Zaon MRX causing radio interference 2

I'm starting a new thread on this topic as the old one sort of drifted
off-topic and its conclusions don't seem to reflect what I've found...

I have a Zaon MRX which is *using external ship's power* which is
causing radio interference. I know it's the Zaon because when the
radio goes to static, in flight, as if the squelch wasn't adjusted,
turning off the Zaon immediately stops the problem.

Following the recommendations of this forum, I've installed one, then
two, then three ferrite cores on the Zaon end of the power cord. Each
additional core has reduced the number of static problems I've had,
but not to zero (and not to where I don't have to frequently turn the
damned thing off!).

Calling Zaon tech support today (800-496-9430 x-311/312), they say
they have a particular problem with sailplanes -- something about our
radios being particulary sensitive because they're low power compared
to a larger, standard GA unit on a power plane.

As such, they don't have any real solutions for running with external
power. He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

Anybody have any other suggestions?

Eric

Eric,

We have installed our MRX in the panel, and so far without issues. I
put one large dia (non split) ferrite on the power line to to MRX.
Ferrites are designed to work at a particular range of frequencies, so
you might look into that. Also, run the power line through the core
3-4 times. each time improves noise suppression. Don't use the clamp
on half shell type ferrites because if the two halves are not
contacting, the ferrite does not do it's job. Otherwise, turn the
squelch up! ;-)

Matt

I have the same problem. The Becker radio has a separate battery
though. I have not tried ferrite cores.

What I found was I could stop the problem by applying inward pressure
on the power cable, but once I released the pressure it was back to
unsquelched radio. It stops also if I move the unit further away from
the radio. I cannot figure out why the problem is intermittent. I
would think it would constantly cause interference, but it comes and
goes.

I'd be interested to know if yours stops with pressure applied to the
plug.

I have not tried adjusting radio squelch settings as the radio is at
the bottom of the stack and the adjuster is buried within. And I
cannot force the problem to happen on the ground.

Bob

Itsaplane wrote:
As such, they don't have any real solutions for running with external
power. He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

1) Does the static problem go away when you use it's internal battery?
If it doesn't, your problem isn't the power lead and could be a radio
wiring problem, or maybe an MRX defect.

2) Have you tried another MRX to see if it has the same problem? Try to
borrow the newest one you can find, as the older ones did not have as
much "rf emission control".

3) Run a new power lead to the MRX directly from the battery terminals,
using shielded, twisted pair cable. Connect the shield to the negative
(-) terminal on the battery, along with the negative lead. Don't connect
the shield to anything at the MRX end. I believe this cable from Radio
Shack will work:

$9.89

50-Ft. Audio Cable - RadioShack.com
50-Ft. Audio Cable
Model: CL2 UL Approved | Catalog #: 278-513

Do the simplest - but still safe - installation to test the idea. You
can do permanent installation it works, including fusing the lead at the
battery.

--
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 Jul 22, 2:32*pm, Eric Greenwell wrote:
Itsaplane wrote:

* As such, they don't have any real solutions for running with external

power. * He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

1) Does the static problem go away when you use it's internal battery?
If it doesn't, your problem isn't the power lead and could be a radio
wiring problem, or maybe an MRX defect.

2) Have you tried another MRX to see if it has the same problem? Try to
borrow the newest one you can find, as the older ones did not have as
much "rf emission control".

3) Run a new power lead to the MRX directly from the battery terminals,
using shielded, twisted pair cable. Connect the shield to the negative
(-) terminal on the battery, along with the negative lead. Don't connect
the shield to anything at the MRX end. I believe this cable from Radio
Shack will work:

$9.89

50-Ft. Audio Cable - RadioShack.com
* * * * * * * * 50-Ft. Audio Cable
Model: CL2 UL Approved *| *Catalog #: 278-513

Do the simplest - but still safe - installation to test the idea. You
can do permanent installation it works, including fusing the lead at the
battery.

--
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" atwww.motorglider.org


I too have the Radio/Mrx intermittent squelch problem, as do 3 or more
of my club members; all of us are using an external battery source,
not all of us have a transponder, so I don’t think the transponder is
the problem. In my particular case, I'm using a separate/ dedicated
battery with shielded cable to power the MRX & Transponder.

