Airmar TM165HW

TM165HW has much in common with the B75-series, same size, 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 P66. B75 comes in High, Medium and Low frequancyrange though, while the TM165HW is HW - High Wide. With B75 those frequencybands translates to these details with model frequencyband/ conenagle:

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 SS75HW and TM185HW) but this is the first time they apply it to a 600W-element. 

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 TM185H 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 can still 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:

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 as 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.

That leaves us with the fisherman fishing in less then 50-ish meters, looking for a transom mount transducer, 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 even 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.

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 the competitions product development when doing so. We would have liked to see it with a coneangle around 20 degrees instead of 30 though, 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. Basicaly it is a better option then TM150M due to the higher wattage and higher frequencyband, but it would have been even better 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 way as 10 years ago.