X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 19 Jan 2011 12:22:53 -0500 Message-ID: X-Original-Return-Path: Received: from elasmtp-mealy.atl.sa.earthlink.net ([209.86.89.69] verified) by logan.com (CommuniGate Pro SMTP 5.4c1) with ESMTP id 4791419 for lml@lancaironline.net; Wed, 19 Jan 2011 10:47:13 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.69; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=mFRAIKLqdb5LZmyo3nWesMNsCHOjbx2PBZgx2CvhaIF/51U7CmNScCNL5ED8jA7z; 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 [216.57.118.194] (helo=[192.168.1.103]) by elasmtp-mealy.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1PfaEt-0000YV-8q for lml@lancaironline.net; Wed, 19 Jan 2011 10:46:27 -0500 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: multipart/alternative; boundary=Apple-Mail-265--682792982 Subject: Re: [LML] Re: Antennas X-Original-Date: Wed, 19 Jan 2011 10:46:26 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <7048B878-3492-4A6F-A445-8F2EDA33894B@earthlink.net> X-Mailer: Apple Mail (2.1082) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940cbd8434047f28da0853d0f567e93ac8c350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.194 --Apple-Mail-265--682792982 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Wayne, I'm going through a similar process on my IV-P right now. I am by no = means an expert yet but I have learned a few things which would have = caused me to do it all differently if I had known before. Firstly, carbon or any conductor near your antenna is bad. Hopefully = not a problem for you. Jim Weir describes it as "more than an eigth of = a wavelength long within a quarter wavelength of the antenna." This = basically means that the Bob Archer nav antenna doesn't work in a IVP = winglet because Lancair made the top of the winglet out of carbon. = ...although interestingly a few people that have a King nav radio are = able to function with this setup. By the way, I strongly recommend buying Weir's kit. It's $29. The book = he sends with it is worth the $29 even if you throw the copper foil and = torroids away. Give him lots of lead time though (3 weeks?). = http://www.rst-engr.com/rst/catalog/airplane_antenna.html Secondly, if your antenna installation is marginal, you don't want to = compromise it with splitters if you can help it. A standard splitter = robs 50% of the signal strength which I think Bob Archer says translates = to 30% range reduction. Using the standard approach, you would have = two splitters on the way to your Garmin. So 25% signal strength. If = it were me I would work pretty hard to eliminate the nav1/nav2 splitter = and if I could come up with a place for a separate GS antenna I would do = it. In Jim Weir's book, however, there's a design for a vor/loc <-> = GS splitter which is frequency selective so is supposed to have lower = losses than a standard splitter used in that vor/loc <-> GS application. = I haven't tried it yet but it sounds good. You might consider only hooking the new nav antenna to your SL30 only = and figuring if that radio or antenna fails some day you are going to be = looking for a waas vnav approach. On the com side, I know Bob Archer has two switches left to select = between com units for transmit. but you still have to live with a = splitter on the receive side. I like Bob Pastusek's idea of putting in = a belly whip better. Bob has a carbon fuselage right there which is = probably helping with the ground a bit. In my understanding you need = ideally a 22" radius ground plane for optimal performance. You can do = that with a foil X with 22" inch legs. Beware the 1/8 wavelength = within 1/4 wavelength rule though. Thirdly, BNC connectors have losses so I would be looking for ways to = cut those to a minimum. I'm not sure which Bob Archer Nav antenna you are thinking of. But the = one that is designed for a IV wingtip is looking for a big ground in the = inboard side. You'll have to get Bob Archer's advice on doing it in an = all glass environment. I do wonder how well it's going to perform = sitting behind human water bags and an engine when you are on final = approach. Might want to go test that before the glue dries. Colyn On Jan 18, 2011, at 9:13 PM, Robert R Pastusek wrote: > Wayne wrote: >=20 > Installing my avionics and its time for antennas, I installed a comm = antenna in the vert/stab years ago and everything is closed back there. > I am installing a S/L30 Nav/Com which has an internal diplexer and the = manuel says not to install an external diplexer, however I am thinking > they are talking about using an external diplexer for one antenna for = Nav/Com. I am also installing a GNS530W and in the rear of the unit = there > is a place for a Nav and GS antenna. My plan is to install a Bob = Archer VOR antenna in the ceiling of the baggage area and that would = give me > one Nav ant and one Comm ant. I would use a splitter coming from the = Nav ant and connect to the Nav port on the S/30 and to the Nav port=20 > and the GS port on the 530W GPS which has two different ports for GS = and Nav. I would use a T/R switch for the com on the S/L30 and the > com on the 530W GPS. I emailed Bob about this installation and he said = he believed it would be ok but didn't know if the GS connection fr the > splitter to the 530W would completely rob the signal from the S/L 30. = Please give me your recomendations as I know there are many 2 place > Lancairs flying with no antenna problems. > =20 > Wayne, > Diplexers work, but for the cost of another antenna (probably less = than the diplexer?) you can build true redundancy in your radio system, = and I=92d recommend that. I have a Bob Archer antenna installed in the = tail of my IV-P and a =93bent whip=94 antenna on the belly with a 32=94 = aluminum ground plane inside the fuselage behind it. I have an SL-30 for = Comm/Nav 1 and an SL-40 for Comm 2. After some testing, I hooked the = belly antenna to #1 (the SL-30), and can routinely talk out to the line = of sight of the other radio. Not so with my Bob Archer hooked to the = SL-40=85it=92s good out to 40-50 miles or so, and with more static on = receive. I often move ATC to the #2 when I need to talk to flight = service because of the significantly better range and reception on the = #1 system with the whip antenna. The bent whip like I have would easily = work on a 2-seat Lancair. > =20 > My 2 cents=85=20 > Bob Pastusek --Apple-Mail-265--682792982 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 Wayne,

I'm going through a = similar process on my IV-P right now.   I am by no means an expert = yet but I have learned a few things which would have caused me to do it = all differently if I had known before.