A few observations:
1) The separate battery for my Mrx is not fully isolated as Eric
suggested above, but it is fully shielded up to the Positive and
ground busses at the panel, and the Mrx unit has been serviced and
upgraded recently.
2) The squelch problem does not occur when the internal battery is
used on the Mrx.
3) I’ve noticed, for example, I can be on 123.3 when the squelch
interference occurs however if I quickly switch to 123.5 or any other
frequency no open squelch is detected. I can then go back on the
original 123.3 freq. and the squelch problem is still occurring. This
odd Mrx squelch interference behavior has also occurred on other
frequencies, a complete mystery to me.

Perhaps a full isolation of the Mrx external power system will be my
next step as I’ve nearly run out of ideas. We seem to have a deep pool
of smart minds here; perhaps someone will be able to take up the
challenge of this annoying mystery that Zaon has so far failed to do.

21

Rick:

There is nothing surprising about what you describe. That is how
harmonic interference is likely to play out. Let's say for instance
that the MRX has a 9.5 Mhz microprocessor clock; the 13th harmonic of
that would be 123.50 Mhz. But microprocessor oscillators don't need
to be perfectly precise. If yours happens to be low by 0.2% then
yours falls on 123.30 and someone else will find interference on
another nearby frequency or not at all if the 13th harmonic happens to
land right between radio channels or on a frequency that pilot B never
tunes in. I have an MRX with sloppy external power connections and
have never had interference; so maybe I am the pilot B case. Of
course, I don't really know what clock freqencies are actually used in
the MRX and I don't know which harmonic is the nasty in this case --
my numbers are just for illustration.

Bob:

The business of pushing on the connector is most likely that your
fingers are capacitively coupling into the spurious radio propogation
path between the MRX and radio. The propogation path is shunted or in
some manner altered enough to make a big difference in the
interference that you are hearing. I'll bet that if you just squeezed
the connector without pushing you would find the same effect.

Steve Koerner
(retired EE)

"Itsaplane" wrote in message
...
I'm starting a new thread on this topic as the old one sort of drifted
off-topic and its conclusions don't seem to reflect what I've found...

I have a Zaon MRX which is *using external ship's power* which is
causing radio interference. I know it's the Zaon because when the
radio goes to static, in flight, as if the squelch wasn't adjusted,
turning off the Zaon immediately stops the problem.

Following the recommendations of this forum, I've installed one, then
two, then three ferrite cores on the Zaon end of the power cord. Each
additional core has reduced the number of static problems I've had,
but not to zero (and not to where I don't have to frequently turn the
damned thing off!).

Calling Zaon tech support today (800-496-9430 x-311/312), they say
they have a particular problem with sailplanes -- something about our
radios being particulary sensitive because they're low power compared
to a larger, standard GA unit on a power plane.

As such, they don't have any real solutions for running with external
power. He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

Anybody have any other suggestions?

Eric

Has anyone tried a cap across the power leads right at the Zaon's case?
I don't know what the connectors are like, so I don't know how close you can
go.
Inside the power connector would be ideal.
But a 25 volt or higher .01 uF in parallel with a .001 uF might help, and
shouldn't hurt anything at DC.

Tim Ward

On Jul 23, 12:50*am, "Tim Ward" wrote:
"Itsaplane" wrote in message

...



I'm starting a new thread on this topic as the old one sort of drifted
off-topic and its conclusions don't seem to reflect what I've found...

I have a Zaon MRX which is *using external ship's power* which is
causing radio interference. *I know it's the Zaon because when the
radio goes to static, in flight, as if the squelch wasn't adjusted,
turning off the Zaon immediately stops the problem.

Following the recommendations of this forum, I've installed one, then
two, then three ferrite cores on the Zaon end of the power cord. *Each
additional core has reduced the number of static problems I've had,
but not to zero (and not to where I don't have to frequently turn the
damned thing off!).

Calling Zaon tech support today (800-496-9430 x-311/312), they say
they have a particular problem with sailplanes -- something about our
radios being particulary sensitive because they're low power compared
to a larger, standard GA unit on a power plane.

As such, they don't have any real solutions for running with external
power. * He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

Anybody have any other suggestions?

