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Handheld Comm Interference In Flight

 
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art(at)zemon.name
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PostPosted: Sun Aug 25, 2019 3:43 am    Post subject: Handheld Comm Interference In Flight Reply with quote

I pulled and replaced fuses one at a time until I isolated the circuit that is generating the noise in my handheld. It is the MGL EFIS, believe it or not. After identifying the fuse, I started disconnecting individual devices. The circuit contains two MGL Challenger 10.4 inch screens and the MGL iBOX (the backend brains box of the system). The screens are the sources of the noise. When I pull the power connector off the back of a screen, I get much less noise.
Any thoughts on this? I can't very well wrap my EFIS screens in Faraday cages. At this point, I am pretty much ready to give up on the notion of a handheld radio as a backup communication device.
    -- Art Z.
Quote:
On Sun, Aug 4, 2019 at 8:30 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
During my flight home from AirVenture, I decided to test my handheld radio in flight. There was so much hum that it was unusable. This was a low-ish frequency hum, not pulsing. Definitely not what I have heard in the past as a higher frequency "alternator whine."
Here are the details:
I have the Yaesu Vertext FTA 550 handheld VHF radio. It works great on the ground.
I plugged in the Yaesu headset adapter into the radio. I plugged my headset into the adapter. 
I have a second comm antenna on the airplane but, since the second comm radio is not installed, I have the coax with BNC connector readily available under the front of the instrument panel. I connected the second comm antenna to the handheld. The two comm antennas are mounted on top of the airplane, about 3 feet apart.
I tuned to a nearby ASOS. The audio was buried under such a loud hum that I could barely hear it. I tried a different ASOS; same result. I turned off the comm radio in my panel and the hum was still present. I did not try transmitting.
The in-panel comm radio (a VAL COM 2000) does not have any hum.
Other devices in the airplane which were turned on at the time:
  • Lycoming engine with primary and backup B&C alternators with B&C voltage regulators. Ignition is from two newly rebuilt magnetos.
  • PS Engineering audio panel.
  • VAL NAV 2000 VOR/ILS/GS receiver.
  • AeroLEDS landing lights on wig-wag 
  • AeroLEDS Pulsar NSP wingtip lights with strobes on but nav/position lights off.
  • MGL iEFIS system
  • iPad and smartphone

What ideas do you have? Carrying a handheld radio for backup communication is kind of pointless if I can't communicate with it.


 

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PostPosted: Sun Aug 25, 2019 4:49 am    Post subject: Re: Handheld Comm Interference In Flight Reply with quote

Is the handheld using aircraft power or internal batteries?

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PostPosted: Sun Aug 25, 2019 4:56 am    Post subject: Re: Handheld Comm Interference In Flight Reply with quote

Can a remote antenna be connected? It might make a difference if the antenna is just a couple of feet farther away from the MGL EFIS.

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PostPosted: Sun Aug 25, 2019 5:30 am    Post subject: Handheld Comm Interference In Flight Reply with quote

Hi Art,
I should have thought of that when you 1st described the problem. One of the other EFIS makers had a similar issue early in production; the display itself was radiating at its scan rate (typically 30-60 Hz). I can't remember what was done to cure the problem back then. If it were me, I'd play with the handheld a bit, changing frequencies to see if some are better/worse than others, and then contact MGL directly with as much data as possible. They seem to be 'stand up' people, so I'd bet on them at least trying to help you. Ranier Lamers of MGL posts occasionally on the VAF forum, so they do pay attention to builders.
Charlie
Virus-free. www.avast.com [url=#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]

