X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 04 Jan 2012 16:38:21 -0500 Message-ID: X-Original-Return-Path: Received: from elasmtp-scoter.atl.sa.earthlink.net ([209.86.89.67] verified) by logan.com (CommuniGate Pro SMTP 5.4.3) with ESMTP id 5337007 for lml@lancaironline.net; Wed, 04 Jan 2012 10:06:02 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.67; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=Ms2/wVc1hzSjM5AB8/OLbt8M8RFijPpGh7jfPRtTEXqezzscM4waZ70fgLcwal/p; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [72.73.82.58] (helo=[192.168.1.24]) by elasmtp-scoter.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1RiSP5-0004yT-Hn for lml@lancaironline.net; Wed, 04 Jan 2012 10:05:23 -0500 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-967--510028189 Subject: Re: [LML] 4P com issues X-Original-Date: Wed, 4 Jan 2012 10:05:22 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1084) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da94071e62380e8f8792805b17e631f9eeab5350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 72.73.82.58 --Apple-Mail-967--510028189 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Ralf, That sounds like a good plan. I'm no antenna expert but I did = accumulate a few data points that I think might be beneficial to the = group: - define "good". Good is it works if you have line of sight to the = transmitting station. e.g. 100 miles at altitude. my cessna = installation is not "good". - I also have a Bob Archer in my tail. =46rom talking to several, if = you have an excellent installation you'll get 40+ miles range out of = that but there's a null directly in front of and behind the airplane. = Bob Archer himself admits the null issue. As long as you never fly = direct-to you might be happy with that. - Belly installation works best on a IV. Ideally you want a 22" radius = ground plane although slightly less seems to work. - Tim Ong did some tests that showed on a carbon airplane you'll do = somewhat better with the ground plane OUTSIDE the skin. - Bob Pastusek has a belly whip mounted slightly behind the front of the = gear doors with an 18" internal aluminum ground plane connected to an = SL30. His reception is "good" by above definition. - I had a similar installation connected to a gns530W. My reception = had some prominent nulls. I installed an external ground plane. = We'll see what happens. - connectors have some signal loss. Diplexors have significant signal = loss. Switches have some signal loss. I think I read somewhere on Bob = Archer's web page that the loss from a diplexor is about a 50% reduction = in range. - Get Jim Weir's RST-8020 antenna installation book. Even if you don't = build your own antenna, it's really good basic easy to understand = theoretical background that will improve whatever you do. It's = available here as part of his kit for $29. = http://www.rst-engr.com/rst/catalog/airplane_antenna.html He may be = willing to sell just the book for $10 and he may be willing to email you = the .pdf . Mail order from Jim may take a few weeks. - somebody asked about using a nav antenna for a com antenna. The = antenna length is optimized for the wavelength used. e.g. a com = antenna should have a vswr of around 1.0 at the middle of the com = frequency range. com signals are vertically polarized. nav signals are = horizontally polarized. A com monopole needs a good ground plane. You = could put one sticking up or down out of a wingtip if you provided the = ground plane in the wingtip surface. All that said, if I had it to do over again, this is what my IVP com = installation would look like: - Com 1 antenna as far forward on the belly as I could get 18" radius. = Wire directly to the radio with only the one connector at the radio. - use a commercial whip with the lowest vswr I can find. - lay in an external copper tape 8-pointed ground plane (like an = asterisk) and connect it all with conductive paint. Conductive paint = alone works great but there's some belief that it develops fissures over = time so the copper tape makes a more reliable system. - Com 2 also on the belly 36" or more back. take what I can get for = ground plane. The rationale is it's better than a portable whip and = probably good enough for ground ops. (If I had a fiberglas airplane I = would put it the other way up in the baggage compartment) - Com 2 wiring includes 2 connectors: 1 at radio and one accessible that = I can disconnect and plug in my portable. This is bad for com 2 but = more reliable than a diplexor and more optimal for the portable. Colyn On Jan 3, 2012, at 3:03 PM, = wrote: Dear subscribers, =20 My com radio is not working as it should. In some areas it is working = perfect. In other areas it does not work well. It seems to be worse at = high altitude/high speeds and along the shore lines or over the great = lakes. It is possible that I can barely read the controller and 20 miles = further it is decent. On the ground or around an airport it always works = ok. Sometimes I get a lot of static noise (depending on the airport). = Sometimes the controller sounds like he would talk out of an helicopter. = I am using the bose head sets. =20 I have metallic paint. I got static wicks =96 all grounded well. I got a = Garmin GNS530W, a Garmin GNC250XL and a Garmin GMA340 Com Panel (see = pic) =20 I got the following antennas: - VOR (in the fiberglass wing tip internally) =96 never had an = issue - transponder (wing root externally) =96 never had an issue - marker (externally under the 0 of the N# - see pic) =96 never = had an issue - GPS1 (internally in vertical stab. ) works ok =96 if I do two = rolls in a row the GPS loses signal =96 other than that no issues - GPS2 (internally in vertical stab.) works fine - COM (internally in vertical stab.) =96 I don=92t know exactly = where it is (was already in when I got the plane) but I get the cable = out of the vert. stab. so I guess it must be in there somewhere. =20 The COM antenna gets split with a duplexer for the GPS1 and GPS2 COM = input =20 I assume that my radio problems are related to the metallic paint and = the carbon bottom of the tail /elevator the shield the antenna please = tell me if you have a different opinion. =20 All my antenna cables are split at a little interface plate behind the = panel (see pic). It is fairly easy to disconnect and reconnect the = cables. =20 My plan of action is (please feel free to tell me if I am talking = nonsense) - Remove the marker antenna on the belly (I never use the = marker signal on an ILS, I monitor the GPS 530 for my location and = distance to way points, I would not notice if I lose this function) - Place an external COM antenna at the location of the marker = antenna (I got about 1sqft of aluminum shield on the inside of the plane = there - I would need a recommendation for which antenna to pick) - Reconnect the antenna cables at my interface plate: COM1 uses = new external COM antenna (old marker antenna), COM2 uses existing = internal antenna, the marker would have no antenna anymore - I would leave the duplexer in there for now and use only one = output for the COM2 =96 I would remove the duplexer later it everything = works fine - The COM1 input would be connected directly to the antenna = without the duplexer =20 Thanks for your help =20 Ralf =20 =20 =20 -- For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html --Apple-Mail-967--510028189 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 Ralf,

