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[TG11] Axiom 9 with rv 100 - increasing clutter as I speed up
05-06-18, 03:53 AM (This post was last modified: 05-17-18 07:29 AM by Chuck - Raymarine - Moderator.)
Post: #1
[TG11] Axiom 9 with rv 100 - increasing clutter as I speed up
Hello Everyone

After some advise on my axiom 9 sounder matched with a rv100 transducer
Now my issue is that my sounding cabilitys when doing under 5 knots is fantastic, as soon as I go above 6 knots I get a lot of surface clutter, I can reduce that with the surface filter but in takes away from my picture and I no longer get the bait definition to clearly mark fish. I have changed the transducer position a lot of times and seem to have got it in the best postion but still when going above 5-6 knots i get a lot of clutter. Any advise on this issue would be fantastic.

I have attached some soundings I’ve got whilst going under 5 knots for marlin and was pleasantly surprised the imaging I was getting with a small transducer.
Thank you in advance
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05-16-18, 09:30 PM (This post was last modified: 05-17-18 07:29 AM by Chuck - Raymarine - Moderator.)
Post: #2
RE: [TG11] Axiom 9 with rv 100
Hello Westernport,

I'm sorry to say I can't see the attachments you mention, but it would be great to see any clear, high-resolution images you have of the sounder performance both at low and higher speeds.

There are three things which can affect the quality of the sounder image as you speed up. In order of how frequently we come across them:

1. Air bubbles across the face of the transducer: air blocks the ultrasonic sound very effectively and cause a big drop in the signal levels getting back to the transducer
2. Electrical noise from engine electrical systems, picked up through transducer or power cabling
3. Acoustic noise (the hull resonating with engine vibration at a harmonic of the transducer operating frequency.)

Air across the face of the transducer is the one everyone knows about, but the other two are also surprisingly common. Any one of these can lead to an increase in clutter as you speed up, even air, because if the signal level from the bottom return drops, the sounder will increase the auto Gain level in order to try to keep the bottom echo visible.

The way to find out whether the problem is noise or aeration is to look what happens with the sounder image when in all Manual Gain/Intensity/Surface Filter. Using manual settings means that you can objectively see what changes as you speed up.
If you can post clear, high-res images or screenshots of your Axiom's screen at a range of speeds from idle to normal cruise, with Speed Over Ground displayed in a data overlay or the side data bar, withe the sounder in:
65% Gain
15% Intensity
0% Surface Filter
then we can see what's going on. The attached document gives some more detail.

Regards,
Tom


Attached File(s)
.pdf  Assessing_Sounder_performance-201804TG.pdf (Size: 952.59 KB / Downloads: 71)

Raymarine since 1999.
Interests: Diagnosis of problems in sonar/fishfinders, NMEA2000, ethernet comms, autopilots
Location: Sydney, Australia
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06-04-18, 05:53 AM
Post: #3
RE: [TG11] Axiom 9 with rv 100 - increasing clutter as I speed up
I assume this procedure can also be used to diagnose intermittent loss of depth reading while underway? I have the same system and have experienced this even while maintaining constant speed and RPM. Reading comes and goes regardless of depth. Moved the xdcr up a little and seemed to have some effect.
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06-12-18, 07:11 PM
Post: #4
RE: [TG11] Axiom 9 with rv 100 - increasing clutter as I speed up
Hello SteveME,

Yes, that's right. This is how we go about diagnosing any sounder performance problems, here in Australia.

If you can take some images (clear, high-resolution, full-screen) both in whatever setup you normally use and the levels I mentioned before and post them here, I'd be happy to have a look.

Thanks,
Tom

Raymarine since 1999.
Interests: Diagnosis of problems in sonar/fishfinders, NMEA2000, ethernet comms, autopilots
Location: Sydney, Australia
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