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Article: Sunray Inline Probes

Before I bought a Sunray probe for my DFX I thought that the extra weight and cables were not worth any benefit the probe might provide. I had various handheld probes and I thought that I did not need anything else. However, after reading many posts and articles I was intrigued enough to make the purchase. I was glad I did. The benefits of the Sunray probes are many and there are many ways to put them to good use. The reason the Sunray probes are more capable than most handhelds is the increased detection distance and that they use the detectors circuitry. The Sunray probe is actually a 1" coil and you can switch between the main coil and the probe with the flick of a switch. The benefits fall into three categories; target investigation, pinpointing and retrieval.

Target Investigation
When a large target, like a soda can, pinpoints as a shallow target there are a few ways to determine the object's true size. You can raise the coil as you swing over the target. If the signal does not disappear when the coil is raised, it could be a large target. You can pinpoint and determine the area of the target's footprint (turn ratchet pinpointing off on the DFX). If it is spread out and not a point source then it is probably a large target. Sometimes these methods work well, but there are times when doubt remains. The Sunray probes have an approximate range of 2" to 4". This is much better than the typical handheld probe. If the target is pinpointing at 2" you can use the Sunray probe to verify this. If the probe does not detect the target you know that the target is deeper and that it is a large target. This technique works before and during target retrieval. When the target is within reach of the probe you can trace out its footprint to get a better idea of the target's dimensions. When pinpointing, or during retrieval, you can leave the probe in normal, non-pinpointing mode. Since it uses the detector's circuitry it will respond to targets in normal discrimination mode as well. This can come in handy when there is more than one target in the area and you are determining which one to dig.

Pinpointing accurately is very important. You can avoid damaging a target if you know precisely where it is. The damage done from digging in the grass in parks or sports fields is minimized by digging smaller plugs. After pinpointing a target with the detector I use the probe to pinpoint it more accurately. If the probe doesn't respond to the target then I have further indication of its depth. When you have a hard-to-see surface target, the probe can find it easily. Using the probe to verify a target's location has saved me a lot of time.

Target retrieval is done in many different ways. Depending on the environment, you may be digging plugs with a turf knife or going to town with a big shovel. Either way, the probe can help locate the target. Without a probe you use your detector to ascertain whether the target is in the hole or not. If it is out of the hole you wave handfuls of dirt in front of the coil until you isolate the target. With the probe you can accomplish the same task without having to move around an unwieldy detector. You can also be more precise. Handheld probes can do this too, but most of them have to be within an inch or so of the target. The Sunray's depth capabilities allow it to find the target without tearing through the entire pile of dirt. When the target is in the hole you can spiral the coil down into the hole and determine if it is in the side or bottom. We have all had targets that were in the side of the hole and a few inches away from where we thought they were. The Sunray can help zero in on these targets with ease.

Hypothetical Retrieval
Here is a step-by-step list of how a target could be retrieved using the Sunray probe. You may not use every step every time, but this will give you an idea of how the probe can help.

  1. Pinpoint the target with the detector
  2. Kneel down and turn on the Sunray
  3. Use the Sunray to pinpoint the target more accurately if possible
  4. If it is a surface target or can be retrieved with a coin probe, you are done
  5. Cut a plug or dig a hole
  6. Use the probe to ascertain if the target is in the hole or not
  7. If it is out of the hole use the probe to find the target
  8. If it is in the hole use the probe to narrow your search
  9. Repeat steps 5, 6, 7 and 8 until the target is retrieved.

The only thing that can trip you up using the Sunray is that sometimes it does not engage properly. I do not know if others have experienced this phenomenon, but it happens on my DFX and on my SE. When you flick the switch to turn on the Sunray it may not respond to targets. To prevent this from occurring, try the following:

  • Before switching to the probe, put the tip of the probe on a clean patch of ground, or in the air if necessary
  • Flick the switch
  • Wait for a threshold tone
  • Find the target

It is also easy to forget to switch back to the regular coil after target retrieval. You may think your detector is acting strangely until you realize that you forgot to flick the switch. I have acquired a habit of visually checking the switch when I start swinging the detector.

Mounting the Sunray probe is fairly straightforward. I mounted mine differently than the suggested configuration on both my machines. I mounted it the way I did because the standard configuration made the switch difficult to reach (on the DFX). I also wanted the probe and the switch to be close together and I wanted them to be right next to me when I laid the detector down and started digging. The pictures below show the standard configuration and my configuration on both units. If you mount your Sunray on the DFX like I did, you have to have the lower rod at full extension, or not use the nut and bolt for the lower probe holder; use the lower rod spring clip to hold it. You may notice that my SE has the Sunray switch on the right side. I ordered it this way since I swing with my left hand.

Sunray DX-1 Probe in standard configuration
The Sunray DX-1 probe for the DFX - custom configuration
SE with Sunray X-1 Probe in standard configuration
The Sunray X-1 probe for the Explorer SE - custom configuration
DFX and SE with Sunray Probes in custom configuration

Happy Hunting!
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