Matronics Email Lists :: View topic - Amps spike when transmitting on comm2

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Amps spike when transmitting on comm2

Matronics Email Lists Forum Index -> RV10-List

View previous topic :: View next topic

Author Message

rwwende

Joined: 12 Mar 2010
Posts: 23

Posted: Sun Jun 15, 2014 6:51 pm Post subject: Amps spike when transmitting on comm2

Any ideas what would cause my amp reading to spike when I transmit on my sl40.  I have the vpx-pro and advance flight 4500.  Every time I transmit on my comm 2 the reading spikes to 30 amps and I get the audible warning.  This does not happen on comm 1, GNS 430w.

flying-nut(at)cfl.rr.com
Guest

Posted: Sun Jun 15, 2014 7:12 pm Post subject: Amps spike when transmitting on comm2

I'd suspect a grounding problem .... either a floating ground or a 

ground loop.

First I'd swap antennas at the radio to see if the problem is in the 

coax and in particular the coax ground at the antenna, and second, I'd 

ring out the ground connections to the SL40.  If you have a comm panel 

I'd check that as the third guess.  Let us know what you find.

Linn



On 6/15/2014 10:51 PM, rwwende wrote:

 	  Quote: 	
		   



 Any ideas what would cause my amp reading to spike when I transmit on my sl40.  I have the vpx-pro and advance flight 4500.  Every time I transmit on my comm 2 the reading spikes to 30 amps and I get the audible warning.  This does not happen on comm 1, GNS 430w.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=424908#424908





 -----

 No virus found in this message.

 Checked by AVG - www.avg.com

rene(at)felker.com
Guest

Posted: Sun Jun 15, 2014 7:55 pm Post subject: Amps spike when transmitting on comm2

I have a similar problem with my sl30.  I talked to GRT and they recommended

that I put a balum on the wiring harness.  It appeared to clear up the

problem and then it happened again the other day.



More testing is needed.



Rene'

N423CF

801-721-6080



--

rv10flyer

Joined: 25 Aug 2009
Posts: 364

Posted: Sun Jun 15, 2014 7:56 pm Post subject: Re: Amps spike when transmitting on comm2

My SL-40 com 2 has similar issues(the only squawk in the plane since new). It is all wired/coaxed the same. I think the SL-40 puts out more power.

_________________
Wayne G.

johngoodman

Joined: 18 Sep 2006
Posts: 530
Location: GA

Posted: Mon Jun 16, 2014 5:26 am Post subject: Re: Amps spike when transmitting on comm2

 	  rwwende wrote: 	
		  Any ideas what would cause my amp reading to spike when I transmit on my sl40.  I have the vpx-pro and advance flight 4500.  Every time I transmit on my comm 2 the reading spikes to 30 amps and I get the audible warning.  This does not happen on comm 1, GNS 430w. 	




My setup is similar to yours. I haven't noticed large spikes, but I have noticed that there is a different "quality" between Comm 1, and Comm 2. Most of my comm issues I've been able to trace to the audio panel, so I would certainly keep that in mind.



John

_________________
#40572 Phase One complete in 2011

Mike Whisky

Joined: 05 Jun 2006
Posts: 336
Location: Switzerland

Posted: Mon Jun 16, 2014 6:17 am Post subject: Re: Amps spike when transmitting on comm2

John,

What did you do to the audio panel or what was the problem? I would not know how the audio panel could be involved in the problem. 



Regards

Michael

_________________
RV-10 builder (flying)
#511

maca2790

Joined: 26 Jan 2011
Posts: 59
Location: Australia

Posted: Mon Jun 16, 2014 2:19 pm Post subject: Re: Amps spike when transmitting on comm2

 	  rene(at)felker.com wrote: 	
		  I have a similar problem with my sl30.  I talked to GRT and they recommended

that I put a balum on the wiring harness.  It appeared to clear up the

problem and then it happened again the other day.



More testing is needed.



Rene'

N423CF

801-721-6080



-- 	


What form did the Balun take Rene'?

I think checking the Grounds as others have suggested is a good point. Or swap the Radios and Coax around and see what happens. You could try bypassing the current sensor with a .01 uf Capacitor.



cheers

John MacCallum

rene(at)felker.com
Guest

Posted: Mon Jun 16, 2014 3:50 pm Post subject: Amps spike when transmitting on comm2

It was just a magnet that wraps around the harness.  I bought several sizes

from the aviation department at Amazon and then used the one that fit.  More

test are called for.  I cannot test on the ground for the most part, only

happens in the air except when it doesn't...you know how that goes.



