Today's Message Index:
----------------------
1. 09:43 AM - Antenna help (Robin Young)
2. 12:51 PM - Re: Antenna help (b.j. mcclure)
3. 01:06 PM - Re: Antenna help (Robin Young)
4. 02:01 PM - Re: Antenna help (b.j. mcclure)
5. 03:16 PM - Re: Antenna help (Robin Young)
Message 1
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Guys, I am trying to increase the range of my comm radios. New antennas
will have to be installed in the fuselage. The VHF-5T antenna would have to
be installed on a about a 35 degree angle to fit vertically.
The SA-006 is a folded dipole antenna that can be installed as engineered in
the fuselage as it is only 26" high and 9.5 inches wide. The manufacturer
claims 170 mile range air to ground.
My original antenna are the foil ones supplied by Glasair back in 1983. The
navs are doing Ok but the comms need to be replaced. What recommendations
do you have? RObin Young
Message 2
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| Subject: | Re: Antenna help |
First I would caution you to adjust your expectations. Line of sight
for VHF freqs is approximately 120 miles at 10,000 feet. A claim of 170
miles is, in my opinion, unlikely to be achieved on anything near a
regular basis. As a project engineer with Bendix avionics in the 70's
we struggled to get 130 to 140 miles using digital techniques and 25
watt transmitters at that altitude (10,000). If you read the ad
carefully for the SA-006, the writer does not claim 170 mile
performance, only that it occurred. The most important part of the
equation is altitude of the antennas involved. At 20,000 the line of
sight is approximately 1.4 times the 10,000 ft distance or roughly 170
miles. If you routinely fly at that altitude you will likely
communicate over those distances. I fly a Glasair III with standard S-H
antenna and routinely get line of sight comm. Any tilting of the comm
antenna from vertical will diminish performance since the comm signal is
vertically polarized. Theoretically a tilt from vertical of 45 degrees
causes roughly a 30% loss of signal strength. In practice it's not
quite that bad because of scatter/reflections from things metal on the
aircraft. Also remember there is an engine in front of a fuselage
mounted antenna which will effect the radiation pattern of the antenna.
Curious why the foil antenna need to be replaced. If Tx and Rx meet
spec, the antenna is installed per the book and all coax and connectors
are properly done, you should be able to comm line of sight distances.
Have you done a VSWR on your setup?
Sorry for the long diatribe but hate to see anyone spend bucks that may
not yield a performance increase.
Regards,
B.J. McClure
CentOS 5.4, Linux 2.6.18-164.11.1.el5 x86_64 13:25:22 up 9 days, 6:57, 1
user, load average: 0.17, 0.12, 0.09
On Thu, 2010-02-18 at 12:36 -0500, Robin Young wrote:
> Guys, I am trying to increase the range of my comm radios. New
> antennas will have to be installed in the fuselage. The VHF-5T
> antenna would have to be installed on a about a 35 degree angle to
> fit vertically.
>
> The SA-006 is a folded dipole antenna that can be installed as
> engineered in the fuselage as it is only 26" high and 9.5 inches wide.
> The manufacturer claims 170 mile range air to ground.
>
> My original antenna are the foil ones supplied by Glasair back in
> 1983. The navs are doing Ok but the comms need to be replaced. What
> recommendations do you have? RObin Young
>
>
>
>
Message 3
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BJ...thanks for the reply. I did not put the foil antenna in the vertical
stabilizer when I built the plane. My primary radio has been a whip
antenna on a ground plane with the back up radio antenna in too much of a
horizontal, it has a very low range. I want to improve them but they cannot
be removed and reused.
You seem knowledgeable about the Sa-006. It will fit better than the
VHF-5t. It is also cheaper for some reason. Is it a choice I should
consider? Thanks RObin
_____
From: owner-glasair-list-server@matronics.com
[mailto:owner-glasair-list-server@matronics.com] On Behalf Of b.j. mcclure
Sent: Thursday, February 18, 2010 3:51 PM
Subject: Re: Glasair-List: Antenna help
First I would caution you to adjust your expectations. Line of sight for
VHF freqs is approximately 120 miles at 10,000 feet. A claim of 170 miles
is, in my opinion, unlikely to be achieved on anything near a regular basis.
As a project engineer with Bendix avionics in the 70's we struggled to get
130 to 140 miles using digital techniques and 25 watt transmitters at that
altitude (10,000). If you read the ad carefully for the SA-006, the writer
does not claim 170 mile performance, only that it occurred. The most
important part of the equation is altitude of the antennas involved. At
20,000 the line of sight is approximately 1.4 times the 10,000 ft distance
or roughly 170 miles. If you routinely fly at that altitude you will likely
communicate over those distances. I fly a Glasair III with standard S-H
antenna and routinely get line of sight comm. Any tilting of the comm
antenna from vertical will diminish performance since the comm signal is
vertically polarized. Theoretically a tilt from vertical of 45 degrees
causes roughly a 30% loss of signal strength. In practice it's not quite
that bad because of scatter/reflections from things metal on the aircraft.
Also remember there is an engine in front of a fuselage mounted antenna
which will effect the radiation pattern of the antenna. Curious why the
foil antenna need to be replaced. If Tx and Rx meet spec, the antenna is
installed per the book and all coax and connectors are properly done, you
should be able to comm line of sight distances. Have you done a VSWR on
your setup?
Sorry for the long diatribe but hate to see anyone spend bucks that may not
yield a performance increase.
Regards,
B.J. McClure
CentOS 5.4, Linux 2.6.18-164.11.1.el5 x86_64 13:25:22 up 9 days, 6:57, 1
user, load average: 0.17, 0.12, 0.09
On Thu, 2010-02-18 at 12:36 -0500, Robin Young wrote:
Guys, I am trying to increase the range of my comm radios. New antennas
will have to be installed in the fuselage. The VHF-5T antenna would have to
be installed on a about a 35 degree angle to fit vertically.
The SA-006 is a folded dipole antenna that can be installed as engineered in
the fuselage as it is only 26" high and 9.5 inches wide. The manufacturer
claims 170 mile range air to ground.
My original antenna are the foil ones supplied by Glasair back in 1983. The
navs are doing Ok but the comms need to be replaced. What recommendations
do you have? RObin Young
st Email Forum -
atures Navigator to browse
uch as List Un/Subscription,
load, 7-Day Browse, Chat, FAQ,
more:
//www.matronics.com/Navigator?Glasair-List">http://www.matronics.com/Navigat
or?Glasair-List
WEB FORUMS -
vailable via the Web Forums!
//forums.matronics.com">http://forums.matronics.com
bution Web Site -
ous support!
-Matt Dralle, List Admin.
//www.matronics.com/contribution">http://www.matronics.com/contribution
Message 4
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Now I understand your motivation. I have never used nor tested the
SA-006. I would ask for a list of customers who have purchased it and
ask them if they get satisfactory performance. This is a terrible
suggestion but is it possible to open the vertical fin and install
there? It's as near a perfect location as you will find. Remember the
radiation pattern for a theoretical dipole is toroidal (doughnut) in
shape. Little energy is radiated or received off the ends of the
antenna. Once you start tilting and bending the antenna you no longer
have much knowledge what the radiation pattern looks like. Making that
determination requires a field strength meter and lots of painstaking
data collection and plotting. Any legitimate antenna designer should
have data for their antenna mounted in an ideal install. It may also be
computer generated as opposed to measurement in an anechoic chamber.
You might ask if they also have data for the antenna with any degree of
deformation. It might give you some clues as to what you can expect.
Sorry I couldn't be of more help.
B.J.
CentOS 5.4, Linux 2.6.18-164.11.1.el5 x86_64 16:43:22 up 9 days, 10:15,
1 user, load average: 0.12, 0.10, 0.10
On Thu, 2010-02-18 at 16:05 -0500, Robin Young wrote:
> BJ...thanks for the reply. I did not put the foil antenna in the
> vertical stabilizer when I built the plane. My primary radio has
> been a whip antenna on a ground plane with the back up radio antenna
> in too much of a horizontal, it has a very low range. I want to
> improve them but they cannot be removed and reused.
>
> You seem knowledgeable about the Sa-006. It will fit better than the
> VHF-5t. It is also cheaper for some reason. Is it a choice I
> should consider? Thanks RObin
>
>
>
>
> ______________________________________________________________________
> From: owner-glasair-list-server@matronics.com
> [mailto:owner-glasair-list-server@matronics.com] On Behalf Of b.j.
