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CHIRP - Help!

Old 02-27-2013, 11:56 PM
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Default CHIRP - Help!

I'm trying to understand the principals behind CHIRP and therefore the transducer requirements.

I'm looking at the Garmin CHIRP module (GSD26) and see that its frequency range is 25-210khz. The CHIRP transducers (Airmar) are LH/LM covering 3 frequency bands. Do I need to select any two frequency bands i.e. LH or LM when selecting my transducer? IOW if I select a B265LH I'm then able to use frequency ranges of (L) 42-65khz and (H) 130-210khz? If so, what about ther M freq range 85-135khz, can the GSD26 have all three freq ranges connected? Also, where can I download a user manual for the GSD26 to have a read through before buying? I only found installation manual on the Garmin website.

sorry but it just not make sense to a layman
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Old 02-28-2013, 12:54 AM
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I've got the Garmin 4208 plotter and GSD22 but thinking about installing the CHIRP module and TM265LH transducer.The marketing tells me that the GSD26 is capable of scanning all frequencies (25-210khz) depending on the transducer. I can only see a setting for Low Chirp and High Chirp which tome means you cannot scan through 25-210khz but rather L/H or L/M but not all at same time?

Last edited by Wildfish; 02-28-2013 at 04:31 AM.
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Old 02-28-2013, 04:28 AM
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anyone
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Old 02-28-2013, 04:34 AM
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You only get two channels and it is either LM or LH. The GSD26 uses the XID to identify the transducer and utilizes the appropriate frequency for the connected transducer.
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Old 02-28-2013, 05:00 AM
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Originally Posted by stiletto View Post
You only get two channels and it is either LM or LH. The GSD26 uses the XID to identify the transducer and utilizes the appropriate frequency for the connected transducer.
Thanks, that's how I thought it worked. The marketing seems a little misleading, even a salesman has been telling me that CHIRP scans through all frequencies (42khz to 210khz) at the same time. I've dug up an install manual and the operators manual and there's not mention of being able to connect all frequency bands (L/M/H) at same time.
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Old 02-28-2013, 05:32 AM
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Originally Posted by Wildfish View Post
Thanks, that's how I thought it worked. The marketing seems a little misleading, even a salesman has been telling me that CHIRP scans through all frequencies (42khz to 210khz) at the same time. I've dug up an install manual and the operators manual and there's not mention of being able to connect all frequency bands (L/M/H) at same time.
Most salesmen I have run into know very little. There are some good ones, but they seem to be the exception. The forum sponsors here are very good.
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Old 02-28-2013, 05:35 AM
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Originally Posted by stiletto View Post
Most salesmen I have run into know very little. There are some good ones, but they seem to be the exception. The forum sponsors here are very good.
Thanks, I'm hoping one of the forum sponsors will wade in on this and explain the CHIRP technology in layman's terms.
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Old 02-28-2013, 06:16 AM
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PM Gill, Semperfifishing. He has an incredible amount of knowledge on this subject. He helped me tremendously in my current electronics re-fit. I bought a CHIRP system through Simrad, and i am sure i will be back talking to him once i try to start unsing it.
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Old 02-28-2013, 06:33 AM
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You might want to look here:

http://www.airmartechnology.com/
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Old 02-28-2013, 08:34 AM
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Originally Posted by Wildfish View Post
The marketing seems a little misleading, even a salesman has been telling me that CHIRP scans through all frequencies (42khz to 210khz) at the same time.

I've dug up an install manual and the operators manual and there's not mention of being able to connect all frequency bands (L/M/H) at same time.


The salesman is correct.....Good for him!




A CHIRP can sweep linearly thru all the frequencies in the band...both High and Low ..and transmit both bands at the same time. (2 bands at a time only..not 3)

Example:
When the GSD-26 is using the dual band in the CHIRP mode with a B265LH this is what occurs:

The low band is linearly sweeping and firing all frequencies from 42 kHz thru 65 kHz.
And at the same time..
The high band is linearly sweeping and firing all frequencies from 130 kHz to 210 kHz.
A total fired bandwidth of 103 kHz from just one transducer....that is amazing.
In addition..the beamwidth also will be from 25 to 16 degrees on the Low band and from 10 to 6 degrees on the High band.


Or one can customize the frequencies being fired in the bands...

One can select a specific combination of frequencies for the high and low bands.
From my own personal experience with CHIRP..put it in dual band auto and let it do the work for you.
In auto....so easy even a caveman can use it.
...................................

A CHIRP sonar combined with an Airmar CHIRP transducer achieves unprecedented resolution and target separation.
The fisherman's ability to separate fish from bottom structure or from each other in a large school is now within a matter of inches vs sometimes feet as in a traditional sonar system.

CHIRP fishfinders transmit less total peak power than a tone pulse fishfinder...but puts far more actual energy onto the target.
A CHIRP's wide-band, frequency modulated pulses (130-210kHz, or 42 to 65 kHz for example) can be very long in duration and put 10-50 times more energy into the water.
The CHIRP signal processing itself is revolutionary and unparalleled with its pattern matching capability of the transmitted bands and return echos.

Airmar CHIRP transducers have exceptional bandwidth and superb low Q ,high quality broadband ceramic elements.


So..in a nutshell....there are many advantage for a CHIRP system depending on ones needs and fishing conditions.
CHIRP is not for everyones fishing requirements.......but if you are considering a total re-fit or a new boat then CHIRP could warrant a serious consideration.


