tek_dmn,
@tek_dmn@mastodon.tekdmn.me avatar

Okay #hamRadio people, question time.

It seems that like 75% of the QRM in my vehicle is the stereo system. A certain amount is the subwoofer amp, most definitely, but just power cycling the headunit is enough to see a noticable S-meter change (from like S2 to S6). Knowing that my power lines are (unfortunately) ran together, and that it would take basically ripping apart my entire dash (for the 4th time) to re-do any wiring back there, any ideas on what I can do to mitigate this, without re-cabling my entire frontend (or moving things, since my radio placement is... kinda permanant for better or for worse on top of the dash)

#amateurRadio

weezmgk,
@weezmgk@mastodon.social avatar

@tek_dmn Could put some toroids on the power input to the sub amp power supply. If you're presently using chassis ground as your battery return, put a return cable to batt negative of the same gauge as the B+. Bear in mind that if you put toroids on the CAN bus line, it could disable it if that isn't a shielded cable already. Same thing happens if you put toroids on ethernet cables which are unshielded. Good luck

tek_dmn,
@tek_dmn@mastodon.tekdmn.me avatar

@weezmgk And now comes the part where I list off everything I forgot already existed.

  1. Already have a toroid on the sub positive line, if I'm not mistaken, though I might actually have it on the ground, don't ask, the sub has been the cause of a LOT of other weird electrical issues and putting a choke on a few grounds mostly took care of them. Then again, those are likely unnecessary because...
  2. Everything is wired directly to battery negative right now.
  3. All of my wiring is mostly separate from everything else in the vehicle. The sub power lines run along the driver side floor, and the sub audio lines run across the passenger side, along with the sub control line (asserts amplifier on/off state) and the antenna feedline.)
weezmgk,
@weezmgk@mastodon.social avatar

@tek_dmn I guess the only remaining thing to do is take the sub amp out and shoot it.

If this is not an OEM sub amp, maybe consult with the mfr?

tek_dmn,
@tek_dmn@mastodon.tekdmn.me avatar

@weezmgk Most definitely not OEM for the car, hah. Putting everything I have into a tiny little Hyundai (I know, I know) scares me at times.

What gets me though, is I can manually power the sub off just by removing the control line from the connector block. I still get interference which means while it's part of the issue, my stereo headunit itself seems to be the primary culprit, which is just... weird.

weezmgk,
@weezmgk@mastodon.social avatar

@tek_dmn If this is a new piece of kit, I would try returning or exchanging it. The filtering in the switchmode Dc-dc converter to bump 13.8 to 40-50ish muat have probs. Do you hear any trash in the audio output?

tek_dmn,
@tek_dmn@mastodon.tekdmn.me avatar

@weezmgk Subwoofer output, everything is normal, as expected.

Radio output, unless every trucker (and my father who's an audio engineer) have lost their ears, everything is clean.

Now, I can tell you that the radio QRM is indeed affected by the sub, if I drop the squelch I can hear it.

weezmgk,
@weezmgk@mastodon.social avatar

@tek_dmn Rats.

If you can return or exchange it for a different brand unit, I would.

NB: QRM is man-made noise, may imply intentional or malicious noise. QRN is natural or environmental noise.

tek_dmn,
@tek_dmn@mastodon.tekdmn.me avatar

@weezmgk And I'd argue that interference from the systems that I installed would count as man-made. :taz_blep:

weezmgk,
@weezmgk@mastodon.social avatar

@tek_dmn weeelll 🤔

  • All
  • Subscribed
  • Moderated
  • Favorites
  • hamradio
  • DreamBathrooms
  • mdbf
  • ethstaker
  • magazineikmin
  • GTA5RPClips
  • rosin
  • thenastyranch
  • Youngstown
  • osvaldo12
  • slotface
  • khanakhh
  • kavyap
  • InstantRegret
  • Durango
  • provamag3
  • everett
  • cisconetworking
  • Leos
  • normalnudes
  • cubers
  • modclub
  • ngwrru68w68
  • tacticalgear
  • megavids
  • anitta
  • tester
  • JUstTest
  • lostlight
  • All magazines