Dff3 frequency setting
- Thread starter gregg
- Start date
Good afternoon Gregg,
Thank you for providing that information. The Frequency slider on the DFF3 does not change the frequency by the specified offset that you choose. For example, lets say the low frequency side is set to 50khz in the transducer setup menu. Then you slew the frequency by -20. You might think that that would put the output frequency at 30kHz. The best of my knowledge it does not work like that, the frequency slider changes the frequency as a percentage so you don't really know what frequency you are using.
The best way to do this would be to use a manual transducer setup and put the frequency you want to use for both the high and low frequencies and not play with the changing the frequency slider in the main sounder menu.
When you change the frequency on the transducer installation page you should cycle power to the DFF3 when finished.
C-Bass
Thank you for providing that information. The Frequency slider on the DFF3 does not change the frequency by the specified offset that you choose. For example, lets say the low frequency side is set to 50khz in the transducer setup menu. Then you slew the frequency by -20. You might think that that would put the output frequency at 30kHz. The best of my knowledge it does not work like that, the frequency slider changes the frequency as a percentage so you don't really know what frequency you are using.
The best way to do this would be to use a manual transducer setup and put the frequency you want to use for both the high and low frequencies and not play with the changing the frequency slider in the main sounder menu.
When you change the frequency on the transducer installation page you should cycle power to the DFF3 when finished.
C-Bass
Sorry still don't get it. My understanding was that I could adjust frequency to decrease interferences etc.
While sounding in normal operation?
In the trans set up pic below please tell me what I'm seeing line for line etc.
Is the band width some thing different?
And in the 2nd pic of settings menu page is the frequency adjust -10 to + 10
Please explain how to use this as well thanks
Also maybe you could advise as to where I can get a operating manual to use the dff3? Could only find the 32 page one on line and dosen't cover any settings etc.
Thanks for your help and sorry to be hard work.
While sounding in normal operation?
In the trans set up pic below please tell me what I'm seeing line for line etc.
Is the band width some thing different?
And in the 2nd pic of settings menu page is the frequency adjust -10 to + 10
Please explain how to use this as well thanks
Also maybe you could advise as to where I can get a operating manual to use the dff3? Could only find the 32 page one on line and dosen't cover any settings etc.
Thanks for your help and sorry to be hard work.
Good afternoon Gregg,
It is a little confusing. I will try to explain.
Starting with the first picture:
Transducer Setup Type:
HF: Your photo shows 170 kHz, this is the center frequency that the high frequency channel is set to.
Bandwidth HF: Your photo shows 52. Bandwidth allows you a range of frequencies on the high frequency channel.
In your example, you have the center frequency set to 170 kHz with a bandwidth of 52. Which means you will be able to slew the frequency 26 kHz above and below 170 or (52/2=26). When center frequency is set to 170 kHz and the bandwidth is 52 you will be able to go up to 196 kHz and down to 144 kHz. Lets say you choose a different center frequency of 200 and you keep the bandwidth at 52. This will give you the ability to choose 26 kHz above 200 and 26 kHz below 200. So now you will be able to up to 226 kHz and down to 174 kHz.
The low frequency works the same way. The bandwidth allows you to adjust the frequency up and down from the center frequency or (Bandwidth/2= the range you can adjust the frequency above the center frequency and the range you can adjust the frequency below the center frequency. For example, if you choose the LF center at 50 kHz and you choose a 20 kHz bandwidth. You will be able to slew the frequency up 10 kHz and down 10 kHz (20/2=10). So know you could go up to 60 kHz and down to 40 kHz.
