Author Topic: Scanning at 262 and 455 kHz  (Read 3686 times)

0 Members and 1 Guest are viewing this topic.

Offline Rickard

  • Hero Member
  • *****
  • Joined: May 2009
  • location: Luleň Sweden
  • Posts: 504
  • Unit(s): 999, 981, M37, LowBird-1, LowBird-2
Scanning at 262 and 455 kHz
« on: May 29, 2010, 02:31:27 AM »
time for 265 kHz as well
hendirk

Yes Hendrik, we shouldn't forget about the 265 kHz option (or is it 262?) in the old SI transducer. Unfortunately, I have the HDSI transducer permanently mounted to my towfish, and I have my SI transducer hull mounted, so I can't test the SI transducer with the towfish. But, this winter I used the SI transducer for sector scanning under ice and made some comparisons between 265 and 455 kHz. I used two 10 m HB original extensions, if I recall correctly. Anyway, the 360 degree scans shown below are obtained at 265 and 455 kHz, respectively. Depth from the transducer is 5.5 m (16 ft) and range (radius) is 50 m (150 ft). Both images are transformed from rectangular to circular with slant range correction (the water column is thus eliminated). What you see are some 80 years old concrete barges close the Stensborg island outside the city of Luleň in Sweden. To me they tell that the 265 kHz frequency can be very useful in some situations. Perhaps it's much better than 800 and 455 kHz in a towfish application with long cable?

Sector scan at 265 kHz.
ila_rendered


Sector scan at 455 kHz.
ila_rendered


Offline Jolly Roger

  • Hero Member
  • *****
  • Joined: Mar 2009
  • location: Germany, Lake Constance
  • Posts: 801
  • HB Addicted
  • Unit(s): 998Cx SI
  • Software: latest (mostly)
  • Accessories: AS GR50, custom towfish and: A boat!!
Re: Scanning at 262 and 455 kHz
« Reply #1 on: May 29, 2010, 02:39:09 AM »
Wow Rickard,
these pictures are amazing! Congratulations!

Regards / Harry
YES,......
WE SCAN!

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: Scanning at 262 and 455 kHz
« Reply #2 on: May 29, 2010, 04:59:00 AM »
Nice slant range.   I guess the transducer must be moving and not stationary???????

Chuck

Offline Rickard

  • Hero Member
  • *****
  • Joined: May 2009
  • location: Luleň Sweden
  • Posts: 504
  • Unit(s): 999, 981, M37, LowBird-1, LowBird-2
Re: Scanning at 262 and 455 kHz
« Reply #3 on: May 29, 2010, 05:57:39 AM »
Chuck,

The transducer is rotated at a stationary position (a hole through the ice). Last year there was a long discussion on this method here: http://www.xumba.scholleco.com/viewtopic.php?t=851&postdays=0&postorder=asc&start=30

Rickard

Offline abraquelebout

  • volunteer rescue diver, surfer, publicist
  • Full Member
  • ***
  • Joined: Apr 2010
  • location: france
  • Posts: 247
  • Unit(s): 898, 1198, helix G2
  • Software: deep,,drdepht,reef.
  • Accessories: towfish lowbird /LSS2-hdsi, 60mcable
Re: Scanning at 262 and 455 kHz
« Reply #4 on: May 29, 2010, 07:50:53 AM »
nice images, i hope that the 255 khz and 455 for  more width, and 455 - 800 for detail
in 455 there 35 m left and right in 800 khz no more than 15 meters
today bad weather, more wind and waves... the sea is not ok for test :'(
the towfish is now conected at 55 metres of clear signal cable...i'm waithing better condition

Offline sonar2000

  • Chief
  • Global Moderator
  • *
  • Joined: May 2009
  • location: Kerr Lake NC
  • Posts: 5970
  • It is not lost ...it has been misplaced.
  • Unit(s): (1) 1197 (1) 1198
  • Software: 6.6
  • Accessories: Tow Fish
Re: Scanning at 262 and 455 kHz
« Reply #5 on: May 29, 2010, 11:55:20 AM »
thanks, Rickard.  I had not thought of this.  good picture...
Chuck


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo

 

Related Topics

  Subject / Started by Replies Last post
0 Replies
2677 Views
Last post August 06, 2011, 02:05:00 AM
by drpelle
9 Replies
5434 Views
Last post August 12, 2013, 04:46:10 AM
by Chapaj
16 Replies
6354 Views
Last post September 02, 2011, 09:34:45 AM
by sonar2000
4 Replies
2201 Views
Last post April 03, 2012, 02:24:53 PM
by sonar2000
20 Replies
6078 Views
Last post January 23, 2014, 06:32:11 PM
by riverlogger


SimplePortal 2.3.3 © 2008-2010, SimplePortal