alpinelakespilot2000
Well Known Member
My panel is firing up this week and I've noticed a noise issue with my GPS that I could use some help troubleshooting:
Step 1: tested intercom system: it works fanastically with both headsets and with my mp3 music input-no unwanted noise anywhere.
Step 2: I added the Lowrance 2000c GPS and powered it up using AA batteries. No noise in system at all.
Step 3: when I powered up the GPS using the power cord attached to my avionics buss and avionics ground buss I noticed that it introduced a relatively quiet but high-pitched tone into my intercom/headphones.
Step 4: I found that if I powered the GPS through the panel mounted power port (cigarette lighter), also grounded at the av. buss, the noise remained as in Step 3, but got quieter.
Step 5: In experimenting further, I found that if I used the power coming from my av. buss but removed the ground from the avionics ground buss and grounded it against the airframe elsewhere, the tone remained but got really quiet. I almost wouldn't notice it if I wasn't looking for it.
Thus, the main issue seems to be with the GPS ground wiring. Any suggestions on how to remove the noise entirely?
Thanks.
Step 1: tested intercom system: it works fanastically with both headsets and with my mp3 music input-no unwanted noise anywhere.
Step 2: I added the Lowrance 2000c GPS and powered it up using AA batteries. No noise in system at all.
Step 3: when I powered up the GPS using the power cord attached to my avionics buss and avionics ground buss I noticed that it introduced a relatively quiet but high-pitched tone into my intercom/headphones.
Step 4: I found that if I powered the GPS through the panel mounted power port (cigarette lighter), also grounded at the av. buss, the noise remained as in Step 3, but got quieter.
Step 5: In experimenting further, I found that if I used the power coming from my av. buss but removed the ground from the avionics ground buss and grounded it against the airframe elsewhere, the tone remained but got really quiet. I almost wouldn't notice it if I wasn't looking for it.
Thus, the main issue seems to be with the GPS ground wiring. Any suggestions on how to remove the noise entirely?
Thanks.