Eric

Has anyone tried a cap across the power leads right at the Zaon's case?
I don't know what the connectors are like, so I don't know how close you can
go.
Inside the power connector would be ideal.
But a 25 volt or higher .01 uF in parallel with a .001 uF might help, and
shouldn't hurt anything at DC.

Tim Ward

Tim, are you recommending a polarized .01 and a ceramic .001?
I, too, have the dreaded ZAON issues.


Thanks,
Tim Larsen

On Jul 23, 4:06*pm, qflyer1 wrote:
On Jul 23, 12:50*am, "Tim Ward" wrote:



"Itsaplane" wrote in message

....

I'm starting a new thread on this topic as the old one sort of drifted
off-topic and its conclusions don't seem to reflect what I've found....

I have a Zaon MRX which is *using external ship's power* which is
causing radio interference. *I know it's the Zaon because when the
radio goes to static, in flight, as if the squelch wasn't adjusted,
turning off the Zaon immediately stops the problem.

Following the recommendations of this forum, I've installed one, then
two, then three ferrite cores on the Zaon end of the power cord. *Each
additional core has reduced the number of static problems I've had,
but not to zero (and not to where I don't have to frequently turn the
damned thing off!).

Calling Zaon tech support today (800-496-9430 x-311/312), they say
they have a particular problem with sailplanes -- something about our
radios being particulary sensitive because they're low power compared
to a larger, standard GA unit on a power plane.

As such, they don't have any real solutions for running with external
power. * He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

Anybody have any other suggestions?

Eric

Has anyone tried a cap across the power leads right at the Zaon's case?
I don't know what the connectors are like, so I don't know how close you can
go.
Inside the power connector would be ideal.
But a 25 volt or higher .01 uF in parallel with a .001 uF might help, and
shouldn't hurt anything at DC.

Tim Ward

Tim, are you recommending a polarized .01 and a ceramic .001?
I, too, have the dreaded ZAON issues.

Thanks,
Tim Larsen

At RF frequencies you want a ceramic capacitor.

As has been suggested here before by others you may also want to split
the power leads and feed through separate ferrite chokes so you are
filtering differential mode noise as sell. Although feeding both
though a small ferrite choke solved my RF interference problems.

Darryl

"qflyer1" wrote in message
...
On Jul 23, 12:50 am, "Tim Ward" wrote:
"Itsaplane" wrote in message

...



I'm starting a new thread on this topic as the old one sort of drifted
off-topic and its conclusions don't seem to reflect what I've found...

I have a Zaon MRX which is *using external ship's power* which is
causing radio interference. I know it's the Zaon because when the
radio goes to static, in flight, as if the squelch wasn't adjusted,
turning off the Zaon immediately stops the problem.

Following the recommendations of this forum, I've installed one, then
two, then three ferrite cores on the Zaon end of the power cord. Each
additional core has reduced the number of static problems I've had,
but not to zero (and not to where I don't have to frequently turn the
damned thing off!).

Calling Zaon tech support today (800-496-9430 x-311/312), they say
they have a particular problem with sailplanes -- something about our
radios being particulary sensitive because they're low power compared
to a larger, standard GA unit on a power plane.

As such, they don't have any real solutions for running with external
power. He did suggest either a) trying more ferrite cores on the
Zaon power lead (!), b) trying a ferrite core on the negative (?) side
of the radio's power lead, or for the sure fix c) running the Zaon off
its internal battery or a *separate* external battery other than the
one driving the radio.

Anybody have any other suggestions?

Eric

Has anyone tried a cap across the power leads right at the Zaon's case?
I don't know what the connectors are like, so I don't know how close you
can
go.
Inside the power connector would be ideal.
But a 25 volt or higher .01 uF in parallel with a .001 uF might help, and
shouldn't hurt anything at DC.

Tim Ward

Tim, are you recommending a polarized .01 and a ceramic .001?
I, too, have the dreaded ZAON issues.


Thanks,
Tim Larsen


Actually, I was thinking of a couple of ceramic surface mount chip caps
inside the power connector.
But having looked at the Zaon input power specs of 40 Vdc, I might go for 50
V caps.
However, since this is connected to wiring that doesn't have an alternator
to drive the voltage up and put spikes on it, you could make the case that
16 wvdc would be okay.

I don't own a Zaon, have never attempted this, attempt at your own risk,
etc.

But in theory, it shouldn't hurt anything.
Tim Ward