template operator== not working

This is my XYZ_POINT.h file

template<typename T>
class XYZ_POINT
{
private:
    T x;
    T y;
    T z;
public:
    XYZ_POINT(void) {};
    XYZ_POINT(const T allVals) : x(allVals), y(allVals), z(allVals) {};
    bool const operator==(const XYZ_POINT<T> &xyzTest);
}

In my cpp file I have this.
template<typename T>
bool const XYZ_POINT<T>::operator ==(const XYZ_POINT<T> &xyzTest)
{
    return ((x == xyzTest.GetX()) &&(y == xyzTest.GetY()) &&(z ==
xyzTest.GetZ()));
}

In the main file I have this

int _tmain(int arc, _TCHAR* argv[])
{
    XYZ_POINT<double> dXYZPnt1(1,0,0);
    XYZ_POINT<double> dXYZPnt2(3,0,0);

    if (dXYZPnt1 == dXYZPnt2)
    {
        bool b = true;
        b = false;
    }
}

Doesn't compile with the following error
error LNK2019: unresolved external symbol "public: bool const __thiscall
XYZ_POINT<double>::operator==(class XYZ_POINT<double> const &)"
(??8?$XYZ_POINT@N@@QAE?B_NABV0@@Z) referenced in function _main

If I move the implimentation to the header file it compiles fine.

What am I doing wrong?

The actual implimentation is more complex then I'm demonstrating and I need
to include some header files that I don't want in the declaration.

Thanks

Mark