Loop Antenna For 3.5 Mhz

  
C1 = 3 750 pF 500 V silver-mica capacitor. C2= 100 pF preset capacitor (Jackson C803). C3 = 75 pF variable capacit
Loop Antenna For 3.5 Mhz - schematic

or (Jackson C809), plus knob. C4 = 12.7 pF variable capacitor (Jackson C16), plus knob. C5 = 22 nF mica capacitor. = 250 f.s.d. 40 40 mm moving coil meter (Maplin LB808). D = HF silicon diode. R = 1 kft resistor (see text). L1 = 51/e turns of PVC covered stranded 7/0.2 mm wire. Outside diameter: 1.2 mm, 1 kV/1.5 A rating (see text). L2 = 13 turns 16SWG tinned wire, 1 inch internal diameter. Feedline = 46 inch RG58 coaxial cable, plus plug to suit transmitter. Box = ABS box type MB3,118 96 45 mm. Maplin ref. LH22. Terminal blocks = qty. 4 12-way 2 amp terminal block. Maplin ref. FE78. Spacers = qty. 3 insulated spacer type M3, 30 mm long, Maplin ref. FS40T. Spokes = qty. 4 8-foot lengths of 5/ 1/ inch molded hardwood (DIY store). Vertical support = 23 0.8 0.8 inch wood (DIY store). Wood base = 12x8x0.5 inch plywood or similar 21/2 inch steel support bracket. elektor electronics usaFig. 4-1 (b) 1.4 lengths molded hardwood 30" x^/ax 1/4". Varnished. 2BA holes drilled in the centre. Glued and bolted together. 2.8 off 6-way 2-amp polythene terminal blocks used as insulated wire spacers. 3.5Ve turns of PVC stranded wire (for specs see components list). 4.See Fig. 3. 5.Wood vertical support 23" 0.8" 0.8", wood stained. 6.2" x2BA bolt. 7.Box front vertical support, 4V2" x1/2" 3/4", wood stained. 8.Wood base 12" 8" xW (for similar), wood stained. 9.21/2 steel support bracket behind wood vertical support. 10. Drilled and secured with glue and c/s wood screws. Note: "= inch =2.54 cm. Suitable for receiving or transmitting (10 W or less) on the 80-m band, this loop antenna might be helpful when an outside antenna is not possible.




Leave Comment

characters left:

New Circuits

.