Today's Message Index:
----------------------
1. 05:07 AM - Re: Antenna placement. (Brian Lloyd)
2. 09:04 AM - Re: Antenna placement. (David Lloyd)
3. 09:46 AM - Re: Antenna placement. (Doug McNutt)
4. 03:09 PM - Re: Antenna placement. (Fred Fillinger)
5. 10:10 PM - Re: Antenna placement. (LessDragProd@aol.com)
6. 11:30 PM - Re: Antenna placement. (Jim and Vivian)
7. 11:32 PM - Re: Antenna placement. (Ron Koyich)
Message 1
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: Brian Lloyd <brianl@lloyd.com>
On Aug 25, 2004, at 12:53 AM, Dean Psiropoulos wrote:
> --> Avionics-List message posted by: "Dean Psiropoulos"
> <deanpsir@easystreet.com>
>
> I read the antenna section of Lectric Bob's book but didn't see
> anything
> about proper placement of them. I purchased commercially available
> antennas
> for Transponder, Marker Beacon and a combination VOR/LOC/Glideslope.
> I want
> to install the VOR/LOC/Glideslope on the bottom of the fuselage below
> the
> horizontal stabilizer of my RV-6A. I'm thinking this should not be a
> problem and when you're in the air it would seem like the optimum
> place for
> it! But I'm no antenna expert so is this a good place to put it? Or
> is
> there a better one?
This is a pretty good place for it. The only problem with having it
there is the possibility it could get damaged during ground handling.
> Do I need a splitter to separate LOC/VOR signals from
> Glideslope (read something about this in Lectric Bob's book but not
> quite
> sure if I need it)?
It depends on your receiver. Most receivers have separate inputs for
VOR/LOC signals and GS signals. You need a splitter for that. OTOH
the Apollo SL-30 receiver has the splitter built-in so you just connect
the antenna and go.
In my installation I ran into the reverse problem: my SL-30 expected
both signals on one cable but I had separate GS and VOR/LOC antennas.
I used a splitter as a combiner to solve the problem.
> Also, I've heard that one should separate receive
> antennas from transmit antennas like comm and transponder. How far
> from
> other antennas should communication and transponder antennas be placed?
Transponder is less of a problem than comm antennas as the frequency is
so different. I don't usually worry about the distance from the
transponder antenna as much other than to not have my other antennas
shield the transponder antenna from the ground.
As for distance between nav and comm antennas, more is better. Do what
you can to get separation.
Also, putting the airplane between the antennas helps a lot. Mounting
one antenna on the top and one on the bottom will help a lot.
> If
> two comm. antennas are installed, how far apart from each other should
> they
> be? How far from transponder antenna should the comm. antenna be
> placed?
> Any other words of wisdom on antenna placement? Thanks.
More distance is better. Do what you can and don't sweat the rest.
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 2
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
I agree with Brian....
An antenna mounted under the tail will get damaged by a rock sooner than
later. Between the main gear legs would be ideal mounting location if that
area is not already a nest of antennas, otherwise, the top of the vertical
stab. Be very diligent about careful grounding and non-grounding of the
antenna and feed coax cables, connectors, etc. Use good quality coax and
connectors. This is where a lot of comm. problems arise between dual comm.
units. If possible put one comm. antenna on top and one on the bottom for
RF isolation. I am still fighting a comm. problem between a King KX-155 and
a Garmin 430, with both antennas on top in the standard Cessna side by side
mounting that most seem to use.
David
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: Avionics-List: Antenna placement.
> --> Avionics-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
>
> On Aug 25, 2004, at 12:53 AM, Dean Psiropoulos wrote:
>
> > --> Avionics-List message posted by: "Dean Psiropoulos"
> > <deanpsir@easystreet.com>
> >
> > I read the antenna section of Lectric Bob's book but didn't see
> > anything
> > about proper placement of them. I purchased commercially available
> > antennas
> > for Transponder, Marker Beacon and a combination VOR/LOC/Glideslope.
> > I want
> > to install the VOR/LOC/Glideslope on the bottom of the fuselage below
> > the
> > horizontal stabilizer of my RV-6A. I'm thinking this should not be a
> > problem and when you're in the air it would seem like the optimum
> > place for
> > it! But I'm no antenna expert so is this a good place to put it? Or
> > is
> > there a better one?
>
> This is a pretty good place for it. The only problem with having it
> there is the possibility it could get damaged during ground handling.
>
> > Do I need a splitter to separate LOC/VOR signals from
> > Glideslope (read something about this in Lectric Bob's book but not
> > quite
> > sure if I need it)?
>
> It depends on your receiver. Most receivers have separate inputs for
> VOR/LOC signals and GS signals. You need a splitter for that. OTOH
> the Apollo SL-30 receiver has the splitter built-in so you just connect
> the antenna and go.
>
> In my installation I ran into the reverse problem: my SL-30 expected
> both signals on one cable but I had separate GS and VOR/LOC antennas.
