Icom Pcr1000/1500 aerial modified for balcony mounting

created: Sep. 2019

Fig.1 Icom PCR1000/1500 receivers are supplied with a telescopic aerial that is apparently intended for mounting on a windscreen pillar. The plastic housing at the aerial base has a double-sided foam tape for sticking to the pillar.

The telescopic aerial consists of 6 sections. The lowest section is almost fully contained in a black plastic housing (fig. 2). When fully extended, the telescopic aerial measures 65 cm - including the part hidden by the plastic housing. Based on this length, the resonant frequency is estimated at 113 MHz. However, it should be possible to shift the resonant frequency upward by retracting some telescopic sections. When fully collapsed, the aerial's physical length is 15 cm.

Removing the housing cover reveals that the coax's earth is not connected (fig. 3). Subsequently a bare single-core wire (0.5mm diameter) is inserted into the coax braid to create an connection for the counterpoise. The wire is then brought out through the same hole as the coax. Finally, the cover is reattached to the housing.

Fig. 3 After removing the housing cover, the connection of the coax to the aerial base can be seen. However, the coax shield is unconnected

Fig. 4 A stainless steel clothes peg forms the basis of the balcony mounting

To construct the balcony mount, the aerial is affixed to the clothes peg with two cable ties. The other end of the earth wire is soldered to a small copper sheet (4 x 4 cm). The copper sheet is then placed inside the clothes peg's jaw.

Fig. 5 The aerial attached to the clothe peg while the retrofitted earth wire is soldered to a small copper sheet

Fig. 6 Completed aerial is clipped onto the balcony's handrail. Through the retrofitted earth wire & copper sheet, the handrail serves as counterpoise

Fig. 7 Another view of the aerial clipped on to the balcony handrail

Fig. 8 With the retrofitted earth (grey trace), the aerial achieved lower SWR at resonance (~ 115 MHz). When the original aerial without earth connection is clipped on to the handrail, its SWR is poorer (black)

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