I have a hall effects sensor, where would the capacitor go?



I think I will try switching the antenna cables......



Rene' Felker

N423CF

801-721-6080

--

flying-nut(at)cfl.rr.com
Guest

Posted: Mon Jun 16, 2014 4:19 pm Post subject: Amps spike when transmitting on comm2

Now I'm curious.  would you post the part numbers for the hall effect 

sensor and the magnet???

I'm used to seeing ferrite cores on cables to reduce noise, but never 

magnets.  Most hall effect sensors are a 'switch' that gives a 0V/+V  

output and lack the processing circuits for an analog output.

Linn



On 6/16/2014 7:50 PM, Rene Felker wrote:

[quote] 



 It was just a magnet that wraps around the harness.  I bought several sizes

 from the aviation department at Amazon and then used the one that fit.  More

 test are called for.  I cannot test on the ground for the most part, only

 happens in the air except when it doesn't...you know how that goes.



 I have a hall effects sensor, where would the capacitor go?



 I think I will try switching the antenna cables......



 Rene' Felker

 N423CF

 801-721-6080

 --

rene(at)felker.com
Guest

Posted: Mon Jun 16, 2014 5:10 pm Post subject: Amps spike when transmitting on comm2

GRT CS-01 Current Sensor -- Current Sensor, +/- 100 AMP. Suitable for

aircraft

with 60 amp alternators.



It is a Ferrite Core....just clamped around the wire bundle.  

Rene'

N423CF

801-721-6080



--

toaster73(at)embarqmail.c
Guest

Posted: Mon Jun 16, 2014 5:34 pm Post subject: Amps spike when transmitting on comm2

I have a ferrite core around my fuel pressure wire because when I transmit

on the SL30 fuel pressure would go out of limits. The core knocked the

effect down enough to only a couple of pounds of pressure change. So not a

big deal now. More loops of wire through the core made for additional noise

ellimination (to a point).

-Chris



N9191AR



--

flying-nut(at)cfl.rr.com
Guest

Posted: Mon Jun 16, 2014 5:54 pm Post subject: Amps spike when transmitting on comm2

You'll get minimal noise reduction with the ferrite core clamped around 

the bundle.  A toroidal ferrite core with the signal wires wrapped a 

couple of turns would be better.  I'm wondering if your antenna coax 

runs near the wire that the HE is on.  A bad antenna coax could be 

coupling energy onto that cable and the HE is responding to it.  It's a 

WAG but possible.

Linn



On 6/16/2014 9:09 PM, Rene wrote:

[quote] 



 GRT CS-01 Current Sensor -- Current Sensor, +/- 100 AMP. Suitable for

 aircraft

 with 60 amp alternators.



 It is a Ferrite Core....just clamped around the wire bundle.

 Rene'

 N423CF

 801-721-6080



 --

johngoodman

Joined: 18 Sep 2006
Posts: 530
Location: GA

Posted: Tue Jun 17, 2014 5:16 am Post subject: Re: Amps spike when transmitting on comm2

 	  Mike Whisky wrote: 	
		  John,

What did you do to the audio panel or what was the problem? I would not know how the audio panel could be involved in the problem. 



Regards

Michael 	




Everything goes through my PMA9000EX. Which radio to transmit on, etc. It even records. There are split modes, swap modes, music, all kinds of junk. In short, there are a lot of wires, and a lot of things going on inside. Almost every comm issue I've had was solved by a quick "re-boot" of the audio panel.



John

_________________
#40572 Phase One complete in 2011

rwwende

Joined: 12 Mar 2010
Posts: 23

Posted: Sun Apr 19, 2015 4:11 pm Post subject: Re: Amps spike when transmitting on comm2

Well I think I finally found the cause of this problem.  The sl40 comes with 12" pig tail coax attached to the tray.  It has a nut type connector that pinches the shield to the connector, and it was loose.  I tighten the nut and it solved the problem.



The actual amp draw indicated on the vpx-pro when transmitting ranged from 2.5 at the higher freqs, and 4.5 at the lower freqs, 123.x and below.  The amp gauge on the EFIS only spiked when I transmitted on the lower freqs.



If you are having this issue, check the coax at the back of the tray.

Display posts from previous:

	Matronics Email Lists Forum Index -> RV10-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum