By Mike Hillis
Decided to get me another AT Pro.
Last hunt back I was out in a light drizzling misty rain with my metal detector wrapped in a walmart bag and decided I needed a wet weather detector. Did a review and I know its not the new darling around town but I remembered how well the Garrett coil performed for me in the past and decided to get another one.
Looking forward to chatting about it later.
I had never really used my GBP for coin hunting before but on a recent camping trip my Nox ran out of battery at a bad time and my wife was using my T2 so I was left with my Gold Bug to use. I was in a place where ground balancing was needed occasionally and I also like to flick between All metal and Disc mode often but it's terribly annoying to do that on the GBP so I decided I'd get around to modding it when I got back with a switch to make life easier. I only found a dollar coin using the GBP that afternoon but we had already virtually cleaned up the area.
You'l find the story on the Gold Bug Mod here
Seeing I've now got my GBP modded I wanted to take it for a test run, the weather was rainy today but I had a job to do near a lakefront beach area I had a feeling would be worth detecting due to how busy it gets in summer so I put my GBP in the car.
I put my 11" coil on it, first time I've ever used it as I bought my GBP to be a prospecting machine.
Seems a decent coil for covering ground but feels nose heavy to me, I'm not used to the coil having a large front with the shaft mount near the rear.
It was a quick 1 hour hunt due to the weather and I had no idea about what Target ID number is what on the GBP as I mostly use the Nox. I remembered 78/79 is the NZ gold coins on the T2 and with the GBP having the same numbers it helped find a couple of gold coins, other than that I was just digging stable target ID's.
My total haul, not bad for a small amount of time.
I got a few older coins, one of them American but it looks like the surface is rubbed off, I can't see a date on it.
Not a bad hunt for the time I spent on a detector I'm not overly used to using for coin hunting. My new switch is great, a real time saver. A good bit about living in a tourist hotspot is all the foreign coins to be found. The Queenstown area has about 30,000 people living in it and gets over 3 million tourists a year.
I had an idea some time ago to add a switch to my Gold Bug Pro for easy changing between Disc mode and All Metal mode without having to adjust my threshold every time, I got the idea from seeing KiwiJW flicking between All metal and Disc on his GB2 to check targets when we were creek detecting, I thought that's a good idea, it's a shame it's annoying to do that on the Gold Bug Pro.. I also wanted an easy way to be in Disc mode and do a ground balance without again having to switch to All metal to do it so I thought a 3 way switch with on / off / momentary on would be perfect for the task.. I mentioned it here and EL NINO77 pointed out it's been done already but just with an on/off switch on this thread here
Anyway, I had myself some spare time today so I ripped it open and started modding.
You'll see on the photo I indicated what needs cut to add the switch
No, that's not a short and curly 🙂
This seemed the best location for the switch, it was a tight fit but it's by far the most comfortable position for the switch to be once it's all assembed again
All done, now lets assemble it again and test it out
And there we have it, I can now use the switch to change between Disc and All metal modes so you don't have to keep messing with your threshold, Disc is in the middle, All Metal pushed forward where it locks in position and if I pull back on the switch it goes to All metal and as soon as I let go the switch reverts back to Disc mode by itself, this is very handy for a ground balance as you pull the trigger switch backwards and hold down the GG button and do your ground grab and then just let go of both the switch and GG button and you're back in Disc mode balanced.
Quite a nice simple mod to do but resolves one thing that annoyed me about my Gold Bug Pro. I think my next project will be to backlight the screen.
I'm not claiming this to be my idea as it looks like it's been done before using an On/Off switch as someone else has had the same idea, I just modified the idea to have my momentary All Metal mode for quicker ground balancing in Disc Mode. My switch type is an On/Off/Momentary On switch. The switch has an optional water resistant cover which I don't know if I'll put on it, as the detector isn't waterproof anyway and it makes the switch feel weird as then it's all rubbery.
Keep in mind this will void your warranty, I didn't care about that as I bought my GBP's in Australia and I would never bother to send one back for repair as postage would be a killer, if it developed a fault. I'd try fix it myself.
By Steve Herschbach
This great resource was written by project engineer Dave Johnson and published by White's in 2002. It has become very hard to find, which is a shame because it provides insights not only on the MXT and GMT but on metal detector design in general. I took the liberty of scanning my copy this morning and converting it to html and posting here at White's MXT Engineering Guide
Hopefully White's will not mind.
As I noted, there is some information here you will not see anywhere else. How many of you experienced MXT owners know this following information regarding the ground balance setting on the MXT from the report?
"Electronic ferrite material and most "negative hot rocks" (cold rocks) will usually read in the 75-88 range. Most soils will read somewhat lower. Readings will almost never go below 25 except in salt or moist alkali soils. When readings indicate smaller numbers than 50 you may notice some reduction in sensitivity. Below 35, some rusty iron may give unpredictable responses. Below 25, iron objects may give unpredictable responses and/or may disappear entirely and the sound on nonferrous objects may become slightly more abrupt."