Parts list for matching system
(10 m circumference loop).
pa0nhc 20181221 / 20200607 / 202112 20 / 20221205    Copyright pa0nhc.
(C) The use, publication, copy and modification of all info on this site is only permitted for non-commercial purposes, and thereby explicitly mentioning my radio amateur call sign "PA0NHC" as the original writer / designer / photographer / publisher. (C)  
==>> On every new page FIRST PRESS F5 <<==

New PCB.

New larger PCB 210x80 mm, v20200605-23.    To  order the PCB, see my PCB service.
Larger Rel+ connections, optimized CMC L1,  larger spaces for C4x / C8x and R2/3 2W.

Use ONLY the specified ferrite cores !

Cabinet : Hammond 1555VZGY
L1 : Common Mode Choke. 13t RG316 wound in 29mm mix31 ring core FairRite core 2631801202
Tr1 is wound on 61mm #61 ferrite ring core (FT240-61) or FairRite core 5961003801
P0/P1 is primary 9t 5mm wide, insulated twin speaker cord, with its both wires in parallel.
. S0/S3 is secondary 3t 6.3mm wide, insulated twin DC cord, with its both wires in parallel.
R1 is a 5W anti-condensation heather. Conrad 401956
L2,3,4 are Fastron 22 uH chokes in command lines. Conrad 440433
Both DC and RF connector strips are each  : DG950-9,5-03P Conrad 1327229
REM : The loop output with also such a connector, is handier than with screw bolts and solder eyes..
h1,2,3,4,5 are 4.5mm holes for fixing into a box. See for drilling distances the topsilk of the PCB.


v. 20200606

Order Nrs

Box Hammond 1555VZGY UV proof splash watertight. 1977734
PCB pa0nhc  PCB 20200605-23 pa0nhc@gmail.com
Tr1 RF magnetic RFpower transformer.    See construction.  Updated 20221204

61mm mix #61 ferrite ring core : Fair-Rite  5961003801 .  or FT240-61.
Do NOT use any other ferrite mix ! <<===

     Both pri. and sec. are each wound with :

Two AWG12 PTFE silver plated wires. 
Use for primairy winding 2 different colors to be sure it is correctly wound with both wires IN PARALLEL..
Use for secondary winding 2 different OTHER colors  to be sure it is correctly wound with both wires IN PARALLEL..
See photo.
Wind and connect two wires in parallel.. DO NOT TWIST.
This wire is very slippery. Fix with tywraps.

Fix winding ends in place with black tywraps.   See photo.

==> Wind all turns very tight against the ring core body <<==
==> Wind the secondary turns in-between the primary turns <<==  See photo 

If no PTFE wire is avaialable, you can use easier to handle :
2x2,5 mm2 speaker twin lead 5mm wide or DC power cord 6,3mm wide.

     Winding data :
Pri0-Pri9 :
9 turns, two silver plated PTFE wires wound and connected in parallel (40m).
: 3 turns, two silver plated PTFE wires wound between primary turns and
                    connected in parallel.
S1            : Secondary tap after 1 turn from start (80m).
See the topsilk of the PCB and the photo for how close to wind and how to solder.








L1 Common Mode Choke (balun).  See construction.
Wind 13 turns thin coax neatly in the hole beside each other.
Fixate winding ends to the core, and the CMC to the PCB, with small black ty-wraps.

Ferrite ring core ==>> Fair-Rite 2631801202 (28/19/14mm) ==>> MIX #31 <<==
(or Ferroxcube => mix 3S4 <= core type TX29/19/15-3S4,  ).

DO NOT use any other ferrite mix !

2 m Coax RG316 (or RG174) suitable up to 400W.




