X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 06 Nov 2013 14:45:38 -0500 Message-ID: X-Original-Return-Path: <2thman1@gmail.com> Received: from mail-pd0-f175.google.com ([209.85.192.175] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6579166 for lml@lancaironline.net; Wed, 06 Nov 2013 13:56:43 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.192.175; envelope-from=2thman1@gmail.com Received: by mail-pd0-f175.google.com with SMTP id g10so10521175pdj.34 for ; Wed, 06 Nov 2013 10:56:07 -0800 (PST) X-Received: by 10.66.122.66 with SMTP id lq2mr3307785pab.183.1383764167515; Wed, 06 Nov 2013 10:56:07 -0800 (PST) X-Original-Return-Path: <2thman1@gmail.com> Received: from [192.168.0.14] (71-212-96-147.tukw.qwest.net. [71.212.96.147]) by mx.google.com with ESMTPSA id wr10sm20516825pbc.17.2013.11.06.10.56.06 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 06 Nov 2013 10:56:07 -0800 (PST) References: In-Reply-To: Mime-Version: 1.0 (1.0) Content-Type: multipart/alternative; boundary=Apple-Mail-3186C6E4-A59D-4DA4-9719-9228EFABBD06 X-Original-Message-Id: Content-Transfer-Encoding: 7bit X-Mailer: iPad Mail (11B511) From: John Barrett <2thman1@gmail.com> Subject: Re: [LML] Carbon is a good ground plane X-Original-Date: Wed, 6 Nov 2013 10:30:35 -0800 X-Original-To: Lancair Mailing List --Apple-Mail-3186C6E4-A59D-4DA4-9719-9228EFABBD06 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Thanks to all for the input. Jack's comment about prop interference with th= e signal is interesting. Would that be a concern with a metal prop? How ab= out a carbon fiber prop as mine is with nickel leading edges? John Sent from my iPad > On Nov 6, 2013, at 4:31 AM, Jack Morgan wrote: >=20 > I agree with Kevin. I also have no xpdr issues using the carbon as a groun= d plane. The nav/com/xpdr/gps frequencies are plenty high to insure good cap= acitive ground coupling to the carbon. The resistance of the carbon is plent= y low for RF purposes. >=20 > John... Don't know where your xpdr antenna actually is. If it way forward a= t the firewall station the problem may be interaction with the propellor. Ju= st a guess at this point. The prop blades passing near the xpdr have been id= entified as the issue on other installations I saw in the early days. Mine i= s located just behind the spar box on my IV with no ground plane or problems= . >=20 > Jack Morgan >=20 >> On Nov 6, 2013, at 6:01 AM, Lancair Mailing List wrote: >>=20 >> 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 h= aving trouble with is the noise in the cockpit. I suspect interior and suc= h will absorb some of that noise when I get to it. Otherwise they are getti= ng 5x5 on the signal quality (or at least that is what they are telling me w= hen I ask). >>=20 >> Both the TXPDR and communications seem (thus far) pretty clear trouble fr= ee. =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 discu= ssing and trying to quantify. =20 >>=20 >> Kevin >> N969RJ (flying) >=20 --Apple-Mail-3186C6E4-A59D-4DA4-9719-9228EFABBD06 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

Thanks to all for the input. Jac= k's comment about prop interference with the signal is interesting. Wo= uld that be a concern with a metal prop? How about a carbon fiber prop= as mine is with nickel leading edges?

John

= Sent from my iPad

On Nov 6, 2013, at 4:31 AM, J= ack Morgan <jmorgan1023@comcas= t.net> wrote:

I agree wit= h Kevin. I also have no xpdr issues using the carbon as a ground plane. The n= av/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 p= urposes.

John... Don't know where your xpdr antenna actua= lly is. If it way forward at the firewall station the problem may be interac= tion 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 sa= w in the early days. Mine is located just behind the spar box on my IV with n= o ground plane or problems.

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

From: = Kevin= Stallard <kevin@arilabs.net>
Subject: TXPDR Antenna and such
Date= : November 5, 2013 11:58:13 AM E= ST
To: lml@lancaironline.net

For what it is worth, I'm using the carbon as my ground plane.
I've been on a couple of cross country flights and the only thing ATC i= s having trouble with is the noise in the cockpit. I suspect int= erior and such will absorb some of that noise when I get to it. Otherw= ise they are getting 5x5 on the signal quality (or at least that is what the= y are telling me when I ask).

Both the TXPDR and communications seem (= thus far) pretty clear trouble free.

I decided not to put on a= n additional ground plane because the resistance of the carbon, while worse t= han copper or aluminum, is still pretty decent. I took a chance and it= seems to be working out so far.

Perhaps at some point I'll be proven= wrong, but I think it is worth discussing and trying to quantify.
Kevin
N969RJ (flying)

=

= --Apple-Mail-3186C6E4-A59D-4DA4-9719-9228EFABBD06--