Microwave path engineering 1

[MacCloed]

I have encountered a consultants design that uses different diameter antenna on a single path with one end having a 6 foot antenna and the other having an 8 foot antenna. I have been doing this for 10 years and have never come across this before, usually, both antennas are the same size for each path. Can anyone out there let me know why/what the application for this mismatchmight be??? From the highlands, MacCloed

 

[tmcdonal]

Actually the use of different diameter antennae is not unusual and is usually driven by antenna heights requiring longer waveguide runs, thus greater fixed losses at one end.

 

It's only a one foot delta for the waveguide lengths between the 6 vs. 8 foot (diameter!) dishes.

Perhaps a better (possible) explanation is that the consultant carefully calculated that the link required roughly 7 foot dishes at each end. He then checked his dish catalogue and found that such dishes are available only in 6 or 8 foot diameters, but not in 7 foot diameters. For a few seconds he frowned, then his face brightened. Smiling at his own cleverness, he assigned the smaller 6 foot dish up in the windy highlands and the larger 8 foot in the calm lowlands next to the pub.

MacJ. MacHarvey
MacVE1BLL
MacOttawa

 

[jbartos]

Theoretically, the larger diameter antenna reflects or receives the marginally higher microVolts, power, "stronger signal," etc., influences the sensitivity of reception, etc.
Imagine an exaggeration: a 1" diameter antenna versus 96" diameter antenna.