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Jabiru LED landing lights.


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I took a spectrum analyser to my plane couple of days ago to see just hot much noise is getting in the radio. From the OSRAM 7W LED fitted to the strut with the fibreglass mount.

 

- there is some capacitive coupling from the lamp body into the strut.

- the majority goes out the leads and down the strut (we know) 

 

The noise floor was about -107dBm  with peaks to -97dBm every 500kHz that moved around with temperature and voltage.

Ideally, the radio needs to see a noise floor of less than -120dBm as not to become desensitized. 

There was also a bit of contribution by the EFIS

 

A single small RF choke clipped on the the wire reduced the interference by about 10dB, pretty good. 

 

There is limited space behind the lamp , , so I am going to make a replacement light socket- spade lug lead that has a high performance choke in it.

The first two I make, one will go to KiwiAviator. That's nail it. 

 

Ideally, you just run the DC up to the LED lamp and have the LED controller under the dash, but that requires wiring changes, so bugger that. 

 

-glen

 

 

 

 

 

lamp2.jpg

lamp1.jpg

lamp3.jpg

Edited by RFguy
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The LEDS are actually flashing and it's the circuit that does this that causes the interference. So, if you know the flash rate, build a simple PI filter to suit. Maybe a Spec analyzer picture with the led light off and a pic with the led on on would be good to compare the two. Something I might play with just to 'refresh' my fast fading electronics knowledge.

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yep, and since there is no concept of ground, you'll need a balanced PI filter. 

and you need capacitive input, because the internals will draw in pulses. 

Edited by RFguy
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On 04/03/2021 at 9:17 AM, RFguy said:

yep, and since there is no concept of ground, you'll need a balanced PI filter. 

and you need capacitive input, because the internals will draw in pulses. 

All over my head. Hats off to both of you

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  • 1 month later...

right, finally getting onto this

proto. goes to Kiwi Av.

I need some 1" diameter type 43 cores. I seem to be out, only have 0.82" and 2.4" -43 cores. will get some.

two capacitors in parallel across the pins.   A 0.01uF disc ceramic (must be ceramic)  with almost no leads, and a 0.1uF disc ceramic ....

more later. wound with M22759 std wire. 

What I have done is a bit overboard, but kills it.  fits ok.

 

all gets potted up and vibration and water proofed

 

 

choke4.jpg

choke3.jpg

choke2.jpg

choke1.jpg

Edited by RFguy
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Quite often just wrapping the wire around a ferrite rod will do the trick.

Edited by Jabiru7252
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I think you are right Kevin, ferrite rods are good  as the end to end capacitance is quite low, although they can also act like antennas. The pair of capacitors makes a large difference - IE providing a local place for the current pulses to be drawn from . That also establishes common mode for the noise so the common mode wound inductor had to the best job it can.  The common mode winding also serves the purpose of providing no net magnetizing field  (DC goes both directions so net DC field is zero) otherwise the core's permiabiity would be reduced susbstantially.  I need to get some more FT114-43s, then wont need the extra core,  I can be well spacewound then, reducing interwinding inter turns capacitance--- those are 2 x FT82-43. to hit it with a hammer, need 3 to 4k ohms acrss that inductor  at 120 MHz. why so high ? Well, in the unfortunate configuration where those long wing power wires  end up being 1/2 waves, they will look like 1k or 2k ohm, and will take the power quite efficiently. so the idea is to get the impedance as high as possible. going up to 10k is even worthwhile, but a bit difficult, as even a  tenth of a pico farad of stray capacitance can get around your choke !

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  • 1 month later...

Pleased to hear it !.

Yeah that was a bit of a frankenstein. I've since bought some of the more physically suitable cores.

 

However the real 'trick' to it working is the use of the capacitors on the lamp itself. This is where the very fast current (electrons) transients get supplied from the local stored energy (capacitors).  It might not need the ferrite cores, but hitting it with a hammer always works...

 

 

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Has anyone come up with a workaround for the tail beacon light on 230/430 Jabs which on my machine and some others I am aware of failed. When the original light failed I contacted Jabiru and there was no replacement available. A replacement which just plugs in would be nice!

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Posted (edited)

Hi

I am looking for same.  (tail beacon) I pulled out the device, made by Kuntzlemann, A really nice unit with fresnel lens .

I talked to the company owner, its all potted. they have new ones, but nothing exact. . You can also buy just the lens assembly.

 

same one ?

Edited by RFguy
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Don't know much about the Jabiru lights, but I installed these Led bulbs which work in dual mode, similar to some camping headlamps, i.e. press switch once - steady light, switch off then on - flashing strobe effect. No need for any electronics, straight in Led bay15s bulb replacement.

