SEF search coil review
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Gary's Detecting SEF 12x15 search coil review
By Gary's detecting

Test machine Teknetics T2

SEF search coil review and pictures
Winter is again upon us and the crop fields are planted, its time to go back to our old friends the pasture fields and woodland, as we all know searching grassland can be somewhat soul destroying, there's always that nagging feeling in the back of your know the one!, the one that says "the good finds are all to deep" especially when you dig faint signal only to find it's a Victorian coin at 11" deep.
As a rule the search coil size regulates the maximum depth a machine can achieve, however there is always a trade off between depth and sensitivity to small targets.

The search coil took exactly 1 week to arrive from Bulgaria to the UK safe and sound by courier and well packaged

So what am I hoping to achieve by using a larger coil on my machine.
Firstly I have chosen the Teknetics T2 as the donor machine because I have been using it for ever and know it's capabilities on my test sites.
I know the maximum depth it can achieve and the way it responds to both ferrous and non ferrous targets.

I won't be expecting a massive depth improvement on coin sized targets...perhaps 8-10%, bigger targets such as artefacts and "cough cough" a large conductive pot should be considerably better...however my main aim is to get better ground coverage with a smoother overall operation.

Just as a comparison here are the results of my outside air tests
Machine Settings
No discrimination : Sensitivity high until chatter, back off until stable

Air test comparing coils


Low conductivity Roman coin

UK Pound coin)

Victorian Copper Penny

High conductivity target Aluminium lid 4" x 3"

Standard T2 search coil
Sensitivity 89
11.5" 13" 14.5" 23"
SEF 15x12 search coil
Sensitivity 80
12" 13.5" 16" 30"

As suspected no big deal on smaller targets but quite impressive on the highly conductive Aluminium lid, which could represent large silver or Bronze

Teknetics T2 sef coil field test

Below you can see the SEF coil compared to the standard T2

Metal detector search coil picture metal detecting sef coil

The SEF coil has a better standard of finish than the standard T2 coil... note the coil wire has an added shrink wrap for protection
sef coil build quality picture
sef coil 12x15 metal detector

Very soon I will be publishing my field test, lets see if this coil can add extra life to my T2 !

In the field
The snow had finally cleared I was desperate to try the SEF coil for the first time, a quick visit to a pasture field in north Oxfordshire would be enough time to get a feel for the coil and see how it dealt with wet grass.
I have to say the SEF coil was a pleasure to use, the field was reasonably free from modern junk just the odd shotgun cartridge or 50. I ran the machine at 75 sensitivity, 19 Discrimination, and 2+ audio. Iron rejection was faultless, the pin pointing really impressed me for a large coil...bang on every time.
A short 2 hour search uncovered the usual scrap lead etc, several shotgun cartridges, 3 small Victorian coins, 2 musket balls, a fragment of a hammered coin, a small Roman and a beautiful Gold mourning ring with the owners name and date clearly visible 1734, we are currently searching local records to re unite this wonderful piece with a family member.
Nothing was deep on this particular session, as the season progresses I'm sure the SEF coil will turn up something good

Gold found with the Teknetics T2 Gold found with the SEF coil

My second outing was to a familiar pasture site which has produced some interesting artefacts many years back, however recently it has been very hard work, if it wasn't for the fantastic views we most probably would give it a miss.

Sef coil on the Teknetics T2

The first thing I noticed was the T2 would not auto ground balance with the SEF coil, this is nothing to worry about you can either not ground balance the machine and search in factory default mode (which is what I normally use) or switch over to the all metal section which is on the left of the screen and manually ground balance from there. I have found in the past that quite a few machines have trouble ground balancing on heavily grazed pasture, perhaps it is something to do with the years of animal droppings.
I used my "Lazy pasture" set up for this particular search which was sensitivity 75, discrimination 25, 1+ on the audio, this allowed me to have a steady search without to much spitting and popping allowing more time to concentrate on the more solid 2 way targets.

SEF search coil very stable

The targets came thick and fast...sadly nothing nice to report only shotgun cases and copper coinage, what really impressed me was the amount of targets detected in a small space of time, the bigger coil certainly upped my finds rate.

SEF coil for deep pasture

With regards to depth I am sure it is just a matter of time before I find something to confirm the depth advantage of the SEF coil, as for now I am just simply happy with its ground coverage, lightness and stability.
Many thanks to Mdetectors for supplying the coil at a fantastic price.
I will be adding to this review when I have something to report.

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