My last hunt of the year's finds, and some new things learned about coils.

[Neil in West Jersey]

The rain washed all the snow away yesterday, and with temps forecast in the 50's today, I thought it would be a good opportunity to try the "non V" 9.5 Eclipse Coil from my DFX on the V3. I returned to what has become my favorite site (the one I found the KG III a few weeks back).

I found a good spot to balance the V3 and then got a ground probe reading. The recommended RX was only 2 even with no signal loss or noise :veryangry: I know I got a recommended RX of 8 or 10 at this exact spot with the D2, so needless to say I wasn't happy. I tried raising it up to 5 or so, but it became very unstable. I made a decision not to waste any time, and went back to my car for a quick change to my 5.3 inch Eclipse coil. I always keep an extra coil on hand with the lower rod attached. This allows for quick changes in the field without having to unscrew the bolts. ( Only $9.95 from White's) I got a recommended RX of 13 with the 5.3 and had it up to about 14 with no problem.

I got pretty good depth with this coil. My only finds of the day were a plain saddle shield, a dateless Buffalo at about 5 inches, and a 1918 Wheatie and a Pyrex fuse. It seems like only yesterday when these coins would have thrilled me. I also found the odd coin object. It rang like a nickel, but it is thinner and larger. The Wheatie was 6 inches and rang out nicely from under a thick tree root. It took a bit of time, but eventually I was able to wrestle it out with the help of my Lesche.

Needless to say, my 9.5 inch coil is NOT V3 compatible. I will be ordering a 9.5 V nulled Concentric coil, but for now the 5.3 is my coil of choice.

 

[The Beep Goes On]

I've got the 5.3 as well (although I had to send it back since it failed the null tests). I sold my 9.5 with the DFX, although I tested it first and it failed spectacularly. Nice info...thanks Neil!

 

[Neil in West Jersey]

OK This has been confirmed. One major setting change makes non "V nulled" coils compatible with the V3

I still had my detector in my car from yesterday's outing, so I drove over to a spot not far from my office during my lunch break (in my dress shoes & slacks and a button down shirt!...After all, why wait???). First I tried Best Data with the same results as yesterday. Then I switched to 22.5KHz and got a recommended RX gain of 1 with the display going crazy. Just as I expected! Then I bumped it down a notch to 7.5KHz and got a recommended RX gain of 11!!! GREAT NEWS!!! Then, one more bump down to 2.5KHz and I got a recommended gain of 12!!! I wish I had thought to try the TX boost, but I was in a bit of a hurry to get back. It is my understanding that this may be a bit much for non V coils anyway.

Now it makes makes sense: The frequency range of the DFX coil is from 2.5KHz - 15KHz. Due to the fact that the frequency of 22.5KHz falls outside that range, the coil is out of tune with the detector.

I can use my older coils in 2.5 or 7.5Khz!!!!!

 

[The Beep Goes On]

Good to know and a nice bit o' reasoning.

 

[Aurium]

That makes sense as the coils are typically designed for a specific set of frequencies. I would also guess there are power limitations they have to comply with as well. e.g. each coil design would or should have a power input rating, where overdriving them would be detrimental to performance. (since these are relatively low power, there is probably very little risk of damaging something)

Not having the specifications in front of me, I'm only guessing, as I am sure one of the Whites engineers responsible for designing and spec'ing the coils could elaborate ad nauseum.

 

[Neil in West Jersey]

When I spoke to one of the engineers at White's, I was told that the older DFX coils should work fine, but may overload with the TX Boost on. He neglected to tell me that the 22.5 KHz was out of its range.

 

[jbow]

n/t

 

[jbow]

I just ordered two extra lower rods, three extra sets of nylon nuts and bolts, and a box cover, I think it will fit the V3...

Julien

 

[Neil in West Jersey]

I just ordered two extra lower rods, three extra sets of nylon nuts and bolts, and a box cover, I think it will fit the V3...

Julien

I am sure they will work. I used the lower rod from my old PRL1 and I borrow another one from my DFX so I can switch quickly. It takes less than a minute.

One word of caution: Make sure you tighten the cam lock!!!