An improved broadside coupled, open pin field connector. The connector incorporates lossy material to selectively dampen resonance within pairs of conductive members connected to ground when the connector is mounted to a printed circuit board. The material may also decrease crosstalk and mode conversion. The lossy material is selectively positioned to substantially dampen resonances along pairs that may be connected to ground without unacceptably attenuating signals carried by other pairs. The lossy material may be selectively positioned near mating contact portions of the conductive members. Multiple techniques are described for selectively positioning the lossy material, including molding, inserting lossy members into a housing or coating surfaces of the connector housing. The lossy material alternatively may be positioned between broad sides of conductive members of a pair. By using material of relatively low loss, loss when the conductive members are used to carry signals is relatively low, but an appreciable attenuation of resonances is provided on pairs connected to ground. As a result, an overall improvement of signal to noise ratio is achieved.