Mike Hillis - Fisher F5 and 5" coil

[BH_Landstar_]

Hi Mike,

I have an F5, had it since August and used the stock coil that came with it. I've just got the 5" DD coil (due to a very trashy area I've found) and have noticed that it see's dimes as quarters and and quarters as half dollars.

The VDI reads dimes in at 79 - 81 and quarters in at 89 - 97. Have you seen or noticed this ? What has caused the VDI to jump this high with these coins using the 5" coil ?

Nickels are still seen in the 28 - 32 VDI range.

Also did a test with the gold ring I found a few weeks ago, with the stock coil it reads 30, with the 5" coil it reads 33 - 34. Again, why has the VDI range (numbers) jumped ?

Also, while I am here on this subject, how often do you use the 5" DD on the F5 ? And has it helped find gold / jewelry better than the stock coil ?

I've noticed that the 5" coil is hot on the F5 as well, I was a little bit supprised on how hard it hits on coins in the ground.

TIA ..... Ian

 

[shooter]

Can't help you on the F5 but when I use it (5") on my F75 LTD she hits real hard on coins and the depth is unbelievable, Going to check that VDI number ID cause I never really took notice, I'll let you know.

 

[go-rebels]

In my test bed the 11" DD, 5" DD and 4x6 coils yield the save VDI on buried nickels, zinc pennies and silver dimes when using BP mode.

 

[patti]

Hi!

I do not have the 5" coil but I have noticed a jump in IDs with my 11" DD vs. stock coil. I am in process of returning the 11" DD because it is faulty (Fisher and the finnish importer have been great and really helpfull with this case btw.) as it cannot see big copper coins that give an ID close to 99 on the stock coil. Also euro coins which ID around 52-62 have elevated IDs on the 11". Lower range items such as pulltabs do not cause this jump in IDs. Fisher said that its calibration must be off and that causes the problem with higher IDs. Now after reading that Mike gets the same IDs with every coil (even though it is F75) makes me think that the jump in IDs and the faulty coil go hand in hand? Maybe your 5" coil is also faulty? Check it out with a coin that gives an ID as close to 99 as possible on the stock coil and see whether the 5" coil sees it or not.

HH,

patti

ps. What is BP mode?

 

[BH_Landstar_]

Going to wait to see what Mike says on the issue before I start to see if the coil has a fault.

Took it out for a run today, it's a quarter hog with the 5" DD coil. Total clad today = $9.95.

 

[Mike Hillis]

Hi Ian,

All three of my F5 coils do the same thing. Each of the three coils id just a little differently and sometimes ground numbers are different than air numbers. For instance, my stock coil will id a quarter in the air around 80/81 but id's pretty consistantly in the ground as a 84. My 11" DD will id the same quarter in the air as a 84 and real close to that in the ground, though sometimes I see them a little higher, like around a 85/86. My 5" DD ids them in the air around a 85/86 and sometimes in the ground as high as 89/90. Ground minerals as well as high sensitivity can also raise the id numbers.

You will also see the ground phase numbers differ between the coils.

You numbers seem high though. Those are in the ground numbers? I haven't found much jewelry with the 5" coil yet, but then again, I don't use it that often. I'll have to get it out and go hunt a basket ball court or two while I'm off.

HH
Mike

 

[Mike Hillis]

Hi Patti,

go-rebels and shooter (and Roland should show up soon )are trying to help answer F5 questions by posting information about their F75 which will not help at all but will cause a bit of confusion as they are totally different machines with different operating characteristics. But hey, someone might read the F5 posts someday looking for F75 information

The F5 has an expanded id range for high conductors that is fairly unique among today's metal detectors. Whites DFX and V3i have this same ability in their low (3kHz and 2.5 kHz) single frequency non-normalized target id modes but that is not their normal operating mode and ground minerals often prohibit the use that particular mode. However this is standard operating procedure for the F5 and ground minerals do not prohibit this functionality.

The F5 has the largest ground balance adjustment range that Fisher makes with an expanded range around the ferrite end of the scale. That means that even though the high conductive target id range is expanded so that you can easily tell the difference between, say a copper cent and a dime (for us USA folks), there is no target fading/discrimination for high conductors due to being too close to the ground balance point. Another feature of this is that the F5 keeps the high conductors within the high conductor range, prohibiting the wrap around to the ferrous range ( like I experienced all the time with Whites units using the non-normalized single low frequency modes in my mineralized ground - translated - means that quarters read like iron).

If your F5 has trouble with large, highly conductive copper/bronze coins, or mason jar lids, then you are probably mis-calibrated as your dealer said and it needs a trip to the doctor.

HH
Mike

 

[Woodchuck]

When I had my F2 the 5" sniper coil was real hot on quarters better than the regular coil.But then again the F2 was hotter than my F5 IMHO

 

[BH_Landstar_]

Hi Ian,

All three of my F5 coils do the same thing. Each of the three coils id just a little differently and sometimes ground numbers are different than air numbers. For instance, my stock coil will id a quarter in the air around 80/81 but id's pretty consistantly in the ground as a 84. My 11" DD will id the same quarter in the air as a 84 and real close to that in the ground, though sometimes I see them a little higher, like around a 85/86. My 5" DD ids them in the air around a 85/86 and sometimes in the ground as high as 89/90. Ground minerals as well as high sensitivity can also raise the id numbers.

You will also see the ground phase numbers differ between the coils.

You numbers seem high though. Those are in the ground numbers? I haven't found much jewelry with the 5" coil yet, but then again, I don't use it that often. I'll have to get it out and go hunt a basket ball court or two while I'm off.

HH
Mike

Hi Mike,

Thanks for the reply / info.

In the ground with the stock coil .... Dimes 72 - 74, some have been + - 2 in the ground, pennies 70 - 72 and again + - 1, quarters 79 - 85 (most at 83 / 84). With the 5" coil, the pennies are now up in the high 70's, the dimes in the low to mid 80's and the quarters hit anywhere from 89 - 95 in the ground (air test 90 - 97).

Tests in the trashy area I was at yesterday (soccer field / base ball field, same field, doubles up as both). The quarters where found with ease with the 5" coil, but with the stock coil the coins did not even show / get seen due to the amount of trash that this area has. I am sure there is a ring or two hiding in this trashy area too, just got to go back there and clean it out and see, but time is against me, the ground here is starting to freeze hard and then once spring / summer comes around, the field is going to be heavily used again, thus more trash to filter out again when fall comes around or when the area is not being used during the summer for local games and other events.

I'm going to leave the 5" coil on the F5 and use it all the time due to its ability to work well in trashy area's as well as in open non trashy area's, I was getting coins out of the ground that I'd been over before that the stock coil missed. Most of the coins where 3 - 6 inches deep yesterday, not sure why the stock coil did not see these. I did notice that alot of the quarters found with the 5" coil where on edge, maybe this is the reason why the stock coil failed to see them ?! Any thoughts on this Mike ?

 

[Monte]

These are not restricted to the Fisher F5 and the 5" DD coil. I have experienced the same on my Teknetics Omega (same frequency) and Gamma and have seen it on the F5. In a number of my posts in the Teknetics Forum I have called readers attention to why it is important (and interesting) to include the ground Phase read-out and Sensitivity and Discriminate settings you use, but to also mention which detector model and search coil used. That's because the VDI readings can vary between search coils as well as the Ground Phase read-outs. There are differences in the coil windings and balancing, and smaller coils see less ground than do the larger coils.

In most cases, when switching between coils on any of the 7.8 kHz models, I see a little lower Ground Phase from the 5" DD but a slightly higher VDI reading on the higher-conductive targets. The US 5

 

[Monte]

In the ground with the stock coil .... Dimes 72 - 74, some have been + - 2 in the ground, pennies 70 - 72 and again + - 1, quarters 79 - 85 (most at 83 / 84). With the 5" coil, the pennies are now up in the high 70's, the dimes in the low to mid 80's and the quarters hit anywhere from 89 - 95 in the ground (air test 90 - 97).

That's not uncommon in what I found when I switched to the 5" DD months ago. They do up-read a little on the VDI, but it's just a matter of learning that, and it mainly allies to the higher-conductive coins/targets, not the lower-end specimens.

Tests in the trashy area I was at yesterday (soccer field / base ball field, same field, doubles up as both). The quarters where found with ease with the 5" coil, but with the stock coil the coins did not even show / get seen due to the amount of trash that this area has. I am sure there is a ring or two hiding in this trashy area too, just got to go back there and clean it out and see, but time is against me, the ground here is starting to freeze hard and then once spring / summer comes around, the field is going to be heavily used again, thus more trash to filter out again when fall comes around or when the area is not being used during the summer for local games and other events.

In trashier suites the 5" DD is a killer coil to use! We had out hard ground freeze up for about 4 days last week and now we're back to very thawed and very soft wet ground. The problem is that no matter how frozen or thawed the ground gets, the blasted trash seems to hang around.

I'm going to leave the 5" coil on the F5 and use it all the time due to its ability to work well in trashy area's as well as in open non trashy area's, I was getting coins out of the ground that I'd been over before that the stock coil missed. Most of the coins where 3 - 6 inches deep yesterday, not sure why the stock coil did not see these.

I had been swapping the three coils around on my Teknetics Omega through the summer, mainly using the 5" DD and 10" elliptical Concentric. then for the entire month of September I left ONLY the 5" DD coil mounted. I recovered coins down to 7" or maybe slightly more, but most were in the surface to 4" range with many in that 4"-6" zone. The 5" DD coil did well on them, and the separation in trash was beautiful! I hunted building rubble sites, playgrounds, vacant lots, old town sites, and several open sports fields and open park lawns. The 5" DD is a good pick for a lot of use, but great in the littered areas.

I did notice that alot of the quarters found with the 5" coil where on edge, maybe this is the reason why the stock coil failed to see them ?!

Different search coil sizes and internal winding designs can make a difference, but working w/o influence of nearby trash can also help find the difficult positioned coins.

Good luck working the F5 and 5" DD!

Monte

 

[BH_Landstar_]

Thanks for the info Monte.

While I've got your atten, can you explain if there is any differences between the G2 and the Gold Bug SE / Pro ? I ask as I am 99.9999% sure that they are one and the same unit, just rebranded.