Ground Balance F4

[JeffNS]

Hi all. New to the forum. Recently purchased a Fisher F4. I understand how to GB the machine and have no problem performing the required steps but I'm wondering what I should be hearing during the process.

When I switch to AutoTune/All Metal mode I don't get a hum....I get a rather scratchy sounding buzz at best. Just not sure if it should be a smooth tone or if what I'm experiencing is normal.

The F4 also seems to be much more sensitive to EMI than it's little brother the F2....even with the 8" coil....I also have the 11" DD.

Any tips/suggestions about the F4 would be greatly appreciated. I'm trying to determine if my unit has a defective GB as I've read somewhere about a recall awhile back.

Thanks for reading.

 

[JeffNS]

n/t

 

[rick in mi]

Havnt heard of any recalls?? my f4 works great.Start out in allmetal mode,find clean ground[no noise]push positive arrow dicrimination swing coil push again untill you hear a slight buzz or hum in background pump coil listen for hum,is it pushing into the ground or pulling out? what most guys want is slight pushing in[positive]adjust by turning your ground ballance knob cw or ccw,its very important that you do this over clean ground.Good luck,hope this helps you out,maybe some more experienced guys will chime in also.

 

[Ken in NC]

I am now using the F5, but used an F4 previously and was very impressed with the machine. I had better luck adjusting the ground balance when in pinpoint mode.

Raise the coil and turn the GB knob to either extreme, but not in the fixed position, and press the PP button, then lower the coil to your normal sweep height (over a clear spot of ground). If you have the GB knob turned to the + extreme, the machine's volume will rise quite a bit. You can then back down the GB as you raise and lower the coil until you have a neutral report.

If you get no report when you first try this, turn the GB knob to the other extreme, as you probably have it in the most negative position.....I cannot recall which way was which.

The pinpoint mode is an easy way to check on your GB. I may be wrong, but when using the F4 I wanted the PP mode to not report on the bare ground.....to only give a sound over targets.

 

[Ken in NC]

Jeff

Regarding the EMI sensitivity, it just seems to be the nature of the new Fisher and Teknetics machines. I have owned two Tek Omega 8000's, the F4, and now the F5. I found that all of the four that I used had to be ran at less than maximum sensitivity in town. However, at the nearby beach, I can run the F5 all the way up, so I know it is not the machine, but rather the electronic noise in the air

Odd that some machines do not pick it up (for example the Tesoro). Perhaps the Fisher and Tek machines are just more sensitive, or have higher gain

One thing I have noticed is that turning down the sensitivity on the F5 does not kill the depth of the machine. It still does just fine for me. So in that respect, I don't let it bother me that much anymore.

I imagine if you could look at all the radio frequencies in the air at your detection site, you would be shocked. Pagers, cell phones, GPS signals, TV, radio stations, emergency services, power transmission lines, electric fences, etc. I am aware that each is supposed to have their set operating frequencies, but imaging there is interference just the same.

 

[bthom]

I did read somewhere.. maybe on this forum, about people lining the interior of main detector casing with tinfoil to solve EMI0 problems.. I have to say its not a big issue with my f4, even working closely to the f2 we have....you can just lower the sensitivity a bit ( i do this in all metal )

 

[JeffNS]

I did read somewhere.. maybe on this forum, about people lining the interior of main detector casing with tinfoil to solve EMI0 problems.. I have to say its not a big issue with my f4, even working closely to the f2 we have....you can just lower the sensitivity a bit ( i do this in all metal )

I occassionally with a guy swingin' an F2 and it definitely crosstalks with my F4....just how close are you able to get when you use the F4 and F2 on an outing? When you set GB would you describe the background hum as a smooth tone or a "scratchy/broken" buzz?

 

[Hopskippy]

I adjust the GB on my F4 exactly the way the instructions says too by pumping it up and down over a clean area in auto tune/all metal mode while adjusting the GB knob to find the QUIET spot on the knob. I then set mine back to a slightly positive GB by adjusting the GB knob back to positive until I get a slight tone as I push down towards the ground.I never change the preset threshold level that it is at when I turn it on. I always hunt in the disc mode, usually with NOTHING notched out. I find that if I notch out iron and foil, it seems to be less sensitive towards smaller deeper coins, 5" and deeper.
My son has the F2 and we always hunt together. I always use the 11"DD coil and he always uses the 8" coil. How close we can get to each other before crosstalk begins is determined by the sens. level we are able to run at. If away from power lines and running at max sens., we start getting crosstalk at approx. 50 feet.

