Quote:
Originally Posted by rabbit73
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I was originally on AVS this past April 2015 when I was starting with my current set up. At that point in time, I was aiming for an 8 bay, and wasn't planning on a more expensive antenna till now.
I'll have to hop on there and send him a message, or create a similar thread.
Quote:
Originally Posted by rabbit73
I suggest you try just one 91XG at first for a comparison with your HDB8X. One 91XG has a narrow horizontal beamwidth, so azimuth aim is critical. For best results, the antenna must be aimed directly at the transmitter. You will not be able to "split the difference."
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I already know about how sensitive a pair of 91XGs are when stacked. That's why I plan to put up a rotor, since some signals need the antenna pointed directly at them. And to take extra time to make sure their both pointed the same direction when mounted.
Quote:
Originally Posted by rabbit73
To keep losses low, Calaveras is using halfwave coaxial baluns, and combining the two antennas in parallel, giving 37.5 ohms, which is converted to 75 ohms by a quarter wave 50 ohm matching section. Any losses before the input of the preamp directly reduce the antenna gain. Losses after the preamp are less harmful because of the Friis Cascaded Noise Figure Equation that says the preamp NF primarily determines the system noise figure.
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Are there any instructions on the internet on how to build the halfwave coaxial baluns, and how to combine the two antennas in parallel, giving 37.5 ohms, which is converted to 75 ohms by a quarter wave 50 ohm matching section?
Worst case snario, I'd buy a combiner and use that (with equal lengths of RG6 of course).
(I won't be doing this before April, just want to do my research now).