Peak or Null

[thejoker]

old timer

Use peak. check it back in null. If you where off or marking a little fast it will catch it



Last words at the alamo........HELPS ON THE WAY BOYS!!!!!

Exactly, use it to verify your locate..... Unless your an old timer, and like the null response......

[ifinditunderground]

I don't believe I have ever really worked in Null. So I guess the answer is Peak.....

[Metroman]

I don't understand the physics of it, but the metrotech 810 seems to be the exception to the rule. I know I love mine. My comments above are mostly towards using RD's & Subsites. Those are the 3 pieces of equipment I know the most of.

I use the 9800.The 810 bleeds off too much for my taste.RD's and Subs work good i just cant stand the high pitch noise LOL

[yahoo]

that high pitched noise has saved me many times when making a good sweep on high.....and even saved me when i was on my way back to the truck not paying attention......

[Dave72]

I use peak pretty much all the time.. but I was taught that on a 90 bend, peak will be off one way and null will be off the other (dang, i always forget which is which..).. and the true path is between the 2 and closer to the peak path.

Plus, if your peak and null agree then that means the depth reading will be perfect.. if theyre off then there is something else carrying some signal and the depth will be wrong. (not that we give out depth.. but maybe if you're doin a diy help for a pal on his own stuff etc)

[Metroman]

that high pitched noise has saved me many times when making a good sweep on high.....and even saved me when i was on my way back to the truck not paying attention......

I have a hearing imbalance my lows require about 50 db for me to hear them but my highs only require about 20 db.Yeah i cant stand yappy little dogs either, really hurts my ears.

[AvoidDisaster]

Just my worthless information. I hope you can get some use out of it.

If you understand the basic principles involved with a sine wave (a sideway "S" in it's simplest form) with the beginning being zero amplitude value (the amount of power applied to the rf signal) and the end being zero amplitude value (Measured in dB or decibels which is a ratio of power output) one hertz is the equivalent of a one second time interval in which the sine wave travels from the zero amplitude value line to the highest peak (measured in +dB) and returns to ithe zero amplitude value line and then decends in value to the lowest amplitude value (measured in -dB) . This is one cycle or one hertz. A transmitter with an output of say 8.9 kHz is actuall sending out a signal or sine wave that occilates at 8,900 cycles a second. Now to your question. Peak mode uses only one peak or the highest amplitude value in dB of the occilatin sine wave to pinpoint the signal transport pipeline making locating accuracy extremely high if you are not walking fast and moving your equipment slowly across the intended target. The null mode uses the lowest amplitude valleys on EITHER side of a peak in the sine wave to pinpoint a peak. It is not as accurate but the margin of error is minimal if you are in a production locate environment as it allows you to move faster with almost equivalent accuracy. if you are alloted 24" or more in your state for error tolerance you should be ok but if you have the time I recommend the initial locate be done in null and the return walk to the transmitter be completed with the peak if time permits. You will greatly reduce the error margin using BOTH methods. So the answer from me I guess is Both are necessary and valuable tools to assist with accuracy and can compliment one another if time permits.

I hope this is of some use to you.

[paintitout]

I use peak 90% of the time, more so since I went to the RD 4000. I have a Verifier for a second piece of equipment and on that one I use the Null a lot it is a lot better Null than the RD's. It is probably 50/50 with the Verifier.

[CoxHaters]

Just my worthless information. I hope you can get some use out of it.

If you understand the basic principles involved with a sine wave (a sideway "S" in it's simplest form) with the beginning being zero amplitude value (the amount of power applied to the rf signal) and the end being zero amplitude value (Measured in dB or decibels which is a ratio of power output) one hertz is the equivalent of a one second time interval in which the sine wave travels from the zero amplitude value line to the highest peak (measured in +dB) and returns to ithe zero amplitude value line and then decends in value to the lowest amplitude value (measured in -dB) . This is one cycle or one hertz. A transmitter with an output of say 8.9 kHz is actuall sending out a signal or sine wave that occilates at 8,900 cycles a second. Now to your question. Peak mode uses only one peak or the highest amplitude value in dB of the occilatin sine wave to pinpoint the signal transport pipeline making locating accuracy extremely high if you are not walking fast and moving your equipment slowly across the intended target. The null mode uses the lowest amplitude valleys on EITHER side of a peak in the sine wave to pinpoint a peak. It is not as accurate but the margin of error is minimal if you are in a production locate environment as it allows you to move faster with almost equivalent accuracy. if you are alloted 24" or more in your state for error tolerance you should be ok but if you have the time I recommend the initial locate be done in null and the return walk to the transmitter be completed with the peak if time permits. You will greatly reduce the error margin using BOTH methods. So the answer from me I guess is Both are necessary and valuable tools to assist with accuracy and can compliment one another if time permits.

I hope this is of some use to you.

No hablo espanol

[Dave72]

This is one cycle or one hertz. A transmitter with an output of say 8.9 kHz is actuall sending out a signal or sine wave that occilates at 8,900 cycles a second. Now to your question. Peak mode uses only one peak or the highest amplitude value in dB of the occilatin sine wave to pinpoint the signal transport pipeline making locating accuracy extremely high if you are not walking fast and moving your equipment slowly across the intended target. The null mode uses the lowest amplitude valleys on EITHER side of a peak in the sine wave to pinpoint a peak.

Dont get confused with those diagrams that show the signal level (which they draw as a sinewave portion typically). I think its better to picture the end-on (like cut a cable and look into the end of it) diagrams.. the signal radiates out like concentric circles (the actual sine wave of the signal only collapses and reverses them over and over.. but theyre still concentric circles of signal level centered on the conducting thing). When you locate in peak, you orient your antenna to maximize to the horizontal signals (the 'top' part of the concentric circles).. when you switch to 'null', your antenna is set to maximize with the vertical portions of the signal 'circles' (the 'left' and 'right' side of those circles).

Same effect, but just to know that you're not looking at a sine-wave in the ground at right angles to the cable/etc.. rather you're maximizing an antenna's orientation to an rf signal.

With that you can see that there is a peak over every cable/etc.. even when you have signal bleeding to something else.. you would just get multiple peaks. However in null, the null 'max' may not be centered above your cable because of skewing of the fields by some other adjacent cable (or a chainlink fence etc etc).

[Linden Riddle]

You use the "the 'top' part of the concentric circles" for a null response, too.

[Dave72]

Rereading my early morning post, I agree I should have added that at the end of my first paragraph there, Linden.. good catch.

[yahoo]

peak ....all the way ....null..not at all

[mr. null]

i like null, tis my last name... tend to use it alot, but if im going to paint i check the peak, null and the verify the depth. depth verfication is a crucial part of knowing whether the signal is round or distorted.