Boat Forum / Electronics / March 2008

I posted this on another bulletin where a contributor had bonded all
his underwater metal with 1" copper straps and needed to test.  Copied
here for anyone having electrolysis problems.
An ohm meter is a poor way to check bonding connections.  I use a 12

What are a couple or three antenna tuner for mast/sloper sailboat antennas?

I am thinking of writing my own navigation software.
Not to save money, but just for the fun of it, and
because I would like it to be an "open system" so that
I can easily add features to it from time to time.

Jack,
I found that with the 540 in Garmin/Garmin i/o mode I could indeed
upload a set of way points from a route generated by my old Navmaster
III program without invoking an additional SD chip but although this set

I'm an old ham on the air for many years.  I have helped hundreds of
people get their licenses over the years from a 7-year-old boy to an 88
year old man and his 84 year old "honey".
One of the biggest mistakes people studying for their ham licenses of

Dear Group:
Any recommendations for an HDTV antenna to be installed on the mast
below the radar antenna?   Also, does it really need to be "amplified"
by 12 volts of juice?  The thirteen year old antenna now on the boat

I have on board devices from Raymarine, working under SeaTalk protocol
and also a Raystar plotter using a NMEA GPS signal. On the boat there
is a NMEA to SeaTalk Bridge Unit, so exists a "mixing" of all the
data. Upto now : no problems !

Good day all
One newbie here needs a bit of help regarding sounder
wattage. All other variables being equal, how much
advantage is a 1KW (Tru The Hull) sounder over a similar

I have a brand-new grand Banks currently being commissioned-  it has
8D AGM batteries.  The starting battery has been slowly discharging -
it has been at 11.9 V for the past 10 days and is now down to 11.8.  I
have tried to alert the yard to this problem and they say they will

Our unit worked perfectly until we switched boats. When we purchased
the radar (used) the seller gave us a hand-drawn diagram to wire the
radome with. Has been rewired several times over the years but this
time "somebody" lost the diagram - and no, it wasn't the same as the

The 540s plotter/sounder can display graphical tidal data but only seems
to display this data for stations within ~30nm of plotter gps location
but "animated" present tidal data is available anywhere the chart is panned.
Is there any way around this limitation since it makes trip ...

I was recently off the coast of Mexico and using a Garmin
chartplotter for position. My friend came up and chided me for being
inside the 5 mile buffer he prefered to be off the coast. I insisted
we were at five miles based on the GPS reported distance to the Punta

I am interested in buying an ICOM IC-M802 HF Marine transceiver. If it
has been modified (openned up) to operate on the Ham bands, that would
be great...if it hasn't that is OK too.
I have seen a number of used units available lately. Recent selling

What would make a zinc dissolve while at sea??  We have no generator or
inverter.
Would a SSB cause it?
No other boat or land around..