GPS & RADIO INTERFERANCE

[tkcenterline]

I have a Rayathon deck mount GPS and a Hummingbird marine radio. I leave the radio in the scan position. When I turn on the GPS, The radio will pick up a thump, thump, thump, thump, thump sound. This interferance will not allow the radio scanner to work. I can not get rid of the thumping, even if I turn up the squalish. As anyone else had this problem. If so, how do you get rid of it. Someone told me to cover the cables with alum foil. I tried this. Doesnt work!! Help!!

 

[18rabbit]

Re: GPS & RADIO INTERFERANCE

A couple things could be happening. The GPS may be the source of the problem for one (or both) of a couple reasons. (1) Electrical interference and/or (2) inadequate conductor(s).<br /><br />(1) Electrical interference with VHF is a common problem that is usually easy to solve with a noise filter. You can filter the noise at the source (if known) and have a ‘clean’ system from that point on or you can filter the current going into the radio. I use Newmar filters…have a 100-amp filter right at each alternator’s output. The PC-10 (10-amps) is ideal for filtering the power going into your VHF (about 5-amps when broadcasting).<br /><br />Newmar’s website www.newmar.com<br />See info on noise filters http://www.newmarpower.com/pdf/Manual-PC Filters.pdf <br /><br />(2) Before you buy a filter, verify your conductors (wiring) is sized appropriately for the current, load, and length. You may be experiencing a condition where the GPS’s head is pulsating the available power in the wiring due to inadequate conductivity. If your wiring is too small, sharing power/ground or daisy chaining, battery voltage is too low, the current drop is excessive due to long wire runs, corroded connections, etc … anything that can interfere with conductivity, your VHF will let you know about it.<br /><br />Start by checking the wire…continuity (pwr/gnd connection directly to the battery?) wire size? and contacts (clean?). If everything looks good there, start looking at filters.<br /><br />EDIT: About the aluminum foils on the wires thing…you should have a clean connection for the foil directly to the battery’s ground (or grounding plate), not shared with anything else.