Fisher F75 SE question ...

[Willee - Texas]

I have used two other F-75 SE detectors and noticed that in the DE (default) mode the gain jumped at a setting somewhere around 88 and you could hear the extra gain kick in with a slight background tone.

The F75 SE camo detector I just got does not seem to do that.
No apparent jump in gain or background tone even up to 99.

Anyone think that might be a problem requiring a trip back to Fisher?
Otherwise, the detector seems to work just fine.

Willee

 

[Elton]

I know on all my F75 type units the electronic operation noise of the machine has kicked in around those numbers 86, 88, and for sure at 90 and up.

 

[Big Boys Hobbies]

Willie,
Doesn't sound right. It should kick in on those #'s. I would call them and at least ask.

 

[jim tn]

I get a very faint background hum at sen 87-88 with my LTD. I'm not aware that it is extra gain kicking in, but the internal electronics. HH jim tn

 

[gmanlight]

Mine kicks in at 86 /87

 

[TerraDigger]

It ain't a F75, but the T2 has gain increase/decrease tied directly to the level of discrimination selected. I'll bet the F75's are built to do the same thing. However, the disc gain ratio numbers will vary between the machines. Bart has a copy of my airtests regarding this with the T2. You may wish to perform benchtests on your machine to get a idea of disc level gain variances. And no, First Texas will not discuss this with customers. You have to find it out for yourself.

 

[shooter]

Have to agree mine kicks in about about 88 and up but I'll
run it and through the limiter on the Sun-Ray phones and a it doesn't bother me. But I would really call Felix and ask about it.

 

[markg]

Mine is about 88 too.

 

[Willee - Texas]

I thought there was extra gain added once you go past 87 on the sensitivity.
Dont know exactly how it works but it is there by design.

The F-75 is no doubt the deepest detecting detector I have ever used.
Once it is set up and tuned in for the ground you are hunting it really gets down there.

I guess I will send this one in for a tune up.
Beach and shallow water hunting for the next 4 months so I wont miss it till next winter.

Willee

 

[Cal_Cobra]

I just sent my camo F75 LTD to FT and they said it had a bad coil, so they sent it back with a new coil and said they did nothing else. Cool, it's working great again! My first test drive with it after they returned it was with the new 15" DD coil. I had the sensitivity on 90 the first trip out and noticed the background hum, and figured it was due to the new coil While testing various settings with the 15" coil I saw that the hum went away at lower settings.

Next trip out I put the new 11" DD coil on, and set the sensitivity at 90....WTH the hum is on this coil too! It wasn't before, so even though FT claims they didn't do anything to the F75 LTD, I suspect it got a code upgrade because I never got a background hum before, and frequently ran the sensitivity in the 90's. Now at 87 and above the hum is present. It's kind of like a threshold in disc mode.

It would be great to know what changed in the SW versions, but Dave J has made it pretty clear on this forum in the past that they don't care to share that info

Willee I believe the extra gain is if you run the sensitivity under 6 or higher then 21.

HH,
Brian

 

[jbow]

If you are getting equal depth and sensitivity to targets witout extra noise... why worry about it. Have you compared the two to see if they perform the same. I'll be really interested to know. I have an early camo F75-LTD and don't recall any hum at high sens, I do hear the internal electronics once up into the 90s. However, if I am missing some improvement I will send mine in too. I think y T2 has been back to Texas three times, my original F-75 went once, the Omega has not had to go, nor has the LTD... yet.

I need to know more about this... thanks.

Julien