 

https://www.ebay.com.au/itm/Dual-Mode-Constant-Strobe-LED-Replacement-Nav-Bulb-SET-Super-Bright-10-30VDC-/332637497097?_trksid=p2349624.m46890.l49286

 

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Posted (edited)

I bought one of those for a bicycles. They are quite low output.

Certainly good for night time work.

 

----Compared to a beacon with the fresnel  lens they are pretty low light output . 

The fresnel lens  is good for 10x brightness on axis....

Edited by RFguy
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23 minutes ago, RFguy said:

I bought one of those for a bicycles. They are quite low output.

Some bicycle gear works well with our little aeroplanes but not lights and horns; we need many times the brightness and range. My favorite bike shop once found me a great little bicycle horn that they thought would be ideal for the plane. 

I got them to blow it while I stood 20m away. Ear-splitting to those nearby, out in the street I could barely hear it.

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Bosi are you talking about Wing Tip lights or the tail beacon ?

Daytime work or night work ?

 

 

 

 

 

 

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3 hours ago, RFguy said:

Hi

I am looking for same.  (tail beacon) I pulled out the device, made by Kuntzlemann, A really nice unit with fresnel lens .

I talked to the company owner, its all potted. they have new ones, but nothing exact. . You can also buy just the lens assembly.

 

same one ?

I know the guys out at YLIL have replaced tail beacons in their Jab 160s, so there must be something available. 

Istria are the maintenance firm at YLIL, maybe they have a source?

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4 hours ago, RFguy said:

Hi

I am looking for same.  (tail beacon) I pulled out the device, made by Kuntzlemann, A really nice unit with fresnel lens .

I talked to the company owner, its all potted. they have new ones, but nothing exact. . You can also buy just the lens assembly.

 

same one ?

Yep that's what I am after, a replacement which is fairly straight forward and inexpensive. Jab now have the replacement listed on the website at $950 but last time I called even these were unavailable. Most of them don't seem to last much beyond 5 years or so I guess dependant on use. 

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Posted (edited)

Have you got the dead one  still ?

I am going to have a serious go at resurecting mine. might not be too hard. depends on what potting mix they used. wont be much that died.

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4 hours ago, RFguy said:

Have you got the dead one  still ?

I am going to have a serious go at resurecting mine. might not be too hard. depends on what potting mix they used. wont be much that died.

Yep .... still in the tail.

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This is the setup on mine. The light must be glued into the fibreglass housing because it does not want to come out!

20210610_100352.jpg

20210610_102225.jpg

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I undid the nut on the bottom and mine just came out. wow, did it live outdoors? the sun has not been kind to that lens. it might polish up OK otherwise chuck. Mine is pristine although the plane lived in a hanger.

Maybe your's has a ring of silicone goop holding it in. 

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38 minutes ago, RFguy said:

I undid the nut on the bottom and mine just came out. wow, did it live outdoors? the sun has not been kind to that lens. it might polish up OK otherwise chuck. Mine is pristine although the plane lived in a hanger.

Maybe your's has a ring of silicone goop holding it in. 

Got it! There was some goop and double sided tape as well. The top comes off with a hex head key but that's as far as I managed to get. Kuntzleman 610 326 9068 no luck for a replacement but a quick search of the web reveals 

 

"This self contained 14 Volt beacon uses surface mounted LED (Light Emitting Diode) technology and meets FAA requirements for anti-collision light systems in both airplane and rotorcraft categories. This rugged little unit measures 1.7 inches in diameter, 3.5 inches tall and weighs 8.4 ounces. The average current draw at 14 volts is 0.6 Amps with a peak input current of 1.2 Amps. It has a flash rate of 60 per minute and will not produce EMI or RFI interference. The color is Aviation Red LEDs through a clear Polycarbonate Fresnel lens. The manufactures projected life for their LEDs is up to 100K hours.

Mounting is accomplished by a #10-32 stainless steel stud that is in the bottom center of the base. NOT TSO’D"

 

54mm hole to go in so there would have to be some options out there.

20210610_114055.jpg

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Faded and scratched Polycarbonate will polish up nicely using a loose leaf calico buffing wheel on a bench grinder with a spindle extension.

 

Use some blue Josco polishing compound, and don't let the heat build up in the polycarbonate when buffing.

 

https://www.josco.com.au/resource/select-the-right-buff-and-compound/

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"The manufactures projected life for their LEDs is up to 100K hours".

pity they didnt get a good engineer to do his homework on the rest of the electronics nor the construction.

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