 

[bthom]

I did read somewhere.. maybe on this forum, about people lining the interior of main detector casing with tinfoil to solve EMI0 problems.. I have to say its not a big issue with my f4, even working closely to the f2 we have....you can just lower the sensitivity a bit ( i do this in all metal )

I occassionally with a guy swingin' an F2 and it definitely crosstalks with my F4....just how close are you able to get when you use the F4 and F2 on an outing? When you set GB would you describe the background hum as a smooth tone or a "scratchy/broken" buzz?

I'll have to test it properly, we usually just go coin shooting for easy targets so don't bother with the GB, I tend to forget about the cross talk then within about six meters it starts to chatter a bit.

 

[JeffNS]

I did read somewhere.. maybe on this forum, about people lining the interior of main detector casing with tinfoil to solve EMI0 problems.. I have to say its not a big issue with my f4, even working closely to the f2 we have....you can just lower the sensitivity a bit ( i do this in all metal )

I occassionally with a guy swingin' an F2 and it definitely crosstalks with my F4....just how close are you able to get when you use the F4 and F2 on an outing? When you set GB would you describe the background hum as a smooth tone or a "scratchy/broken" buzz?

I'll have to test it properly, we usually just go coin shooting for easy targets so don't bother with the GB, I tend to forget about the cross talk then within about six meters it starts to chatter a bit.

Sounds about like the same distance before I get crosstalk from my buddy's F2. I always like to adjust the GB in AutoTune then switch to Disc mode. I read a post indicating that even though the manual indicates you can only adjust GB in AutoTune that it will carry over the GB settings in DISC mode until the unit is powered off in which case it resets to preset GB.

I'm mainly curious to know what the TONE sounds like while you're GB'ing. I don't get a tone as such....at least not like the tone you get when in pinpoint mode....it's very buzzy/scratchy sounding. Any chance you can record sound while you GB your F4? I'd love to compare. I'll try to borrow a friends camera and post to Youtube so everybody can listen to what I'm listenin' to.

 

[bthom]

Have you seen this video...
http://www.youtube.com/watch?v=D9k5DGmjIwo

you can hear what it sounds like..

I did read somewhere.. maybe on this forum, about people lining the interior of main detector casing with tinfoil to solve EMI0 problems.. I have to say its not a big issue with my f4, even working closely to the f2 we have....you can just lower the sensitivity a bit ( i do this in all metal )

I occassionally with a guy swingin' an F2 and it definitely crosstalks with my F4....just how close are you able to get when you use the F4 and F2 on an outing? When you set GB would you describe the background hum as a smooth tone or a "scratchy/broken" buzz?

I'll have to test it properly, we usually just go coin shooting for easy targets so don't bother with the GB, I tend to forget about the cross talk then within about six meters it starts to chatter a bit.

Sounds about like the same distance before I get crosstalk from my buddy's F2. I always like to adjust the GB in AutoTune then switch to Disc mode. I read a post indicating that even though the manual indicates you can only adjust GB in AutoTune that it will carry over the GB settings in DISC mode until the unit is powered off in which case it resets to preset GB.

I'm mainly curious to know what the TONE sounds like while you're GB'ing. I don't get a tone as such....at least not like the tone you get when in pinpoint mode....it's very buzzy/scratchy sounding. Any chance you can record sound while you GB your F4? I'd love to compare. I'll try to borrow a friends camera and post to Youtube so everybody can listen to what I'm listenin' to.

 

[JeffNS]

Thanks for taking the time to post the vid...I had forgotten that I had viewed it before. My F4 tone during the GB process doesn't come close to sounding like his. Actually, at best...when I have the GB set on my machine it sounds similiar to his but I never get that solid and loud tone at the beginning. Maybe it's nothing to be concerned about. I haven't hunted in All Metal mode yet with my F4...gave it a short try earlier this afternoon but it was very confusing to me and I wasn't able to lock onto a target. I'd swing in All Metal until it sounded off then I'd switch to Disc mode with nothing notched and it wouldn't register on the VID. I'll do some more testing. I've got all summer to play and if I don't think the machine is working properly I'll box it up and send it to Fisher for a looksee while it's still under warranty.

