Harbor Freight 9 Function Metal Detector Mod Using Bounty Hunter Coils?

[TCosbyJr]

I have a 20% coupon for Harbor Freight and could get their 9 Function metal detector shipped for only $43. I figured it would be a fun project to experiment with for a such a low price. It seems in the last few years quality has improved, and there are many great reviews in the last 3 years for it. I'm not sure but it appears to be nearly identical to the old Radio Shack Micronta detectors too.

I was curious if anyone knew the frequency of the HF detector coil?

A common post I have read online are that the Bounty Hunter detectors operate at the same frequency as the ones made in China, such as the Harbor Freight model. So I wanted to know do they use the same frequency or close enough to use the coils? As I know some of the Bounty Hunters/Teknetics can use the same coils, but do vary in frequency a bit.

It wouldn't be much effort to add a 5-Pin DIN 240 Degree plug and socket to the Harbor Freight detector so it could use the Bounty Hunter coils - and make it a much more useful detector.

[Hardkrome]

I picked one up also to mess around with and maybe butcher. It seems to work fairly well for what it is. One thing I noticed is that the meter pegs out every time it picks something up, and the discrimination seems like it need some work. It will let thru tiny beeps of stuff that is tuned out.

For 45 bucks im impressed with how it works.

[TCosbyJr]

Same reasons I want one myself, a cheap project to get better acquainted with some internal workings of detectors. I thought the meter was perhaps worthless just like my BH Tracker IV meter, if you hear a sound the meter is pegged (perhaps a visual clue for the "hard of hearing"?).

Thanks for the details. I've talked to a few other people lately that admitted to owing one and they all felt it was a well spent $45. I figure if I can wire additional coils or not, it will be a great little investment.

[TCosbyJr]

I found some more information on the coils and the Harbor Freight detector. I posted this here before but it never showed up in the thread so here goes again..

The Fisher F2 uses 5.9kHz frequency and Bounty Hunter are typically 6.6kHz - and the coils work great between the two. After much digging online it appears the Harbor Freight 9 function detector is 5.8khz, thanks to ultralightpilot for testing.

It looks like just wiring in a 5-Pin DIN 240 Degree socket and testing the HF detector are in order to see how well the BH coils will work. Anyone have any tips or other information to add about wiring the HF detector coil/detector to the socket correctly? I have the basic details of the BH coil pinout but I am curious to which is which on the HF.

I'll make a new post in the future once I do the coil mod and post air-test results using the stock coil and the BH 4" and 8" coils.

[Skippy]

The Bounty Hunter coils have a TX coil of 2.4mH, with 240nF (220 + 20) across it, giving the 6.6KHz tuned frequency. The Fisher F2 adds another 47nF (I think) across the TX coil, reducing the frequency to 6KHz. Hope this helps.

[TCosbyJr]

The Bounty Hunter coils have a TX coil of 2.4mH, with 240nF (220 + 20) across it, giving the 6.6KHz tuned frequency. The Fisher F2 adds another 47nF (I think) across the TX coil, reducing the frequency to 6KHz. Hope this helps.

Thanks Skippy, indeed that does help fill in the missing data.

I admit I am out of my league which is obvious, it seemed there was more than just a socket that's why I posted. I'll continue reading any data I come accross and see if I can eventually do something with it as I progress - thanks.

[WM6]

After much digging online it appears the Harbor Freight 9 function detector is 5.8khz, thanks to ultralightpilot for testing.

Factory name of those "9 Function" detector is MD6008.

Working frequency is 5.95kHz (exactly).

For banging meter pointer can help to put resistor (of about) 500 Ohms in parallel with meter contacts.

Here some pics:



Mine can detect 1 Euro coin at 21cm in highly mineralised testing substrate in Tone mode (Sens max), 30mm silver coin at 20cm, 15mm 1.1gram gold pendant at 13cm and gold nugget of 1.1gram at 7cm which is excellent. Tested with factory 8" coil.

Surprisingly it is not deeper in All Metal mode as expected (for comparisons: it can detect mentioned gold nugget in All Metal mode at 5cm).

Tone identification between Ferro-objects and noble metal targets (like silver) works well, but sound of noble metal could be set higher, to be more enjoyable and more distinctive.

[TCosbyJr]

Factory name of those "9 Function" detector is MD6008.

Working frequency is 5.95kHz (exactly).

For banging meter pointer can help to put resistor (of about) 500 Ohms in parallel with meter contacts.

Thanks for the informative post and images - especially about the resistor. I have some 560 Ohm resistors handy so I'll try one out.

The detector has rather impressive depth for the price, and seems to beat my Bounty Hunter detectors. I've talked to several people online that claim it finds US Quarters at 7" (18cm) in the ground, which is great. If the disc works good enough/better to eliminate some iron and trash I'll have to get a few more of the MD6008's for spares.

