Zaon MRX causing radio interference

[[email protected]]

With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
experiencing some radio interference and linked this to the MRX: the
radio gives white-noise static -- like the squelch is not properly
adusted. When I turn the MRX off it goes away.

I've heard putting a "ferrite core" around the MRX's (and the
radio's?) power cord might help. (Here's one:
http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ350156591274QQcmdZViewItem
).

Does anybody else have this problem? Have you solved it in some way?

Thanks,

Eric
DG-300

[jcarlyle]

JJ Sinclair reported an MRX/radio interference problem several years
ago on this forum. When I installed my MRX in my panel I took the
precaution of installing a ferrite bead around the power cable, and
I've had no interference problems. It's good electrical practice to
use ferrite beads on DC supply leads. If you can, loop the power cable
so it goes through the ferrite core more than once in order to get the
best high frequency attenuation.

-John

On Mar 24, 1:58 am, wrote:
> With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
> experiencing some radio interference and linked this to the MRX: the
> radio gives white-noise static -- like the squelch is not properly
> adusted. When I turn the MRX off it goes away.
>
> I've heard putting a "ferrite core" around the MRX's (and the
> radio's?) power cord might help. (Here's one:http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ3501565...
> ).
>
> Does anybody else have this problem? Have you solved it in some way?
>
> Thanks,
>
> Eric
> DG-300

[qflyer1]

On Mar 24, 2:58*am, wrote:
> With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
I have the same problem. I also had the problem with the previous
model. I did the ferrite bead and it didn't do the job.
I finally sent it in and they replaced the power mosfet and that did
the trick.
I'm about to send this one in for a firmware upgrade and to deal with
this issue. Hopefully the same way.

Cheers,
Tim
1FL

> experiencing some radio interference and linked this to the MRX: the
> radio gives white-noise static -- like the squelch is not properly
> adusted. When I turn the MRX off it goes away.
>
> I've heard putting a "ferrite core" around the MRX's (and the
> radio's?) power cord might help. *(Here's one:http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ3501565...
> ).
>
> Does anybody else have this problem? *Have you solved it in some way?
>
> Thanks,
>
> Eric
> DG-300

[Darryl Ramm]

On Mar 24, 6:01*am, qflyer1 > wrote:
> On Mar 24, 2:58*am, wrote:> With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
>
> I have the same problem. I also had the problem with the previous
> model. I did the ferrite bead and it didn't do the job.
> I finally sent it in and they replaced the power mosfet and that did
> the trick.
> I'm about to send this one in for a firmware upgrade and to deal with
> this issue. Hopefully the same way.
>
> Cheers,
> Tim
> 1FL
>
> > experiencing some radio interference and linked this to the MRX: the
> > radio gives white-noise static -- like the squelch is not properly
> > adusted. When I turn the MRX off it goes away.
>
> > I've heard putting a "ferrite core" around the MRX's (and the
> > radio's?) power cord might help. *(Here's one:http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ3501565...
> > ).
>
> > Does anybody else have this problem? *Have you solved it in some way?
>
> > Thanks,
>
> > Eric
> > DG-300
>
>

Make sure you are installing a large enough ferrite bead (beads is
slang, fat walled cylinders might be a better description) that allows
the power cable to go through the middle and be wrapped around the
outside several times. Use a thin gauge wire cable to help with this
and the bead can still be small and allow you to feed the cable
through several times. It may be worth trying to installing this close
to the Zaon end of the power cable if it does not work elsewhere.

Darryl

[Henryk Birecki]

Here is a reply I sent to JJ's note on March 9 2007. As an added bonus
a question (good for EE job interview): Why does wrapping DC power
cord around ferrite core work to suppress noise? The supply and return
currents should cancel itself.

John's choke is a real overkill, but it is "guarranteed to work".
Coils are JW Miller & Bourns FB20010-3B-RC (DigiKey M8694-ND - may be
different now) cost
about 70-85 cents each depending how many you buy. Capacitor is a
standard ceramic 0.47 microFarad. I may have used 1 uF. I do not have
part number, but there is nothing particularly special about it (just
do not get one rated for 1kV ).

----WWWW-----WWWW----
I
-----
-----
I
----WWWW-----WWWW----


Best I can do for schematic is above. Put it as close to the noise
generator as possible.


