This article demonstrates use of a GR1606B RF impedance bridge for measurement of the feed point impedance of a MHz loaded mobile whip. The antenna is roof mounted on a vehicle and measurements are made looking into 4m of RG58C/U, then transformed to feed point impedance using three tools:
- RF Transmission Line Loss Calculator (TLLC);
- a Smith chart; and
- Calculate VSWR and Return Loss from Zload (or Yload) and Zo.
Key metrics are:
- F=7.05MHz
- R=35Ω
- ReactanceDial offset=200
- ReactanceDial=442
- X=(442-299)/7.05=34.33Ω
- Z=35+j34.33Ω;
- Feed line is 4m of Belden 8262 (RG58C/U).
Continue reading Demonstration of the GR1606B for antenna Z measurement and calcs