2D sonar: is Garmin’s split frequency mode the same as HB’s new Dual Spectrum Chirp?

[BassTracker175]

Could Anyone help explain?

Seems to me Garmin’s Split frequency mode will do two frequencies at the same time, but then it won’t do chirp around each frequency; HB may be do two chirps at the same time?

[LWINCHESTER2]

Probably need Todd to give particulars. I know my 7610xsv could do dual chirp at the same time. Don't remember all the details but I did a head to head comparison of the GT15 against the Airmar TM150 and when doing the test I used both manually set specific frequencies with both to the same frequency and with both set to chirp at the same time. I remember two things stood out in the test. The GT15 was every bit as good as the Airmar and running both on the same frequency at the same time, mounted within an inch of each other I got no interference. If anybody else can do that I want to see it. But to your question - it may depend both on the unit and transducers in question because both hardware and software are involved. I would expect that the unit sonar would have to be "dual channel". You are probably not referring to a Humminbird entry level unit. There is also a lot of "chirp" going around that's not through a real chirp transducer. It's contagious.

One thing I would mention that I saw using Lowrance 200/83 non chirp. In deep water the ping rate is reduced. Then if you try running both frequencies through the same element there is another reduction. I got better performance running a single frequency than two frequencies. Just something to think about.

[Wayne P.]

Could Anyone help explain?

Seems to me Garmin’s Split frequency mode will do two frequencies at the same time, but then it won’t do chirp around each frequency; HB may be do two chirps at the same time?

You are not even close with your speculation of what Dual Spectrum is.

Humminbird's Dual Spectrum 2D sonar is a CHIRP frequency range of 140 to 240 kHz, that is the FULL setting and is adjustable to use any range or single frequency within that range.
There are two fixed frequency ranges in that FULL range.
Narrow is the upper end of the FULL range- 180-240 kHz.
Wide is the lower end of the FULL range--150-220 kHz.

No such thing as two anything at the same time.

[BassTracker175]

Thank you Wayne! Glad you are here!

So HB’s dual spectrum don’t work at the same time? Then I stilll don’t see where the “dual” is for! As to CHIRP, isn’t it chirping from low frequency (140kHz) to high frequency (240kHz) by gradually changing frequency in the range? So in FULL mode, it should cover both Wide and Narrow modes (80%?). I think the Wide and Narrow modes are two special modes extending the FULL range (20%) at both ends, and more for manual in special scenarios. Am I right?

Garmin or any manufacturers can have this called “High” chirp, “medium” chirp and “low” chirp. They can market the feature as TRIPPLE spectrum, LOL.

[Wayne P.]

Probably need Todd to give particulars. I know my 7610xsv could do dual chirp at the same time. Don't remember all the details but I did a head to head comparison of the GT15 against the Airmar TM150 and when doing the test I used both manually set specific frequencies with both to the same frequency and with both set to chirp at the same time. I remember two things stood out in the test. The GT15 was every bit as good as the Airmar and running both on the same frequency at the same time, mounted within an inch of each other I got no interference. If anybody else can do that I want to see it. But to your question - it may depend both on the unit and transducers in question because both hardware and software are involved. I would expect that the unit sonar would have to be "dual channel". You are probably not referring to a Humminbird entry level unit. There is also a lot of "chirp" going around that's not through a real chirp transducer. It's contagious.

One thing I would mention that I saw using Lowrance 200/83 non chirp. In deep water the ping rate is reduced. Then if you try running both frequencies through the same element there is another reduction. I got better performance running a single frequency than two frequencies. Just something to think about.

Humminbird's Dual Spectrum CHIRP is done via LowQ CHIRP rated 2D sonar piezo.
Humminbird Dual Beam single frequency and CHIRP use the standard 2D piezo using either 83/200 kHz, 50/200 kHz, or 200/455 kHz and their CHIRP ranges but not do not ping both at the same time, they alternate if both are chosen to be displayed. Units that have Imaging frequencies rotate through the chosen image frequency and 2D frequencies and at no time are any pinged at the same time.

A slow ping rate is typically automatic for deeper water since the unit waits for the return echo before transmitting the next ping--takes longer for the sound round trip in deeper water.