nulling of concentric coil for tgsl

[rajesh]

Tx coil = 30 awg wire clockwise on a 8 inch diameter form.
Rx coil =30 awg wire clockwise on a 4 inch diameter form.
Bx coil = 23 turns Reverse clockwise directly on top of the Rx coil
TGSL is working well with concentric coil BUT 101A PIN NUMBER 7 VOLT IS 1.6 . how to reduce this

Do I have to reduce or increase the turn of the bucking coil ?

[waltr]

You need an extra loop on the buck coil for nulling like Don explains here:
https://sites.google.com/site/dbcoil...ncentric-coils

[rajesh]

hi waltr
we read this document Tx coil = 105 turns counter clockwise on a 95mm diameter form. & Rx coil =193 turns counter clockwise on a 43mm diameter forThere are no 6 mili henary inductance of coil at 95mm dia TX coil
http://chemelec.com/Calculators/A-Inductance.htm

6.0092 mH

29.0604 Ohms

30 AWG

10.9 mils (1 mil = .001 in)

0.2 in

10 in

10.1308 in

10.0524 in

281.5929 feet

0.0857 pounds

107

5.8315

18 (Based on wire diameter)

[waltr]

Look and read Dbower's TGSL coli build doc agaian.
Note the text: "This is a small section of wire between the Tx and Bx coils that can be
very helpful in final nulling. By moving around this small wire loop, the
null can be fine tuned."
and the photo showing this small "extra" loop of wire. This is used to adjust the buck coil coupling to NULL .

Null adjustment in DD or Concentric is a VERY FINE adjustment and can be very touchy. In a concentric one MUST have the TX and Buck coil ratio very close to correct to be able to do the fine Null adjust. Equations may get you close but usually NOT close enough. Therefore, you may need to add or remove turns on the Buck coil to get close enough to use the "small extra loop" to obtain Null.
You do need to experiment.

[rajesh]

Look and read Dbower's TGSL coli build doc agaian.
Note the text: "This is a small section of wire between the Tx and Bx coils that can be
very helpful in final nulling. By moving around this small wire loop, the
null can be fine tuned."
and the photo showing this small "extra" loop of wire. This is used to adjust the buck coil coupling to NULL .

Null adjustment in DD or Concentric is a VERY FINE adjustment and can be very touchy. In a concentric one MUST have the TX and Buck coil ratio very close to correct to be able to do the fine Null adjust. Equations may get you close but usually NOT close enough. Therefore, you may need to add or remove turns on the Buck coil to get close enough to use the "small extra loop" to obtain Null.
You do need to experiment.

hi waltr when we increase turn of bx coil to reduce volt in 101a but sensitivity going loose

[rajesh]

hi waltr currently we have measure 101a pin number 7 1.1 dc volt detector working no problem But the volts are not going to zero like it does from DD coil

[waltr]

First, have NO METAL near the coil. Place the coil at least a meter away from any metal. I use a cardboard box to put the coil on.

Getting the buck coil's number of turns is the hardest part since the null only shows when the buck coil's inductance is very close to the correct value.
Observe the Phase of the RX relative to TX with two channel O'scope to guess at whether you need to increase or decrease the turns on the buck coil.
When close the phase will shift and amplitude will drop. Now use the 'extra loop' to fine adjust.