How to increase the sensitivity of the device Fisher 1280

[smity]

good day
Tell me please, who had experience in increasing the sensitivity of the instrument Fisher in 1280, without prejudice to work in salt water, what may be possible?
thank you

[SVEN1]

Just go to the bottom of the webpage and download the Wader Tuning file.
Will work on the 1280.
http://www.treasurelinx.com/detectorpro.html
If that's what your looking for.

[smity]

Thanks for the link to upgrade, can someone tried it and knows the actual results, do not want to open the case once again.
Best regards.

[SVEN1]

Thanks for the link to upgrade, can someone tried it and knows the actual results, do not want to open the case once again.
Best regards.

A number of us retuned our Divers and Waders and it works if your detector is not up to factory specs. Plus you can tune past factory specs for better performance.
Tuning the 1280 is like the Wader, actually the tuning info came from a Fisher service manual then adapted to the Wader which is supposed to be the same as the 1280.

[Davor]

I've seen a schematic indicating that gain blocks use TLC27M4 which sucks in a 1/f noise department, and there are cheap alternatives running at least twice as quieter. As I seen on photos, all chips are welded and not easily replaced, so this is just a thought.

[smity]

If you change the frequency instead of 2.4 KHz to 4.8 kHz WILL OPERATE IN THE WORSE SEA WATER, NO ONE had the experience of such an experiment?

[Altra]

Hi Smity
Changing the frequency up will make it detect saltwater even more. That's why the designer used 2.4khz to be less sensitive to salt. I used a 1280 for almost 2 years beach hunting. At the time I thought it was the greatest detector on the market. I found lots of deep silver coins in wet and dry sand. In that time (late 80's) I only found two gold rings. My friends using XL500's and PI2000's pi detectors were finding many gold rings and a lot of nails too. I did an experiment where I tied a 14k gold ring to a length of fishing line. I waded into the salt water and dropped the ring . The 1280 would pick up the ring at about 3-4in on the surface of the sand. When I buried the ring about 3 inches it could not pick it up. I wasted a lot of time hunting with the 1280 thinking this was a salt water detector. Bottom line don't waste your time saltwater hunting using anything other than a PI or multi-frequency detector. There is no magical "mod" to make a single frequency VLF detector work in salt. Some of the newer vlf's have "salt mode" it keeps the detector from falsing, but bury a target in wet sand and it will be undetectable. One exception is a TR with salt balance, these will only work on white coral/limestone beaches where zero iron mineral exist.

[Davor]

I think a simple criss-crossing of gain blocks inputs by a switch could do the trick and interchange the GB/Disc functions, thus making any single channel discrimination detector seaworthy. Tuning such a rig could become a bit confusing, and it will not help with minerals on the beach, but could just do the trick with seawater.

TGSL, IDX and SMW come to mind as well.

I intend to engage a separate GB channel in my IGSL so that it behaves on the beaches. In such case all the tuning remains logical. I have a spare channel in IGSL that is currently all but redundant.

BTW, PI machines also struggle with minerals, so that makes them more or less even. With VLF I have also discrimination, and my batteries last much longer. OK, monocoil is easier to drag around. What goes around ...

[Altra]

I wish you luck. When one channel is ignoring iron minerals it will be falsing on salt. When the other channels is ignoring salt it will be falsing on iron oxides. If you try to do some mixing or balance of the two, sensitivity will probably suffer on some range of targets. Somewhere on the forum years back a guy modified a tgsl so that the all metal channel was salt balanced instead of fe. Can't remember if he field tested it or not.

[Davor]

Yes, I'm aware of the problem. The only way of having both iron and salt balanced simultaneously would involve analogue multiplication of both channels. However, I realised that I don't need complicating it that far. As GB assumes a single phase at a given terrain, it is much better to have a GB adjusted separately from discrimination criteria and have it all.

In short...

Most detectors use one channel to perform two functions; as a balance (tone producing), and as an all-metal channel for discrimination. It works fine on easy grounds, and we know it doesn't on sea water. It also struggles with conductive soils, as all metal is skewed so much that the non-ferrous window accepts ferrous responses in counter-phase, making detection confusing.

My conclusion is that by simply relieving the all metal channel to set only that particular function, and use a separate channel for ground balance. It will maintain discrimination criteria regardless of the ground conditions, while it gives me freedom to set the ground phase as needed.

There are few flies killed by this approach. Most important one is that this approach will balance highly conductive and ferrous ground, such as salty terra rossa I'm having fun with, and not just "normal" soil, or "pure" sea water, while it gives me ability to set discrimination criteria accurately, and avoid counter-phase ground creeping into a non-ferrous discrimination window.

[smity]

Many thanks to the professionals for useful conclusions and advice, get an interesting topic about the problems of the detectors in the marine saline environments.
It is also interesting to hear the opinions of other users Fisher 1280, what were finding gold?
Best regards.

[smity]

Thus, the instrument phisher 1280 sees small targets of gold, maybe you can try to make the frequency of 2.4 KHz in place -4.8 KHz, and interference from salt water to squeeze discrimination (gruntbalans set by pruning sensitivity ferrite) to put the controller discrimination in position 4 .?
Possibly increase the sensitivity of the instrument?
At the moment the device without changes in the settings does not see a large ring of gold by 15 cm in the air and is the size of a ring of silver at 18 cm
In the wet sand has not tested the ring, I'll try to test in the near future, the different coins of different metal composition sees almost the same as in the air.
Best regards.

[smity]

Altra
.......... When I buried the ring about 3 inches, he could not lift his .....................


Today tested the COIL FISHER 1280 With 8 inches of wet sea sand at the water's edge of the shore, a wedding ring is 22 mm diameter dropped into the wet sand at 15 cm unit sees him with a small signal at 14 cm is a normal signal as well as a copper coin 12mm device sees on 11cm.
Indicators that in wet sand, the same distance that does not vary!
Here I think you need to open the unit to improve the instrument settings to better left with such indicators.??
What is your opinion *?