> I used a splitter as a combiner to solve the problem.
>
> > Also, I've heard that one should separate receive
> > antennas from transmit antennas like comm and transponder. How far
> > from
> > other antennas should communication and transponder antennas be placed?
>
> Transponder is less of a problem than comm antennas as the frequency is
> so different. I don't usually worry about the distance from the
> transponder antenna as much other than to not have my other antennas
> shield the transponder antenna from the ground.
>
> As for distance between nav and comm antennas, more is better. Do what
> you can to get separation.
>
> Also, putting the airplane between the antennas helps a lot. Mounting
> one antenna on the top and one on the bottom will help a lot.
>
> > If
> > two comm. antennas are installed, how far apart from each other should
> > they
> > be? How far from transponder antenna should the comm. antenna be
> > placed?
> > Any other words of wisdom on antenna placement? Thanks.
>
> More distance is better. Do what you can and don't sweat the rest.
>
> Brian Lloyd 6501 Red Hook Plaza
> brianl@lloyd.com Suite 201
> +1.340.998.9447 St. Thomas, VI 00802
>
>
Message 3
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: Doug McNutt <douglist@macnauchtan.com>
At 08:06 -0400 8/25/04, Brian Lloyd wrote:
> some good comments on antenna placement.
I would add that the transponder antenna should be on the belly. The reason is
that the interrogators are on the ground and you don't want airborne metal between
them and the antenna.
I once saw transponder antennas on top though. They were on a pair of O-2's (Cessna
337) being converted from Vietnam service for local use by the FBI. After
a few minutes I realized that the interrogators were in the F-4E's flying above.
--
--> The best programming tool is a soldering iron <--
Message 4
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: "Fred Fillinger" <n3eu@comcast.net>
Dean Psiropoulos wrote:
> ...
> I want to install the VOR/LOC/Glideslope on the bottom of the
> fuselage below the horizontal stabilizer of my RV-6A. I'm thinking
> this should not be a problem and when you're in the air it would
> seem like the optimum place for it! But I'm no antenna expert so
> is this a good place to put it?
> ... How far from other antennas should communication and
> transponder antennas be placed? If two comm. antennas are
> installed, how far apart from each other should they be?
Installation manuals are inconsistent regarding distances and even
unspecific. Minimum 2 feet between any antennas and from metal gear
legs is a reasonable guideline. However, you might post the proposed
VOR antenna location to an RV list. As long as the whiskers are
extending mostly clear of the fuselage, it should work. But having
used an antenna analyzer and field strength meter on aircraft
installs, it's easy to disrupt radiating pattern by poor placement. A
lousy 360-degree radiating pattern on a VOR dipole can be unacceptable
if fringe reception in all directions at low altitudes is important to
you, and your mention of glideslope issues suggests potential IFR. On
the other hand, installing a "V" dipole on the top of the vertical fin
is extremely common on production aircraft, because it works rather
well.
Reg,
Fred F.
Message 5
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: LessDragProd@aol.com
How about just installing Bob Archer's (Sportctaft Antennas) NAV antenna.
It is specifically designed to be mounted in the fiberglass wingtip. There is
no better operating NAV antenna available.
And no rocks to hit it, no drag.
The only problem is that you can't see them on aircraft that have them
installed.
Talk to Bob Archer at (310) 316-8796, or Email him at
_bobsantennas@earthlink.com_ (javascript:void)
Jim Ayers
Less Drag Products, Inc.
In a message dated 08/25/2004 9:05:27 AM Pacific Daylight Time,
skywagon@charter.net writes:
--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
I agree with Brian....
An antenna mounted under the tail will get damaged by a rock sooner than
later. Between the main gear legs would be ideal mounting location if that
area is not already a nest of antennas, otherwise, the top of the vertical
stab. Be very diligent about careful grounding and non-grounding of the
antenna and feed coax cables, connectors, etc. Use good quality coax and
connectors. This is where a lot of comm. problems arise between dual comm.
units. If possible put one comm. antenna on top and one on the bottom for
RF isolation. I am still fighting a comm. problem between a King KX-155 and
a Garmin 430, with both antennas on top in the standard Cessna side by side
mounting that most seem to use.
David
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: Avionics-List: Antenna placement.
> --> Avionics-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
>
> On Aug 25, 2004, at 12:53 AM, Dean Psiropoulos wrote:
>
> > --> Avionics-List message posted by: "Dean Psiropoulos"
> > <deanpsir@easystreet.com>
> >
> > I read the antenna section of Lectric Bob's book but didn't see
> > anything
> > about proper placement of them. I purchased commercially available
> > antennas
> > for Transponder, Marker Beacon and a combination VOR/LOC/Glideslope.
