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Old 15 October 2008, 23:30   #1
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Garmin Transducer

Earlier today I accidentally ordered a Garmin, single frequency (200khz), transom mount transducer from an ebay seller in the US. I meant to order the dual frequency version but didn't read the description properly until later today - my bad!

I've contacted the seller who also sells the dual freq version and offered to pay the additional amount ($9) but unfortunately he's already dispatched the order. He's happy to exchange the item if I send it back but obviously I'll have to pay the postage both ways

Soooo.... my questions are....how important is it to have the alternative frequency and for general leisure use around the south coast is it likely to be a big advantage?

Am I right in thinking the lower freq (50khz) is for deeper water?

The the lower freq also operates at a slightly different angle, is this likely to help me in any way?

Cheers for any help chaps
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Old 16 October 2008, 09:28   #2
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Originally Posted by Andy JC View Post
Am I right in thinking the lower freq (50khz) is for deeper water?
Yes wavelength is 4 times greater with the 50 kHz model and therefore it penetrate at least 4 times as far

Quote:
Originally Posted by Andy JC View Post
The the lower freq also operates at a slightly different angle, is this likely to help me in any way?
The issue is more one of beam spread - the higher frequency operation will be a narrower beam. This means that when you have your rib bobbing along on the briney there is a good chance that the beam won't be travelling perpendicular to the seabed. This means that the reflection is likely to return to a point on the surface other than where you are. A wider transmit and receive beam (such as on the 50 kHz mode) will be more tolerant of this type of angular misalignment.

If you are only ever in relatively shallow water (10m ish) then this shouldn't be too much of a restriction. In and around Poole harbour I don't think my Garmin has even switched to the 50 kHz range.

Hope this helps
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Old 16 October 2008, 15:44   #3
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Dont think you will notice any real difference if used as a general depth finder as opposed to a fishfinder. I wouldnt worry about it. it should give a good reading to around 100 mtrs or more. As for cone angle, whilst it is true it is somewhat dependent on frequency, it is also somewaht dependent on the design of the transducer itself.
Save your money, relax, have a beer.
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Old 17 October 2008, 10:12   #4
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Save your money, relax, have a beer.
Bit late for that, I've ordered the dual freq from the same guys and arranged to send back the single freq when it arrives.

Won't stop me having a beer though



Thanks for the advice guys
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Old 17 October 2008, 13:03   #5
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It may be handy to have a spare, or sell the surplus one on here
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Old 17 October 2008, 13:54   #6
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It may be handy to have a spare, or sell the surplus one on here
Now that's not a bad idea

Now listed in the 'Buy and Sell' section!

Cheers Dai
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