Last edited by semperfifishing; 03-01-2013 at 06:51 AM.
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Old 02-28-2013, 09:45 AM
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Here is some more info ... http://www.fishtec.co.za/CHIRP%20Training.pdf
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Old 02-28-2013, 01:06 PM
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Originally Posted by semperfifishing View Post


The salesman is correct.....Good for him!




A CHIRP can sweep linearly thru all the frequencies in the band...both High and Low ..and transmit both bands at the same time. (2 bands at a time only..not 3)

Example:
When the GSD-26 is using the dual band in the CHIRP mode with a B265LH this is what occurs:

The low band is linearly sweeping and firing all frequencies from 42 kHz thru 65 kHz.
And at the same time..
The high band is linearly sweeping and firing all frequencies from 130 kHz to 210 kHz.
A total fired bandwidth of 103 kHz from just one transducer....that is amazing.
In addition..the beamwidth also will be from 25 to 16 degrees on the Low band and from 10 to 6 degrees on the High band.


Or one can customize the frequencies being fired in the bands...

One can select a specific combination of frequencies for the high and low bands.
From my own personal experience with CHIRP..put it in dual band auto and let it do the work for you.
In auto....so easy even a caveman can use it.
...................................

A CHIRP sonar combined with an Airmar CHIRP transducer achieves unprecedented resolution and target separation.
The fisherman's ability to separate fish from bottom structure or from each other in a large school is now within a matter of inches vs sometimes feet as in a traditional sonar system.

CHIRP fishfinders transmit less total peak power than a tone pulse fishfinder...but puts far more actual energy onto the target.
A CHIRP's wide-band, frequency modulated pulses (130-210kHz, or 42 to 65 kHz for example) can be very long in duration and put 10-50 times more energy into the water.
The CHIRP signal processing itself is revolutionary and unparalleled with its pattern matching capability of the transmitted bands and return echos.

Airmar CHIRP transducers have exceptional bandwidth and superb low Q high quality broadband ceramic elements.


So..in a nutshell....there are many advantage for a CHIRP system depending on ones needs and fishing conditions.
CHIRP is not for everyones fishing requirements.......but if you are considering a total re-fit or a new boat then CHIRP could warrant a serious consideration.
Is this the same for the new Furuno? and is there any new information?
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Old 02-28-2013, 04:11 PM
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Originally Posted by velooce View Post
Is this the same for the new Furuno? and is there any new information?
I have been provided no details of the Furuno CHIRP system other than the photo below showing their beta version being assembled at a undisclosed test faciity.







Guess we need to just hold on for more information ...

Last edited by semperfifishing; 12-03-2014 at 03:52 PM.
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Old 02-28-2013, 07:22 PM
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Thanks semper, excellent explanation. I've been doing a lot of research and so far there's some great screen shots of the CHIRP sounders, especially the Garmin but I'm finding it hard to find a happy owner. So far at a local dealer he tells me of a Simrad and Raymarine CHIRP module that he has had to credit. One owner has fitted a fcv-295 (still using Airmar R599) with great results. There's a few guys using FCV295 in our club and I've only heard good things. Also just dug up some info on the new Furuno CHIRP. They seem to have only opted for the LF frequency bands, no mention of 80-130khz?

Oh yeah, the dealer said that the Raymarine had an incredibly slow scroll speed. In depths of 100ft or more the user rendered it useless.

Last edited by Wildfish; 02-28-2013 at 07:35 PM.
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Old 02-28-2013, 07:36 PM
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Originally Posted by Wildfish View Post
Thanks semper, excellent explanation. I've been doing a lot of research and so far there's some great screen shots of the CHIRP sounders, especially the Garmin but I'm finding it hard to find a happy owner. So far at a local dealer he tells me of a Simrad and Raymarine CHIRP module that he has had to credit. One owner has fitted a fcv-295 (still using Airmar R599) with great results. There's a few guys using FCV295 in our club and I've only heard good things. Also just dug up some info on the new Furuno CHIRP. They seem to have only opted for the LF frequency bands, no mention of 80-130khz?
Furuno supports the low and high frequency, but not the mid frequency according the Furuno reps at the Miami Boat Show.
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Old 02-28-2013, 07:51 PM
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Originally Posted by stiletto View Post
Furuno supports the low and high frequency, but not the mid frequency according the Furuno reps at the Miami Boat Show.
which probably makes good sense. I believe most people fit the LH type ducers anyway.
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Old 02-28-2013, 07:58 PM
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Originally Posted by Wildfish View Post
which probably makes good sense. I believe most people fit the LH type ducers anyway.
I am not sure why they omitted it. Sure most people do LH, but its not that hard for them to support using the high frequency as a mid frequency.
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Old 02-28-2013, 08:17 PM
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Originally Posted by stiletto View Post
Furuno supports the low and high frequency, but not the mid frequency according the Furuno reps at the Miami Boat Show.
They are probably just trying to give the fish a sporting chance...
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Old 02-28-2013, 09:32 PM
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Originally Posted by stiletto View Post
I am not sure why they omitted it. Sure most people do LH, but its not that hard for them to support using the high frequency as a mid frequency.
I have just read the Airmar CHIRP training document http://www.fishtec.co.za/CHIRP%20Training.pdf and found their picture of low frequency very interesting. Here's the echo's from different frequencies on the same target (compliments of Airmar). I know which echo looks best to me, why worry about the rest?
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Old 03-01-2013, 02:01 PM
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Question - If you were looking at the Garmin741 with transom mounted chirp that rated for 300w RMS would that give you better performance than a 500- 600 watt thru hull transducer. Given your fishing is done in 100 to 900 feet of water ( bottom fishing and tuna fishing)
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