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  #11  
Old 09-17-2014, 10:00 AM
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hlangebro hlangebro is offline
 
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I was wondering if there would be a difference if the antenna was on the lower surface of the tip instead of the upper?
Just pondering that maybe the strobe and landing lights are shading the ILS beam more if it is on the upper. Maybe having it on the lower gives a better reception??
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  #12  
Old 09-17-2014, 11:13 AM
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RV6_flyer RV6_flyer is offline
 
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Quote:
Originally Posted by hlangebro View Post
I was wondering if there would be a difference if the antenna was on the lower surface of the tip instead of the upper?
Just pondering that maybe the strobe and landing lights are shading the ILS beam more if it is on the upper. Maybe having it on the lower gives a better reception??
I have had mine on the upper surface for 17-years. Never any issue. I also have an SL30. Can typically pick up a VOR signal before I can hear the ID. VOR Range is typically more than the FAA says it should be. GS and LOC both work very well. I also have a wingtip Landing Light, Nav Light, and Strobe light inside the wingtip.

As Bob Turner suggested, I would try a swap of your SL30 with a friend and see if his does the same and how yours works in his airplane.
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  #13  
Old 09-17-2014, 11:49 AM
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hlangebro hlangebro is offline
 
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I am goin to change and redo my grounding this weekend. I thought it was good, but I will also add ground straps...
Currently I dont know of anyone nearby who has a SL30, so I have to do what I can do in the meantime...
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H?kan Langebro
San Diego, CA

RV-7A, slider
Lycoming O-320 D1A, 160hp C/S
First flight 6-11-13

Re-engineering a Lancair 320..!


http://www.youtube.com/watch?v=AJuQ68tccTQ
http://www.mykitlog.com/hlangebro/
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  #14  
Old 09-17-2014, 01:57 PM
BobTurner BobTurner is online now
 
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I just read on a different post that you did not do the wiring yourself.
Get under the panel with a flashlight and look at the nav coax, from the radio outward as far as you can trace. Make certain that a GS splitter was not inadvertently installed (you're looking for a small square box).

At 6 miles out the localizer and GS signals follow very nearly the same path, so I doubt antenna placement is the issue. It's true the GS is off to the side of the runway; you could yaw the plane toward it, see if it makes a difference (I would be very surprised of it did).
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  #15  
Old 09-17-2014, 02:06 PM
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Quote:
Originally Posted by BobTurner View Post
SL-30 has an internal splitter. So if localizer works okay, GS does not, and you have NOT installed any external splitters, the only thing left is the radio.
Not necessarily. Localizer frequencies are much higher than VOR frequencies. If the antenna is not properly coupled to the airframe it will have different capacitive and inductive reactance and may be usable at VOR freqs but not at the localizer freqs.

If the antenna does not have a solid low impedance ground to the airframe then it probably won't work well.
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  #16  
Old 09-17-2014, 02:17 PM
BobTurner BobTurner is online now
 
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Quote:
Originally Posted by rocketbob View Post
Not necessarily. Localizer frequencies are much higher than VOR frequencies. If the antenna is not properly coupled to the airframe it will have different capacitive and inductive reactance and may be usable at VOR freqs but not at the localizer freqs.

If the antenna does not have a solid low impedance ground to the airframe then it probably won't work well.
Bob J, I think what you meant was "GS frequencies are much higher than localizer frequencies".
Not sure I'd say "much"; they are 3 times higher.
We all agree (see earlier posts) that he needs a good proper connection to the end rib. But is *sounds* like he has that covered.
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  #17  
Old 09-17-2014, 06:04 PM
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I do believe the SL30 has a built in splitter, so that wouldn't change anything... unfortunately
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San Diego, CA

RV-7A, slider
Lycoming O-320 D1A, 160hp C/S
First flight 6-11-13

Re-engineering a Lancair 320..!


http://www.youtube.com/watch?v=AJuQ68tccTQ
http://www.mykitlog.com/hlangebro/
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  #18  
Old 09-17-2014, 06:27 PM
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rocketbob rocketbob is offline
 
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If you can get your hands on an antenna analyzer or a network analyzer that would be your best bet. Most ham radio guys have one. I've solved a lot of antenna problems with mine.
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N9187P PA-24-260B Comanche, flying
N678X F1 Rocket, under const.
N244BJ RV-6 "victim of SNF tornado" 1200+ hrs, rebuilding
N8155F C150 flying
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  #19  
Old 09-17-2014, 06:32 PM
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cfiidon cfiidon is offline
 
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Quote:
Originally Posted by BobTurner View Post
SL-30 has an internal splitter. So if localizer works okay, GS does not, and you have NOT installed any external splitters, the only thing left is the radio.
I agree with Bob. It sounds like the radio is the culprit.
However, I looked at a pic on your build log and it looks as though the antenna pigtail is tie wrapped in an odd manner. Review the Archer installation instructions for how to position wires as an improper installation can cause "issues".
Also by adding a coax connector at the wingtip antenna you have introduced a small amount of signal loss. I doubt that is the issue, however. The path of the coax across the antenna is an easy fix to try before you send the radio out for test/evaluation.

Don
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  #20  
Old 09-17-2014, 06:33 PM
BobTurner BobTurner is online now
 
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Quote:
Originally Posted by hlangebro View Post
I do believe the SL30 has a built in splitter, so that wouldn't change anything... unfortunately
It would produce exactly the symptoms you see. A GS-VOR splitter is not a simple one-into-two box. It preferentially sends 330 MHz signals to the GS output, and 110 MHz signals to the VOR/Localizer output. So if your installer put an external one in by mistake (and just left the GS output open since there is no where to connect it with the SL-30) then the GS signal has been mostly removed before it gets to the SL-30.
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