On Sun, Aug 25, 2019 at 6:49 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
I pulled and replaced fuses one at a time until I isolated the circuit that is generating the noise in my handheld. It is the MGL EFIS, believe it or not. After identifying the fuse, I started disconnecting individual devices. The circuit contains two MGL Challenger 10.4 inch screens and the MGL iBOX (the backend brains box of the system). The screens are the sources of the noise. When I pull the power connector off the back of a screen, I get much less noise.
Any thoughts on this? I can't very well wrap my EFIS screens in Faraday cages. At this point, I am pretty much ready to give up on the notion of a handheld radio as a backup communication device.
    -- Art Z.
Quote:
On Sun, Aug 4, 2019 at 8:30 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
During my flight home from AirVenture, I decided to test my handheld radio in flight. There was so much hum that it was unusable. This was a low-ish frequency hum, not pulsing. Definitely not what I have heard in the past as a higher frequency "alternator whine."
Here are the details:
I have the Yaesu Vertext FTA 550 handheld VHF radio. It works great on the ground.
I plugged in the Yaesu headset adapter into the radio. I plugged my headset into the adapter. 
I have a second comm antenna on the airplane but, since the second comm radio is not installed, I have the coax with BNC connector readily available under the front of the instrument panel. I connected the second comm antenna to the handheld. The two comm antennas are mounted on top of the airplane, about 3 feet apart.
I tuned to a nearby ASOS. The audio was buried under such a loud hum that I could barely hear it. I tried a different ASOS; same result. I turned off the comm radio in my panel and the hum was still present. I did not try transmitting.
The in-panel comm radio (a VAL COM 2000) does not have any hum.
Other devices in the airplane which were turned on at the time:
  • Lycoming engine with primary and backup B&C alternators with B&C voltage regulators. Ignition is from two newly rebuilt magnetos.
  • PS Engineering audio panel.
  • VAL NAV 2000 VOR/ILS/GS receiver.
  • AeroLEDS landing lights on wig-wag 
  • AeroLEDS Pulsar NSP wingtip lights with strobes on but nav/position lights off.
  • MGL iEFIS system
  • iPad and smartphone

What ideas do you have? Carrying a handheld radio for backup communication is kind of pointless if I can't communicate with it.


 

--
https://CheerfulCurmudgeon.com/Love the stranger for you yourselves were strangers in Egypt. Deut. 10:19



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art(at)zemon.name
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PostPosted: Sun Aug 25, 2019 5:46 am    Post subject: Handheld Comm Interference In Flight Reply with quote

Internal batteries
    -- Art Z.


On Sun, Aug 25, 2019 at 8:03 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:

Quote:
--> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>

Is the handheld using aircraft power or internal batteries?

--------
Joe Gores
 

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art(at)zemon.name
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PostPosted: Sun Aug 25, 2019 6:00 am    Post subject: Handheld Comm Interference In Flight Reply with quote

Charlie,
I already posted on the MGL users' forum. Hopefully, I will hear back soon. I figured I should close the loop here, too.
Cheers,
    -- Art Z.


On Sun, Aug 25, 2019 at 8:45 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:

Quote:
Hi Art,
I should have thought of that when you 1st described the problem. One of the other EFIS makers had a similar issue early in production; the display itself was radiating at its scan rate (typically 30-60 Hz). I can't remember what was done to cure the problem back then. If it were me, I'd play with the handheld a bit, changing frequencies to see if some are better/worse than others, and then contact MGL directly with as much data as possible. They seem to be 'stand up' people, so I'd bet on them at least trying to help you. Ranier Lamers of MGL posts occasionally on the VAF forum, so they do pay attention to builders.
Charlie
[/url] Virus-free. [url=https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link]www.avast.com [url=#m_-5307110112801134938_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]

