Testing The New 8.5 x 11 DD Coil On The Ace 250

Hi Everyone

Here is my report and initial tests of the new Garrett 8.5? x 11? DD PROformance search coil, fitted to the Garrett Ace 250.  Most 250 owners will be using the standard coil, and much of this report is a comparison between that and the new DD coil.

The build quality is very good, and the new coil seems to be a strong design.  It is a good fit onto the lower stem, and there is no drooping or need for any coil support.  When first fitted it looks enormous, compared with the standard coil. But the biggest surprise is the weight, or to be more correct the lack of weight.

6.5? x 9? (No Coil Cover) = 454gms or 16oz

6.5? x 9? (With Coil Cover) = 515gms or 18.2oz

8.5? x 11? (No Coil Cover) = 468gms or 16.05oz

So for all of its extra size, the new coil come in just a fraction heavier than the standard coil.

Below are some pictures of both coils side by side.





Now onto some air testing of the two coils. I know many of you will not agree with tests done in this way, but they have been done to provide a comparison.

Below are some pictures of the targets used in the test. These include UK and US coins, and some jewelry and junk items.









I tried to keep the test between the two coils identical, and as fair as possible. The tests were done on a wooden surface, away from any metals or electrical interference. I ran the targets past the coils at a normal sweep speed, and not whipping them to achieve better results. I only recorded good two way signals. The 250 was set in the All Metal mode, and each coil was tested at sensitivity settings of 4 and 6. It should be noted that the DD coil suffers more from electrical interference than the standard coil.  But I have found this to be a characteristic of all the DD coils I have used in the past.

Below is a table showing the test results.



As you can see from the results, the new DD coil performed very well.  At equal sensitivity setting it out performed the standard coil on almost every target. But by design the DD coil should perform better in badly mineralized ground and on salt beaches. So in theory on a wet salt beach where the standard coil could be run at a sensitivity of 4, the DD coil may run at sensitivity 6. If this was the case, the depth improvement could be as much as 30%.

Much of this is just theory, and I hope to get out to the beach very soon, and put it to the test. At least the comparison chart gives you a good example of how the new coil performs, under air test conditions.

I hope some of this information will help other 250 users considering purchasing the new coil.

Kind Regards Tarot.


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Coil Test Update

Hi Everyone

When I wrote the original report, I did not have the coil cover for the new DD coil.  The covers have just become available, and I can now update the weight comparison (With a surprising result !!).



Firstly all of the weights shown in grams are very accurate, but some of the conversions to ounces have been rounded up or down. In the original report the weight of the 8.5? x 11? coil was wrongly converted, and should have read 16.5 oz.

So to clarify the weight comparison, I have relisted the weights below together with the new coil cover data.

6.5? x 9? Coil Cover = 61gms or 2.2oz

8.5? x 11? Coil Cover = 46gms or 1.6oz

As you can see, the 8.5? x 11? coil cover is much lighter than the 6.5? x 9? coil cover.  This has been achieved by having a more open design, and being a much thinner profile.



6.5? x 9? (No Coil Cover) = 454gms or 16oz

6.5? x 9? (With Coil Cover) = 515gms or 18.2oz

8.5? x 11? (No Coil Cover) = 468gms or 16.5oz

8.5? x 11? (With Coil Cover) = 514gms or 18.2oz

So the 8.5? x 11? coil + cover is actually 1gm lighter than the 6.5? x 9? coil + cover. (Amazing considering its much larger size)



I have still not been able to get out detecting with the new coil, but hope to get out after the holidays.  I will update this thread with the results.


Kind Regards Tarot


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