Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Display Modes
 
Old 10-16-2020, 12:10 PM   #11
Senior Member
 
arctictraveller's Avatar
 
Join Date: Mar 2013
Posts: 4,234
"Sometimes the solution to problems like this are multi-pronged, i.e. a "Belt, Suspenders, AND Duct Tape" kind of solution. I'll watch this thread for future developments."


I just installed new LED headlights, so I'll be interested in seeing where this thread leads, although I don't use the Am / FM radio. I do have an RFI issue though that may be related. My 2M / 440 ham rig will cause a hard reset in my stereo once in a while when I key up. Got any insight on this one?

__________________
Arctic Traveller
KC6TNI
2001 GTRV
Advanced 4wd
Agile Ride improvement package
arctictraveller is offline   Reply With Quote
Old 10-16-2020, 01:08 PM   #12
Member
 
Timerider's Avatar
 
Join Date: Apr 2020
Location: Bishop, CA
Posts: 57
@A.T.: My "two cents" is probably much too wordy, so insert my heartfelt apologies here, but it would still read as follows:

The laws of physics are, of course, the same in both cases of possible/probable EMI, but there are some key differences in your ham radio case: 1) we can safely ASSUME the presence of a radiating RF source, i.e. your transmitting antenna, 2) there may be excessive unwanted coupling between the ham rig antenna and the stereo receiver's antenna, and 3) there may be a sudden voltage transient on the 12V supply caused by the transmitter of your ham rig turning on, which differs from the HID headlight case, in that the interference/problem with the HIDs is apparently continuous and steady-state, whereas your ham rig creating a hard reset of your stereo sounds like a transient condition/problem.

I'm always a fan of checking the basics first, just to try and avoid unwarranted assumptions, so let's pursue number 3) first - just for giggles. The justification for doing so is that there's an old rule of troubleshooting that goes something like: "When you hear hoofbeats, expect horses, not zebras." (unless you're in Africa, of course). So if the stereo reboots immediately when you "key up", and doesn't continuously remain in some kind of "reset" state while you're talking, then the first suspect in my mind would be a voltage transient on the 12V supply to the stereo. (Any chance your 2-meter / 440 MHz ham rig draws its power from a point that is both somewhat distant from the battery and also fairly close to where the stereo gets its power? Like the fuse block?)

The first test that I would perform is to grab a digital storage oscilloscope (if you have one), or maybe a good smart digital multimeter with "glitch capture" or Min/Max recording capability, and monitor the voltage to the stereo, measured at a point that's as physically close to the stereo itself as possible. Check the basic DC level first, with the stereo turned up as loud as you would normally be playing it (to simulate the Max. or at least "representative" power demand.) Then, look for glitches with the MIN/MAX or glitch-capture mode while you "key up" the ham rig a few times. Look for brief voltage transients that drop the voltage below about 10 Vdc or so when you press the transmit button. Some audio equipment manufacturers go cheap on power supply filtering, and also set their power-on-reset circuits a little on the "sensitive" side.

If you find these kinds of low-voltage transients, then a large-ish filter capacitor (and maybe a few smaller ones as well) on the 12V supply to the stereo, located as close to the stereo's power input terminals/wiring as possible, or maybe installing larger-gauge wires to supply power to your stereo, might be the first solutions to try.

If you have any further thoughts or questions about this, feel free to PM me!

Mike

P.S. If you're not using the "AM/FM radio", what kind of "stereo" is this? Are you playing CD's or something? 8-tracks? (Just kidding.) And if so, how loud do you have your stereo turned up? Is it drawing a lot of power through possibly under-sized 12V supply wires? Are you transmitting with more than just a few watts out of your ham rig to punch through the QRM? Sorry for all of the post-scriptum questions, but you've engaged my curiosity - at least a little bit.
__________________
"Silver Kitten": 2002 E-350 7.3 RB-50 SMB Quigley 4x4, Agile RIP-kit
"My Metal Mistress": 1982 Cessna T182 - "Sleeps 0, but leaps tall mountains in a single bound."
Timerider is offline   Reply With Quote
Old 10-16-2020, 03:15 PM   #13
Senior Member
 
REDOVAL's Avatar
 
Join Date: Jan 2015
Location: Lomita, CA
Posts: 851
Garage
Quote:
Originally Posted by arctictraveller View Post
"Sometimes the solution to problems like this are multi-pronged, i.e. a "Belt, Suspenders, AND Duct Tape" kind of solution. I'll watch this thread for future developments."


I just installed new LED headlights, so I'll be interested in seeing where this thread leads, although I don't use the Am / FM radio. I do have an RFI issue though that may be related. My 2M / 440 ham rig will cause a hard reset in my stereo once in a while when I key up. Got any insight on this one?
Where is your ham radio power lead connected to? I assume you are using the factory wiring for the audio receiver in the dash correct?

My ham setup (also 2m/70cm Yaesu FTM-400XDR) has no interference issues or noise related to my audio system (very large setup). It is wired directly to a battery distribution panel that is independent from any factory wiring.