 

[bthom]

yes does sound a bit odd.. mine is exactly like the video.. you may have really really strange ground or its not working as it should, I assume you have tried it in different places?.With the all metal mode initially I found it very odd too.. to much info , then I stated using it at the beach where the ground conditions were very consistent and targets rarer than messy ground, it was a good place to learn.. it to would find a target in all metal, then flip over to discriminate to make sure it wasn't another bottle cap. Now I use all metal quite a bit where the ground is not to messy, you soon learn what the sounds mean.. deep, shallow, big, small etc. I like it because you really get to "hear" the ground, you no your not missing anything.

 

[JeffNS]

yes does sound a bit odd.. mine is exactly like the video.. you may have really really strange ground or its not working as it should, I assume you have tried it in different places?.With the all metal mode initially I found it very odd too.. to much info , then I stated using it at the beach where the ground conditions were very consistent and targets rarer than messy ground, it was a good place to learn.. it to would find a target in all metal, then flip over to discriminate to make sure it wasn't another bottle cap. Now I use all metal quite a bit where the ground is not to messy, you soon learn what the sounds mean.. deep, shallow, big, small etc. I like it because you really get to "hear" the ground, you no your not missing anything.

Really appreciating your feedback. Perhaps I just have strange ground conditions where I'm at. I have tried in several locations and some are worse than others. Haven't tried it at the beach though but definitely will.

 

[crusher28]

Try wrapping the coil wire with 3M emi tape from top to bottom (radio shack) My f5 did the samething, now I can hunt right under power lines and Gb with no problem. Coil wires seem to be much thinner then they use to and not shielded as good

 

[JeffNS]

Try wrapping the coil wire with 3M emi tape from top to bottom (radio shack) My f5 did the samething, now I can hunt right under power lines and Gb with no problem. Coil wires seem to be much thinner then they use to and not shielded as good

I may give that a shot...also heard that those line filters that clamp onto the outside just as it enters the box does something to improve things....forget what it's called.

Thanks for the tip.

 

[BH_Landstar_]

Ferrite ring is what is called.

 

[Boston Metal]

The manual offers two ways to ground balance, the preferred way to pump as described above and a "quick and easy" way using the pinpoint. I'll copy and paste that below. For me, the quick and easy way is superior, I can get the machine humming perfectly and running real hot very sensitive, it is like a different machine when it is purring like that.

I haven't tried ground balancing every-time before going into disc mode, because I thought the manual says GB doesn't work in that mode. If it is true that the GB those settings are retained over the factory presets in disc it would be great. Does anyone have a contact we can use at Fisher to find out? Any other F4 users GB every-time before going into disc mode?

Follow these directions exactly it takes 30 seconds and works very well. From the Manual:

Find a patch of ground free of metal

1) Set the ground-balance knob at the pre-set position, 100% clockwise.
2) Position the searchcoil about 6

 

[NJEric]

Been using my F4 since spring time, and I'm having the same GB issue. My unit doesn't sound anything like the F4 in Dinger51s utube video. In all metal mode I don't get a "smooth" sound that allows me to "bounce" the unit. I've also been wondering if I have a defective machine. I've tried to GB in many different areas none of them near any electomagnetic lines or other interference. I find a variety of clad, but don't feel that the GB is correct since I'm not following protocol for this function. Any ideas?

 

[JeffNS]

I still have issues with GBng by F4...at times. It's absolutely imperative that you perform the GB over ground that is completely void of all metal. Mineralized ground will do funny things. My personal take is that my F4 probably requires a tune-up...yes...brand new and came from FRL not calibrated properly. That being said I've been fairly successful with it...but it is a chatty machine for sure and very susceptible to EMI. It'll go absolutely nuts when used anywhere near power lines unless you back off the sensitivity...way off! Other detectors wreak havoc with it...cell phones do the same thing...and my Garrett Pro Pointer will make it chatter like a chipmunk on steroids too. If my unit is indicitive of all F4's then I can't say I'm all that happy with it. I recently purchased a used CZ3D and it's MUCH more stable. I'll probably send mine back to Fisher over the winter and see if they can improve things.

Good luck.