Today's Message Index:
----------------------
1. 05:12 AM - Re: DIY LOC/VOR_G.S. Antenna (merlewagner2)
2. 11:34 AM - Re: Re: DIY LOC/VOR_G.S. Antenna (Robert L. Nuckolls, III)
3. 12:19 PM - Re: best practices for Molex? (prestonkavanagh)
4. 05:07 PM - Transponder and/or ADSB Antenna Installation and Radiation ()
5. 09:19 PM - Re: Transponder and/or ADSB Antenna Installation and Radiation (Robert L. Nuckolls, III)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: DIY LOC/VOR_G.S. Antenna |
I agree the VHF antenna (without the GS antenna ears) will work very well for receiving
the GS freqs.
I wanted to see how the performance could be enhanced with the antenna tuned to
the different bands. The only verifiable method to prove this would be testing
the antenna with and without the GS elements. I just don't have the time to
do this at the moment. A future test.
I am going crazy getting the Tailwind ready for it's first flight this weekend.
Everytime I try something another problem arises. Guess that is why this is
experimental aviation.
I do know that trimming the GS elements adjusted the antenna VSWR to the freq range
I wanted. I did this in real time by watching my NANOVNA output while trimming.
So the ears do have a major impact on the freq band.
I also ran the antenna to an antenna multi-coupler versus the splitter you show.
This also guarantees improved reception as the signal level is reduced with
the splitters.
--------
KC1DNJ
General Radiotelephone
Commercial SEL
A&P
Building scale P51, rebuilding Tailwind W10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497393#497393
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: DIY LOC/VOR_G.S. Antenna |
At 07:11 AM 7/22/2020, you wrote:
><wagnermerle@gmail.com>
>
>I agree the VHF antenna (without the GS antenna ears) will work very
>well for receiving the GS freqs.
>
>I wanted to see how the performance could be enhanced with the
>antenna tuned to the different bands. The only verifiable method to
>prove this would be testing the antenna with and without the GS
>elements. I just don't have the time to do this at the moment. A future test.
I'm planning an experiment centered on
Jim Wier's suggestion for a dual band
121.5/406 Mhz ELT antenna. These two
frequencies are not harmonically related.
I've got the elements built. Planning
to explore balun options too. I'll document
the exercise and post here.
> I am going crazy getting the Tailwind ready for it's first flight
> this weekend. Everytime I try something another problem arises.
> Guess that is why this is experimental aviation.
Sounds like the engineering flight test hangar
at Beech!
>I do know that trimming the GS elements adjusted the antenna VSWR to
>the freq range I wanted. I did this in real time by watching my
>NANOVNA output while trimming. So the ears do have a major impact on
>the freq band.
When I get the ELT experiment done, I'll
repeat repeat your VOR-LOC/GS experiment
and see what I get. We'll compare
notes.
>I also ran the antenna to an antenna multi-coupler versus the
>splitter you show. This also guarantees improved reception as the
>signal level is reduced with the splitters.
Be wary of distribution amplifier type couplers.
The 'ideal' gain is zero. I.e. same output for a given
input at the frequencies of interest. Keep in mind that
our navigation equipment is sorta tailored to be compatible
with legacy practices for transmitted signals, typical
(passive) antennas, reasonably low loss coax, etc.
Adding active devices into the feedline has some
risk for (1) overloading the receiver(s) on
the ILS system and/or (2) increasing risks for
inter-modulation interference of desired signals
by unrelated/undesired signals.
Study the specs for your chosen device for assurance
that the thing adds value and does not add risk.
Bob . . .
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: best practices for Molex? |
Thanks to all, for both the pin gender and comments on Molex. I'll revise accordingly.
Cheers, PK
--------
PBK3
PA-12, BD-4, RV6a, gliders
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497395#497395
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Transponder and/or ADSB Antenna Installation and Radiation |
Greetings,
I am a member of a composites aircraft community and the question came up
(again) about the installation location of these high frequency antennae.
Assuming that the airplane is build of mostly fiberglass (and not carbon
fiber) there is the temptation to mount these two antennae inside the
airframe so that the antennae are fully enclosed by the fuselage and the
airplane is more aerodynamic.sounds good so far.and each antenna will have a
ground plane.
So the questions are:
-Is the ground plane better to be square/ round/ or hexagon/ or some other
shape?
-If the diameter of the ground plane cannot be exactly a square and the same
dimension as indicated on the installation guide what is the problem(s) with
it being slightly to wide or slightly too narrow than spec, or if the
antenna is not installed in the exact center?
-The book says the two antennae should be mounted at least two feet from
each other so what if they were installed closer.or even co-located on the
same ground plane?
-What about mounting these masts near human body parts (ouch)?
-What about mounting these masts near other avionics or other electrical
equipment?
Thanks everyone for you kind assistance!!!
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Transponder and/or ADSB Antenna Installation |
and Radiation
>
>So the questions are:
>
>-Is the ground plane better to be square/ round/
>or hexagon/ or some other shape?
Why not eliminate the need for ground planes with
vertically polarized dipoles mounted to inside surfaces
of empannage?
https://tinyurl.com/y3w4hf8y
>-If the diameter of the ground plane cannot be
>exactly a square and the same dimension as
>indicated on the installation guide what is the
>problem(s) with it being slightly to wide or
>slightly too narrow than spec, or if the antenna
>is not installed in the exact center?
ditch the ground planes
>-The book says the two antennae should be
>mounted at least two feet from each other so
>what if they were installed closer=85or even co-located on the same ground
plane?
Mount one on left side forward, the other
right side aft. Getting separation shouldn't
be a problem.
>-What about mounting these masts near human body parts (ouch)?
>
>-What about mounting these masts near other
>avionics or other electrical equipment?
back in the tail?
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|