Scott
__________________
2002 Ford E350 V10 Traveler
Vantage Optics Headlights
www.VantageOptics.com
REDOVAL is offline   Reply With Quote
Old 10-16-2020, 06:40 PM   #14
Senior Member
 
Join Date: Dec 2015
Posts: 144
Quote:
Originally Posted by arctictraveller View Post
I just installed new LED headlights, so I'll be interested in seeing where this thread leads, although I don't use the Am / FM radio. I do have an RFI issue though that may be related. My 2M / 440 ham rig will cause a hard reset in my stereo once in a while when I key up. Got any insight on this one?

Since it's VHF/UHF, I'm assuming it's 50W output, so maybe 100W draw (probably less, since it's likely a class C amp rather than class A or AB). Unless you really chose poorly on your source for power and ground, I doubt that it's a power draw issue. Have you checked your antenna's VSWR? because symptoms like you describe are usually due to RF coming down the outside of the cable due to a mismatch. If so, tune your antenna and/or put ferrites on the cable to choke the RF off the shield. Also make sure that where you mounted the antenna has a good ground to the chassis - a lot of the metal elements on the van aren't well bonded to ground.
Wowbagger is offline   Reply With Quote
Old 10-17-2020, 11:13 AM   #15
Senior Member
 
arctictraveller's Avatar
 
Join Date: Mar 2013
Posts: 4,234
My apology's to the original poster, it seems I have completely derailed his thread, sorry. I've gotten some good ideas though, but it's probably best if I start a different thread. Never the less, thanks for the replys, there are a couple things I'll check.
__________________
Arctic Traveller
KC6TNI
2001 GTRV
Advanced 4wd
Agile Ride improvement package
arctictraveller is offline   Reply With Quote
Old 10-21-2020, 12:46 AM   #16
Orv
Senior Member
 
Join Date: Sep 2018
Posts: 619
Garage
There's a lot of trial and error in this stuff. I'd be tempted to try a small capacitor across the positive and ground wires of the headlight harness, close to the light. Maybe 0.1 uF or so -- a ceramic disc capacitor should be fine, and the exact value doesn't matter. The idea is the capacitor doesn't conduct DC, but forms a low-impedance path for RF. This might work well in combination with ferrite beads (which create higher impedance for RF.) The idea is to prevent the wiring harness from becoming an antenna that radiates the RF noise created by the lights.
__________________
N8SRE
1990 E-250 Sportsmobile w/ penthouse top, converted when new by SMB Texas.
Orv is offline   Reply With Quote
Old 11-07-2020, 09:18 AM   #17
Senior Member
 
bigriver's Avatar
 
Join Date: Feb 2014
Location: Columbia River Gorge
Posts: 649
Thanks to all y'all for all the great info and no worries AT on the hijack. I posted this right before a trip and lost track of it in all the hustle of getting ready and then the trip itself. Hopefully you got yours figured out.

My specific problem is my FM reception is negatively effected when I turn on my new HID headlights. It's not a variable whine that might be associated with engine rpms but more like the FM station has become much farther away. I run with headlights on at all times and dealt with the issue so far by turning them of when listening to radio but I'm going to need to get this figured out eventually.

So - with all that said - do we think this is a head unit grounding issue or something else?
__________________
Joe
2003 EB50 7.3L PSD Q4X4
2000 Chevy Express 3500 High Top EB37 - Sold
2003 EB30 - Sold
bigriver is offline   Reply With Quote
Old 11-07-2020, 10:01 AM   #18
Senior Member
 
moorefc's Avatar
 
Join Date: Feb 2009
Location: PNW or maybe Baja Sur
Posts: 381
Quote:
Originally Posted by bigriver View Post
Thanks to all y'all for all the great info and no worries AT on the hijack.
So - with all that said - do we think this is a head unit grounding issue or something else?

Perhaps you could describe what you have done, given the advice, etc. That way others would have something to go on......
__________________
Pac NW and warmer places
1995 E250 EB 5.8 2WD on to a new owner
2006 E350 EB Elect Top 2WD
moorefc is offline   Reply With Quote
Old 11-07-2020, 11:18 AM   #19
Senior Member
 
bigriver's Avatar
 
Join Date: Feb 2014
Location: Columbia River Gorge
Posts: 649
Quote:
Originally Posted by REDOVAL View Post
As mentioned above you should look into relocating the grounds and making sure they are properly done. I have not had this issue with any of the ones I have personally installed. I recommend using the factory ground studs on both sides of the body on the engine side of the core support.

Scott Thompson
Vantage Optics
Right. Install instructions show a chassis ground lead coming off the harness but I don't recall there being those leads on the ones I received so there is no chassis ground. I'll take it all apart and see where I went wrong... wouldn't be the first time Thanks all.
__________________
Joe
2003 EB50 7.3L PSD Q4X4
2000 Chevy Express 3500 High Top EB37 - Sold
2003 EB30 - Sold
bigriver is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Sportsmobile SIP or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 10:50 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.