Quick review of the new 12x15 (white) SEF Coil *With 2 Firsts*

[hodr]

So last weekend I received my new 12x15 in the mail, but until today I did not have a chance to take it out for a spin. I did turn on my machine and run around the yard a bit, however I found the coil to be very EMI sensative (at least in my yard) and as such was not able to do much testing. Truth be told, I expected to have to return it.

So, today I spent 2 hours at a local park. The park has fairly low levels of EMI, is pretty clean, and is known to have deep targets.

Right away I noticed the difference in weight from the D2 that I normally swing. The 12x15 is heavier, but not so much so that it burdoned me during my 2 hour hunt. And all day hunt may make me change my tune though. First off, I noticed that this guy is pretty sensative to EMI. For comparison, in this park I can run my D2 with the settings at 10/75/92 and hear very infrequent falsing, if any. What I found with the 12x15 is that I could run it pretty hot, if I kept the RX gain very low. From an RX of 6-8 it starts getting pretty chatty. RX 9 and above are pretty much unusable. With the settings at 8/70/88 I could comfortably detect without the coil driving me completely nuts. These settings were also pretty consistant using single frequency modes, with 2.5khz being the noisiest. TX Boost did not cause an overload with the 8/70/88 settings, however it did increase the amount of falsing (I hardly ever run TX Boost anyways).

I didn't do much testing with salt modes or corrolation, as in my experience these tend to drop the depth quite a bit.

During the 2 hour hunt I went over a pretty well worked stretch of the park, and found a decent number of coins (only 1 of which was really deep). I found 5 wheat pennies, 1 1911 V-Nickel (a first), and 1 1910 Barber Quarter (my first Barber anything). Most of the coins were found 4-5 inches deep, with the exception of 1 wheat penny that was easily 10 inches, if not a foot down.

I am pretty happy with the depth, with the weight / balance, and with the coverage I get with the coil. I just with it were a little bit more stable. I feelt that if I could run it at 8-10/70/88-92 without too many chirps, it would be my favorite coil. As is, it may only come out when I know I am in a low EMI area and where I need the extra depth (like farm fields).

-Hodr

 

[Rob (IL)]

Thanks for the report. Now if we knew the sensitivity % readings this would help to tell how good is the null of the coil.

 

[hodr]

I don't recall the procedure to get this number. If you would outline it for me I can check on Sunday when I go out again.

 

[Rob (IL)]

Go to sensitivity on the live controls and hit zoom. You will see a signal% and noise% on the right side of the screen. If you don't see them just make sure that RX is highlighted. Do this with the settings you were using 8/80/88.

 

[hodr]

I definitely tried to do this (as I heard the requests for the signal % before) and I just now went out into my garage to double check. From the live menu, if sensitivity is highlighted, pressing zoom just brings up a fullscreen sensitivity menu. The same if I press highlight and make sure RX is selected.

Pressing zoom again just increases the font on this page.

----Edited Below----

And just as more information, this coil doesn't calm down inside my garage unless I set it to 4/30/30 or so. I understand I probably have a decent amount of EMI at my house, but that seems pretty extreme.

 

[Rob (IL)]

[attachment 228160 2012-03-30_153112.jpg]

If you have a VX3 you see this, if you have a V3i you would see a box for TX boost between RX and AM. See the RX is highlighted, its in a black bar.

 

[hodr]

Thank you Rob. I was bringing up that screen, but I never had RX on that screen highlighted (I had RX on the live bar highlighted and thought thats what everyone was referring to).

So, in my garage (non-ideal work space, lots of metal and power).

With the settings at 8/70/88, which is where I did the majority of my detecting. Signal was 23%, and noise floated between 1.5% and 3.2%

Hope these numbers help.

Ohh, and the other thing I may have forgot to mention up top. I dug 3 nickels (two jeffersons, 1 V) and they all came in around 18-19 on the VDI. Unlike the black 12x10 SEF which skews the numbers a bit higher.

 

[Rob (IL)]

Those numbers look OK and so does the non skew of the nickel reading. We usually have to hunt in the 10 - 12 RX range. Next time you are out see what happens at RX 10 and 12. I don't care if you can hunt at these RX I just want to see how different it is from my black one.

 

[basstrackerman]

My white 12x10 with settings rx 12 am 70 disc 90 the numbers are top 14 bottom or noise is floating from if held still 3 to if moved up past 150

 

[hodr]

Those numbers look OK and so does the non skew of the nickel reading. We usually have to hunt in the 10 - 12 RX range. Next time you are out see what happens at RX 10 and 12. I don't care if you can hunt at these RX I just want to see how different it is from my black one.

Wen't back out to the field with low EMI to do some more testing.

The noise numbers remain about where they were before, however the signal numbers are much lower. 8/70/88 gives a signal of about 7, and 12/70/90 runs it up to 10. I was able to run the unit a tad bit hotter today as I noticed it behaves better with a different filter, and for whatever reason when I run mixed mode audio.

 

[Rob (IL)]

Looks like you are all set to go.

 

[basstrackerman]

rob the signal and noise numbers...what is ideal for them? is there a max? my signal was 40% with rx set at 11 and noise was low like 3 or 4 ..the d2 coil showed signal down at 7 to 8% and noise was much higher like 35 or so.. what effect does it have on detecting?

 

[Rob (IL)]

Well you have me confused. In one post you said, "with settings rx 12 am 70 disc 90 the numbers are top 14%". In the other post you said, " my signal was 40% with RX set at 11". If the first statement is true it is running close to a V nulled coil, if the second statement is true it is running the same as the old black SEF coils.

Then you asked is there a limit. The answer is YES, 40% is about the MAX you should run. To get it lower you have to lower the RX.

OK, here is the long version of what they mean.
Sensitivity Probe,
This function is activated by selecting the Sensitivity Live Control and pressing ZOOM. You'll see Signal % and Noise %.

On the right side of the screen are two live signal quality numbers in %. The Signal number tells you what percent of the total signal range is currently being received; that is, how much

 

[basstrackerman]

well my first post was a quick check last night in the dark in my yard just to see what it was all about.. then i posted of todays numbers at a different location hunting with a friend. at rx 11 signal stays at or just under 40 and noise is very low. the d2 coils numbers... signal is really low but noise was alot higher

 

[Rob (IL)]

Hodr said,"8/70/88 gives a signal of about 7, and 12/70/90 runs it up to 10." These aren't close to yours. His are close to what my D2 reads.

I don't have a White one to test so I will have to wait to see what readings other guys get. Your last readings look like the Max you can run is RX 10 -11.

 

[basstrackerman]

yes rx of 10 gives me my max, 11 makes signal go over 41% every time.. tested my d2 coil...rx gain of 15 makes signal go to 5% and noise 1-2% thats coil waist high holding still. so is my sef coil defective? should i swap it out? i do get good depth with it..just cant crank it up from what im seeing.

 

[Larry (IL)]

It could be defective but I doubt it. Your numbers are more in line with what I have heard before, that the White coils are just about the same as the black ones except they are white and a little lighter. We need more of the White coil information from others to draw a conclusion.

 

[basstrackerman]

ok..maybe i will call the florida store and see if they can send me another one. or i will just suck it up and keep using it.

 

[Schultzie]

So that tells me they are NOT v-rated. In all fairness, the ad says they are "optimized" for the V3i, it does not sat it is v-nulled.

 

[Larry (IL)]

We have said many dozens of times that [size=large]ONLY[/size] White's coils are considered [size=large]V RATED[/size]. All aftermarket coils may or may not be [size=large]V COMPATIBLE[/size] to a certain degree. I don't know how much more simpler we can put this in words.