Aquapulse AQB1 with the 20uS setting

[Hari]

Hi everyone ,
I am planning to purchase the Aquapulse AQB1 with the 20uS setting instead of the standard 40uS one.
Has anyone on the forum had any experience with this setting?
Thanks in advance for your comments or advises.
Hari

 

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[BVI Hunter]

It's seems you know your stuff, can you say why you are choosing that? Just so some of us can get some extra knowledge!
Thanks!

 

[OBN]

Seems with the higher (uS) you would have a hard time finding smaller gold. Even 20uS is high I believe.

Good post here on the machine

http://www.treasurenet.com/forums/s...1b-detection-ranges-various-coils-probes.html

 

[Hari]

Thanks for your replies.
in reply to BVI hunter I just want to say I am from France and staying in India for 2 years.
I have a XP Deus and completly satisfied with the machine on land but on the wet sea beach it is not yet the best.(by far)
There are very few posts on the MD forums about the AQB1 perhaps because it is made for diving and it is used mostly by professionals.
I don't have any experience with this machine but from what I have read it seems to be a very good PI detector but not so powerful on wet sand or shallow water because of the minimum setting at 40uS.
Having read on the forum a post by Eric Foster mentioning that we could ask the manufacturer for the 20uS minimum setting
I thought it could be helpful for small gold, low carat in shallow water or on the beach.
I contacted the Manufacturer in GB and he said that yes he can provide the 20uS setting but he does'nt have any feed back from users in that setting so for this reason I am trying to find someone who could share his experience with that (20uS) setting.
I guess it won' t be easy...

 

[sponge]

Thanks for your replies.
in reply to BVI hunter I just want to say I am from France and staying in India for 2 years.
I have a XP Deus and completly satisfied with the machine on land but on the wet sea beach it is not yet the best.(by far)
There are very few posts on the MD forums about the AQB1 perhaps because it is made for diving and it is used mostly by professionals.
I don't have any experience with this machine but from what I have read it seems to be a very good PI detector but not so powerful on wet sand or shallow water because of the minimum setting at 40uS.
Having read on the forum a post by Eric Foster mentioning that we could ask the manufacturer for the 20uS minimum setting
I thought it could be helpful for small gold, low carat in shallow water or on the beach.
I contacted the Manufacturer in GB and he said that yes he can provide the 20uS setting but he does'nt have any feed back from users in that setting so for this reason I am trying to find someone who could share his experience with that (20uS) setting.
I guess it won' t be easy...

I would just get a sand shark. Its a PI beast.

sent from a sending device.

 

[Octopulse]

Okay, here's the deal with the AQ1B (compact).....I have one and know it well so feel qualified to offer some advice.

1. The minimum delay is 40µs.
2. The current circuitry isn't capable of any lower than this.
3. It is a high powered machine and does take some practice. It needs regular tuning (SET AUDIO) in order to maintain a slow tickover speed (Threshold). There is no SAT / Autotune and no shielding so that is why tuning is important.
4. It has reduced sensitivity on smaller low K rings but is very deep seeking on bigger rings and most higher K rings.
5. It would not be my preferred choice on the wet beach and very shallow water if you are after the smaller rings.
6. It is animal of a detector but needs to be tamed.....


I hope this helps,
Tony

 

[BVI Hunter]

Hairi
Have you looked at the SeaHunter 2? Very happy with mine on sand, surf and scuba,.

 

[Hari]

Thanks to Sponge and BVI Hunter for sharing their enthusiasm for their prefered detector .

