Lowrance Mark-4 HDI Operation Manual EN - Page 26

Custom range menu NOTE: When using a custom range, you may not receive any digital depth readings, or you may receive incorrect depth information. Ping Speed Controls the rate the transducer uses to send sonar waves into the water. Ping speed adjustments can help reduce interference from other transducers. When using fishing modes, ping speed settings are optimized for the selected fishing conditions, so in most cases, adjustments are not necessary. Frequency Controls the transducer frequency used by the unit. This unit supports three conventional sonar frequencies: 50kHz, 83kHz and 200kHz. 200 kHz has the highest sensitivity and best target separation in shallow water. 83 kHz offers a wider cone angle for more water coverage. 50 kHz provides the best depth penetration. Sonar Operation | Mark-4 & Elite-4 HDI 24