> > I want
> > to install the VOR/LOC/Glideslope on the bottom of the fuselage below
> > the
> > horizontal stabilizer of my RV-6A. I'm thinking this should not be a
> > problem and when you're in the air it would seem like the optimum
> > place for
> > it! But I'm no antenna expert so is this a good place to put it? Or
> > is
> > there a better one?
>
> This is a pretty good place for it. The only problem with having it
> there is the possibility it could get damaged during ground handling.
>
> > Do I need a splitter to separate LOC/VOR signals from
> > Glideslope (read something about this in Lectric Bob's book but not
> > quite
> > sure if I need it)?
>
> It depends on your receiver. Most receivers have separate inputs for
> VOR/LOC signals and GS signals. You need a splitter for that. OTOH
> the Apollo SL-30 receiver has the splitter built-in so you just connect
> the antenna and go.
>
> In my installation I ran into the reverse problem: my SL-30 expected
> both signals on one cable but I had separate GS and VOR/LOC antennas.
> I used a splitter as a combiner to solve the problem.
>
> > Also, I've heard that one should separate receive
> > antennas from transmit antennas like comm and transponder. How far
> > from
> > other antennas should communication and transponder antennas be placed?
>
> Transponder is less of a problem than comm antennas as the frequency is
> so different. I don't usually worry about the distance from the
> transponder antenna as much other than to not have my other antennas
> shield the transponder antenna from the ground.
>
> As for distance between nav and comm antennas, more is better. Do what
> you can to get separation.
>
> Also, putting the airplane between the antennas helps a lot. Mounting
> one antenna on the top and one on the bottom will help a lot.
>
> > If
> > two comm. antennas are installed, how far apart from each other should
> > they
> > be? How far from transponder antenna should the comm. antenna be
> > placed?
> > Any other words of wisdom on antenna placement? Thanks.
>
> More distance is better. Do what you can and don't sweat the rest.
>
> Brian Lloyd 6501 Red Hook Plaza
> brianl@lloyd.com Suite 201
> +1.340.998.9447 St. Thomas, VI 00802
Message 6
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: "Jim and Vivian" <jimscjs@mbay.net>
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: Avionics-List: Antenna placement.
> --> Avionics-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
>
> On Aug 25, 2004, at 12:53 AM, Dean Psiropoulos wrote:
>
> > --> Avionics-List message posted by: "Dean Psiropoulos"
> > <deanpsir@easystreet.com>
> >
> > I read the antenna section of Lectric Bob's book but didn't see
> > anything
> > about proper placement of them. I purchased commercially available
> > antennas
> > for Transponder, Marker Beacon and a combination VOR/LOC/Glideslope.
> > I want
> > to install the VOR/LOC/Glideslope on the bottom of the fuselage below
> > the
> > horizontal stabilizer of my RV-6A. I'm thinking this should not be a
> > problem and when you're in the air it would seem like the optimum
> > place for
> > it! But I'm no antenna expert so is this a good place to put it? Or
> > is
> > there a better one?
>
> This is a pretty good place for it. The only problem with having it
> there is the possibility it could get damaged during ground handling.
>
> > Do I need a splitter to separate LOC/VOR signals from
> > Glideslope (read something about this in Lectric Bob's book but not
> > quite
> > sure if I need it)?
>
> It depends on your receiver. Most receivers have separate inputs for
> VOR/LOC signals and GS signals. You need a splitter for that. OTOH
> the Apollo SL-30 receiver has the splitter built-in so you just connect
> the antenna and go.
>
> In my installation I ran into the reverse problem: my SL-30 expected
> both signals on one cable but I had separate GS and VOR/LOC antennas.
> I used a splitter as a combiner to solve the problem.
>
> > Also, I've heard that one should separate receive
> > antennas from transmit antennas like comm and transponder. How far
> > from
> > other antennas should communication and transponder antennas be placed?
>
> Transponder is less of a problem than comm antennas as the frequency is
> so different. I don't usually worry about the distance from the
> transponder antenna as much other than to not have my other antennas
> shield the transponder antenna from the ground.
>
> As for distance between nav and comm antennas, more is better. Do what
> you can to get separation.
>
> Also, putting the airplane between the antennas helps a lot. Mounting
> one antenna on the top and one on the bottom will help a lot.
>
> > If
> > two comm. antennas are installed, how far apart from each other should
> > they
> > be? How far from transponder antenna should the comm. antenna be
> > placed?
> > Any other words of wisdom on antenna placement? Thanks.
>
> More distance is better. Do what you can and don't sweat the rest.
>
> Brian Lloyd 6501 Red Hook Plaza
> brianl@lloyd.com Suite 201
> +1.340.998.9447 St. Thomas, VI 00802
>
>
Message 7
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| Subject: | Antenna placement. |
--> Avionics-List message posted by: "Ron Koyich" <Ron@Koyich.com>
>> There is no better operating NAV antenna available.<<
Wow! Big claim.
A pair of balanced blades works pretty well - JUST to be argumentative,
how is the Archer antenna better, Jim?
Ron
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