The second picture: Shows the Frequency Adjust Setting. This is the part that is a little confusing. The slider in your photo shows the HF Frequency Adjust to 1 and the Low Frequency Adjust to 0. When the frequency adjust is set to 0 that means the transducer is operating at the center frequency you have selected in the Transducer setup menu. Using the photos that means your low frequency is transmitting at 45 kHz. Now the second photo shows the the HF Frequency Adjust set at 1. We know that your HF Center Frequency is set to 170 kHz and you have it adjusted to 1. Ideally that would mean you are transmitting on the HF at 171 but it does not work that way. The Frequency Adjust is not a 1 for 1 adjustment. I believe it is a percentage but i don't know what percentage. Which means if you slide the frequency adjust up to 10 that does not mean you are transmitting at 180 kHz, it is something different, it is a percentage difference and I don't know what percentage. I will try to find out for you.
Which means if you want to run the HF at 200 kHz. You should set the HF Center frequency to 200 kHz in the transducer setup menu for high frequency. Then make sure the Frequency Adjust slider is set to 0, then you know for sure that the HF is transmitting at 200 kHz.
The low frequency: If you want to set the transducer to work at 28 kHz, then you should set the LF Center Frequency at 28 kHz in the transducer setup menu, keep the frequency slider at 0, then you know the transducer is pinging at 28 kHz on the low frequency channel. If you do decide to change the Frequency Adjust slider- you can go up or down with that number but i cannot tell you what frequency the transducer will be pinging at by just looking at the slider number.
C-Bass
It is a little confusing. I will try to explain.
Starting with the first picture:
Transducer Setup Type:
HF: Your photo shows 170 kHz, this is the center frequency that the high frequency channel is set to.
Bandwidth HF: Your photo shows 52. Bandwidth allows you a range of frequencies on the high frequency channel.
In your example, you have the center frequency set to 170 kHz with a bandwidth of 52. Which means you will be able to slew the frequency 26 kHz above and below 170 or (52/2=26). When center frequency is set to 170 kHz and the bandwidth is 52 you will be able to go up to 196 kHz and down to 144 kHz. Lets say you choose a different center frequency of 200 and you keep the bandwidth at 52. This will give you the ability to choose 26 kHz above 200 and 26 kHz below 200. So now you will be able to up to 226 kHz and down to 174 kHz.
The low frequency works the same way. The bandwidth allows you to adjust the frequency up and down from the center frequency or (Bandwidth/2= the range you can adjust the frequency above the center frequency and the range you can adjust the frequency below the center frequency. For example, if you choose the LF center at 50 kHz and you choose a 20 kHz bandwidth. You will be able to slew the frequency up 10 kHz and down 10 kHz (20/2=10). So know you could go up to 60 kHz and down to 40 kHz.
The second picture: Shows the Frequency Adjust Setting. This is the part that is a little confusing. The slider in your photo shows the HF Frequency Adjust to 1 and the Low Frequency Adjust to 0. When the frequency adjust is set to 0 that means the transducer is operating at the center frequency you have selected in the Transducer setup menu. Using the photos that means your low frequency is transmitting at 45 kHz. Now the second photo shows the the HF Frequency Adjust set at 1. We know that your HF Center Frequency is set to 170 kHz and you have it adjusted to 1. Ideally that would mean you are transmitting on the HF at 171 but it does not work that way. The Frequency Adjust is not a 1 for 1 adjustment. I believe it is a percentage but i don't know what percentage. Which means if you slide the frequency adjust up to 10 that does not mean you are transmitting at 180 kHz, it is something different, it is a percentage difference and I don't know what percentage. I will try to find out for you.
Which means if you want to run the HF at 200 kHz. You should set the HF Center frequency to 200 kHz in the transducer setup menu for high frequency. Then make sure the Frequency Adjust slider is set to 0, then you know for sure that the HF is transmitting at 200 kHz.
The low frequency: If you want to set the transducer to work at 28 kHz, then you should set the LF Center Frequency at 28 kHz in the transducer setup menu, keep the frequency slider at 0, then you know the transducer is pinging at 28 kHz on the low frequency channel. If you do decide to change the Frequency Adjust slider- you can go up or down with that number but i cannot tell you what frequency the transducer will be pinging at by just looking at the slider number.
C-Bass
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