> mcclure
> Sent: Thursday, February 18, 2010 3:51 PM
> To: glasair-list@matronics.com
> Subject: Re: Glasair-List: Antenna help
>
>
>
>
> First I would caution you to adjust your expectations. Line of sight
> for VHF freqs is approximately 120 miles at 10,000 feet. A claim of
> 170 miles is, in my opinion, unlikely to be achieved on anything near
> a regular basis. As a project engineer with Bendix avionics in the
> 70's we struggled to get 130 to 140 miles using digital techniques and
> 25 watt transmitters at that altitude (10,000). If you read the ad
> carefully for the SA-006, the writer does not claim 170 mile
> performance, only that it occurred. The most important part of the
> equation is altitude of the antennas involved. At 20,000 the line of
> sight is approximately 1.4 times the 10,000 ft distance or roughly 170
> miles. If you routinely fly at that altitude you will likely
> communicate over those distances. I fly a Glasair III with standard
> S-H antenna and routinely get line of sight comm. Any tilting of the
> comm antenna from vertical will diminish performance since the comm
> signal is vertically polarized. Theoretically a tilt from vertical of
> 45 degrees causes roughly a 30% loss of signal strength. In practice
> it's not quite that bad because of scatter/reflections from things
> metal on the aircraft. Also remember there is an engine in front of a
> fuselage mounted antenna which will effect the radiation pattern of
> the antenna. Curious why the foil antenna need to be replaced. If Tx
> and Rx meet spec, the antenna is installed per the book and all coax
> and connectors are properly done, you should be able to comm line of
> sight distances. Have you done a VSWR on your setup?
>
> Sorry for the long diatribe but hate to see anyone spend bucks that
> may not yield a performance increase.
>
> Regards,
> B.J. McClure
> CentOS 5.4, Linux 2.6.18-164.11.1.el5 x86_64 13:25:22 up 9 days, 6:57,
> 1 user, load average: 0.17, 0.12, 0.09
>
>
> On Thu, 2010-02-18 at 12:36 -0500, Robin Young wrote:
>
> > Guys, I am trying to increase the range of my comm radios. New
> > antennas will have to be installed in the fuselage. The VHF-5T
> > antenna would have to be installed on a about a 35 degree angle to
> > fit vertically.
> > The SA-006 is a folded dipole antenna that can be installed as
> > engineered in the fuselage as it is only 26" high and 9.5 inches
> > wide. The manufacturer claims 170 mile range air to ground.
> > My original antenna are the foil ones supplied by Glasair back in
> > 1983. The navs are doing Ok but the comms need to be replaced.
> > What recommendations do you have? RObin Young
> >
> >
> >
> > st Email Forum -
> > atures Navigator to browse
> > uch as List Un/Subscription,
> > load, 7-Day Browse, Chat, FAQ,
> > more:
> > //www.matronics.com/Navigator?Glasair-List">http://www.matronics.com/Navigator?Glasair-List
> >
> > WEB FORUMS -
> > vailable via the Web Forums!
> > //forums.matronics.com">http://forums.matronics.com
> >
> > bution Web Site -
> > ous support!
> > -Matt Dralle, List Admin.
> > //www.matronics.com/contribution">http://www.matronics.com/contribution
> >
> >
>
>
>
> href="http://www.matronics.com/Navigator?Glasair-List">http://www.matronics.com/Navigator?Glasair-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/c
>
>
>
Message 5
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BJ, thank you for the talk points. I have contacted a dealer for some
references and hopefully will get the manufacturer contact also.
If anyone else has experience with a folded dipole antenna on a glasair,
please comment. RObin
_____
From: owner-glasair-list-server@matronics.com
[mailto:owner-glasair-list-server@matronics.com] On Behalf Of b.j. mcclure
Sent: Thursday, February 18, 2010 5:02 PM
Subject: RE: Glasair-List: Antenna help
Now I understand your motivation. I have never used nor tested the SA-006.
I would ask for a list of customers who have purchased it and ask them if
they get satisfactory performance. This is a terrible suggestion but is it
possible to open the vertical fin and install there? It's as near a perfect
location as you will find. Remember the radiation pattern for a theoretical
dipole is toroidal (doughnut) in shape. Little energy is radiated or
received off the ends of the antenna. Once you start tilting and bending
the antenna you no longer have much knowledge what the radiation pattern
looks like. Making that determination requires a field strength meter and
lots of painstaking data collection and plotting. Any legitimate antenna
designer should have data for their antenna mounted in an ideal install. It
may also be computer generated as opposed to measurement in an anechoic
chamber. You might ask if they also have data for the antenna with any
degree of deformation. It might give you some clues as to what you can
expect.