Tony , I apreciate your comment since you are one of the rare users of the AQB1
Actualy I got the information from
Bob Williams ([email protected])
Here is a quote from a recent email:

"environment is different to the land application, the standard base setting for the AQ1B is 40uS with the REJECT control extending this to over 100uS. The standard AQ1B has to be able to operate with the complete range of coils and in deep water in the open sea; this requires the delay to be able to allow for the energy returned from the salt water with any of the coil options available. In shallow water and in particular in fresh water then a lower base setting can be accommodated and even more so with the smaller sizes of loops. The 40uS can be factory pre-set for the base setting to be 20uS and I would provide this if required and recommend that the 20cm coil is used.
I hope this information is helpful.''
Tony, where did you get the info that it is 25uS?
Could yours be a older model?
It would be nice to find out...
Hari

 

[dewcon4414]

Im with Joe.... are you sure thats a 20 uS? Many of the PIs now are close to at least 15 uS.... the lower the pulse delay the better chance at smaller gold items. I was thinking the aquapulse was near 10 uS..... cant see Eric Foster helping design one with that high a pulse delay. The faster the delay.... in others the lower the numbers, the more looks the machine gets. Depending on your conditions you may well have to run a little higher uS to get it stable.

Dew

 

[Octopulse]

Hmmmm the plot thickens.
I have spoken with Aquascans technicians last year. I have the latest AQ1B which is the smaller case version (compact). I asked for the 20us version but was told this can't be done. The latest version has a quicker delay than the previous version (tall can).

 

[dewcon4414]

Again odd.... since the Sand Shark is around 22 uS, DF is 15uS, and the Infinium is like 12uS..... see a patern? Pulse delay is the key to flexibility on a PI.

 

[Jolly Mon]

The Aquapulse has a relatively high initial pulse delay because it is designed for deep salt water and for finding shipwreck artifacts.

It is not designed to find tiny rings in the wet sand.

Will it find gold ?? You betcha...scroll over to page two of this thread: http://www.treasurenet.com/forums/s...recoveries-off-north-douglas-beach-trail.html

 

[dewcon4414]

Jolly..... i think you hit it on the head. They may be designed for DEEP water much like the JW Fisher 6 and 8X because of the high salt content.

 

[BVI Hunter]

Jolly..... i think you hit it on the head. They may be designed for DEEP water much like the JW Fisher 6 and 8X because of the high salt content.

I maybe wrong, but was told once its to do with the water pressure at depth? is this the case? (Isn't the ocean as salty at 10ft as it is at 100ft?)

So, is there a general guide to machine / depth?... ie - use SH2 from surf to 30ft, then AQ 1b from 30ft onwards etc etc.

 

[Jolly Mon]

I maybe wrong, but was told once its to do with the water pressure at depth? is this the case? (Isn't the ocean as salty at 10ft as it is at 100ft?)

So, is there a general guide to machine / depth?... ie - use SH2 from surf to 30ft, then AQ 1b from 30ft onwards etc etc.

I don't think water pressure has much if anything to do with PI performance as long as the unit doesn't leak. I think it is simply the deeper the salt water, the more mineralization there is both above and below the coil. Imagine how large the detection field is with an Aquapulse fitted with a 15 inch coil at a depth of 20 feet.
The smaller the coil, the less the effect because the smaller the detection field and so the detector has less mineralization to deal with.

Frankly, I wouldn't be surprised to see your Sea Hunter hang right with an Aquapulse coil for coil under most conditions, including at substantial depth. It is a very good PI.

 

[BVI Hunter]

...

 

[sponge]

V. True! I have pulled up buckets of coins from 60ft - am VERY happy with my SH!

Buckets. Like 5 gal buckets? DID HE SAY BUCKETS. BUCKETS. Thats freakin awsome. Was there a hoist involved. I cant wait to read the whole treasure tale BVI. I still drool over the beeping coral pics. ok lets get back too which detector is best for sunkin treasure.

sent from a sending device.

 

[Sir Gala Clad]

BVI: The salinity of water can rapidly change in only a short distance or period of time.
Depending on the change of tide and currents from rivers both above and underground.
In addition to the water being saltier or less salty, you may notice a small change (a few degrees) in temperature.

