Mechanicals - Fisher F75 SPECIAL EDITION User Manual

F75
LIMITED
Comprehensive Operating Manual & Guide to Metal Detecting

Mechanicals

BATTERIES
(not included)
The F75 requires four AA batteries.
These non-rechargeable chemistries may be used: Alkaline, Nickel Oxy-Hydroxide
(Panasonic Oxyride or Duracel PowerPix), and lithium iron disulfide (Energizer L91).
Nickel metal hydride and nickel-cadmium rechargeable chemistries may also be used.
Zinc-carbon and so-called "heavy duty" batteries may not work, especially in cold weather.
Do not use these batteries.
Expect 40 hours of service in the field with one set of alkaline batteries.
Rechargeable batteries will usually deliver over 25 hours of service without recharging, but
when they start running low, they die suddenly with little warning.
Always install batteries which are of the same type and the same state of charge. Otherwise
battery life will be determined by the weakest battery, because the good batteries cannot
deliver their power with a dead battery blocking the current.
All 4 batteries are installed with the positive terminals facing upward.
The LCD screen shows battery condition on the right.
IMPORTANT: To avoid stressing the battery spring connection, install the batteries using this technique:
1. Position the bottom (negative) side of the battery on top of the spring.
2. Do not install the top of the battery into the compartment yet.
3. Push down on the battery to compress the spring.
4. With the spring compressed a bit, then tip the battery upright and push back into the compartment.
2
RIGHT WAY
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1
WRONG WAY
Comprehensive Operating Manual & Guide to Metal Detecting
Detecting Activities (continued)
Relic Hunting (continued)
or documentation, their context will be lost.
The ground balancing and Fe O bar graph features of the F75 can be used to map the soils
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of a site. In this way you might determine which areas have been dug, backfilled, or subjected
to fire. This information in turn helps to reveal the history of the site.
To find promising sites to hunt, conduct research at your local library, look for clues in old
newspapers, and seek information on the internet. Where did buildings used to be? Which
have since been torn down? Where did people gather for public events like dances and
county fairs? Where did train and stage lines run? Where were the swimming holes? In
almost every town there is a historical society and museum of local history. Most museums
are grateful for anything they can put on display, and when you dig something you cannot
identify, the curator can often identify it for you. If you work closely with the local historical
society or museum, landowners will be more willing to grant you permission to search their
property.
Some of the most promising sites for relic hunting are places being cleared for development.
After the site is built on, whatever is in the ground will become inaccessible. The property
owner can often be persuaded that the site should be searched immediately while it is still
searchable.
Gold Prospecting
In the United States, gold is found in many places in the western states, Alaska, and in a few
localities in the Appalachians. The old saying "Gold is where you find it", means that to find
gold, you should look in areas where the yellow metal is known to be present.
Hillsides are the best areas for gold prospecting using a metal detector, because hillsides
cannot be cleaned out by panning and dredging the way streams can. Also, gold on hillsides,
not far from its source vein, tends to be larger, and hence more readily detected, than alluvial
(placer) gold which tends to get pounded to pieces and worn away as it rolls along the
streambed with gravel during floods. Gold is valuable because it is a scarce commodity. Even
in a good gold producing area, you will often spend an entire day without finding any gold.
Meanwhile you will dig bits and pieces of other metal-- birdshot, shells and bullets from
hunting and target practice, bits of rusted barbed wire, chips off shovels and other mining
tools, rusted tin cans, etc. Hot rocks -- rocks containing concentrations of iron oxides that
sound like metal when you pass over them -- are also a nuisance in many gold areas.
Discrimination is usually ineffective because the loss of sensitivity resulting from discrimination
is enough to cause those little nuggets to vanish. If you have gone many hours without finding
gold and are wondering if there is something wrong with your metal detector or how you are
using it, the most important clue is this: if you are digging tiny pieces of trash metal, then if
gold were present you would have found small gold pieces too!
Because most gold nuggets are tiny, and are usually found in soil which is high in iron oxide
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