Coil's Cable Shortening Doubt

[Skullgolddiver 589]

I have an easy and maybe stupid question to present now...

Observing my TDI Bh, with both of the coils I own (the original 12" and the aftermarket Detech 8"), I can clearly see way too long wire around the shaft and I'm forced to make several loops up to the control box near the handle.

Supposing to measure the right lenght for the maximum extended shaft, and to cut away the hipmount mile long cable.....Am I doing a disaster or not?

I actually can't remember the technical cable's specs in the amazing pdf Steve posted time ago, but if I'm correct it talked about to reduce some current resistance with a slight performance improvement too...Have I seen a mirage or what?...

I'm not kidding 😜...

It's just me, looking for something to play with, suffering for a missed AQ. 

[Valens Legacy 920]

As long as you make the connections properly and get a good seal on the finished item you will have no problems. Most coils will have extra wire on them so that they will fit what ever shaft it is on.

 

[palzynski 567]

8 hours ago, Skullgolddiver said:

I have an easy and maybe stupid question to present now...

Observing my TDI Bh, with both of the coils I own (the original 12" and the aftermarket Detech 8"), I can clearly see way too long wire around the shaft and I'm forced to make several loops up to the control box near the handle.

...

And it is the opposite with the Garrett Apex , their coil cables are too small for tall guys ...Just at the limit for me hopefully ... More testing from the manufacturers before delivering to the customers would probably be a good thing ... 🙂

[Tony 466]

I have chopped off about 12” of my TDIBH cable.......no problems at all.

[Joe Beechnut OBN 2,497]

On 4/7/2021 at 6:00 PM, Skullgolddiver said:

current resistance with a slight performance improvement

I've tested, No performance gain due to the small amount cut off....18 inches a VLF and if I remember correct a subject over on (Findmall) Technology forum many years ago  .......

Only gain I have found .......  less chance of the cable moving or exposure to the conditions, with I have tried several different things, one was running the coil cable thru the shaft.. .. and exact length needed. (both pictured)

I love going thru and reading the old Findmall post with Eric, Wire Chief, Mr Bill, Reg...etc..

The capacitance and the resistance of the coil cable has to be taken into consideration as a total value of the coil.

Depending on the exact particulars, chopping off a lot of cable would change the way the electronics looks at the coil. Adding length would affect it also.

Now in reality I have chopped fairly good sized amounts off of cables in order to permanently pole mount the electronics box. The need to get rid of excess cable length was there. I have not noticed a drop off in performance, although it could happen depending on the unit.

Mr. Bill

 

Re: Coil Cable - straight or spiralled? Frank Hamill Date: August 19, 2002 08:43AM

One addition thing. In the other two PI's I owned in the water the currents of the ocean along with swinging against the resistance of the water cause the coil wire to move...when the coil wire would move the units would give target signals which were not there. After Terry told me about running the wire straight up it still moved in the currents. So I split malt straws and put them one by one around the straight up coil wire and taped them lightly...Falsing of that "type" stopped. A users answer to the problem. However this coil on the Goldquest SS does not need the straws as you put the connection next to the rod connection and straight up is no problem as the distance between the rod and the connection is mere nothing. On my other PI's the distance between connection and rod was several inches and allowed the movement of the coil which caused falsing. From a users standpoint who goes in the water this is a great feature that is needed to be put into coils that are used underwater.
Thank you again....Frank

Coil Cable - straight or spiralled? Eric Foster Date: August 19, 2002 04:19AM

Hi Frank and Larry,
Good to hear reports of the units performing well. There are always some surprises that come back from the field, though. Why running the coil wire straight up the pole rather than spiralled around, should make a difference to the field pattern has me puzzled. One of the properties of coax cable is that there is no external field generated by the cable. Does winding the cable clockwise give a different result to it being anti-clockwise?
How is this change in field pattern manifested?
Do other detectors show this problem?
Eric.

 

Re: Shorter coil cable question. Eric Foster Date: May 10, 2005 05:34PM

Hi Tommy,
Shouldn't affect it at all, as the capacitance of the coil/cable circuit will be reduced.
Eric.

