Electronicity   

Rick "C_Language"

Breakers and fuses are the primary devices used to prevent fire and other damage due to excess current flow. These devices will open an electrical circuit when the current exceeds a specified limit.

Most common uses are:

1. To prevent damage or fire due to overheating of conductors. In this case, it is important to note that the fuse or breaker should be near or at the source of the power. A fuse at the load end of a conductor will do no good if the conductor is somehow shorted to ground or other return path.
2. To limit or prevent damage to electrical devices sourcing or receiving electric power. In this case it doesn't matter where the fuse is.

Safety Tips:

1. Locate the fuse or breaker as close as possible to the source of power. It is common for supply cables of electronic devices like VHF radios to have a fuse near the radio end of the cable. This fuse is intended to protect the radio. The source end of the cable must also be protected to prevent the cable from bursting into flames if there is a short circuit along the cable.
2. Make sure that all conductors connected to a circuit are sized appropriately for the protection device. A common hazard is to tap off of an existing circuit to power a device like a lamp or fan. More than once I have seen fans supplied with 22 gauge wire connected to circuits protected with a 20 amp breaker.

Comments:
Two fuses are better than one.
ABYC calls for the fuse to be within 7" of the power source with the exception of the starter circuit.

(also Tech Net fuses)

Dave "Dyad"
This would include things like the windlass and watermaker, etc.

Tip: Check brushes once in awhile. If they are worn and touch the commutator, the commutator may be seriously damaged.  A ten dollar fix becomes a high dollar fix.  Replacement brushes are recommended.

Query: What's the main cause of brush wear?
Dave: Arcing.  It literally erodes the brushes. Usually the positive one wears fast.  Not allowing the motor to stop before changing directions wears them down extremely fast.

(also Tech Net electric motors)

Dave "Dyad"
Almost everything onboard is contaminated with salt.
It's important to use non-acid flux when soldering.

The use of heat sinks is a subtlety. Use too much and it removes heat from the solder.
Comment:
Use a wet shoe lace as a heat sink. (Salty Paws)

Query: Would rosin core flux work?
Dave: It doesn't work well in the long term, but it looks and works good when first applied.  It eventually turns crumbly.

Comment:
Solder made for electrical connections works best.
Dave: Yes, look for electrical solder specifically.

(also Tech Net soldering iron)

Rick "C_Language"
1.  Have a good antenna system with good connections.

2.  Look for electrical noise sources on the boat which are not always obvious.

3.  Turn RF gain up. (Not to be confused with AF - audio frequency.)  Turn squelch off if having problems.

4.  Use stereo headphones. This really helps eliminate ambient boat       noise.

5.  Try the noise blanker.

6.  Time constant on AGC (automatic gain control): Adjust to "fast" to improve reception.

Comments:
Noise blanker helps with wind generator noise. (Hosanna)
Blanker helps eliminate gas generator noise from other boats in the anchorage. (Salty Paws)

Issue: Danfoss refrigerator makes a lot of noise.
Rick: Add a choke on power line. Capacitor can reduce the noise but not eliminate it.

Issue: When engine is running the reception is poor.
Rick: The alternator is most likely the cause. Disconnect the alternator.
First test to see if it really is the cause.
Comment:
Turning off the alternator really helps. My regulator is now on a toggle switch. (Shamal)
Engine control panel may be causing the noise.

(also Tech Net  single sideband)

Rick "C_Language"

1. Tune your antenna before your first transmission after selecting a new frequency band.
    If your rig has a tune button use it, don't depend on the auto tune function. Depending on auto tune can cause the first part of your transmission to be low or missing (also known as clipping.)  For example, when transmitting, "Southern Sails" only "ails" is sometimes heard. It is okay to have the auto tune function enabled in case you forget to use the tune button.

2.  Select high power especially when checking in on a net. Don't assume that the receiving station has good conditions on their end.
    Exceptions: When using your rig for email, select the lowest power that will work. SailMail and Winlink will usually work on low power (~20 watt.) Also if you know that propagation is good to the receiving station, select a lower power. Selecting a lower power will save battery, extend your radio's life, and is less likely to interfere with receiving stations.

3.  Speak loudly.
Marine radios are set to minimize background noise like wind or engines. If using a Ham rig, make sure that settings for mic gain and ALC (Automatic Level Control) are set appropriately.

4.  Make sure DC power at the radio is good and batteries are charged.
Verify voltage is good to radio during transmit. Should be less than 1 volt drop between battery and radio power terminals.

5.  Turn off any high current equipment that can cause interference on the power supply to the radio.  Inverters and battery chargers are typical sources of noise.

