Real-time RFI excision at the Very Large Array

We present commissioning data for a new correlator mode of the Very Large Array that removes radio frequency interference on nanosecond to microsecond timescales. Such blanking can remove intermittent, impulsive forms of interference in order to avoid corrupting integrated measurements carried out over longer timescales. Commissioning tests indicate that optimal parameters are a blanking duration of approximately 3μs and blanking threshold of 5σ
rms
. We present science verification observations of a redshifted spectral line target in a particularly problematic radio frequency environment near 1139 MHz. The success of the blanking to largely mitigate these sources of interference highlights the potential for carrying out surveys of extragalactic redshifted Hi and OH in formerly adverse observing conditions, such as during the daytime and in compact array configurations.