L2,3,4 Fastron 09P220k-51  . RF chokes,   d=9, RM5. Imax >= 330 mA, Fsr >=  10 MHz.  440433
Rel1 Fujitsu FTR-K1CK012W. 440V~ / 16A.
12V mains voltage relay (high voltage / current). 
R1 56 ohm 5W wire wound resistor (anti condensation heather). 401986
R2,3 10k 1W or 2W metal film resistor (static charge bleeders). 419567
"50 Ohm"
Degson DG950-9.5-03P-14-00AH fits the PCB.  Screw terminals 5.3 mm2.  RM9,5.  1327229
  4x water tight cord grips for RG400 coax, 5,3mm relay line, and 2x 3,7mm loop connection twin DC line.
For RG58 feeder, relay cable and antenna connection wires, use : "2,5 - 6,5 mm" size.
For thicker coax feeder use bigger 7-12mm size. 
Install with some Vaseline (petroleum gelly) to make them water tight.


C1 Capacitor 100n 50V RM5 531855
C40-46 Total value abt. 890 pF. 8x100p Wima FKP2 630V + 1x180pF 630V film or  1kV NP0   OR 500V Mica.    MEASURE resonance as being 7100 kHz.  
C80-88 Total value abt. 6400pF, 8x680pF Wima FKP2 630V + 1x 270pF 630V film  OR 500V Mica.    MEASURE resonance as being 3650 kHz.  
Series tuning capacitors 

Use as much as possible capacitors in parallel. For instance :
Silver MICA and/or

-  Low inductance
polyester film  WIMA FKP2 630Vdc and/or
-  Ceramic NP0 (zero temperature coefficient).

Use as much as possible the same values in parallel, to divide the total RF current equally over all paralleled Cs.
Check that all C s can handle the RFvoltage and RF current at working frequency.

I total =  26 A @ 80m, 9,7 A @ 40m in sec. winding, and 2,9A in pri. winding.
Umax over series tuning Cs is 220VpRF. Use : 630Vdc capacitors. 

You have to determine the optimal total capacitor value yourselves. See "Construction".
See these capacitor values below (meaured at the new PCB) as a guide.

C80 in total 6400pF or 9x 680pF + 270pF
C40 in total   890pF or 8x 100pF + 89pF

          IMPORTANT : 
The two output wires between PCB and loop are made of one piece of 6,3mm wide and 20cm long DC cord. The length is critical !! and influences C40 and C80 values.
Determain values for C40 and C80 with the definitive length of 20cm of antenna connection DC cable !! To be able to feed  wires through the two cord grips at the top of the box, and to connect to the loop feedpoint, do split the 20cm long 6.3mm DC cord for as short as possible length. Keep wires paralleled, as this also influences the values of C40 and C80 !! 

          Determining values the of C40 and C80 : 
Easiest done using a GOOD NanoVNA V2Plus4   => Sold at  www.tindie.com the original vendor.
REM : all other named NanoVNA on NanoVNA.com are not original but 
(bad) cheap copies of old designs.

For measuring C40 and C80 with NanoVNA V2Plus4, use low inductance resistors as dummy loads :
Use for 80m a load of 0,555 Ohm or 18x 10 Ohm 0,25W resistors in parallel.

Use for 40m a  load of 5,5 Ohm or 4x 22 Ohm 0,25W resistors in parallel. 

For 10 min 100W power endurance test :
Induction free 0.6 ohm RF resistor 100W for 80m test.
Induction free 5.6 ohm RF resistor 100W for 40m test.
On cooling profile 0.6 K/W..


Wima, FairRite : Mouser.com.


Silver mica :

D1 Diode 1N4001 564843
2x Solder able brass or copper screw M5x10. (Must be inserted from, and soldered onto the bottom side of the PCB).  
4x Solder able brass or copper nut M5  
Stainless steel screws M4x30 (for fixing the PCB into the box)
Stainless steel (lock) nuts M4. 
REM : the PCB MUST be mounted at leas 15 mm above the box bottom
METAL nearer than 15mm to the Tr1 ring core can noticeable lowers its Ui value !!!
and the resonance frequencies of the transformer circuit.

2x Connector strips each  : DG950-9,5-03P  1327229
in tune box.
2x 600pF 2kV. (2x600pF in series and balanced => 4kV.)