That sounds like a good = plan.   I'm no antenna expert but I did accumulate a few data = points that I think might be beneficial to the = group:

- define "good".   Good is it works = if you have line of sight to the transmitting station.   e.g. 100 = miles at altitude.  my cessna installation is not = "good".
- I also have a Bob Archer in my tail.   =46rom = talking to several, if you have an excellent installation you'll get 40+ = miles range out of that but there's a null directly in front of and = behind the airplane.  Bob Archer himself admits the null issue. As = long as you never fly direct-to you might be happy with = that.
- Belly installation works best on a IV.  Ideally = you want a 22" radius ground plane although slightly less seems to = work.
- Tim Ong did some tests that showed on a carbon = airplane you'll do somewhat better with the ground plane OUTSIDE the = skin.
- Bob Pastusek has a belly whip mounted slightly behind = the front of the gear doors with an 18" internal aluminum ground plane = connected to an SL30. His reception is "good" by above = definition.
- I had a similar installation connected to a = gns530W.   My reception had some prominent nulls.   I = installed an external ground plane.   We'll see what = happens.
- connectors have some signal loss.  Diplexors = have significant signal loss.   Switches have some signal loss. =  I think I read somewhere on Bob Archer's web page that the loss = from a diplexor is about a 50% reduction in range.
- Get Jim = Weir's RST-8020 antenna installation book.  Even if you don't build = your own antenna, it's really good basic easy to understand theoretical = background that will improve whatever you do.  It's available here = as part of his kit for $29.  http://= www.rst-engr.com/rst/catalog/airplane_antenna.html   He may be = willing to sell just the book for $10 and he may be willing to email you = the .pdf .   Mail order from Jim may take a few weeks.
- = somebody asked about using a nav antenna for a com antenna.   The = antenna length is optimized for the wavelength used.   e.g. a com = antenna should have a vswr of around 1.0 at the middle of the com = frequency range.  com signals are vertically polarized.  nav = signals are horizontally polarized.   A com monopole needs a good = ground plane.  You could put one sticking up or down out of a = wingtip if you provided the ground plane in the wingtip = surface.


All that said, if I had = it to do over again, this is what my IVP com installation would look = like:
- Com 1 antenna as far forward on the belly as I could = get 18" radius.  Wire directly to the radio with only the one = connector at the radio.
- use a commercial whip with the = lowest vswr I can find.
- lay in an external copper tape = 8-pointed ground plane (like an asterisk)  and connect it all with = conductive paint.    Conductive paint alone works great but = there's some belief that it develops fissures over time so the copper = tape makes a more reliable system.
- Com 2 also on the belly = 36" or more back.    take what I can get for ground plane. =   The rationale is it's better than a portable whip and probably = good enough for ground ops.  (If I had a fiberglas airplane I would = put it the other way up in the baggage compartment)
- Com 2 = wiring includes 2 connectors: 1 at radio and one accessible that I can = disconnect and plug in my portable.   This is bad for com 2 but = more reliable than a diplexor and more optimal for the = portable.

Colyn


Dear = subscribers,
 
I have metallic paint. I got static = wicks =96 all grounded well. I got a Garmin GNS530W, a Garmin GNC250XL = and a Garmin GMA340 Com Panel (see pic)
I got the following = antennas:
- VOR (in the = fiberglass wing tip internally) =96 never had an = issue
- transponder = (wing root externally) =96 never had an issue
- marker = (externally under the 0 of the N# - see pic) =96 never had an = issue
- GPS1 = (internally in vertical stab. ) works ok =96 if I do two rolls in a row = the GPS loses signal =96 other than that no issues
- GPS2 = (internally in vertical stab.) works fine
- COM = (internally in vertical stab.) =96 I don=92t know exactly where it is = (was already in when I got the plane) but I get the cable out of the = vert. stab. so I guess it must be in there = somewhere.
 
 
I assume that my = radio problems are related to the metallic paint and the carbon bottom = of the tail /elevator the shield the antenna please tell me if you have = a different opinion.
 
 
- Remove the = marker antenna on the belly (I never use the marker signal on an ILS, I = monitor the GPS 530 for my location and distance to way points, I would = not notice if I lose this function)
- Place an = external COM antenna at the location of the marker antenna (I got about = 1sqft of aluminum shield on the inside of the plane there - I would need = a recommendation for which antenna to pick)
- Reconnect the = antenna cables at my interface plate: COM1 uses new external COM antenna = (old marker antenna), COM2 uses existing internal antenna, the marker = would have no antenna anymore
          I would leave = the duplexer in there for now and use only one output for the COM2 =96 I = would remove the duplexer later it everything works = fine
- The COM1 = input would be connected directly to the antenna without the = duplexer