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Originally Posted by brado
I've tried the rabbit ears horizonal at 40 - 45 in, and also tried them at 78 - 84 in. Why the difference of opinion?
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The difference is in the orientation of the elements. Rabbit ears achieve their best gain when the elements are exactly opposite each other (an ideal dipole). When the elements are tilted up into a "V" configuration, the maximum achievable gain is less. Since the effective electrical resonances also change when you do this, the individual elements must be lengthened in order to get the peak resonance to occur at your desired channels. Even when tuned this way, the "V" configuration will not get as much gain as the horizontal configuration.
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Are the gain claims btwn winegard and antennacraft apples to apples? I noticed that the the winegard has a little better gain but is a little smaller.
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Yes, I believe they are using the same scale. There are commonly two ways to count antenna gain. One is to use dBd (decibels relative to an ideal dipole), and the other is to use dBi (decibels relative to an ideal isotropic antenna). I believe that both Winegard and Antennacraft data sheets specify dBd as their units.
For future reference, if you ever need to compare dBd gains to dBi gains, then you can take the dBi number and subtract 2.15 from it to get the equivalent dBd number.
Most antenna makers choose to use dBd as their reference. dBd specs tell you how the antenna compares to a properly sized dipole antenna (cut to the optimum length for the frequency in question). Positive numbers indicate more gain than a dipole antenna, and negative numbers indicate less gain.
Isotropic antennas are hypothetical antennas that are completely omnidirectional in every possible direction (front, back, left, right, up, down, etc.). These hypothetical antennas don't really exist, and are mostly used as a point of mathematical comparison when using antenna modeling software to compute the gain of an antenna.
The difference in gain between a dipole antenna and an isotropic one is 2.15 dB. Some antenna manufacturers might publish dBi numbers because they come out 2.15 dB higher than the equivalent dBd numbers. Maybe they do this because their gain figures are derived from computer models as opposed to using calibrated measurements in a lab against a reference dipole antenna. Maybe they do this to publish higher gain numbers to fool consumers that don't know the difference between dBi and dBd specs. Whenever in doubt, check if the gain spec is against an isotropic or dipole antenna.
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To get from my attic to TV it's about 32 ft. Should I just buy a premade 50 ft cable, or a 32 ft w/ twist on connectors? In other words, which is worse, the extra 18 ft, or the twist on connectors?
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RG6 cable loses about 5 dB of signal for every 100 feet of cable. The 18 foot difference you're talking about is less than 1 dB of signal, so I'd say the difference is not enough to sweat over.
Making your own cables is nice, but it does add a little bit of hassle. The quality of connection will depend on your ability to make a clean connection of the connector to the outer conductor of the coax. If you do not have much experience with this, then I'd recommend saving yourself the trouble and just get a pre-made cable.
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With an attic attenna, do I need to run grounding wire?
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No you do not.