6.  Have a good ground plane. Copper foil is much better than wire due to "skin effect."

Query: How to change power output settings for Icom 706?
Rick: Recommend reading the manual for your radio.

Comments:
Location of the microphone to mouth. Marine microphone recommends speaking directly into the mic, assuming wind. (Le Bella)
Speak sideways into the mic to avoid air puffs. (St Jude)
Use low power if in close proximity. (Salty Paws)
Shore power ground increases reception interference. Better to D/C shore power. (Destiny)
Tune by whistle on low power. Use RF power button on Icom 707 to decrease power. (Le Bella)
Change to FM mode instead of whistling. CW or FSK work too. (Salty Paws)

(also Tech Net Icom)

If you need a long jumper wire for testing AC circuits, buy a cheap extension cord.  Cut the female end off, then plug into a standard wall outlet. (Bees Knees)

GTO cable can be made by stripping the ground braid from standard RG8 coax.

Dip It Whip It can be used on ends of wire to keep them from fraying. (Shining Star).

Rick "C_Language"
Volt Meters are also known as MultiMeters
Typically a MultiMeter will include an Ohm (unit of resistance) and Amperage functions. User should take care not to overload the meter especially in the Ohm or Amperage mode. While using these functions, significant current must pass through the meter and if connected to an active power source. It can draw too much current.  Most contain low current fuses to protect the meter and some are user replaceable.

Here is one common pitfall with using a voltmeter to verify a voltage supply to a device; measuring the voltage without the device connected or while off. Modern voltmeters draw near zero current and if there is some higher than normal resistance in the conductors, connectors, or switches the meter will still likely read full voltage, but once loaded by the device it may drop to a voltage lower than required. To avoid this pitfall, measure the supply while loaded. That is with the device on and consuming full power. With electronic devices you can not always depend on it to load the supply when there is not adequate current or voltage at the device. In this case the device may fail to turn on and load the supply. When in doubt that the device is providing a load, you can use a light bulb (one that will draw significant current) as a load.

Another pitfall is the use of the Resistance (Ohm) function to verify continuity.  It is best to use the lowest Ohm scale as the higher ones may give a false indication. For example when verifying that a switch is good using the KiloOhm it may appear to be good when in fact it is highly resistive. Also, when testing for high resistance make sure your fingers are not touching the probe ends as this could result in measurement of your body's resistance in parallel with the resistance you are trying to measure.

Some Multi Meters are available with Clip-On current measurement probes. While the conventional Amp Meter requires that the probes be in series with the load, the Clip-On type works by measuring the magnetic field produced by current flowing in the conductor. It is important to note that only one conductor should be in the core of the probe. If more than one conductor and the current is flowing in equal magnitude but opposite directions there will be a net of zero magnetic field and the probe will measure zero current. Note that many Clip-On current probes are AC only and will not measure DC current flow.

Thanks to the Sailing Vessel Cat Tales for info on a Multi Meter with Clip-On amp probe that will measure DC current flow: Sears model 82369.

Comment:
Alligator clips are handy to use for diagnostics. (St Jude)

Dave "Dyad"
1.  Use the right terminal; yellow, blue, or red, depending on wire size  If larger than normal terminal must be used, fold the wire back.

2.  Use the right tool for crimping.
     a) Plier type (most common).
     b) Compound lever type (more expensive, good for larger yellow terminals)
     c) Vice grips (only in a pinch) :)

3.  Use your favorite anti-corrosive before crimping for moisture exclusion.  WD-40 is a good choice.

4.  Use heat shrink tubing for support and protection. Or use silicone. Allow to cure before installing.

5.  Do a pull test. It should be able to take 5-10 pounds of tension. It's better to know now than to have failure later. 

Query: Are wire nuts recommended?
Dave: They're not perfect due to vibration. Heat shrink is better.

Query: Can Vaseline be used for anti-corrosion?
Dave: It fails in high heat situations. Acid-free polysilicone is better.

Comments:
Wire ends are in danger of being cut off if using wrong size connectors. (Destiny)
Liquid Tape will repair cracks on terminal plastic. (Beluga)
Molded-on heat shrink terminals are superior to heat shrink tubing. They cost a bit more. (Destiny)
Standard ground wires are now yellow from ABYC code. (Shining Star)
Boat cable is a wire which has more strands per foot. It has tin in it for anti-corrosion. (Beluga)
Some newer connectors come pre-loaded with silicone. (Trumpeter)
Be cautious of using acid-based silicone. They're the ones for plumbing purposes and have a vinegar smell. (C_Language)

(also Tech Net corrosion)