Spectra V3 Normalization Comparison is finally here!!!

[Neil in West Jersey]

I know this is long overdue, but with the weather the way it is and is forecast, I finally had a chance to finish the normalization comparison chart for the V3 using all the different available frequency settings (with the exception of Salt Compensate).

Some of the most interesting and somewhat surprising observations follow:

• VDI compression is still evident in Normalized Single Frequency Modes, although it is not as apparent as in non-normalized modes.
• Target conductivity has an affect on VDI consistency in Single Frequency Modes, especially at 2.5KHz (low conductivity targets give less consistent VDI numbers at 2.5KHz, high conductivity targets give less consistent VDI numbers at 22.5KHz etc.)
• Target strength is greatly affected by frequency. In 2.5KHz, the V3's sensitivity to gold jewelry decreases dramatically.

ALL BENCH TESTING WAS PERFORMED INDOORS USING THE ECLIPSE 5.3 INCH CONCENTRIC COIL. WITH RX GAIN SET TO MINIMUM LEVEL (1).

Please keep in mind that your results may vary due to environmental conditions, equipment used, settings, etc.

CLICK HERE TO DOWNLOAD. You will need Microsoft Excel to view this spreadsheet and the charts.

Thanks to Chris (The Beep Goes On) for his input and support and for allowing me to use his DFX Normalization chart as a template. Please let me know if you find any errors in the spreadsheet.

Enjoy!
Neil

 

[The Beep Goes On]

Looks very nice Neil! It's amazing the the raw freqs can vary by as much as 50 or 60...

 

[Aaron]

Thanks alot guys for all the data. So does all this basically mean that we need to steer away from hunting in single frequencys and stick to the 3 frequency configurations?
Thank you.
One of the village idiots,
Aaron

 

[Neil in West Jersey]

Thanks alot guys for all the data. So does all this basically mean that we need to steer away from hunting in single frequencys and stick to the 3 frequency configurations?
Thank you.
One of the village idiots,
Aaron

On the contrary, I would say that depending on your MD objectives (coins, gold jewelry, relics, etc.) single frequency NON NORMALIZED may be a better option than multi frequency operation. For example, the VDI of a 1950 Quarter in "raw" 2,5Khz is 70, but a 1995 has a VDI of 67. Once you get into multi frequency, they are only separated by one VDI number, making it increasingly difficult to tel l them apart. Silver dimes vs. clad are separated by an average of 5 VDI numbers in 2.5 raw, vs. 3 in Best Data. The lower frequency will expand the VDI separation of high conductiveity targets.

The opposite is true of gold and low conductivity targets such as gold.

Even more importantly, the v3 is dramatically more sensitive to small gold jewelry in 22.5Khz vs Multi Frequency, so if you are looking for jewelry, 22.5 is the way to go!!

2.5Khz will go deeper on Silver & Copper.

 

[ScottTX]

Excellent work Neil! Thanks.

Small correction. You have Silver Jewelry as GJ1. Should be SJ1 to follow your scheme.

 

[butch]

Very interesting! Great work,time well spent.
Butch in Newfoundland

 

[The Beep Goes On]

Btw, I like the VDI's under the chart...helps alot...nice idea.

"VDI compression is still evident in Normalized Single Frequency Modes, although it is not as apparent as in non-normalized modes."

If the raw single-freqs can vary by 50 to 60 for certain targets, what is the max variance for normalized single-freqs?

 

[Neil in West Jersey]

Btw, I like the VDI's under the chart...helps alot...nice idea.

"VDI compression is still evident in Normalized Single Frequency Modes, although it is not as apparent as in non-normalized modes."

If the raw single-freqs can vary by 50 to 60 for certain targets, what is the max variance for normalized single-freqs?

The area with the largest swing in VDI numbers in single frequency normalized seems to be the lower to mid-range targets. The only fairly large swing was the brass Chucky Cheese token which had a VDI swing of 10.

I am going to double check the gold ring VDI over the weekend. This was one of the first targets I worked with and I hope it isn't a typo. Please feel free to alert me of any other anomalies in the data!!

 

[Neil in West Jersey]

I am going to double check the gold ring VDI over the weekend. This was one of the first targets I worked with and I hope it isn't a typo. Please feel free to alert me of any other anomalies in the data!!

I verified it...a swing from 13 to 70 VDI!!! This is a great thing when trying to separate gold from erasers in a schoolyard, The VDI difference jumps from a difference of 2 to a difference of 24 with the press of a button!

 

[The Beep Goes On]

Hmmmm....this change works with alumininum, too, right?

 

[Larry (IL)]

There is a lot of valuable info in the charts......thanks Neil