On Sun, Aug 25, 2019 at 6:49 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
I pulled and replaced fuses one at a time until I isolated the circuit that is generating the noise in my handheld. It is the MGL EFIS, believe it or not. After identifying the fuse, I started disconnecting individual devices. The circuit contains two MGL Challenger 10.4 inch screens and the MGL iBOX (the backend brains box of the system). The screens are the sources of the noise. When I pull the power connector off the back of a screen, I get much less noise.
Any thoughts on this? I can't very well wrap my EFIS screens in Faraday cages. At this point, I am pretty much ready to give up on the notion of a handheld radio as a backup communication device.
    -- Art Z.
Quote:
On Sun, Aug 4, 2019 at 8:30 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
During my flight home from AirVenture, I decided to test my handheld radio in flight. There was so much hum that it was unusable. This was a low-ish frequency hum, not pulsing. Definitely not what I have heard in the past as a higher frequency "alternator whine."
Here are the details:
I have the Yaesu Vertext FTA 550 handheld VHF radio. It works great on the ground.
I plugged in the Yaesu headset adapter into the radio. I plugged my headset into the adapter. 
I have a second comm antenna on the airplane but, since the second comm radio is not installed, I have the coax with BNC connector readily available under the front of the instrument panel. I connected the second comm antenna to the handheld. The two comm antennas are mounted on top of the airplane, about 3 feet apart.
I tuned to a nearby ASOS. The audio was buried under such a loud hum that I could barely hear it. I tried a different ASOS; same result. I turned off the comm radio in my panel and the hum was still present. I did not try transmitting.
The in-panel comm radio (a VAL COM 2000) does not have any hum.
Other devices in the airplane which were turned on at the time:
  • Lycoming engine with primary and backup B&C alternators with B&C voltage regulators. Ignition is from two newly rebuilt magnetos.
  • PS Engineering audio panel.
  • VAL NAV 2000 VOR/ILS/GS receiver.
  • AeroLEDS landing lights on wig-wag 
  • AeroLEDS Pulsar NSP wingtip lights with strobes on but nav/position lights off.
  • MGL iEFIS system
  • iPad and smartphone

What ideas do you have? Carrying a handheld radio for backup communication is kind of pointless if I can't communicate with it.







--
https://CheerfulCurmudgeon.com/Love the stranger for you yourselves were strangers in Egypt. Deut. 10:19


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nuckolls.bob(at)aeroelect
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PostPosted: Sun Aug 25, 2019 7:13 am    Post subject: Handheld Comm Interference In Flight Reply with quote

At 07:56 AM 8/25/2019, you wrote:
Quote:
--> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>

Can a remote antenna be connected? It might make a difference if the antenna is just a couple of feet farther away from the MGL EFIS.

--------
Joe Gores

This is the easiest solution . . . and it will markedly improve
hand-held performance. Assuming it's intended to back
up the panel mounted comm, consider crafting some way
of reconnecting the ship's normal comm antenna to
the hand held. Some builders have routed their
comm antenna coax such that it passed aft through
the cockpit but with a set of connectors that would
allow disconnection. Extra coax 'slack' was coiled
against the side wall and held with a suitable
retainer/cover (velcro'ed on?). When the coiled
breakout was opened and extended, the antenna
side of the feeder was connection to the hand
held with this or some similar arrangement.

See pictures 05, 06 and 09 here:

https://tinyurl.com/y32yn7cl

There have been numerous instances of LCD screen
radiation from instruments un-friendly to the
cockpit RF environment. Connecting the hand
held to a remotely mounted antenna fixed the
noise and improved performance as well . . .
win-win . . .



Bob . . .


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ryansoutham(at)hotmail.co
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PostPosted: Sun Aug 25, 2019 12:50 pm    Post subject: Handheld Comm Interference In Flight Reply with quote

It is very well known for some EFIS systems to radiate some nasty RF. One thing that sometimes works is running a completely separate earth from a screw on the case to ground.

Secondly, I have had good success with handheld radio and extraneous RF by taking the headset fly lead and wrapping it a couple of times around and RF choke (ferrite bead/choke). The ones that are in plastic housings that clip together. I found that it was often about two or three wraps that worked not just passing the cable through once.
It made no difference to do this on the headset leads bit certainly did on the fly lead from the radio itself.
Easy, cheap solution to try.

