In alt.tv.tech.hdtv Bert Hyman wrote:
| (szilagyic) wrote in
| ups.com:
|
| I think I understand what the front-to-back ratio is, but the specs
| on my Winegard PR-8800 (8 bay bowtie) show negative front-to-back
| ratios (-9 dB @ ch 14; -17 dB @ ch 32; -11 dB @ ch 50; -9 dB @ ch
| 69). The "dB over reference dipole" is: 10.7 dB @ ch 14; 12 dB @
| ch 32; 11 dB @ ch 50; 12.5 dB @ ch 69. How can the front-to-back
| ratio be negative, and is this good or bad? I am assuming this
| could be bad in my case as I would like the signal at the back of
| the antenna to be minimal.
|
| Showing the F/B ratio as negative is non-standard, but I -guess
| they're just trying to emphasize that the signal received off the
| back of the antenna is less than that received from the direction
| it's pointing.

Looks like negative DB is used for any direction to indicate how much less
the signal will be relative to the main lobe. Whether side or back or any
other direction, the circles are labeled with negative DB, more negative
as you move to the inner circles.

See: http://www.hdtvprimer.com/ANTENNAS/cm4228.html

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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / |
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