Garmin Fishfinder 140 or Humminbird 565

[korygrandy]

Why should I spend the extra $90 on the Humminbird 565 when I can get the garmin fishfinder 140?

What would the difference be between the 45degree and 15 degree beams on the garmin compared to the 20 degree and 60 degree?

I trailer to white bear and bald eagle lake mn a lot and trailer to a lot of lakes. I'm most interested in getting a good read on the depth so I don't get suprised and hit something or run ground.

 

[dingbat]

Re: Garmin Fishfinder 140 or Humminbird 565

What would the difference be between the 45degree and 15 degree beams on the garmin compared to the 20 degree and 60 degree?

Probably nothing.

I don't have the time to dig into it but chances are that HB is using a different criteria to rate the cone angles of their transducers than Garmin is.
The beam, or cone angle, is effectively your viewing area. The larger the cone angle the wider the viewing area. Its adventurous to have a wider viewing area so some companies like to play games with their marketing of cone angles.

The industry standard is to rate a transducer at -3db (1/2 power) but a few use -10db (1/10 power). A transducer with an 8-degree cone angles at -3 db suddenly becomes a 16 degree cone angle when rated at -10 db.
It's a marketing ploy. The performance of the two is identical.

The same holds true power ratings. The industry standard for rating a sounders output is in Watts RMS. Some advertise their output in Watts Peak to Peak to make it sound like they have a lot more power than they really do. From a marketing perspective, doesn't 2000 W (peak to peak) sounds a lot better than 250 W (RMS)? If a company rates their units output in peak to peak I don't even consider them a viable competitor anymore.

Bottom line, when comparing products you want to compare the cone angles when measured using the same method, preferably, -3db. and you want to compare output power using the same unit of measurement.

 

[korygrandy]

Re: Garmin Fishfinder 140 or Humminbird 565

Thank you for the great technical comparison dingbat. I have a basic digital depth gauge with a transom mounted transducer right now. I suppose it works and I'm not sure that doing a hull mounted transducer will really buy me much time to discover shallow areas with my short 17 1/2' boat. That's my biggest concern.