This is a very Heath Robinson fix but has worked in the past for me. From: owner-aeroelectric-list-server(at)matronics.com <owner-aeroelectric-list-server(at)matronics.com> on behalf of Art Zemon <art(at)zemon.name>
Sent: Monday, 26 August 2019 1:57:55 AM
To: aeroelectric-list(at)matronics.com <aeroelectric-list(at)matronics.com>
Subject: Re: Handheld Comm Interference In Flight

Charlie,


I already posted on the MGL users' forum. Hopefully, I will hear back soon. I figured I should close the loop here, too.


Cheers,
-- Art Z.




On Sun, Aug 25, 2019 at 8:45 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:

Quote:
Hi Art,


I should have thought of that when you 1st described the problem. One of the other EFIS makers had a similar issue early in production; the display itself was radiating at its scan rate (typically 30-60 Hz). I can't remember what was done to cure the problem back then. If it were me, I'd play with the handheld a bit, changing frequencies to see if some are better/worse than others, and then contact MGL directly with as much data as possible. They seem to be 'stand up' people, so I'd bet on them at least trying to help you. Ranier Lamers of MGL posts occasionally on the VAF forum, so they do pay attention to builders.


Charlie


[/url] Virus-free. [url=https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link] www.avast.com [url=#x_m_-5307110112801134938_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]

On Sun, Aug 25, 2019 at 6:49 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
I pulled and replaced fuses one at a time until I isolated the circuit that is generating the noise in my handheld. It is the MGL EFIS, believe it or not. After identifying the fuse, I started disconnecting individual devices. The circuit contains two MGL Challenger 10.4 inch screens and the MGL iBOX (the backend brains box of the system). The screens are the sources of the noise. When I pull the power connector off the back of a screen, I get much less noise.


Any thoughts on this? I can't very well wrap my EFIS screens in Faraday cages. At this point, I am pretty much ready to give up on the notion of a handheld radio as a backup communication device.


-- Art Z.


Quote:
On Sun, Aug 4, 2019 at 8:30 AM Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

Quote:
During my flight home from AirVenture, I decided to test my handheld radio in flight. There was so much hum that it was unusable. This was a low-ish frequency hum, not pulsing. Definitely not what I have heard in the past as a higher frequency "alternator whine."


Here are the details:


I have the Yaesu Vertext FTA 550 handheld VHF radio. It works great on the ground.


I plugged in the Yaesu headset adapter into the radio. I plugged my headset into the adapter.


I have a second comm antenna on the airplane but, since the second comm radio is not installed, I have the coax with BNC connector readily available under the front of the instrument panel. I connected the second comm antenna to the handheld. The two comm antennas are mounted on top of the airplane, about 3 feet apart.


I tuned to a nearby ASOS. The audio was buried under such a loud hum that I could barely hear it. I tried a different ASOS; same result. I turned off the comm radio in my panel and the hum was still present. I did not try transmitting.


The in-panel comm radio (a VAL COM 2000) does not have any hum.


Other devices in the airplane which were turned on at the time:
  • Lycoming engine with primary and backup B&C alternators with B&C voltage regulators. Ignition is from two newly rebuilt magnetos.
  • PS Engineering audio panel.
  • VAL NAV 2000 VOR/ILS/GS receiver.
  • AeroLEDS landing lights on wig-wag
  • AeroLEDS Pulsar NSP wingtip lights with strobes on but nav/position lights off.
  • MGL iEFIS system
  • iPad and smartphone

What ideas do you have? Carrying a handheld radio for backup communication is kind of pointless if I can't communicate with it.











