KARC Field Day Tuner Project

For the 2010 Field Day, KARC decided to add 10 and 15 meter antennas to the half-wave verticals we had for 20 and 40 meters. The FD site layout was designed to have antennas for CW and Phone operation on the same band. The antennas were separated so simutaneous operation on the same band was possible, with no interferece bewtween CW and Phone stations. FD 2010 plans call for two sets of antennas for 10, 15, 20 and 40 - a total of 8 antennas. Members had enough high impedance tuners to support four antennas, but we needed a total of eight. Thus was born the 2010 FD Tuner project.

Martin, KH6MB, agreed to handle procurement and asembly of the tuners. A BOM was generated, procurement started and completed by mid-April and assmembly is in process. Below is a collection of information about the onging project. We'll report on status and results right thru Field Day. (To display a section of interest, click on the + sign to display the information.)

    Circuit Diagram

    Assembly Photo

The rotor shaft of the capacitor should attach to the 50 Ohm side. This keeps the high voltage away from your hand while tuning. Keep about 2 inches spacing between the inductor and the capacitor. The red wire and the brown wire from the inductor to the ground connection on the coax connector are #12 or #10 gage wire. This is where all the current is. The blue wire is #16 gaga. One goes to the antenna the other to the ground mat. These are low current lines. Note the orientation of the inductor; wider spacing wire turns towards back of unit.

    Bill Of Materials

P/NDescriptionQtyCost per KitVendorContactManufacturerNotes
NBA-10142Box, Enclosure1$47.43$1.90Newark1.800.463.9275Bud IndustriesCost for qty 4+
RI-20Inductor 0.1 - 20.0 µH1$75.00 $11.00Palstarpaul@palstar.comPalstarQuote via email
C440Capacitor 5.5 - 83 pF1$45.00 Palstarpaul@palstar.comPalstarQuote via email
Acrylic sheetsPlastic base plate 6″ × 10″ × 3/16″1$7.70 - Min Plastic & Supply1-808-847-1511Min Plastic & Supply 
Plastic RodInsulating Rod ¼″ diameter × 2″2$0.68  
(KNB) 27 Dial, ¼″ diameter bore1$5.00$0.78 Surplus Sales1-402-346-4750Surplus Sales 
(KNB) 44 Dial, ¼″ diameter bore1$5.25$0.78 Surplus Sales1-402-346-4750Surplus Sales 
ARF1005-NDSO-239/U UHF Female Connector1$5.38$0.98Digikey1-800-344-4539AmphenolCost for qty 10+
Lead Free
H724-NDNuts 4-404$0.54B&F Fastener SupplyStainless Steel
Lead Free
H735-NDSplit Lock Washers 6-324$0.41
H725-HDNuts 6-326$0.76
H782-NDPan head Screws 4-40 × 3/8″4$0.59Lead free
H713-NDPan head Screws 6-32 × 3/4″10$0.71
H730-NDSplit Lock Washers 6-3210$0.26
 Wing Nut 6-322$0.55$0.86Local Hardware Store  Stainless Steel
 Solder Spade Lugs 6$0.67  $6.00 Package
 Hook up WireAR$0.34  $3.00 roll
Total Costs (qty extended) >> $196.27$16.30 Total is $212.57 vs. budget of $225.00 ea.

    Project Accounting

KARC ClubClub Treasurer$900.00Check #41303/13/2010$900.00 
KH6MDAl Mariani$225.00Cash03/13/2010$1125,00 
KH6QJKen Taylor$450.00Check 56303/13/2010$1575.00 
AH6TWBill Ridgeway
AH6PTAl Kaopuiki$225.00Check 443203/13/2010$1800.00 
KH6MBMartin Barr($100.00)Cash03/13/2010$1700.00Cash to Martin to purchase hardware
N4EO Jerry Brown$225.00Check 618903/16/2010$1925.00 
AH6S Tiff Lawyer$60.006189 03/15/2010$1985.00Only Palstar tuning capacitor 5.5 - 83 pf
Surplus Sales($31.00)Visa Charge 03/18/2010$1954.00Shipped 03/18/2010
Newark($443.97)Visa Charge 03/18/2010$1454.06Shipped 03/19/2010
MinPlastics($75.42)Visa Charge 03/19/2010$1378.81Purchased 03/19/2010
Surplus Sales($75.25)Visa Charge 03/25/2010$1378.81Shipped 03/25/2010
Palstar($1223.98)Visa Charge 04/01/2010$1378.81Shipped 03/25/2010
Balance > 135.37 Martin has not been reimbursed for parts that exceeded his $100 advannce.

Parts for all nine kits, including assembly hardware, have been inspected and stored together in their boxes at KH6MB's QTH. The purchase of a drill bit for the assembly processing is pending. Final accounting will be presented at the May 2010 club meeting.

Unused funds we be will returned to the KARC Treasury.