432 Feed  -  Antenna Range Measurements                Sept. 29, 2001

(Evaluation of the K4QI feed as constructed by KL6M)

(Actual K4QI Design is available here:  http://www.alaska.net/~ptt/Feeds/k4qifeed.pdf     )

Range setup:

80 feet separation between RX and TX

TX - 5 element yagi  0.6 dB cable loss (RG-214), 0 dBM input

RX - UUT and 1.3 dB cable loss (RG-58)

Absolute measurements:

-39 dBm Horizontal  = 0 Reference

-42 dBm Vertical  = 0 Reference

-28 dBm X-pol (H to V)

                                                            HORIZONTAL RANGE MEASUREMENTS

horiz.gif (10141 bytes)


                                                            VERTICAL RANGE MEASUREMENTS


vert.gif (10430 bytes)



A 0.45 f/D dish requires a feed radiation pattern which has a beam width of about 118 degrees at the 10 dB points.  The K4QI dual dipole feed produces a beamwidth of very close to this target.  It is slightly skewed, probably due to mechanical anomolies, but in general the design does a good job of illuminating the dish.