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https://CheerfulCurmudgeon.com/ Love the stranger for you yourselves were strangers in Egypt. Deut. 10:19


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user9253



Joined: 28 Mar 2008
Posts: 1436
Location: Riley TWP Michigan

PostPosted: Sun Aug 25, 2019 3:24 pm    Post subject: Re: Handheld Comm Interference In Flight Reply with quote

Fly Lead? Is that the wire that connects to the Flyback transformer? Smile

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PostPosted: Sun Aug 25, 2019 5:12 pm    Post subject: Handheld Comm Interference In Flight Reply with quote

Bob,
I tried an external antenna. No difference in noise. I have two antennas installed in the airplane and (so far) only one comm radio. So the other coax is hanging down with a BNC connector on it so I can attach it to my handheld. I got similar noise in-flight whether I used the external antenna or the little whip antenna.
I'll see what MGL says but I suspect that I just won't be able to easily use the handheld for a backup. The key seems to be proximity to the EFIS screen. If I move the handheld a few more feet farther away) then the noise decreases. Maybe I have to put the handheld on the floor behind me, instead of in my lap.
    -- Art Z.
On Sun, Aug 25, 2019 at 10:29 AM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

Quote:
At 07:56 AM 8/25/2019, you wrote:
Quote:
--> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>

Can a remote antenna be connected?  It might make a difference if the antenna is just a couple of feet farther away from the MGL EFIS.

--------
Joe Gores

 This is the easiest solution . . . and it will markedly improve
 hand-held performance. Assuming it's intended to back
 up the panel mounted comm, consider crafting some way
 of reconnecting the ship's normal comm antenna to
 the hand held. Some builders have routed their
 comm antenna coax such that it passed aft through
 the cockpit but with a set of connectors that would
 allow disconnection. Extra coax 'slack' was coiled
 against the side wall and held with a suitable
 retainer/cover (velcro'ed on?). When the coiled
 breakout was opened and extended, the antenna
 side of the feeder was connection to the hand
 held with this or some similar arrangement.
 
 See pictures 05, 06 and 09 here:

https://tinyurl.com/y32yn7cl

 There have been numerous instances of LCD screen
 radiation from instruments un-friendly to the
 cockpit RF environment. Connecting the hand
 held to a remotely mounted antenna fixed the
 noise and improved performance as well . . .
 win-win . . .

--
https://CheerfulCurmudgeon.com/Love the stranger for you yourselves were strangers in Egypt. Deut. 10:19


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PostPosted: Sun Aug 25, 2019 6:39 pm    Post subject: Handheld Comm Interference In Flight Reply with quote

At 08:10 PM 8/25/2019, you wrote:
Quote:
Bob,

I tried an external antenna. No difference in noise. I have two antennas installed in the airplane and (so far) only one comm radio. So the other coax is hanging down with a BNC connector on it so I can attach it to my handheld. I got similar noise in-flight whether I used the external antenna or the little whip antenna.

I'll see what MGL says but I suspect that I just won't be able to easily use the handheld for a backup. The key seems to be proximity to the EFIS screen. If I move the handheld a few more feet farther away) then the noise decreases. Maybe I have to put the handheld on the floor behind me, instead of in my lap.

Interesting . . . does the hand-held have
an adjustable squelch? Can it be tightened
to quiet the noise? If you disconnect the
antenna, does the noise go away?

what kind of airplane again?

You wrote before:

>When I pull the power connector off
the back of a screen, I get much less noise.<

You say 'much less' . . . not zero . . . same
kind of noise or different 'voice'.

>. . . ready to give up on the notion of a
handheld radio as a backup communication device.<

This MIGHT be a function of the
brand of hand held. If a remote antenna
doesn't mitigate the problem, perhaps
the radio has a local vulnerability right
through the case.

Can you borrow another brand to try?

It's been a long time since I've heard
of a radiating screen problem . . . it
used to be pretty common.


Bob . . .


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art(at)zemon.name
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PostPosted: Mon Aug 26, 2019 4:00 am    Post subject: Handheld Comm Interference In Flight Reply with quote

Bob,
answers to questions interspersed below
On Sun, Aug 25, 2019 at 9:54 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

Quote:
At 08:10 PM 8/25/2019, you wrote:
Quote:
Bob,

I tried an external antenna. No difference in noise. I have two antennas installed in the airplane and (so far) only one comm radio. So the other coax is hanging down with a BNC connector on it so I can attach it to my handheld. I got similar noise in-flight whether I used the external antenna or the little whip antenna.

I'll see what MGL says but I suspect that I just won't be able to easily use the handheld for a backup. The key seems to be proximity to the EFIS screen. If I move the handheld a few more feet farther away) then the noise decreases. Maybe I have to put the handheld on the floor behind me, instead of in my lap.

 Interesting . . . does the hand-held have
 an adjustable squelch? Can it be tightened
 to quiet the noise? If you disconnect the
 antenna, does the noise go away?



The radio is a Yaesu FTA 550. I run it from AA batteries so it is completely disconnected from the airplane (unless I connect the external antenna).
I can adjust the squelch but if I turn the squelch high enough to cut the noise, ASOS transmissions don't break the squelch when I am 20 miles or so from the airport (where I want to be listening to the ASOS).
I did not try disconnecting the antenna and listening for noise, since I only focused on configurations where the radio was actually usable.
Quote:
 what kind of airplane again?



Bede BD-4C, all aluminum
 
Quote:
 You wrote before:
 
>When I pull the power connector off
the back of a screen, I get much less noise.<

 You say 'much less' . . . not zero . . . same
 kind of noise or different 'voice'.



Same noise. There are two identical EFIS screens. If I hold the radio where it would be if I were flying, and disconnect the screen in front of the pilot, there is less noise. The copilot's screen is still powered on. If I pull the fuse for the EFIS system (both screens, iBox "brains" box, magnetometer, and AHRS) then the noise goes away entirely.
 
Quote:

>. . . ready to give up on the notion of a
handheld radio as a backup communication device.<

 This MIGHT be a function of the
 brand of hand held. If a remote antenna
 doesn't mitigate the problem, perhaps
 the radio has a local vulnerability right
 through the case.

 Can you borrow another brand to try?



I have an old Icom. I'll give it a try.
 
Quote:

 It's been a long time since I've heard
 of a radiating screen problem . . . it
 used to be pretty common.


  Bob . . .

--
https://CheerfulCurmudgeon.com/Love the stranger for you yourselves were strangers in Egypt. Deut. 10:19


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PostPosted: Mon Aug 26, 2019 1:15 pm    Post subject: Handheld Comm Interference In Flight Reply with quote

Art,
I run an iEFIS Explorer with a Sporty’s SP-400 as my backup comm in my Long-EZ, no problems. Well, I could probably make some of the intercom wiring more elegant.
Now, the SP-400 is normally plugged into a winglet antenna, but it also works fine with just the aerial; I’ve tested it. I’d use it, if the aerial antenna didn’t sit right where I’d like to have my left elbow.
Is it possible you’re running very old software? MGL actually added a bit of clock dithering to reduce EMI, but that update was...4 years ago.
Quote:


Quote:

1 December 2015 version A 1.0.2.6

Added: Spread spectrum clocking on all peripherals, RS232, CAN bus as well as LCD display. This “spreads” EMI spurious emissions over a larger frequency band thereby reducing peak power at any one specific frequency. This aids in suppressing radio RX noise from EFIS in compromised installations.

Quote:
Time: 04:43:10 AM PST USFrom: Art Zemon <art(at)zemon.name (art(at)zemon.name)>
Subject: Re: AeroElectric-List: Handheld Comm Interference In Flight

I pulled and replaced fuses one at a time until I isolated the circuit that
is generating the noise in my handheld. It is the MGL EFIS, believe it or
not. After identifying the fuse, I started disconnecting individual
devices. The circuit contains two MGL Challenger 10.4 inch screens and the
MGL iBOX (the backend brains box of the system). The screens are the
sources of the noise. When I pull the power connector off the back of a
screen, I get much less noise.

Any thoughts on this? I can't very well wrap my EFIS screens in Faraday
cages. At this point, I am pretty much ready to give up on the notion of a
handheld radio as a backup communication device.

-- Art Z.


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