Cheers,


Henryk Birecki




On Mon, 23 Mar 2009 23:58:25 -0700 (PDT), you wrote:

>With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
>experiencing some radio interference and linked this to the MRX: the
>radio gives white-noise static -- like the squelch is not properly
>adusted. When I turn the MRX off it goes away.
>
>I've heard putting a "ferrite core" around the MRX's (and the
>radio's?) power cord might help. (Here's one:
>http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ350156591274QQcmdZViewItem
>).
>
>Does anybody else have this problem? Have you solved it in some way?
>
>Thanks,
>
>Eric
>DG-300

wrote:

>With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
>experiencing some radio interference and linked this to the MRX: the
>radio gives white-noise static -- like the squelch is not properly
>adusted. When I turn the MRX off it goes away.
>
>I've heard putting a "ferrite core" around the MRX's (and the
>radio's?) power cord might help. (Here's one:
>http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ350156591274QQcmdZViewItem
>).
>
>Does anybody else have this problem? Have you solved it in some way?
>
>Thanks,
>
>Eric
>DG-300

[Darryl Ramm]

On Mar 24, 9:31*am, Henryk Birecki > wrote:
> Here is a reply I sent to JJ's note on March 9 2007. As an added bonus
> a question (good for EE job interview): Why does wrapping DC power
> cord around ferrite core work to suppress noise? The supply and return
> currents should cancel itself.
[snip]
>
> Henryk Birecki


Not sure I'd pass an EE job interview, but inductive coupling of the
switched current can produce in-phase noise on both input leads. The
power supply circuit inside the Zaon may have issue with how it
handles RF grounding that makes this more likely.

At least in my case wrapping both leads a few times though the ferrite
choke worked. If it does not then slitting each lead and doing this
separately should fix things. Failing that use a full on filter like
Henryk describes.

BTW a nice power supply cable for the Zaon is aviable from Digikey see

http://www.digikey.com/scripts/dksearch/dksus.dll?KeywordSearch?lang=en&site=US&KeyWords=CP-2196-ND&x=0&y=0

Darryl

[jcarlyle]

Tim, that's very interesting. I have a friend who bought a MRX last
summer. While flying with him last fall I noticed that his MRX was
misreading the altitude of the tow plane. He's planning on sending it
in, but what with his problem and now yours I wonder if there was a QC
problem at Zaon last year. Don't get me wrong, I love my unit and I
know several that are performing exactly as they should - but they're
all older units.

-John

On Mar 24, 8:01 am, qflyer1 > wrote:
> I have the same problem. I also had the problem with the previous
> model. I did the ferrite bead and it didn't do the job.
> I finally sent it in and they replaced the power mosfet and that did
> the trick.
> I'm about to send this one in for a firmware upgrade and to deal with
> this issue. Hopefully the same way.

[Darryl Ramm]

On Mar 24, 12:57*pm, jcarlyle > wrote:
> Tim, that's very interesting. I have a friend who bought a MRX last
> summer. While flying with him last fall I noticed that his MRX was
> misreading the altitude of the tow plane. He's planning on sending it
> in, but what with his problem and now yours I wonder if there was a QC
> problem at Zaon last year. Don't get me wrong, I love my unit and I
> know several that are performing exactly as they should - but they're
> all older units.
>
> -John
[snip]


By how much? And just compared to the towplane? The altitude of the
towplane sent to the Zaon is digital. So it is unlikely to "misread"
it. It uses it's own internal altimeter to calculate the relative
altitude. I would hope they agree to 100' or so. One issue is the Zaon
pressure sensor is exposed to ambient cockpit pressure and not the
static line pressure, so opening and closing vents/speeding up etc.
might affect the relative altitude it displays. If the difference is
more than a few hundred feet I'd next suspect the pressure sensor in
the Zaon.

It may be worthwhile before sending the Zaon back to compare what the
Zaon says to another aircraft that has a transponder that shows the
encoder's pressure altitude and play with opening and closing vents.
Of course if it is just the tow plane then it's encoder may also be
faulty, or maybe it really is an RF related problem that only happens
when close to the other transponder (but unlikely).

Darryl

[jcarlyle]

It was 300-400 feet off, sometimes above and sometimes below us - and
we were doing a normal tow, not boxing the wake. Vents were closed (it
was 35 degrees F on the ground before takeoff). Hopefully he and I
will be able to fly together within the next month. I've got a Becker
ATC4401 that reports the encoded altitude, so we'll be able to compare
that with his MRX in real time at different separation distances and
heights.