The electromagnetic field of both VLF and PI balanced inductions detectors is generated by rapidly switching the current on which flows through a loop of wire.
The resulting magnetic fields radiate through the top of the search coil as well as the bottom. Plus there is spill over of approximately one to two inches from the edge of the search coil.

The key to understanding the difference in depth capability of a Very Low Frequency (VLF) verses a Pulse Induction (PI) detector in salt water is that the VLF generates a continuous electromagnetic field while the field from a PI is not continuous.

Since salt is a conductor, it is easily detected a VLF detector. That is why you may get a false signal when you sweep over a piece of seaweed on dry sand. It would take a very smoggy day to get a return from the top of your detector on dry sand – if there are that many particles in the air you would be better off in home sucking on oxygen from a respirator.

When you go into the water, the coil on a VLF detector will detect the salinity in the water above it and detect it as a target. The detection depth of such a detector is reduced as the return from the salt above the detector (noise) must be subtracted from the return of the target.
As this is impractical with most single frequency metal detectors , multifrequency metal detectors are used for shallow water hunting where there is salt. You may be able to get by with a single frequency VLF in clean fresh water (stirred, not shaken).

Since the return from the salt water above a detector rapidly decays, you will not detect that return with a PI as your receiver will be turned off, unless you are using a very very short pulse delay. Since you do not have to subtract returns from above the search coil, you are able to detect deeper in salt water.

If you are diving or shallow water hunting with an all terrain metal detector you have to be very careful about depth. If you drop it and it sinks deeper than the depth it was designed (usually ten feet) or hit by a wave/surging water you will end up with a very expensive paper weight as it most likely will be destroyed by water seeping in past the seals of the control box.

I maybe wrong, but was told once its to do with the water pressure at depth? is this the case? (Isn't the ocean as salty at 10ft as it is at 100ft?)

So, is there a general guide to machine / depth?... ie - use SH2 from surf to 30ft, then AQ 1b from 30ft onwards etc etc.

 

[Jolly Mon]

Bear in mind that 10us-15us is a very, very short pulse delay in real world applications. It has been my experience that it is impossible to run a Dual Field at its lowest delay setting---even in wet sand---without substantial instability. ( Beach conditions vary, of course ). Once you enter the water, the dissolved minerals both above and below the coil will begin to effect the machine. This is why detectors designed for deep water use generally start at 20us minimum.

Bear in mind that the ability to ignore mineralization is basically what makes a PI, coil for coil, deeper than a VLF.

 

[Octopulse]

Bear in mind that 10us-15us is a very, very short pulse delay in real world applications. It has been my experience that it is impossible to run a Dual Field at its lowest delay setting---even in wet sand---without substantial instability. ( Beach conditions vary, of course ). Once you enter the water, the dissolved minerals both above and below the coil will begin to effect the machine. This is why detectors designed for deep water use generally start at 20us minimum.

Bear in mind that the ability to ignore mineralization is basically what makes a PI, coil for coil, deeper than a VLF.

Couldn't agree more......even my Garrett Shunter needs the delay (ELIMINATION) turned down to about the 9 o'clock position otherwise the regular threshold signal from passing waves/swell will drive you mad. I have still picked up very small gold rings with this setting. With too fast a delay in salt water (even just on the saturated wet sand), a small target signal will be drowned out if a wave passes the coil at the same time. The bigger rings will look after themselves !!!

Here is another interesting observation with the pulse delay. Slower delays can/will detect the bigger gold rings better /deeper than a quicker delay. My AQ1B at minimum delay detects the bigger rings deeper then my Seahunter on it's minimum delay. My understanding is the bigger targets are "charged" up more with the longer pulse transmission.

I used to be greedy with the pulse delay and always had it on minimum (Goldquest SS and Seahunter). I just accepted the constant threshold noise and wondered why I never heard the smaller/weaker signals.......now I know why and my gold tally has really increased.

Well it's 95F today.........so I'm going to the beach with my hookah and AQ1B......

HH
Tony.