[Skullgolddiver 589]

On 4/10/2021 at 7:51 AM, Joe Beechnut OBN said:

I've tested, No performance gain due to the small amount cut off....18 inches a VLF and if I remember correct a subject over on (Findmall) Technology forum many years ago  .......

Only gain I have found .......  less chance of the cable moving or exposure to the conditions, with I have tried several different things, one was running the coil cable thru the shaft.. .. and exact length needed. (both pictured)

I love going thru and reading the old Findmall post with Eric, Wire Chief, Mr Bill, Reg...etc..

The capacitance and the resistance of the coil cable has to be taken into consideration as a total value of the coil.

Depending on the exact particulars, chopping off a lot of cable would change the way the electronics looks at the coil. Adding length would affect it also.

Now in reality I have chopped fairly good sized amounts off of cables in order to permanently pole mount the electronics box. The need to get rid of excess cable length was there. I have not noticed a drop off in performance, although it could happen depending on the unit.

Mr. Bill

 

Re: Coil Cable - straight or spiralled? Frank Hamill Date: August 19, 2002 08:43AM

One addition thing. In the other two PI's I owned in the water the currents of the ocean along with swinging against the resistance of the water cause the coil wire to move...when the coil wire would move the units would give target signals which were not there. After Terry told me about running the wire straight up it still moved in the currents. So I split malt straws and put them one by one around the straight up coil wire and taped them lightly...Falsing of that "type" stopped. A users answer to the problem. However this coil on the Goldquest SS does not need the straws as you put the connection next to the rod connection and straight up is no problem as the distance between the rod and the connection is mere nothing. On my other PI's the distance between connection and rod was several inches and allowed the movement of the coil which caused falsing. From a users standpoint who goes in the water this is a great feature that is needed to be put into coils that are used underwater.
Thank you again....Frank

Coil Cable - straight or spiralled? Eric Foster Date: August 19, 2002 04:19AM

Hi Frank and Larry,
Good to hear reports of the units performing well. There are always some surprises that come back from the field, though. Why running the coil wire straight up the pole rather than spiralled around, should make a difference to the field pattern has me puzzled. One of the properties of coax cable is that there is no external field generated by the cable. Does winding the cable clockwise give a different result to it being anti-clockwise?
How is this change in field pattern manifested?
Do other detectors show this problem?
Eric.

 

Re: Shorter coil cable question. Eric Foster Date: May 10, 2005 05:34PM

Hi Tommy,
Shouldn't affect it at all, as the capacitance of the coil/cable circuit will be reduced.
Eric.

Thanks a loro Joe!And Sorry for late reply!

 

 

[pjrough 86]

On 4/8/2021 at 12:00 AM, Skullgolddiver said:

...

Observing my TDI Bh, ... and the aftermarket Detech 8")..

Speaking on 8" detech coil. Any problems with water leaking inside of the coil housing?

I have mine somewhere. Not tested yet. Waiting for new fancy TDI like this one:

 

 

[Joe Beechnut OBN 2,497]

4 minutes ago, pjrough said:

Speaking on 8" detech coil. Any problems with water leaking inside of the coil housing?

I have mine somewhere. Not tested yet. Waiting for new fancy TDI like this one:

 

 

The machine to have would be the TDI Pro in that box...SEA GHOST has really done some nice mods over the last 2 years.

[Skullgolddiver 589]

5 hours ago, pjrough said:

Speaking on 8" detech coil. Any problems with water leaking inside of the coil housing?

I have mine somewhere. Not tested yet. Waiting for new fancy TDI like this one:

 

 

No leakage for now, but trust me, You might want to open the shell and create a slim open design One...Otherwise Is terribly buoyant and Empty for 95%I Guess.

Excellent work there!

Another One of Yours!

[pjrough 86]

Thanks for info. It's boyant, I know. I counterweight it rather than open. Don't like to modify coils....

The mod was not done by me, by the way. But yes, mainly because of me.