Surf PI Pro

[ionut_mtb]

My coil is 350uH 1R. I used it also in my barracuda and gives 40cm on a ring.

Did you modify something on baracuda? i only get 30cm on a gold ring. (air test) i use speaker/headphones, i tried also with piezo but less depth.

[jladre]

[jladre]

jladre I was just reading TalkingElectronics (1a). A non-polar can be made using back to back electrolytics, with back to back blocking diodes joined between the electros to stop the reversed one burning out. By the way, did the XX board need any mods? I am planning to order a batch of 10 from PCBway. Sven gracefully converted SPL to Gerber for me a while back, as I still haven't purchased paid SPL7 to convert files.

Hello Tim! My board is working good now. I can get a 2.2grams gold ring at 35cm. No need to modify the board. I just put 3.3k resistor between 3906 emitter to the junction of R3 and R17. Don't forget to use piezo speaker.

[Tim]

jladre I was just reading TalkingElectronics (1a). A non-polar can be made using back to back electrolytics, with back to back blocking diodes joined between the electros to stop the reversed one burning out. By the way, did the XX board need any mods? I am planning to order a batch of 10 from PCBway. Sven gracefully converted SPL to Gerber for me a while back, as I still haven't purchased paid SPL7 to convert files.

[homefire]

Sorry, I flagged on the quote. 270mH

[jladre]

I think you would find improvements with a Coil between 300 - 500 uH. Yours seems a bit low.

My coil is 350uH 1R. I used it also in my barracuda and gives 40cm on a ring.

[homefire]

I think you would find improvements with a Coil between 300 - 500 uH. Yours seems a bit low.

[jladre]

in the end its working now

but distance is 12-15cm for 1 Euro... Can i improve distance?
i tuned every POT for best distance my coil is 270uH and dumping Resistor is 390-2W
]

I just made my surf xx today. I almost spend my entire day figuring why i only got 15-20cm on a ring.. i challenge my self not to sleep until i solve the problem. And holla!! thanks God!! I can go to bed now. It just happen that this circuit only love to work on piezo speaker which i dont think that using an ordinary speaker will work the same. Another one is the C7 1uF which I tried to used 2 1uF electrolytic cap put in parallel with reverse polarity with each other that turn out to be a bad idea. So putting 2 470nF in parallel improve the situation. Its too hard if you cannot find the exact parts in your local store.
Atlast my surf xx now works better with 10.5 inches coil can get 30cm on a quarter and medium ring.

[jladre]

27cm air test or wet beach test? this is a difference. without shield underwater i have many false signals, maybe my detector is not well set.

It is in wet salt sand..

[ionut_mtb]

It is just a simple round mono coil made from cat5 wire. I dont put any shield on it.. but machine is under repair now after leaking on last dive.[ATTACH]40387[/ATTACH]

27cm air test or wet beach test? this is a difference. without shield underwater i have many false signals, maybe my detector is not well set.

[jladre]

What type of coil is your 7 inch coil ?

It is just a simple round mono coil made from cat5 wire. I dont put any shield on it.. but machine is under repair now after leaking on last dive.

[daverave]

that was with a 12" coil

[daverave]

with my surf pi which i made some years ago i can get about 40cm on a 2 euro coin.

[6666]

15cm for 1 euro is to short. With 7 inches coil i can get it at 27cm.

What type of coil is your 7 inch coil ?

[jladre]

but distance is 12-15cm for 1 Euro... Can i improve distance?
i tuned every POT for best distance my coil is 270uH and dumping Resistor is 390-2W

15cm for 1 euro is to short. With 7 inches coil i can get it at 27cm.