Zaon MRX causing radio interference

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.

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

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

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

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, 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

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

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

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

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