The Mark-4 CHIRP fish finder is one of the discontinued Lowrance units. For reference, this is the Lowrance part number 000-11827-001. It’s a monochrome unit featuring CHIRP sonar and DownScan, as well as GPS, charts and other navigation features.
Key Feature and Specifications
- Screen: 4.3″ diagonal, 480 x 272 pixel matrix, 16-bit Monochrome TFT, with 11-level LED backlight
- Sonar: 2D CHIRP and DownScan
- Depth Capability:
- 2,500 ft (762 m) for the CHIRP sonar
- 300 ft. (91 m) for DownScan
- Frequency and Coverage:
- 200 kHz (11°) / 50 kHz (45°) for standard CHIRP
- 455 kHz for DownScan, fore to aft. 4°, port to starboard 57°
- 800 kHz for DownScan fore to aft 2°, port to starboard 32°
- Transducer: 000-10977-001, 50/200/455/800 kHz, with transom mount, with blue plug
- Power Output: Max 500 Watts (RMS)
- Power Input: 12 vDC (10-17 vDC min-max)
- GPS: 16-channel, internal
- Charts: BaseMap
- Routes, Waypoints, Tracks: 100; 3,000; 100 (10,000 points each)
Sonar and transducer
As we’ve mentioned above, this is the Lowrance unit number 000-11827-001, which comes with the 000-10977-001 transducer. This transducer covers four frequencies: 50/200 kHz for 2D CHIRP, and 455/800 kHz for DownScan. It also integrates a temperature sensor, comes with 20 ft. of cable, featuring a blue connector.
The unit itself is capable of 3 frequencies for 2D: 50/83/200 kHz. But since the transducer only works with 50/200 kHz, you will only be able to use Low CHIRP and High CHIRP for 2D. Even though it’s a small, monochrome unit, with this deep water transducer, the Lowrance Mark-4 CHIRP unit should be able to scan depths up to 2,500 ft (762 m) in 2D, by using Low CHIRP.
For 2D, the transducer uses conical sonar beams, with angles of 45° for 50 kHz, and approx. 11° for 200 kHz. Thus, it’s pretty obvious that to cover a wider area, it’s best to use the Low CHIRP mode, while if you want more focus, you should go with the High CHIRP. The CHIRP sonar technology also offers excellent target separation and images feature less clutter. Thus, even though the unit’s display is small, the fish targets are easy to distinguish from structure.
For DownScan, this unit is capable of 455/800 kHz, and the supplied transducer does support these frequencies. However, take note that for DownScan the unit does not use CHIRP. However, you can combine the 2D sonar view with the DownScan view, via DownScan Overlay.
For DownScan the beams used are not conical, being rather thin, approx. 2° fore to aft, but wider side to side. Actually, for 455 kHz, the transducer uses a 56° wide beam, while for 800 kHz the beam features an angle of 32°.
Just like the Elite-4 unit, this unit features all the sonar-related functions, including DownScan Overlay, TrackBack, Fish ID, A-Scope, Bottom Lock etc.
GPS and navigation
The Lowrance Mark-4 CHIRP features basic navigation functions. It integrates a 16-channel GPS module. It also comes with the Lowrance Basemaps, which offer contours for over 3,000 lakes, rivers and coastal waters, and coastal contours up to 1,000 ft. However, the level of detail is minimal. The unit also has waypoints and trail recording functions. It can save up to 3,000 waypoints, 100 routes, and 100 tracks (10,000 points per track).
Even though it’s a basic unit, it can still be upgraded with various superior charts via microSD card. It’s actually compatible with Lake Insight™ and Nautic Insight™ PRO and HD, Navionics+, and HotMaps® Premium, Fishing Hotspots® PRO, and Jeppesen C-Map Max-N. It can also use charts modified or created via the Insight Genesis platform.
Control unit features
First of all, the Mark-4 CHIRP unit features a monochrome, 16-level Grayscale display, with a pixel matrix of 480 x 272. It’s also LED backlit, featuring 11 levels of backlight, which considerably increase the unit’s readability in direct sunlight or at night. The unit is IPX7 waterproof which means it can withstand splashes and even immersions in freshwater up to 1 meter.
In terms of connectivity, this unit features an NMEA 0183 port. It also has a high-capacity microSD card slot, for charts upgrades and data transfer.
Last but not least, the Lowrance Mark-4 CHIRP comes with a standard tilt-and-swivel mount. Also, it requires a 12-volt battery as power source.
- Powerful 2D CHIRP sonar;
- DownScan imaging offering a clearer view, excellent for structure observation;
- Possibility to combine both DownScan with the power of CHIRP, via DownScan Overlay;
- Deep water HDI transducer (50/200 455/800 kHz) included;
- Adjustable LED backlight for superior readability;
- Split-screen view up to 3 panels per view;
- Automatic noise filtering;
- Various functions included, such as Fish ID, Amplitude Scope, Bottom Lock, Flasher view etc;
- Sonar recording;
- Fast and accurate GPS;
- Impressive chart compatibility, unit that works with such as Lake Insight™ and Nautic Insight™ PRO and HD, Navionics+, and HotMaps® Premium, Fishing Hotspots® PRO and Jeppesen C-Map Max-N;
- Waypoints, tracks and routes functions;
- Insight Genesis capable;
- Fairly easy to install;
- One year warranty.
- It does not include a unit cover.
The Lowrance 000-11827-001 Mark-4 CHIRP is an excellent unit for small boats or kayaks. It comes with a powerful transducer, and thus the unit can also be used for off-shore fishing. The CHIRP sonar enhances its depth penetration and offers a better target separation, while DownScan is great for structure observation. It’s also a unit with basic navigation, integrating GPS, and the Lowrance base maps. All in all, it’s quite inclusive and versatile for a 4-inch monochrome unit.