SV-intercom-2s music input

Dynon

Dynon Staff
Staff member
Joined
Jan 14, 2013
Messages
13,546
Location
Woodinville, WA
It sounds like either the intercom's or radio's squelch is being broken by noise/energy from somewhere. A few questions:

Is the radio receiving? You'd see that via the RX indicator on both the radio's display and the radio bar on SkyView's display.
If not, does any squelch position on the intercom change things, or even the RPM that it takes before the muting happens?
 

Pilotlight11

I love flying!
Joined
Mar 24, 2016
Messages
28
Location
College Station, Texas
I did fiddle with the squelch but not in a systematic way, so I need to retest that idea. This might prove fruitful as yesterday it did seem that at one point it took 2500 RPMS and then at another it only needed 2000 to cut out. Maybe I did change the squelch between those. I did think if I turned the squelch high enough it should keep it from happening, but I know that did not happen because I remember turning it up full, but again another test is needed. I'm going back tomorrow to sync the carbs again so I'll test then.

Filter is on order.

I don't always pay attention to which lights light up, but I do hear other transmissions and ATIS so I'm assuming it is receiving. I test it with a hand held I have when I need to.

I'm planning on flying to Sebring, FL at the end of the month to have a 600 hour inspection on the engine, so they might have some ideas since Lockwood Aviation probably works on more Rotax than anyone else in the US. If the engine/alt/electrical system is involved I would think they would know.
 

Pilotlight11

I love flying!
Joined
Mar 24, 2016
Messages
28
Location
College Station, Texas
:(I have more and different information, but still no solution.

On my set-up the squelch on the intercom is minimum at the 10 O'clock position.  Without the engine running if squelch is at minimum the music circuit is always muted. At 12 o'clock the music circuit is interrupted but plays some times. At 3 O'clock the music circuit operates normally.  Max squelch is at about 6.

With the engine running the music circuit works up to right at 2000RPMS , regardless of where the squelch is, and will not operate correctly above 2000.

Now, I have (I think) gained another piece of data.  Turning the com unit off and leaving the intercom unit on and the music circuit works up through 3500 rpms. I assume it will work up to 5000.

If I push the squelch button on the com unit (which turns the squelch off) it is fairly obvious (to me at least) that I am hearing a lot of engine interference.

So I went into the com menu and turned the squelch from 50% TO 80% - that had no effect.  I also varied the side tone, but that did nothing either (did not expect it to).

When I go into the menu for Mic Gain it has the notice that 50% should work and gives instruction on varying the gain while continually saying "test" until "good" shows up on the menu - well, no setting would produce "good" - it always shows "low".  Just reporting - not thinking that is involved.

SO, it seems the com unit is interfering with the intercom vis-a-vis the music circuit.  I will have to say that the amount of "noise" from the com unit when its squelch is disabled is very substantial, though it does not interfere with com traffic when the squelch is on.

Does this give anyone any better ideas? 

The installation manual for the com unit suggest putting a VSWR meter between the unit and the antenna to test the ratio. That brought to mind that I used the antenna that was already installed which was for a Garmin SL40. Does this raise any alarms? IS this a test I need to perform? If so is there an inexpensive way to do this?

THanks
Bob
 

jfrii52

I love flying!
Joined
Jan 4, 2019
Messages
2
I am having the same issue regarding music input through the intercom. Mutes at anything over 2000 rpm. Has anyone come up with a possible fix to this. Been fighting it since day one. Checked and re-checked grounding/shielding. I do have a couple items plugged into a cigarette lighter type receipt but not the music source.
 

Raymo

I love aviation!
Joined
Apr 25, 2016
Messages
794
Location
Richmond Hill, GA
Joe,

Need more information about your setup but one thing to check is that your spark plug wires are shielded.
 

jfrii52

I love flying!
Joined
Jan 4, 2019
Messages
2
Ray
Thanks for getting back to me. No - plug wires are not shielded. My setup is all Dynon (Display, Com, Intercom). I do not have a Xponder. Tach wire is shielded as are all the radio/intercom/headset cables. Ignition wires from engine (912ULS) are not shielded. I have a filter ordered that installs between the I-pad OUT and intercom IN but something tells me that is not where the problem is. Joe
 

Raymo

I love aviation!
Joined
Apr 25, 2016
Messages
794
Location
Richmond Hill, GA
I would bet that the unshielded plug wires are your issue. Maybe others with your setup could chime in with their experience?
 

n456ts

Do not write below this line
Joined
Jan 24, 2015
Messages
161
I would bet that the unshielded plug wires are your issue. Maybe others with your setup could chime in with their experience?
It's not an issue with Rotax ignition systems.
 

n456ts

Do not write below this line
Joined
Jan 24, 2015
Messages
161
I would make sure your shielding isn't carrying current. The shielding need to be bonded at only one end and are connected to a non-current carrying ground.
 
Top