Ask Sail: VHF Whine - Sail Magazine

Ask Sail: VHF Whine

Author:
Publish date:

NOISE ON THE BOAT NEGATIVE LINE

Q: I have a new fixed-mount VHF radio, and I have severe alternator whine on both transmit and receive. My old radio did not, even though it was on the same 12V DC line. The manufacturer says new digital radios are more sensitive to alternator noise. However, I had my Balmar 100-amp alternator rebuilt, it checked out, and the noise persists when running the engine. I’ve also tried chokes, added grounding and added more filters that Balmar suggested, with no success. The only thing that did work was your earlier suggestion of trying the radio on a small 12V DC battery. (Except when I touched the black wire to the ship’s DC negative black wire.) I need this lifesaving radio to work when underway under power.

Bill Ailes, Hartsville, PA

GORDON WEST REPLIES

Try the 12V DC line rewired directly to the battery as a test. Red to battery positive. Black to battery negative, NOT to a convenient ship ground point. Run the engine. If you still have noise, have Balmar contact me, so I might better understand why their alternator whine is bleeding through the DC output of their gear. If memory serves you have conventional flooded battery. Therefore, with your well-filled battery acting as a giant noise buffer capacitor, the alternator should not make noise on transmit and receive. Got a well-watered battery? When a ship’s battery runs low on electrolyte, it can no longer buffer noise. Check for water over the top of the plates.

January 2018

Related

Outremer45

Boat Review: Outremer 45

It’s funny the way things that work right almost inevitably tend to look right as well. Case in point: the Outremer 45, a catamaran that can’t help but turn heads with its large rig, nicely sculpted cabintrunk and narrow, purposeful bows. Better yet, under sail the boat more than ...read more

Sunset-Tyrrel-Bay

Charter: Glorious Grenada

In the wake of the hurricanes that devastated the Virgin Islands last year many charterers ended up going farther south to Grenada and the Grenadines where they found the sailing excellent and the vibe just fine“God must have been a sailor when he created the Caribbean,” a friend ...read more

WaterLinesNov

Waterlines: Tangled Up in Pots

I learned to sail on the Maine coast as a boy, and one of the things my elders taught me was to respect fishing gear. If you got caught up with a lobster pot, you did everything you could to get clear without cutting the pot warp. It represented a family’s livelihood and thus was ...read more

7353

Harken’s Reflex 3 top-down Furler

Furl PowerAre you afraid of flying—spinnakers, that is? Harken’s new Reflex 3 top-down furler will tame A-sails on monohulls from 44-58ft and multis from 39-55ft, and Code 0’s on 39-54ft monos and 36-50ft multis. All you do is heave on the furling line and the sail will roll up ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell.Got a tip? Send it to sailmail@sailmagazine.comDitch the stress Owners of high-freeboard yachts best boarded via the stern sugar-scoop like to back them into a slip, but the process can be fraught on a windy day or when there’s a current running, ...read more