Hay's Electronics Mark Ii Metal Detector
By Reg Sniff
From Page 22
January, 1999 issue of Lost Treasure

When a friend of mine, Bill Hays, owner and CEO of Hays Electronics, asked me if I would be interested in field testing the Hays Mark II detector, I had some reservations. The reason for my concern was, I am accustomed to testing more elaborate detectors, and this unit did not directly compare to the much higher priced units.

I realized I would have to adjust my thinking to give this detector a fair evaluation. Once I put everything into perspective, testing this little unit was a little frustrating, yet fun.

The Hays Mark II detector is not designed for the serious treasure hunter to use on a full-time basis. Instead, it is a starter unit for somebody who doesnt want to spend a lot of money, but still wants a detector. It is also a great unit for the young treasure hunter who wants to hunt with dad or mom. It's also a suitable machine for those people who want to experiment to see how detectors work.

Finally, it is a great little detector to carry all the time on trips and other outings. It would be perfect to have along for those emergencies when something of value such as keys and rings are lost.

The Hays Mark II detector, priced at $69.50, is best described as a detector that is reminiscent of the detectors that sold in the early 1970s for $200 to $300. It is a TR-type detector that operates somewhere around 100 Khz in frequency. Although the basic electrical circuitry is very similar to the earlier units, it has gone through several changes over the years.

Powered by a single, 9-volt alkaline transistor battery, the Mark II has only one control, an on/off tuning control. Adjustment is as simple as turning the detector on and rotating the control until a slight threshold signal is heard and begin searching. The control unit is made of plastic, and the coil is 5.5 inches diameter in size.

Testing the Mark II

Field testing began at my house where I analyzed the detector using an initial air test. Bill Hays had informed me that this little detector would readily detect extremely small gold nuggets and had respectable depth on larger objects. I was curious to know if that were true.

I began by testing the Mark IIs sensitivity to small gold. My test piece was a very small nugget, about 1 to 1.5 grain in size. Physically, this little nugget was about pinhead in size. To my surprise, the Mark II responded with a very distinct signal. In fact, the Mark II would detect this small nugget almost 2 inches from the search coil.

A similar air test was then performed on a penny. The coin was still readily audible to a distance exceeding 6 inches and just barely audible at about 7 inches away from the coil; not bad for a detector selling for less than $70.

Testing was then directed to my front yard. There the Mark II brought back old memories of the difficulties of the old TR-type detectors. The Mark II, like all the other TR units I have tested over the years, was very ground sensitive. Bobbing the search coil up and down above the ground just a couple of inches would readily cause the detector to go from silent to full audio output.

The only way I could use this detector at home was to raise the search coil a couple of inches above the ground and adjust for a slight threshold signal. I would then lower the coil and operate in what could be called a silent mode and basically scrub the coil on the ground. To check to make sure the detector was working OK, I would periodically raise the coil slightly to see if the threshold level had changed. The Mark II, like the old TRs, would drift, thus requiring periodic tuning adjustments.

In all fairness, the ground mineralization at my home is extreme. Frankly, it has been difficult to find areas as severe, including many gold hunting sites.

Depth of detection under these conditions was severely limited. Scanning my test targets, I was only able to detect a coin buried about 2 inches deep. All the deeper targets were ignored.

Searching my yard yielded several new coins, mostly pennies and a handful of junk including tinfoil and an aluminum screwcap. All were retrieved from depths of less than 2 inches.

Next, I took the detector to a nearby park and found the same to be true - depth was limited to just a few inches. Also at the park, it didnt take long to get frustrated with all the tinfoil and non-ferrous junk that was also detected. On the plus side, small ferrous objects such as nails were not detected. Previous air testing had displayed the same; most small iron objects such as small nails, wire, etc., were ignored by this detector.

The next juncture took me to a different location where the mineralization was much less severe. There I performed a controlled test and found I could increase depth of detection up to 4 inches on coin-sized objects. This depth was obtained by carefully adjusting the tuning so the audio would be heard if the coil was raised slightly.

Additional testing at a couple of other sites displayed similar results; the detector was very ground sensitive, like the old TR-style detectors. The higher the mineralization, the more severe the problem. Unfortunately, there were no nearby sites where the mineralization was minimal, but, based upon the testing, I would conclude that such sites would produce much more favorable results.

One other inconvenience surfaced while testing this detector; it was physically very short. At about 6 feet tall, I had to search right at my feet to keep the coil close to the ground, something I was not accustomed to doing.

Final testing was concluded at my home. This time I performed additional controlled testing using the detector to find specifically hidden objects. First, I deliberately dropped a key and a piece of brass, similar in shape and size as a ring, into tall grass. With two deliberately lost items, I began searching. Within a few minutes I had found both.

This testing pointed out a real benefit of this detector, the tuning could be adjusted so only strong signals were detected. I was not plagued by a lot of unnecessary weak signals to check. Instead, only the two targets I had previously hidden in the grass were detected.

In conclusion, this detector will not compete with more sophisticated units, but is not priced to either. It is, however, a great economical detector for a person to carry with them at all times. As mentioned before, on outings such as fishing and camping trips, or other trips to the beach or park, this detector could come in very handy should a person lose their keys or a valuable item such as a ring, necklace, etc.

When evaluating this detector, one has to keep the price in perspective. It is not expensive and, as such, does not have common features found on the more expensive units such as ground balancing and true discrimination. In extremely mineralized ground it is difficult to adjust for maximum depth capabilities. In such areas, one should probably scrub the ground and live with the false signals that may occur when the coil is lifted.

On the plus side, this little detector is very sensitive, especially to extremely small gold objects. In areas having very light mineralization, this detector could do a great job of detecting both respectably deep and very small objects.

Although there is no true discrimination feature to be found on the Mark II, due to its nature, this detector has some form of discrimination built in. The Mark II will reject some small ferrous objects such as small nails, wire, etc.

One final plus feature of the Mark II is that Bill Hays has agreed that for a limited time he will provide an electrical schematic (for new units purchased through Rocky Mountain Metal Detectors, see address below). For those with an electronic background, this is a great opportunity to evaluate how TR-type detectors work.

Besides the Mark II, Hays Electronics makes several other instruments including a Mark I which is very similar to the unit field tested, but is equipped with a larger search coil (7 and one-half inch) in diameter. Hays Electronics also makes other electronic instruments including two different models of 2-box detectors, the DS-7 Deep Search, and the DS-7 Super Deep Search, two different Geiger counters, one radiation detector, and an EMF (electromagnetic field) detector.

Hays Electronics also carries a wide range of treasure hunting supplies, including other brands of detectors, books, digging tools, etc.

For more information on the Mark II, one of the other detectors manufactured by Hays Electronics, or a catalog displaying a wide range of products, you can contact: Hays Electronics at (520) 772-2624. For orders or a catalog call (800) 699-2624, or write to P.O. Box 26848, Prescott Valley, AZ 86312.

One final note: After spending considerable time evaluating this detector from an electronic standpoint, I have decided to produce a very brief explanation of how this detector works electronically. The Mark II detector can be ordered with a copy of that evaluation included for $69.50 plus $6 shipping and handling, or a copy of the schematic and evaluation only can be obtained for $5 plus $1 for shipping and handling, from Rocky Mountain Metal Detectors (Western Fire Extinguisher), 131 Spring Street, Pueblo, CO 81004, phone (orders only) 1-800-934-3473, phone (information) (719) 542-2896.

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