X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 03 Mar 2013 10:40:14 -0500 Message-ID: X-Original-Return-Path: Received: from qmta01.westchester.pa.mail.comcast.net ([76.96.62.16] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTP id 6093041 for lml@lancaironline.net; Sun, 03 Mar 2013 08:33:21 -0500 Received-SPF: pass receiver=logan.com; client-ip=76.96.62.16; envelope-from=jmorgan1023@comcast.net Received: from omta10.westchester.pa.mail.comcast.net ([76.96.62.28]) by qmta01.westchester.pa.mail.comcast.net with comcast id 71Sl1l0040cZkys511Ym2F; Sun, 03 Mar 2013 13:32:46 +0000 Received: from [192.168.1.105] ([24.11.157.196]) by omta10.westchester.pa.mail.comcast.net with comcast id 71Yl1l00q4EXR5U3W1Ym7Q; Sun, 03 Mar 2013 13:32:46 +0000 From: Jack Morgan Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: multipart/alternative; boundary="Apple-Mail=_7D2AED00-61A8-4F7D-B82F-6F388982C68C" Subject: Antennas X-Original-Date: Sun, 3 Mar 2013 08:32:48 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <53C463F5-4CA7-48AD-A602-2E6CD1307FB9@comcast.net> X-Mailer: Apple Mail (2.1283) --Apple-Mail=_7D2AED00-61A8-4F7D-B82F-6F388982C68C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Hi Tom, I put the same Archer nav antenna in the other wing tip and used it for = com 2. The slightly higher frequencies of the com range are only a few = DB lower as the antenna is sufficiently broad band. As a practical = matter the vertical polarization deemed best for com has little effect = due to scatter which the com signals experience. I can tune an ATIS at = the fringe distance and compare the 1 and 2 audio quality with only a = slight difference. If you locate the compass magnetometer in the wing = tip, put it on the nav side as the com transmit power could upset it's = magnetic sensor. The wing tips must be eglass rather than the carbon = fiber winglets common on the earlier IV's. I used the archer MBR antenna on the inside of the wing fairing and got = by. It seems too close to the fuselage but seems to work OK. I placed the two GPS/XM antennas under the eglass turtle deck. After = paint completion, I compared the signal strength on my G900 with the = antennas outside the airplane and mounted under the eglass and found no = difference in signal strength. I have had no reception issues with GPS. = My paint choice was base coat/clear coat non metallic white in the = antenna area. I suspect a metallic paint in the antenna area could = impair reception but have no data to support that guess. The XPDR antenna is on the bottom and is the only external antenna. The = fiber provides sufficient ground plane in my opinion. Moving it aft as = necessary to clear your belly tank is not an issue and the fairing = location should be OK also with a foil ground plane extending well into = the fuselage fiber area. I would try to center it on the fuselage = however. Hope this helps. Jack Morgan IVP On Mar 3, 2013, at 6:00 AM, Lancair Mailing List wrote: > From: "Tom & Beth Sullivan" > Subject: Looking for advise on Antenna locations for IVP > Date: March 2, 2013 2:51:44 PM EST > To: lml@lancaironline.net >=20 >=20 > =20 > I did a search on the LML archives and found a pot pouri of = questions, problems and tips, but much of the info had to do with glass = planes (not carbon fiber), and I have some unique challenges as well. > =20 > I have already installed the Bob Archer com antenna in the = vert/stab and a nav antenna in the winglet (think just one). My unique = challenge is the fact that most of my belly between the gear and forward = to the firewall is fuel tank, so this area is unusable for antennas. I = think, based on complaints, that I want at least one more com antenna. = As shown in the attached picture, of the aft fuselage area with my A/C, = there is no way I can get a large ground plane in there. With carbon, = do they usually install it in the fuselage (wondering if the ground = plane does any good behind the carbon)? I may be able to get a = "segmented" one in there, with part of the ground plane inside the A/C = condenser box, and run a ground strap or strip between the segments at = each end of the "pie slice" cut out for the A/C. Otherwise I am limited = to a smaller ground plane, or installing one on the outside of the skin = (already body worked and in primer).=20 > =20 > Also, for the transponder and Marker beacon antennas, wondering if I = could place one at the rear of each wing fairing, as I think the ground = plane (G/P) on those would be smaller, and the G/P could be "seen" = easily through the fiberglass of those fairings. My understanding is = the gound plane need only be as large in radius as the length of the = actual antenna it is connected to? > =20 > Thanks in advance for any advice. > =20 > Tom Sullivan >=20 --Apple-Mail=_7D2AED00-61A8-4F7D-B82F-6F388982C68C Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 Hi = Tom,

I put the same Archer nav antenna in the other = wing tip and used it for com 2. The slightly higher frequencies of the = com range are only a few DB lower as the antenna is sufficiently broad = band. As a practical matter the vertical polarization deemed best for = com has little effect due to scatter which the com signals experience. I = can tune an ATIS at the fringe distance and compare the 1 and 2 audio = quality with only a slight difference. If you locate the compass = magnetometer in the wing tip, put it on the nav side as the com transmit = power could upset it's magnetic sensor. The wing tips must be eglass = rather than the carbon fiber winglets common on the earlier = IV's.

I used the archer MBR antenna on the = inside of the wing fairing and got by. It seems too close to the = fuselage but seems to work OK.

I placed the two = GPS/XM antennas under the eglass turtle deck. After paint completion, I = compared the signal strength on my G900 with the antennas outside the = airplane and mounted under the eglass and found no difference in signal = strength. I have had no reception issues with GPS. My paint choice was = base coat/clear coat non metallic white in the antenna area. I suspect a = metallic paint in the antenna area could impair reception but have no = data to support that guess.

The XPDR antenna is = on the bottom and is the only external antenna. The fiber provides = sufficient ground plane in my opinion. Moving it aft as necessary to = clear your belly tank is not an issue and the fairing location should be = OK also with a foil ground plane extending well into the fuselage fiber = area. I would try to center it on the fuselage = however.

Hope this = helps.

Jack = Morgan
IVP

On Mar 3, 2013, at 6:00 AM, = Lancair Mailing List wrote:

   I have already installed the Bob Archer com = antenna in the vert/stab and a nav antenna in the winglet (think just = one).  My unique challenge is the fact that most of my = belly between the gear and forward to the firewall is fuel tank, so this = area is unusable for antennas.  I think, based on complaints, that = I want at least one more com antenna.  As shown in the attached = picture, of the aft fuselage area with my A/C, there is no way I can get = a large ground plane in there.  With carbon, do they usually = install it in the fuselage (wondering if the ground plane does any good = behind the carbon)?  I may be able to get a "segmented" one in = there, with part of the ground plane inside the A/C condenser box, and = run a ground strap or strip between the segments at each end of the = "pie slice" cut out for the A/C.  Otherwise I am limited to a = smaller ground plane, or installing one on the outside of the skin = (already body worked and in primer). 


= --Apple-Mail=_7D2AED00-61A8-4F7D-B82F-6F388982C68C--