-John

On Mar 24, 3:11 pm, Darryl Ramm > wrote:
> By how much? And just compared to the towplane? The altitude of the
> towplane sent to the Zaon is digital. So it is unlikely to "misread"
> it. It uses it's own internal altimeter to calculate the relative
> altitude. I would hope they agree to 100' or so. One issue is the Zaon
> pressure sensor is exposed to ambient cockpit pressure and not the
> static line pressure, so opening and closing vents/speeding up etc.
> might affect the relative altitude it displays. If the difference is
> more than a few hundred feet I'd next suspect the pressure sensor in
> the Zaon.
>
> It may be worthwhile before sending the Zaon back to compare what the
> Zaon says to another aircraft that has a transponder that shows the
> encoder's pressure altitude and play with opening and closing vents.
> Of course if it is just the tow plane then it's encoder may also be
> faulty, or maybe it really is an RF related problem that only happens
> when close to the other transponder (but unlikely).
>
> Darryl

[qflyer1]

On Mar 24, 10:30*am, Darryl Ramm > wrote:
> On Mar 24, 6:01*am, qflyer1 > wrote:
>
>
>
> > On Mar 24, 2:58*am, wrote:> With my new Zaon MRX PCAS mounted on top of my glare shield, I've been
>
> > I have the same problem. I also had the problem with the previous
> > model. I did the ferrite bead and it didn't do the job.
> > I finally sent it in and they replaced the power mosfet and that did
> > the trick.
> > I'm about to send this one in for a firmware upgrade and to deal with
> > this issue. Hopefully the same way.
>
> > Cheers,
> > Tim
> > 1FL
>
> > > experiencing some radio interference and linked this to the MRX: the
> > > radio gives white-noise static -- like the squelch is not properly
> > > adusted. When I turn the MRX off it goes away.
>
> > > I've heard putting a "ferrite core" around the MRX's (and the
> > > radio's?) power cord might help. *(Here's one:http://cgi.ebay.ca/Noise-Filter-Clip-on-Ferrite-Core_W0QQitemZ3501565...
On the previous model I did wrap several turns on the bead. Only
sending it in fixed the problem.
On this one, I'm not wasting my time. I'm awaiting my rma # as I
write.
Seems to me whatever power supply, or downstream component, design
they used before is the same now.

Tim


> > > ).
>
> > > Does anybody else have this problem? *Have you solved it in some way?

>
> Make sure you are installing a large enough ferrite bead (beads is
> slang, fat walled cylinders might be a better description) that allows
> the power cable to go through the middle and be wrapped around the
> outside several times. Use a thin gauge wire cable to help with this
> and the bead can still be small and allow you to feed the cable
> through several times. It may be worth trying to installing this close
> to the Zaon end of the power cable if it does not work elsewhere.
>
> Darryl

[Eric Greenwell]

jcarlyle wrote:
> It was 300-400 feet off, sometimes above and sometimes below us - and
> we were doing a normal tow, not boxing the wake. Vents were closed (it
> was 35 degrees F on the ground before takeoff). Hopefully he and I
> will be able to fly together within the next month. I've got a Becker
> ATC4401 that reports the encoded altitude, so we'll be able to compare
> that with his MRX in real time at different separation distances and
> heights.

Does his glider have a transponder in it?

Do you know that the towplane encoder was working correctly?

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Darryl Ramm]

On Mar 24, 3:33*pm, Eric Greenwell > wrote:
> jcarlyle wrote:
> > It was 300-400 feet off, sometimes above and sometimes below us - and
> > we were doing a normal tow, not boxing the wake. Vents were closed (it
> > was 35 degrees F on the ground before takeoff). Hopefully he and I
> > will be able to fly together within the next month. I've got a Becker
> > ATC4401 that reports the encoded altitude, so we'll be able to compare
> > that with his MRX in real time at different separation distances and
> > heights.
>
> Does his glider have a transponder in it?
>
> Do you know that the towplane encoder was working correctly?
>

Lets play 20 questions... :-)

Since the temperature was cold. Was this the first tow of the day? Any
chance the transponder had just been turned on within a few minutes
earlier and was still warming up?

17 more questions to go.


Darryl

[jcarlyle]

Eric, the club G103 we were in does not have a transpondert. The
towplane encoder is working properly according to ATC.

Darryl, it wasn't the first tow of the day, so yes, the encoder was
warmed up. Let's ask the other 17 questions after I fly my transponder
equipped glider with him and his MRX in his non-transponder equipped
glider.

