T&T: Transducer mounting

[Peter Bennett]

Tuesday, February 19, 2008, 8:21:30 AM, Kim wrote:

KBET> Larry wrote:


KBET> 3. Despite warnings to the contrary, you can use two depthfinders at the
KBET> same
KBET> time and get accurate readings on both. At least I can using a Humminbird SX

KBET> 100 and a Humminbird Pirhana. It was easier and cheaper to simply buy two
KBET> depthfinders than to use a more expensive single unit and a remote
KBET> indicator.

KBET> Reply;

KBET> This is very interesting.  I have been struggling with this issue this
KBET> season and have heard the opposite from the "transducer pundits" at Gemeco
KBET> www.gemeco.com/.  I wanted to replace a smart transducer that runs at 235
KBET> kHz because it is such low power that it has been useless to us.  We run it
KBET> as a second backup depth finder.  I wanted to install and run a second high
KBET> power sounder.  I thought that I could use two sounders and transducers that
KBET> can run at 50 or 200 kHz and run one at 50 and the other at 200.  The answer
KBET> was a big "Oh No you don't" because the Airmar transducers are all pinging
KBET> at 50 and 200 at the same time and it is the unit that distinguishes.  OK,
KBET> so they hear each other I will still have two sources of depth, right? "Oh
KBET> No you whooten"  was the voice of authority.  You would have nothing but
KBET> interference because they each need to hear the right ping at the right
KBET> time.  The bottom line was that since I already had a 50/200 sounder and
KBET> transducer I could not have another unit onboard that ran 50 or 200.  That
KBET> does not leave too many options.

KBET> I gave up on that project.  Has anyone else had Larry's success?

I expect that a 50/200 transducer will accept either 50KHz or 200KHz
excitation from the sounder, and output pulses of that frequency.
However, it will receive pulses of both frequencies - but the sounder
may filter out the frequency it is not using, so things may work.

I've used two sounders (probably both 200 KHz) at the same time. As
the sounders won't use _exactly_ the same pulse repetition rate, each
should display its own echos correctly, but will show the echos from
the other sounder wandering around the screen.

-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca