MINELAB F1A4 ex military metal detectors - tips, settings, questions

[Guest]

Stock I'd reckon they're probably really good mine detectors as they were designed.
Modded they may be alright? Yet to see any gold finds with them though. Also for what you pay for a modded one you could buy a proven gold detector like a SD2200 with extra coils, quick track button, etc.
There was discussion awhile ago on another forum about them & from memory it was said that they are based on the SD series PI technology but set up to find landmines rather than gold. The mods appear to be made to add extra timings etc. for gold.

https://www.prospectingaustralia.com/forum/viewtopic.php?id=2155

https://www.prospectingaustralia.com/forum/viewtopic.php?id=5383

https://www.prospectingaustralia.com/forum/viewtopic.php?id=2838

 

[Mudguts]

Thanks for your reply
Some people liken the mod 2 to a gpx 4500
Would this be a fair assumption or not really accurate
Thanks guys

 

[Heatho]

Probably not very accurate MG, I'd go a 4500 over it anyday. 4500 is closer to a 5000 than a F1A4 is to a 4500.

 

[Cuckoowaif]

Hi Mudguts ,
I had my unmodified F1A4 on the beach up at The Entrance on the weekend , and ran into another swinger with an AT Gold ..... so , out of interest I found a good signal in the sand and called him over to compare . My machine told me ( just using sound ) that there was something under the sand .... his machine ( using sound and his hi tech screen with discrimination ) that there was something under the sand , probably a precious metal , 20 cm down ( more info than I had at my disposal ! ) .... but in the end I still had to dig a hole ! 20 cm deep was an accurate prediction , but it turned out to be an aluminium can ! So where is the benefit in different machines ? I don't know , but if you enjoy digging holes and finding buried teasure , buy yourself a metal detector .
Steve .
P.S. Last time I saw him , his finds value was 25 cents , mine was $1 .

 

[Twapster]

I was under the impression the Mod 2 F1A4 was similar to the GP 3500

[video=480,360]http://www.youtube.com/watch?v=hmAq7WRl-O8[/video]

 

[downhalo]

The stock machines are better than unmodified SD 2000 and 2100.. due to the fact that they have ground balance, and are extremely sensitive to small gold.. I now own 2 of these units, one modified one stock..
the modded unit can hang with my GP 3000, but only just..

If you're looking for a cheap easy to mod PI, the F1 would be my choice..

Adding things like a stock coil connector, 6.5mm jack and ground track button are simple and improve the machine greatly..

Anywho just my 2 cents..

 

[Goldtarget]

Terrible way to start a story but yesterday a guy i met out was running an unmodded one of these. He swore to me it picked up gold, but neither of us had any to test. Fished out a few sinkers and lead shot and got to digging, safe to say it picked them up in some super hot ground, hardly a "real" test but opened my eyes . Now I'm wondering if anyone can put to paper some confirmed finds (depth, soil type and size of target) I would be very interested.

 

[downhalo]

I've made a couple of posts with pics of my gold finds with the F1A4.

http://forum.kimbucktwo.com/index.php/topic,23295.0.html
http://forum.kimbucktwo.com/index.php/topic,23176.0.html

As to the stats..
1st post
This little bit was pulled off a large tailing pile next to a 30 foot shaft, can't speak as to depth because basically i scratched about an inch off, and it had shifted.. 3rd scoop and i had it in hand..
found with the 12x4 Pulse Made coil (which died a horrible death) backed over the poor thing.. 8.(

2nd post
the smaller nuggets were .2 - .5 of a gram, at a depth of no more than 2-3" at best.. soil type is damn hot, I can't get most of my VLF machines to balance for more than a few swings..
the larger 1.3 gram bit, was pulled out from a depth of about 14cm about 5" *by the depth marks on my pick handle.

- Lt

 

[Goldtarget]

Thanks LT. Very helpful, having the extra comments there saves searching around too.

 

[Cuckoowaif]

Hi down halo ,
Can you explain the mods you have done on your F1A4 ? What does the quick track button do ? How to connect up a switch for controlling which frequency to use ? etc ... PC board pinouts ?
I have looked on line for this stuff but with no joy so far ....
Thanks , Steve .

 

[downhalo]

Mods on the F1A4 (now sold sorry), ground balance, coil connector, headphone jack, (low pass filter for tone control, pain in the ***, not recommended) additional crystal oscillators for 4 frequency settings..

Okay so basically the F1A4 has a 3 position toggle, "off - on - ground balance" If you wire in a Momentary button to the top 2 pins on the toggle switch when pushed it activates the machines "super tracking" really fast ground balance.

As for your second question, you wont find much info around on the frequency mod, Its basically an SD 2000 mod, i adapted to the F1A4..

How it works:

Okay, the stock machine comes with a single crystal, mine was 1.9Mhz (weird since the others were 2.1Mhz.. anyway..

On the board you have your CO(crystal oscillator) i removed mine, and soldered it onto a perf board with the other 3 frequencies, then soldered together all the common ground pins.
on the positive side, i connected 4 wires to the + pad on the board, ran each back to a 2 pol 5 position switch. (so i can switch between the 4 crystals)

It works, for best effect I'm told you should have a timing adjust mod done, never messed with any of that..

A schematic might help, but ain't nobody got time for that..

 

[Twapster]

Appreciate the info DownHalo, not much info around on these machines.

 

[downhalo]

No, plenty of people that know how, not many willing to share.

 

[Cuckoowaif]

No, plenty of people that know how, not many willing to share.

That's what I thought ... but thanks to you downhalo I have somewhere to start .
Thanks , Steve .

 

[Cuckoowaif]

Hey downhalo , what were the other frequencies you used and where did you use them ? How often would you change settings ?
I can picture what you did to mount the extra CO's etc .... Sounds straightforward enough .
Thanks again , Steve .

 

[Redfin]

but ain't nobody got time for that..

Holy Begeezuz, my youngest started saying that, the other 2 caught on, now SWMBO has caught on. 8)

 

[downhalo]

Hey downhalo , what were the other frequencies you used and where did you use them ? How often would you change settings ?
I can picture what you did to mount the extra CO's etc .... Sounds straightforward enough .
Thanks again , Steve .

2.45760Mhz and 3.0Mhz

 

[Twapster]

The Twapster is now a proud owner of an F1A4. I'll be looking to get her modded to Level 2 in due time. Was the only way
I could sneak a purchase by the wife without shocking her on the price of a PI machine.

 

[downhalo]

haha, very nice.. level 2 sounds good, Not sure its $1250 of good..

 

[Twapster]

Agree downhalo I'm hoping someone knows of a cheaper modder? Yep $1250 is a decent wack but $570 for the machine plus the mod when im cashed up will be easier for me. Having the detector sitting there will be motivation to get it done sooner. Im sure I can do the mod1 myself but its the 2nd mod that im after!