Impulse AQ Coil Connector False Signals

[tvr]

23 minutes ago, Johnny Crunch said:

[grumpy old man mode: off]

LOL ... I know that mode too.

[Steve Herschbach]

2 hours ago, GB_Amateur said:

As I sit here on the sidelines, it's easy to toss ideas out there which have likely already been considered and rejected, but...

Would a hardwired version (even option of coil choice) be too much of a manufacturing headache (or cost) to be implemented?  I seem to recall Fisher doing just that -- selling a detector for which you had the choice of hardwired coils.  (Steve, I'm recalling a spreadsheet table you posted of what I think were water hunting detectors and their features.  I can't seem to find it by searching.) 

Those who want swappable coils would have to put up with the capacitative coupling noise.  So I guess I'm suggesting more than just two versions.  All this optionality assumes there will be coil choices once the AQ gets past the current stage.

And of course there's always the portability issue of a hardwired coil, although that concern usually is dominated by the shaft and there's no reason (at least that I can see, other than possibly cost) of requiring the shaft, cuff, etc. not be completely removable, just leaving the coil (via cable) attached to the control unit.

Oh, that's right.  Steve, I just read a post where you said the manufacturers ignore 90% of your suggestions.  Imagine how high that number gets when those suggestions come from mere pawns....

Maybe the answer is that there are already workarounds as have been discussed here.  That costs nothing more than operator time (and possibly a bit of annoyance).

I added the chart to your post. With Tesoro now gone and White’s extremely questionable, it could get a lot shorter soon. I really have a hard time taking the SDC 2300 seriously, so it is getting down to the Sea Hunter, Impulse, and ATX as brand new full warranty options.

I had no idea this would have so many looking for a “solution”. To me it’s just a side note to know about, something to be aware of, and then work around. For mask and snorkel work it is a total non-issue. However, if you are a wader with shallow water flats that extend a very long way, where the connector would be right at that magic depth over a very large area, then it could be a genuine problem. My fix would be to go mask and snorkel, but that is not always an option for a lot of people. I have to admit getting in cold water gets less appealing to me every year.

Yes, many detectors were sold hardwired with coil options. Fishers own CZ-21 with 8” or 10.5”, and Excalibur once upon a time with 8” or 10”, to name a couple. Though Minelab did discontinue the 8” version of the Excalibur.

[Joe Beechnut OBN]

9 hours ago, Skullgolddiver said:

Feel free to laugh of my try to find a solution 🤣as it might sound crazy or at least stupid...

Can't be possible to create an outside connector shielding sock with a 3m shield tape? Something like a cable/connector glove to avoid direct saltwater contact with the area? Is it something to be necessarily fully waterproof?

I've already did that.....Several years ago I was experiencing lot of noise in "rough" salt water hunting with the excaliburs I used. Solution ..completely remove from the saltwater...I started running a longer coil cable with the Control pod and connections "under" my drysuit. So the only thing exposed to the rough conditions was...the coil cable coming from my drysuit, then the coil...........It was like night compared to day............Almost total silence in some bad conditions. See if I can find the pictures of me using and the setup.

I will have to find the post from last year when I envisioned the same with the AQ...

One reason I need more then one AQ..

[Jim in ma]

15 hours ago, Willy said:

Yes, you can do that to solve this problem but you then generate a sensitivity to external EMI for the whole system.

After cutting the wire I took a static bag and placed the mother board in it warped the wires and taped them.    It ran great for me.

[Carolina]

Well here is a shocker. I for one am satisfied with the connector I have now and can work around these issues. Thank you Alexandre, Willy and Carl for all your hard work!

[Joe Beechnut OBN]

25 minutes ago, Carolina said:

Well here is a shocker. I for one am satisfied with the connector I have now and can work around these issues. Thank you Alexandre, Willy and Carl for all your hard work!

I agree Carolina...The Sournia, compostied made or a 300 dollar SS Military Spec.(shielded) fitting..both are going to make noise. Time your hunts with the tides....and the current conditions.

[tvr]

47 minutes ago, Joe Beechnut OBN said:

I agree Carolina...The Sournia, compostied made or a 300 dollar SS Military Spec.(shielded) fitting..both are going to make noise. Time your hunts with the tides....and the current conditions.

Pretty sure I could work around that too. I do like to spend time in the mom and kiddie wash area as it has been productive. That is where composite connector would sound on going from immersion to open air. With multiple detectors available, I could use one for one session and another for the next one away from the thigh to waist deep wash ... then again, it is nice to grab one detector and just cover it; and $300 could be just one ring away from being covered. Without an AQ in hand, I'm still leaning towards being willing to spend the extra for the stainless steel connector, that would limit the capacitive effect, and not place that one limit as a decider on which detector I grab for a hunt.

[okara gold]

8 hours ago, Joe Beechnut OBN said:

I agree Carolina...The Sournia, compostied made or a 300 dollar SS Military Spec.(shielded) fitting..both are going to make noise. Time your hunts with the tides....and the current conditions.

So even a $300 connector will make noise? I just posted on another thread that I'd be willing to pay more for a connector that didn't make noise. Apparently there is no fix.

[tvr]

 

45 minutes ago, okara gold said:

So even a $300 connector will make noise?

Willy posted the following to this thread on July 9th:

"The high voltage and short pulse delay of the Impulse are requiring a strict shielding of all the parts subjected to the pulses (coil, cable and connector).

That effect is due to the small gap of continuity of the cable shield between the the male and female connectors and the changes of capacitance coming from the conductive  water level variations.

It was for that reason that the coil connector was initially made of metal in order to keep the continuity of the cable shielding up to the inside of the enclosure. (Same supplier, other item)

Field tests in the sea water had shown a bad electrolysis effect on its body giving it a nasty look.

A plastic connector had to be used for the AQ.

The GOLD version will even require more attention to this capacitance effect as it will have a much  shorter pulse delay, it will get an (expensive) stainless steel connector to keep a perfect shielding."

My reading of Willy's post, tied into other parts of the discussion, is that the metal connector kept the continuity of the shield such that there wasn't the same level of capacitive effect that is realized with the composite connector. The electrolysis was deemed ugly so they went to the plastic knowing that there was a trade-off. If the original metal connector was one of the nickle or cadmium plated variety, it would not be as resistant to corrosion by electrolysis as a high quality stainless steel. I looked at the Souriau catalog and they had several options for material for the connectors; with a wide range of prices depending on material.

If I am interpreting the information incorrectly, someone please correct me!

[Joe Beechnut OBN]

3 hours ago, okara gold said:

So even a $300 connector will make noise? I just posted on another thread that I'd be willing to pay more for a connector that didn't make noise. Apparently there is no fix.

  To be honest I am not sure, the problem lies.... it may work one place and not another. And how does one go about achieving full global testing of something like this.........

Words from Eric Foster on the subject..

Eric Foster

Splicing a coax does cause a problem, It exposes the central conductor to capacitive effects, and this is what is happening when the cable dips in and out of the sea. When using a short delay, this effect gets worse as it upsets the damping setting. At the point you are sampling, the sudden extra capacitance will give a slight change in the recovery response. Dipping the coil in the water only gives a short beep as the SAT cancels it out. You are OK if the join is always in the water - or always out of it.

You can get rid of the effect by increasing the delay to 15 - 20us, but you will lose some sensitivity to small items.

Wrapping metallic tape around the join can make matters worse, as the tape is ungrounded until it touches the water, and you can get a bigger capacitive change.

The other problem with an unshielded splice, is that it forms a small one turn TX/RX coil that is in series with the main coil. If the spice is up against a metal shaft, it will generate a signal which will vary if there is relative movement.