 Digital receivers of this era, while expensive, were poorly equipped to deal with reflected signals—a severe drawback in urbanised environments.Later generations of receiver design significantly mitigated these limitations; by 2004 technology existed to build receivers capable of detecting and compensating for static multipath interference conditions where a single echo was 10 dB weaker (within a 30 microsecond time difference) or the same strength (the worst case, but within a 12 microsecond range).If the transmitters could be kept at sufficiently precise synchronisation and sufficiently close geographical spacing to operate within these limits, a single-frequency network using the new receiver design would be possible even with the existing North American ATSC digital broadcast standards.