Results 1 to 5 of 5
  1. #1
    IdahoJim's Avatar
    Join Date
    Sep 2011
    Location
    Blackfoot, Idaho
    Posts
    296

    Testing battery voltage comparisons on the TDI SL

    I had some requests for testing to see if the higher battery voltage of the 4-cell L-ion added much depth to the TDI SL. To do the tests I placed the coil on a flat surface with the rod vertical. I taped a marked stick to the rod. For a target, I used a 1984 nickel. To do the test, I moved the nickel vertically toward the coil. GB off, freq center, gain max. White's 12" DF coil, 18" above ground surface. Nickel held flat, parallel to coil.

    16.8v L-ion 12.6v L-ion 10.7v nicad
    16.5" 14.5" 13.75"
    1 grain gold bar, same test, same settings.
    2.0" 2.0" 2.0"

    Nickel test GB on, but set at 0.
    17" 15" 14"

    1 grain gold bar GB on, but set at 0
    3.0" 2.5" 2.25"

    Raising the GB to max added about 1/2" to all figures for both the gold bar and the nickel

    Ground balance back to "off". Sweeping the nickel from side to side, finding the correct sweep speed by target volume....best depth at slow speed sweep.
    14" 12.25" 11.25"

    I didn't bother with the sweep test with the gold bar.

    Results:
    It's obvious the battery voltage has a direct impact on both depth, and sensitivity to small nuggets, assuming the Gb is on. All the test methods were suggested by Reg Sniff, other than the testing of the GB on and off comparisons. One thing I learned from the testing was in finding a weak signal, moving the coil up and down may enhance the target signal, if the target is metal.
    Assuming his health issues don't prevent it, Reg is going to do some experimentation on the SL to try and figure out why sweeping the nickel loses so much depth compared to moving the nickel vertically toward the coil. If we're fortunate, Reg will also test his ideas on improving the range of sweep speeds that work well. Right now, for max sensitivity, the best sweep speed is slow.

    Hat's off to John, down under (Auminsweeper) for his suggestion in a PM to me that the SL is the most sensitive with GB "on", which is contrary to most detectors. Turn that GB on, even if you set it at zero, for max sensitivity. if you can run it full on, better yet!
    Jim
    Last edited by IdahoJim; 06-03-2017 at 08:00 PM.

  2. #2
    deolslyfox's Avatar
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    46,463
    Thanks for sharing !!
    If there's anything I hate worse than diggin' pulltabs, its missin' a gold ring.

  3. #3
    rchalker's Avatar
    Join Date
    Dec 2010
    Location
    Youngstown, Ohio, USA
    Posts
    5,595
    Thanks for the information.
    AKA: Rodney ________ Detectors Used:
    ___________________White's Spectra V3i with DX-1
    ___________________White's TreasurePro
    ___________________Bounty Hunter Discovery 3300


  4. #4
    IdahoJim's Avatar
    Join Date
    Sep 2011
    Location
    Blackfoot, Idaho
    Posts
    296
    Somebody requested that I repeat the tests using aMOno coil. I have a Miner john 5 x 9 Folded Mono, so used that.
    Far different results. Sweep speed is much less critical. It would only detect the nickel at 11". Changing batteries might have made a 1/4" of difference. same with turning GB on and off..... much less difference in detection distance. But, with the 16.8v battery, the White's DF 12" coil is 1" better on the gold bar. Even with the 12.6v battery, the DF still had 1/2" better performance on the gold bar.
    On the sweep speed..the MJ was much less critical, and the optimal speed is faster.
    There was MUCH less difference in distance with the different battery voltages, too. The max difference was about 3/8".
    Turning GB on and off, and cranking it to max made very little difference.
    The MJ coil was noisier with the GB maxed out.

    All this makes me think the mono coil is reaching it's max current with the standard voltage, so extra voltage doesn't accomplish much.
    I would never have guessed that there could be so much difference simply by changing coil types.
    Jim

  5. #5
    deolslyfox's Avatar
    Join Date
    Jul 2008
    Location
    Central Florida
    Posts
    46,463
    This is how we all learn Jim. Thanks !!
    If there's anything I hate worse than diggin' pulltabs, its missin' a gold ring.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in