Author Topic: 250 KHz 981 C versus 450/800 in 997 ? Quality issues?  (Read 2278 times)

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Offline petervanbergman

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250 KHz 981 C versus 450/800 in 997 ? Quality issues?
« on: June 09, 2009, 06:47:19 AM »
Hi! I am about to purchase a new Humminbird, and would like to know the quality difference between the 981 C and 997 or 250 KHz to 400/800 Khz. That you get GPS with the upgrade is a major plus but is the quality difference that important when you get higher definition with higher frequency? Anybody got expericence /knowledge.

Another question is are their any methods of getting low frequency imagery in to these units with external units? ( for example GPR uses low frequency for bottom penetration imagery. ( With magnetic sensoring) you may distinct burried wrecks and also metallic object from wodden ones. Anyone got knowledge in this area and can help me find products for it.

Last a link for purchase channels would be great. ( best bargain for a 997 unit?)
My wife is going to New York in June and would pick up a unit for me there if possible.


regards
Peter Bergman
petervanbergman@yahoo.com
PS! I am a dedicated diver and exploration geologist looking for new info of exploration appliances in the marine environment! The pic is me in UTAH (impact structure).


Offline Jolly Roger

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Re: 250 KHz 981 C versus 450/800 in 997 ? Quality issues?
« Reply #1 on: June 09, 2009, 07:51:36 AM »
Hi Peter,
I asked Robert this question already. He has both a 981 and a 997 and got experience with both units.
Here's his answer: http://forums.sideimagingsoft.com/index.php?topic=46.0

I came to the same conclusion about the 262 kHz. Not really worth to have. I scanned the two boats I found with 262 kHz and was disappointed about the performance. 455 kHz is the kicker!

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

Offline RGecy

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Re: 250 KHz 981 C versus 450/800 in 997 ? Quality issues?
« Reply #2 on: June 13, 2009, 12:12:55 AM »
Peter,

Harald pointed you in the right direction.  In my opinion the 997 or 1197 is the way to go.  The image detail is phenominal and the mapping features of the 997 are impressive also. 

I now run the AS-GHRA gps reciever and the accuracy is excellent.  I ran it right next to a DGPS reciever two weeks ago and it was spot on.

As for the GPR, this unit will not handle anything like that.

Good Luck,

Robert
Humminbird Guru and Forum Administrator


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