-John

On Mar 24, 6:06 pm, Darryl Ramm > wrote:
> On Mar 24, 3:33 pm, Eric Greenwell > wrote:
>
> > jcarlyle wrote:
> > > It was 300-400 feet off, sometimes above and sometimes below us - and
> > > we were doing a normal tow, not boxing the wake. Vents were closed (it
> > > was 35 degrees F on the ground before takeoff). Hopefully he and I
> > > will be able to fly together within the next month. I've got a Becker
> > > ATC4401 that reports the encoded altitude, so we'll be able to compare
> > > that with his MRX in real time at different separation distances and
> > > heights.
>
> > Does his glider have a transponder in it?
>
> > Do you know that the towplane encoder was working correctly?
>
> Lets play 20 questions... :-)
>
> Since the temperature was cold. Was this the first tow of the day? Any
> chance the transponder had just been turned on within a few minutes
> earlier and was still warming up?
>
> 17 more questions to go.
>
> Darryl

[Eric Greenwell]

jcarlyle wrote:

> On Mar 24, 6:06 pm, Darryl Ramm > wrote:
>> On Mar 24, 3:33 pm, Eric Greenwell > wrote:
>>
>>> jcarlyle wrote:
>>>> It was 300-400 feet off, sometimes above and sometimes below us - and
>>>> we were doing a normal tow, not boxing the wake. Vents were closed (it
>>>> was 35 degrees F on the ground before takeoff). Hopefully he and I
>>>> will be able to fly together within the next month. I've got a Becker
>>>> ATC4401 that reports the encoded altitude, so we'll be able to compare
>>>> that with his MRX in real time at different separation distances and
>>>> heights.
>>> Does his glider have a transponder in it?
>>> Do you know that the towplane encoder was working correctly?
>> Lets play 20 questions... :-)
>>
>> Since the temperature was cold. Was this the first tow of the day? Any
>> chance the transponder had just been turned on within a few minutes
>> earlier and was still warming up?
> Eric, the club G103 we were in does not have a transpondert. The
> towplane encoder is working properly according to ATC.

OK, then the MRX should be using it's internal altimeter, as Darryl
thought. If the encoder altitude output is a just a little erratic,
you'd be able to notice while ATC might not. They would not be able to
tell the difference between an unsteady climb and a slightly erratic
encoder, I'm guessing.
>
> Darryl, it wasn't the first tow of the day, so yes, the encoder was
> warmed up. Let's ask the other 17 questions after I fly my transponder
> equipped glider with him and his MRX in his non-transponder equipped
> glider.

Or, you could fly with the MRX in your glider, which would make the MRX
use your encoder altitude instead of it's internal altimeter. That might
tell you if the problem is the internal altimeter.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Andy[_1_]]

On Mar 24, 1:49*pm, jcarlyle > wrote:
> It was 300-400 feet off, sometimes above and sometimes below us - and
> we were doing a normal tow, not boxing the wake. Vents were closed (it
> was 35 degrees F on the ground before takeoff). Hopefully he and I
> will be able to fly together within the next month. I've got a Becker
> ATC4401 that reports the encoded altitude, so we'll be able to compare
> that with his MRX in real time at different separation distances and
> heights.

The MRX internal baro altitude is both displayable and adjustable. It
should not require any other equipment, except an accurate altimeter
set to 29.92, to determine if the problem is the MRX baro sensor.

Andy

[jcarlyle]

Do you know if this function is available in older MRX versions? The
manual which came with my unit (bought August 2006) does not mention
such a capability. I see that the latest manual on the Zaon web site
does explain how to access this function, though. I'll see if my unit
allows me to get to the altimeter calibration menu when I'm next at
the airport.

-John

On Mar 26, 9:00 am, Andy > wrote:
> The MRX internal baro altitude is both displayable and adjustable. It
> should not require any other equipment, except an accurate altimeter
> set to 29.92, to determine if the problem is the MRX baro sensor.
>
> Andy

[Andy[_1_]]

On Mar 26, 8:22*am, jcarlyle > wrote:
> Do you know if this function is available in older MRX versions? The
> manual which came with my unit (bought August 2006) does not mention
> such a capability. I see that the latest manual on the Zaon web site
> does explain how to access this function, though. I'll see if my unit
> allows me to get to the altimeter calibration menu when I'm next at
> the airport.

Don't know when this feature was included. I would suspect it has
always been there but maybe not documented in the user manual. I have
a fairly early unit but I had it upgraded to the latest firmware last
year as I needed the new function that distinguishes whether the
internal baro sensor, or the host aircraft transponder, is being used
for reference altitude. I had not attempted the baro calibration
before the firmware update.

If you have no host aircraft transponder, pressing the multifunction
switch left will report the internal pressure alt being used. If you
do this several times and always see the same pressure altitude it
would suggest that the internal baro sensor is not erratic. If you
find it is constant but not correct, then try the calibration
procedure.

I have found Zaon customer service to be excellent so don't hesitate
to contact them if you need to.

Andy