Firstly, = carbon or any conductor near your antenna is bad.   Hopefully not a = problem for you.  Jim Weir describes it as "more than an eigth of a = wavelength long within a quarter wavelength of the antenna."  This = basically means that the Bob Archer nav antenna doesn't work in a IVP = winglet because Lancair made the top of the winglet out of carbon. =   ...although interestingly a few people that have a King nav radio = are able to function with this setup.

By the = way, I strongly recommend buying Weir's kit.  It's $29.  The = book he sends with it is worth the $29 even if you throw the copper foil = and torroids away.   Give him lots of lead time though (3 weeks?). =  http://= www.rst-engr.com/rst/catalog/airplane_antenna.html

Secondly, if your antenna installation is marginal, you don't want = to compromise it with splitters if you can help it.   A standard = splitter robs 50% of the signal strength which I think Bob Archer says = translates to 30% range reduction.   Using the standard approach, = you would have two splitters on the way to your Garmin.  So 25% = signal strength.    If it were me I would work pretty hard to = eliminate the nav1/nav2 splitter and if I could come up with a place for = a separate GS antenna I would do it.    In Jim Weir's book, = however, there's a design for a vor/loc <-> GS splitter which is = frequency selective so is supposed to have lower losses than a standard = splitter used in that vor/loc <-> GS application.   I haven't = tried it yet but it sounds good.

You might = consider only hooking the new nav antenna to your SL30 only and figuring = if that radio or antenna fails some day you are going to be looking for = a waas vnav approach.

On the com side, I know = Bob Archer has two switches left to select between com units for = transmit.  but you still have to live with a splitter on the = receive side.   I like Bob Pastusek's idea of putting in a belly = whip better.   Bob has a carbon fuselage right there which is = probably helping with the ground a bit.  In my understanding you = need ideally a 22" radius ground plane for optimal performance.   = You can do that with a foil X with 22" inch legs.     Beware = the 1/8 wavelength within 1/4 wavelength rule = though.

Thirdly, BNC connectors have losses so = I would be looking for ways to cut those to a = minimum.

I'm not sure which Bob Archer Nav = antenna you are thinking of.   But the one that is designed for a = IV wingtip is looking for a big ground in the inboard side.   = You'll have to get Bob Archer's advice on doing it in an all glass = environment.   I do wonder how well it's going to perform sitting = behind human water bags and an engine when you are on final approach. =   Might want to go test that before the glue = dries.

Colyn


On Jan 18, 2011, at 9:13 PM, Robert R Pastusek wrote:

Wayne wrote:

Installing my avionics and its time for antennas, I = installed a comm antenna in the vert/stab years ago and everything is = closed back there.
I am installing a S/L30 Nav/Com which has an = internal diplexer and the manuel says not to install an external = diplexer, however I am thinking
they are talking about using an = external diplexer for one antenna for Nav/Com. I am also installing a = GNS530W and in the rear of the unit there
is a place for a Nav and GS = antenna. My plan is to install a Bob Archer VOR antenna in the ceiling = of the baggage area and that would give me
one Nav ant and one Comm = ant. I would use a splitter coming from the Nav ant and connect to the = Nav port on the S/30 and to the Nav port 
and the GS port on the = 530W GPS which has two different ports for GS and Nav. I would use a T/R = switch for the com on the S/L30 and the
com on the 530W GPS. I = emailed Bob about this installation and he said he believed it would be = ok but didn't know if the GS connection fr the
splitter to the 530W = would completely rob the signal from the S/L 30. Please give me your = recomendations as I know there are many 2 place
Lancairs flying with = no antenna problems.
 
Wayne,
Diplexers work, but for the cost of another antenna = (probably less than the diplexer?) you can build true redundancy in your = radio system, and I=92d recommend that. I have a Bob Archer antenna = installed in the tail of my IV-P and a =93bent whip=94 antenna on the = belly with a 32=94 aluminum ground plane inside the fuselage behind it. = I have an SL-30 for Comm/Nav 1 and an SL-40 for Comm 2. After some testing, I = hooked the belly antenna to #1 (the SL-30), and can routinely talk out = to the line of sight of the other radio. Not so with my Bob Archer = hooked to the SL-40=85it=92s good out to 40-50 miles or so, and with = more static on receive. I often move ATC to the #2 when I need to talk = to flight service because of the significantly better range and = reception on the #1 system with the whip antenna. The bent whip like I = have would easily work on a 2-seat Lancair.
My 2 = cents=85 
Bob = Pastusek

=
= --Apple-Mail-265--682792982--