The 2 larger coils that i predominately use for say deep pasture or recently ploughed and rolled are the NEL Storm 14x13 and also the SEF 15x12,the NEL is slightly heavier out of the 2 but not by much,it not only covers ground better than stock but gives vital inches onto targets that the stock coil would miss,as most folks are aware the larger coil you will pick up on larger targets but start missing out on smaller items,that for the most part is the upside and downside of using larger coils,but the NEL Storm seems to buck this trend in my mind and i am finding that it will still pick up on smaller coin size items at depth stil.
The larger SEF 15x12 and also its smaller brother 12x10 are both in my opinion still some of the best after market coils made,albeit they have been out a few years but they still keep producing finds,for the size they are reasonably lightweight and can still swing them all day long without a harness of any kind.Unlike the biggest one i have the BIG Nel at 17x15,its a beast of a coil and will locate deep targets like hoards and in the US CW deep targets,but of course these larger targets require totally clean ground in my opinion other wise you will start getting 'nulled' signals which negates the whole object of looking for larger deep targets,its very easy to get 2 targets ie iron and a desirable target under the coil at the same time while running in discrimination mode and it will null the decent target out.Of course if you are running it in AM mode then that is not a problem as you will dig everything anyway.
Its always handy to have a larger coil in ones coil arsenal for such occasions on site specific permissions that you suspect the targets are worth hunting for,no point in putting a large coil on if you are going to hunt a manicured mansion lawn or play ground etc,but on a CW known site that has been cleared of trash for many years then these larger coils can start earning ones keep,the art is or skill set of the detectorist on when too these coils.
The T2 in the right hands with a skilled operator can be a beast of a machine depth wise,finds wont start jumping out the ground just because you have starpped on the large coil,it dont work like that,but if i say see signs of a possible scattered hoard that coins have been dragged up by deep ploughing and a possible pot is in theat area that is when a T2 and large coil will be the weapon of choice and can earn its keep in just that one find,i have to take into account the reward to effort ratio when using a large coil,if it dont stack up in my favour then i wont use them.
Of course this is just how i use a large/r coil on my T2 and basically this also applies on other detector brands and other after market coils as well,one last closing comment i bought a 15'' T2 coil that the company had on stupidly low prices,wish i had never bought it,used it for maybe under 1 hour and the reason i dont use it and its just gathering dust is the weight aspect,rest assured its a boat anchor and thus this the reason why they are basically giving them away.
