistance of the = carbon is plenty low for RF purposes. John... Don't know where your xpdr antenna actually is. If it way = forward at the firewall station the problem may be interaction with the = propellor. Just a guess at this point. The prop blades passing near the = xpdr have been identified as the issue on other installations I saw in = the early days. Mine is located just behind the spar box on my IV with = no ground plane or problems. Jack Morgan On Nov 6, 2013, at 6:01 AM, Lancair Mailing List wrote: > From: Kevin Stallard > Subject: TXPDR Antenna and such > Date: November 5, 2013 11:58:13 AM EST > To: lml@lancaironline.net >=20 >=20 > For what it is worth, I'm using the carbon as my ground plane. >=20 > I've been on a couple of cross country flights and the only thing ATC = is having trouble with is the noise in the cockpit. I suspect interior = and such will absorb some of that noise when I get to it. Otherwise = they are getting 5x5 on the signal quality (or at least that is what = they are telling me when I ask). >=20 > Both the TXPDR and communications seem (thus far) pretty clear trouble = free. =20 >=20 > I decided not to put on an additional ground plane because the = resistance of the carbon, while worse than copper or aluminum, is still = pretty decent. I took a chance and it seems to be working out so far. >=20 > Perhaps at some point I'll be proven wrong, but I think it is worth = discussing and trying to quantify. =20 >=20 > Kevin > N969RJ (flying) --Apple-Mail=_82BF02FF-7A24-450D-87E6-357F293427D5 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 I = agree with Kevin. I also have no xpdr issues using the carbon as a = ground plane. The nav/com/xpdr/gps frequencies are plenty high to insure = good capacitive ground coupling to the carbon. The resistance of the = carbon is plenty low for RF purposes.

John... Don't = know where your xpdr antenna actually is. If it way forward at the = firewall station the problem may be interaction with the propellor. Just = a guess at this point. The prop blades passing near the xpdr have been = identified as the issue on other installations I saw in the early days. = Mine is located just behind the spar box on my IV with no ground plane = or problems.

Jack = Morgan

On Nov 6, 2013, at 6:01 AM, Lancair = Mailing List wrote:

From: Kevin Stallard = <Subject: TXPDR Antenna = and such