VoyForums
[ Show ]
Support VoyForums
[ Shrink ]
VoyForums Announcement: Programming and providing support for this service has been a labor of love since 1997. We are one of the few services online who values our users' privacy, and have never sold your information. We have even fought hard to defend your privacy in legal cases; however, we've done it with almost no financial support -- paying out of pocket to continue providing the service. Due to the issues imposed on us by advertisers, we also stopped hosting most ads on the forums many years ago. We hope you appreciate our efforts.

Show your support by donating any amount. (Note: We are still technically a for-profit company, so your contribution is not tax-deductible.) PayPal Acct: Feedback:

Donate to VoyForums (PayPal):

[ Login ] [ Contact Forum Admin ] [ Main index ] [ Post a new message ] [ Search | Check update time | Archives: 1, 2, 3, 4, 5, 6, [7], 8, 9 ]

[ Next Thread | Previous Thread | Next Message | Previous Message ]

Date Posted: 21:36:22 03/28/02 Thu
Author: Steve Herschbach
Subject: Goldmaster Prototype 6" Elliptical Coil


Goldmaster 10'' Coil and 6'' Prototype Coil

Hi All,

I have a prototype 6'' concentric coil for the Goldmaster series. I used it a bit last summer in the field, and found it to work quite well. No real problems, but the area I was hunting was very forgiving. I'll give it a harder workout soon.

Small coils are not for everyone and every place. In my area (Anchorage, Alaska), we have a very low mineral background. The bedrock is mostly slate and has almost no iron content. A whole day with a gold dredge will produce a few spoonfuls of black sands. The gold is also small. Anything over a pennyweight is a BIG NUGGET. Six grain and smaller pieces make up the bulk of the finds.

So a guy really should go high frequency around here, and regardless of that, be using small coils. Quite a few people run nothing but the small coils on their detectors. My sharpshooter for some time has been the Gold Bug 2 with 6.5'' coil.

In general small coils will handle the general ground mineralization better as they ''see'' less ground. So theoretically you can run a small coil with a higher gain. But they also tend to hit harder on weak hot rocks, so as always you have to seek the proper balance for good performance. In some places the problems a small coil introduces may outweigh it's benefits. But I always have one in my rucksack!

There is one area where I have found small coils to be at their theoretical best. Scanning quartz samples for gold. We have hardrock mines nearby that have free-milling gold in a relatively clean quartz. Very little sulphides. While working ore dumps I found the worthless surrounding rock to be very hot and hard to detect. So scanning the surface of the ore dumps did not work well. But I found that I can take my Gold Bug 2 with small coil and hand scan samples very effectively. Just jack the machine all they way up, and roll quartz rocks over the bottom of the upside down coil. You just have to get a talent for working with extended fingertips so as to not get signals from your hand.

I have not found any detector that can equal the GB2 for this task. I have a Falcon Gold Probe that has better sensitivity, but it only scans an area about 1/2'' wide. It simply does not have enough coverage for bulk sampling. The Goldmasters are close, but the coil size makes the difference here.

I set up my Gold Bug 2 and GMT next to each other, the GB2 with 6.5'' coil and GMT with the 6'' concentric prototype. The GB2 was set low mineral, full sensitivity as usual for me.

I played with the GMT and ended up with settings you would almost never use while detecting. Gain at max, SAT set to minimum, ground balance set to manual, and audio boost on. One funny thing I noted was that the threshold got quieter with the SAT at minimum. At full gain, as I turned up the SAT a spikier sound was introduced. The SAT has been redesigned on the GMT to supposedly allow for better depth at higher SAT settings. The new SAT design operates through software. All I know is that with the small coil at full gain the machine was quieter with the SAT set to minimum.

I played with the quartz samples for some time, most specifically one that would barely read with the GMT and 10'' DD coil. It was LOUD with the little coil and cranked up settings. The GB2 seemed a bit smoother but slightly softer in response on the test targets. The GMT had a rougher threshold cranked up this high, and if anything seemed to produce a louder audio response.

I really could not decide which was doing a better job. It was that close. All I know for sure is that the little prototype coil takes the GMT from mediocre for this kind of quartz ore testing to HOT. A dramatic difference.

I still have hopes this design may see the light of day as an official factory release. So once again, if anyone has any use at all for a coil like this on a Goldmaster II, V/SAT, GM3, GM4/B, or GMT then please email Steve Houston of White's Electronics at Steve Houston shouston@whiteselectronics.com and give him your thoughts. He is trying hard to make it happen and can use all the support he can get.

Steve Herschbach

[ Next Thread | Previous Thread | Next Message | Previous Message ]

Replies:

[ Contact Forum Admin ]

Forum timezone: GMT-6
VF Version: 3.00b, ConfDB:
Before posting please read our privacy policy.
VoyForums(tm) is a Free Service from Voyager Info-Systems.
Copyright © 1998-2019 Voyager Info-Systems. All Rights Reserved.