Helicopter pilot reported VHF Radio interference at night while landing at the Shady Grove Hospital in Rockville; Maryland creates communications difficulties during a critical phase of flight. This is a recurring issue; reportedly caused by faulty ground lighting at the Landing Zone.

Narrative

VHF radio interference on short final to landing at night at the interim helipad for Shady Grove Hospital (Rockville). Something; most likely the Landing Zone lighting equipment; creates full; steady static on VHF radios in the range of 123.00 to 135.00. This total static interference happens only at night and has been experienced by several pilots at the same parking lot Landing Zone numerous times; but only at night. This creates communication difficulties within the aircraft during a challenging phase of flight; during a challenging time of day at night. These events impact the last 10 seconds; 100 ft. of flight into a parking surrounded by trees on three sides and elevated parking lot lights on the other. This location accounts for XX percent of the company's transports over the past 3 months (XX transports) so this issue is an often re-occurring one. We suspect that an LED light bulb on either the new ground lights (green) or the illuminated windsock (white) could be the issue. Faulty bulb needs to be found and replaced.