Good timing on the post, my MD6008 has been shipped today, it has been on back-order from Harbor Freight for awhile now.

Have you used/owned any of the other metal detectors made by the same company product line? Here is their main detector page and another supplier page. Seems some those look and supposedly find coins better than some of the other detector product lines as well - may have to see if I track down a way to order the MD6035.

[WM6]

If the disc works good enough/better to eliminate some iron and trash I'll have to get a few more of the MD6008's for spares.

Have you used/owned any of the other metal detectors made by the same company product line?

Regarding discrimination. It can discriminate out beer cap at half of Disc. pot button way. I tested some 10 time more expensive models which cannot filter out beer cap (put reversed at testing substrate) at all. So it has acceptable discrimination.

Yes, I have and tested model 6006 too. Here you can find its coil data (if one is interested to build it):



Measured frequency 5.975kHz. Considering its 16cm coil, results are not much worse than those of model 6008. In difference to model 6008, model 6006 it is coming without dual tone identification.

But best thighs and biggest difference to former Chinese models (singing at green grass) are working stability of this new models.

[TCosbyJr]

Regarding discrimination. It can discriminate out beer cap at half of Disc. pot button way. I tested some 10 time more expensive models which cannot filter out beer cap (put reversed at testing substrate) at all. So it has acceptable discrimination.

Great to hear that the discrimination works so well. I tend to just disc out just above iron and dig everything else, I've found several jewelry items that way. Of course some sites are so trashy I have to turn up the disc to avoid digging nothing but trash.

But best thighs and biggest difference to former Chinese models (singing at green grass) are working stability of this new models.

Thanks for the details and pictures. I was curious as eBay has several different models. If they fixed the stability issues with the detectors, and have the depths as advertised, I bet they will be a much more common detector.

I get my md6008 in 4 days, Thursday, can't wait to test it's abilities.

[WM6]

I tend to just disc out just above iron and dig everything else, I've found several jewelry items that way.

This will work in case of silver (coins, jewelry) and most copper coin, but most gold jewelry gone, if we filter out iron (this is general rule for all discriminator detectors).
If gold alloy contain a lot of silver or/and has certain shape, like ring, you can still count as detectable together with iron discrimination.

Wish you happy hunting with your new economy detector.

[TCosbyJr]

This will work in case of silver (coins, jewelry) and most copper coin, but most gold jewelry gone, if we filter out iron (this is general rule for all discriminator detectors).
If gold alloy contain a lot of silver or/and has certain shape, like ring, you can still count as detectable together with iron discrimination.

Wish you happy hunting with your new economy detector.

Good tip, I wasn't aware that would disc out most gold. I will adjust that then depending where I am detecting, as I doubt too many areas would have any to find anyway in my small town area.

Thanks, end of this week will be dry and not freezing at least so I should be able to try it out.

[wildstar1063]

I tried adding the 500 Ohm resistor (Actually 470 Ohms plus 33 ohms) Across the meter, and while it did keep the meter from pegging out, it still goes to the same place every time, just not to the end. it's like the meter is connected to a digital On/Off gate instead of an analog
signal.

Would be interesting if we could get someone who has a Scope to see what is going to the meter, with different metals at different distances from the coil

Chuck E.

[WM6]

I tried adding the 500 Ohm resistor (Actually 470 Ohms plus 33 ohms) Across the meter, and while it did keep the meter from pegging out, it still goes to the same place every time, just not to the end. it's like the meter is connected to a digital On/Off gate instead of an analog
signal.

I know, resistor is not an ideal solution, it help mostly to keep meter pointer not to bump to end of meter scale on every signal. In my case difference between week target signal and strongest target signal is of about 1:3 in pointer movement and this satisfied me for now.

At this point I am not very motivated to do some reverse engineering to get 6008 audio stage/line schematic, but I do not exclude this option for the future.

[sinclairuser]

Hi guys your right about these latest versions of the 600x series, the model i have was bought as a joke present for me
Its marked as L45 and is almost identical to the 6006 above, but the face plate is blue/white and that little raised area above the handle has a red push button pin pointer yours looked from the photo to be missing this button(unless its black of course) .
Mine works very well and does indeed filter out bottle caps completely, ring pulls however not so much as then it ignores some good stuff
But here's the thing my meter when the detector is set up right is readable, iron pulls 2-3 on meter but its a loud clear tone different metals displace the needle differently regardless of tone
Try it set up the MD as per manual with some test samples, the iron is most noticeable the needle sould not go above 3 on a pure iron sample
That's another reason i like this MD with discrimination off you can see iron on the meter!
They used to be crap, frankly the handle/wire still is, better cable makes a difference (better cable made it noticeably more responsive) and a change of lower shaft for plastic pipe or better still a better handle make them more robust.
P.S. don't have the sens too high! about 11 o'clock on my MD.