Airmar TM165HW - the new holy grail of shallow water transducers?

Whenever Airmar launches a new transducer the quality-focused part of the angling-community starts buzzing. That has also been the case with the brand new TM165HW, here we will take a closer look at it.

Airmars new TM165HW - ideal for shallow water?

The buzz is there for good reason. For several decades Airmar has been synonymous with the best images whatever brand of sonar can produce. So when they launch a new transducer it is a big deal, but are they still pushing the envelope or are they strugling to stay current? The new TM165HW might prove to be a bit of both.

The technical bit.

Transducers is about tech, so let us start with a few key-specifications:

• Q-factor 3
• Frequency range 150-250
• Maximum power 600W
• Weight 0,5kg
• Length of cable 9m

TM165HW has much in common with the B75-series, same size and same wattage but offcourse the TM165HW is a transom mount while the B75s are for through-hull mounting. TM165HW uses the same mounting hardware and casing as the popular and proven P66. B75 comes in High, Medium and Low frequencyrange, while the TM165HW is HW - High Wide. With B75 those frequencybands translates to these details with model frequencyband/ coneangle:

• B75H 130-210/ 15-9
• B75M 80-130/ 24-16
• B75L40-75/ 31-24

With TM165HW Airmar has "merged" this with their tech from SS175HW/ TM185HW to create a transducer where the coneangle does not vary dramatically with frequency.

Varience in cone on Airmar TM165HW

With the three examples provided in Airmars technical bulletin we see examples of frequency and cones with TM165HW. 150 kHz - 30 degrees, 210 kHz - 34 degrees and 235 kHz 32 degrees. We have previously seen this in their 1000W High Wide element (like in SS175HW and TM185HW) but this is the first time they apply it to a 600W-element. 

The practical bit.

So what does all this tech translate to when on the water with a fishingrod in your hand? Notice the "fishingrod in your hand", because the wide coneangle on TM165HW makes it less than ideal for those simply looking for depth or structure. (Look to P66, TM260 or TM265HL/B175H for that). Unfortunately, we have not had the chance to try TM165HW yet, but based on the specifications and practical experience with Airmars other transducers, we still dare to make a few assumptions.

As mentioned, the wide coneangle of TM165HW comes with a major downside, it is to wide for showing structure in a good way, or giving very accurate depth. This issue will increase with depth, as shown in this diagram:

Coneangle vs bottom-coverage for Airmar TM165HW.

As your sonar tends to average-out structure within the coneangle, a wide coneangle will never give as accurate depth or information on bottom-composition and structure as a transducer with a less wide coneangle. For the shallow water fisherman that is not a big deal though, as he has scanning sonar (like StructureScan, DownImaging, Downvü etc) for that. But for those venturing into deeper water where the scanning sonars are less than ideal, they are depending on their 2D-sonar for such information. Based on this, TM165HW is not ideal for the guys fishing for fish deeper than 50-ish meters or so (150 feet). Deeper than that and the drawbacks of the wide coneangle are simply larger than the advantages. These three diagrams from Airmars own bottom-coverage-tool gives you the area covered by the 30 degree coneangle in 10, 50 and 100 meters (30, 150 and 300 feet):

Bottom coverage down to 10 meters.

Bottom coverage down to 50 meters.

Bottom coverage down to 100 meters.

That leaves us with the fisherman fishing in less then 50-ish meters, looking for a transom mount transducer that is better than the OEM-transducers from Lowrance, Humminbird and Garmin etc, These guys have typically been using the TM150M, and have been getting excellent results from it. But 165HW should be even better, providing better on-plane performance due to the higher wattage, and better separation due to the wider frequencyband. We can also expect less sidelobes from TM165HW, giving even less noise and a clearer image on our screens.

Conclusion. 

With TM165HW Airmar is trying to cover what used to be a gaping hole in their product-portfolio, but they missed the latest 5-10 years of product development within scanning sonar when doing so. We would have loved to see TM165HW with a coneangle around 20 degrees instead of 30, as the shallow water angler simply does not need such a wide coneangle anymore. Today he has sidescan and LiveSight/ LiveScope/ Panoptix/ 360 to see what is around his boat. As TM165HW is now, it is neither fish nor fowl, which is a crying shame. It is a better option then TM150M for the shallow water guys, due to the higher wattage and higher frequencyband, but it would have been even better and a lot more versatile with a more sensible coneagle.

Airmar, it is time to wake up and look at how modern day fishermen use sonar, it is not the same as 10 years ago.

EDIT 25.05.2020

We have received a few questions on combining TM165HW with Lowrance HDS Gen 3. Technically it can be done, using adapter 000-13977-001 (LINK). But since TM165HW was launched after the softwareupdates for HDS Gen 3 ended, you will not get XID to work, (meaning the transducer will not be automatically recognized by the HDS Gen 3) and you will not be able to choose TM165HW manually from the list of transdecuers in the HDS either. To get around that, you can set transducer to unknow or HST-WSBL, and then on the Sonar-page set frequenzy to high chirp or 200 kHz in the menu to the right (do not use anything else as the TM165HW does not support other frequenzies found in the menu on the HDS when doing this).

Please be advised that this method of operations has some limitations. One is wattage, the TM165HW will (if used with HDS Carbon or Live which supports the XID in the transducer) have a maximum RMS output of 600W. Without a working XID the HDS will limit that to 300W RMS, which obviously limits the transducers capabilities over deeper water.

The second limitation is that Lowrance high chirp is 160-240kHz, while the TM165HW is build for 150-250kHz. So on a Gen 3 you will not be using the full bandwith of the TM165HW, thus limiting how good the resolution can be.

In short: If you plan on upgrading your HDS Gen 3 to a HDS Carbon/ Live in the near future, get the TM165HW (and adapter) now. If you plan on sticking with the HDS Gen 3, look to TM150M or TM185HW instead.