Is there a benefit to using the GQ SS 11" coil instead of the 11" HH Pi coil on the headhunter Pi

[Anonymous]

Hello Eric, Mr. Bill or Reg,
Early this evening I mounted on the 11" GQ SS coil to my Headhunter Pi project I completed last week, On dry land the unit performs great. I'll be testing out this coil at Santa Monica soon.
My question, Will the GQ SS coil help the unit operate with better stability under difficult ground conditions or make the unit operate more on the rough side. I've enclose a picture of my project which is actually a HH Pi circuit board inside a gutted out am/fm radio. This project pi is both a Hip mounted Headhunter pi detector and Probe. Later on will hookup the GQ SS 11" DD coil Reg made.
I hoping the GQ SS coil does help the HH pi <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt="">
Thanks and good hunting,
Paul (Ca).

 

[Anonymous]

Hi Paul,
I have not seen a HH PI schematic and haven't used one, so I am unable to give you some of the answers you are looking for.
I will say that I have found Eric's coils to be some of the quietest I have ever used. However, the quiet feature primarily refers to external noise and not with respect to ground conditions. So, I am not sure just what will happen over the ground.
I am curious why the coil worked so well. I would have expected it to oscillate and require a change in the damping resistor. It could be properly damped, or it could be ringing a little. If it is ringing, I would expect some strange things to occur when you adjusted the delay. At some point, I would expect the detector to definitely act differently.
I guess it is possible the HH was overdamped to begin with. In that case, the HH/SS coil may work just fine.
Does the coil seem to work well over the complete range of the delay pot?
Now, as for connecting the DD coil, I would expect some modification of the pc board would be necessary, if the design was not built to accomodate a DD type search head.
Let me know how the project comes out.
BTW, your mod looks quite impressive. It definitely looks like it a very light weight detector.
If you get a chance, drop me an email. I am curious what test equipment you have.
Reg

 

[Anonymous]

Hi Paul
Using the Goldquest SS coil on the Headhunter PI should be almost a direct install. Although it wouldn

 

[Anonymous]

Good morning bill,
I agree with both you and Reg, Eric's coils do seem to be more quiet than the others. For this reason, I'm hoping the 11" GQ coil will help my project HH Pi operate smooth without reducing the delay or threshold when entering the surf. My project pi is on the border line of getting maxium performance, just needs a little help and hoping the GQ coil helps.
Thank you,
HH, Paul (Ca)

 

[Anonymous]

Hi Reg,
Yes, The GQ coil on the HH Pi works well over the complete range of the delay pot, The GQ coil will work on the HH Pi but the HH PI coil will not work on the GQ. Here's a post from Eric explaining to me a few weeks ago about the two coils..................(The reason you can't swap them both ways is because the inductance are different. The Goldquest SS coil is less than the HH PI coil. The lower inductance on the SS is to enable it to work at 10uS. A lower inductance is OK on the HHPI, but a higher inductance will not allow the TX field to collapse fast enough to work on the SS. Unless that is, you turn the pulse delay (reject) control back to the 15uS point at least. The other factor is that the damping resistors are different, so you may run into a problem there, more likely with the HH coil on the SS)
Sounds like to should help my project here in the Ca. beaches known to be rough on Pi's. I'll keep in touch with you and zip you a e-mail soon.
Thanks and good hunting,
Paul (Ca)