Looking to buy 10" coil for saltwater beach...which freq?:ausflag:

[brissietex]

Hi all...

Since I have definitely decided to stick with my XT-70, I am looking to get one of the bigger coils for beach hunting. My query is which frequency is more stable with some depth on a salty beach? I currently use mainly the 5x10 HF with alot of success but would love to add a bigger coil to add ro my arsenal.

This is assuming that I don't really want to go chasing the tiny stuff like I do with the 5x10 so it mainly coin and ring hunting.

thanks...Keith

 

[nugget71]

B.T is the man to give info on that question. Apparently the 10x5 round DD 18.75khz coil is pretty good and on the beach it would come in handy for small gold targets like studs and small chains. Im sure B.T will give you his input on this one! Lol
Cheers!

 

[B.T]

Id actualy back Barnacle Bill on giving this one. The last beach hunting I did was when I lived in Yeppoon 1 1/2 years ago. The I used a GP3500 a SOV GT and gave my misses the Musky Advantage. Bill as I understand does do beach hunting with his 70 and a while ago put up a good post when he did so.

 

[BarnacleBill]

Hi BT,

I would offer an opinion if I owned either of the large DD's, but I don't . But from what I do know it presents a minor conundrum. When checking the ease with which each of the other coils achieved GB in Auto GB mode on a black sand saltwater beach, the following was observed. The coil fastest to balance was the HF elliptical, next was the LF concentric. This was done by driving the GB manually to it's maximum then timing how long Auto-GB took to achieve it's null.

So this presents an interesting question, a small gold ring at say 7 inches, the round MF DD hits it better because of it's lower frequency and greater ground penetration, or the round HF DD hits it better because of better sensitivity to low conductors? And what roll does black sand play in this?

HH
BarnacleBill

 

[brissietex]

n/t

 

[Jackpine Savage]

compunds the problem too. How much sensitivity that can be run with the HF round DD versus the 7.5Khz DD on your beach. The HF should have greater sensitivity to gold but, if the sens has to be lowered too much the 7.5Khz could be the best bet.

Tom.

 

[B.T]

I no longer hunt beaches, I will perhaps again one day and I really hope to, but maybe the reason why I chose to have both high frequency coils , round and elliptical, will help a little.
I have the elliptical 10x5 as my primary gold hunting coil. It has the greatest sensitivity in the goldfield situations which I hunt and balances oh so good. The larger round 18.75kHz does not appear to have a great deal to offer until the gold gets bigger. Into the ounces range. For me I don't want to walk away from a nice nugget which was just 2 inches off when I could maybe have got it.
This advantage is at the bigger golds detectable limit or range, its last 2 inches of detectable depth. This when you think about it is going to be marginal, a soft mellow "listen for it" sound. Not a jump out at you signal. So I thought about it and "how much big chunky lumps of gold do you expect to find lost on a beach?". How much so that would warrant the larger HF coil? You see I see the larger coil coming in on the much larger buried at depth targets and when we talk about jewellery then how many people walk about wearing gold over 2 to 3 ounces? Maybe there are some coins which will detect deeper with this coil but is it ultimately worth it in that situation?
Hope it can help.

 

[Jackpine Savage]

Hi BT

I have no salt water beach experience which is Brissies main topic. Gold rings are generally easy targets for most all detectors. Because of the round shape they generate a very good return signal and so are a bit less frequency dependant than nuggets but, when you want best depth frequency certainly does come into play along with site conditions. A nice chunky mans ring say about sz 11(US) weighing 10-11 grams would definitely call for the 7.5 Khz coil for my fresh water hunting. I was unable to use the prospecting mode on the X-70 wading in my fresh water lakes. The stock concentric coil generated a very unstable threshold when swept across the sand ripples on the bottom so that hearing deeper targets was nearly impossible.

Tom