Sorry I couldn't be of more help.
B.J.
CentOS 5.4, Linux 2.6.18-164.11.1.el5 x86_64 16:43:22 up 9 days, 10:15, 1
user, load average: 0.12, 0.10, 0.10
On Thu, 2010-02-18 at 16:05 -0500, Robin Young wrote:
BJ...thanks for the reply. I did not put the foil antenna in the vertical
stabilizer when I built the plane. My primary radio has been a whip
antenna on a ground plane with the back up radio antenna in too much of a
horizontal, it has a very low range. I want to improve them but they cannot
be removed and reused.
You seem knowledgeable about the Sa-006. It will fit better than the
VHF-5t. It is also cheaper for some reason. Is it a choice I should
consider? Thanks RObin
_____
From: owner-glasair-list-server@matronics.com
[mailto:owner-glasair-list-server@matronics.com] On Behalf Of b.j. mcclure
Sent: Thursday, February 18, 2010 3:51 PM
Subject: Re: Glasair-List: Antenna help
First I would caution you to adjust your expectations. Line of sight for
VHF freqs is approximately 120 miles at 10,000 feet. A claim of 170 miles
is, in my opinion, unlikely to be achieved on anything near a regular basis.
As a project engineer with Bendix avionics in the 70's we struggled to get
130 to 140 miles using digital techniques and 25 watt transmitters at that
altitude (10,000). If you read the ad carefully for the SA-006, the writer
does not claim 170 mile performance, only that it occurred. The most
important part of the equation is altitude of the antennas involved. At
20,000 the line of sight is approximately 1.4 times the 10,000 ft distance
or roughly 170 miles. If you routinely fly at that altitude you will likely
communicate over those distances. I fly a Glasair III with standard S-H
antenna and routinely get line of sight comm. Any tilting of the comm
antenna from vertical will diminish performance since the comm signal is
vertically polarized. Theoretically a tilt from vertical of 45 degrees
causes roughly a 30% loss of signal strength. In practice it's not quite
that bad because of scatter/reflections from things metal on the aircraft.
Also remember there is an engine in front of a fuselage mounted antenna
which will effect the radiation pattern of the antenna. Curious why the
foil antenna need to be replaced. If Tx and Rx meet spec, the antenna is
installed per the book and all coax and connectors are properly done, you
should be able to comm line of sight distances. Have you done a VSWR on
your setup?
Sorry for the long diatribe but hate to see anyone spend bucks that may not
yield a performance increase.
Regards,
B.J. McClure
CentOS 5.4, Linux 2.6.18-164.11.1.el5 x86_64 13:25:22 up 9 days, 6:57, 1
user, load average: 0.17, 0.12, 0.09
On Thu, 2010-02-18 at 12:36 -0500, Robin Young wrote:
Guys, I am trying to increase the range of my comm radios. New antennas
will have to be installed in the fuselage. The VHF-5T antenna would have to
be installed on a about a 35 degree angle to fit vertically.
The SA-006 is a folded dipole antenna that can be installed as engineered in
the fuselage as it is only 26" high and 9.5 inches wide. The manufacturer
claims 170 mile range air to ground.
My original antenna are the foil ones supplied by Glasair back in 1983. The
navs are doing Ok but the comms need to be replaced. What recommendations
do you have? RObin Young
st Email Forum -
atures Navigator to browse
uch as List Un/Subscription,
load, 7-Day Browse, Chat, FAQ,
more:
//www.matronics.com/Navigator?Glasair-List">http://www.matronics.com/Navigat
or?Glasair-List
WEB FORUMS -
vailable via the Web Forums!
//forums.matronics.com">http://forums.matronics.com
bution Web Site -
ous support!
-Matt Dralle, List Admin.
//www.matronics.com/contribution">http://www.matronics.com/contribution
href="http://www.matronics.com/Navigator?Glasair-List">http://www.matronics.
com/Navigator?Glasair-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
st Email Forum -
atures Navigator to browse
uch as List Un/Subscription,
load, 7-Day Browse, Chat, FAQ,
more:
//www.matronics.com/Navigator?Glasair-List">http://www.matronics.com/Navigat
or?Glasair-List
WEB FORUMS -
vailable via the Web Forums!
//forums.matronics.com">http://forums.matronics.com
bution Web Site -
ous support!
-Matt Dralle, List Admin.
//www.matronics.com/contribution">http://www.matronics.com/contribution
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