Zaon MRX causing radio interference 2

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.

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