Rabbit73, thanks so much for all the helpful information. I think I'm starting to understand a little better. Just a few additional questions.
Quote:
Originally Posted by rabbit73
When the reflector is removed, the antenna becomes bi-directional, with the major lobes of the pattern 180 degrees apart. What you lose is some gain (~3 dB) that the antenna had when it was directional.
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Let me take this logic a step further to see if I am understanding this concept correctly. When switching from a directional/multidirectional antenna to an omnidirectional antenna, you sacrifice signal strength for the ability to receive signal in all directions. In other words, the range on an omnidirectional antenna is less than on a directional/multidirectional antenna. That being said, since we've been discussing a 4-bay antenna in this thread, am I correct in saying that it is recommended that I start with that type of antenna over an omnidirectional antenna?
Quote:
Originally Posted by rabbit73
I suggest you try the antenna in the attic without removing the reflector, first aimed at 260 degrees magnetic with a pocket compass not a smart phone compass, with the VHF dipole broadside to 107 degrees magnetic to see how it does. You might need to try different locations in the attic. Then aim it for 115 degrees. You might be happy with 260 without needing to remove the reflector.
High gain antennas have a narrow beamwidth, so the aim is more critical; that's the tradeoff. Beamwidth is measured at the half-power points, 3 dB down.
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Just want to make sure I understand this correctly. A 4-bay antenna with reflector not removed is directional, but may still receive channels in both major directions shown on my map because the antenna pattern has lobes that allow it to receive signal 180 degrees from the aimed direction, just at a lower strength (see image below). Thus, if it worked, I would not need to sacrifice gain in the aimed direction. If, however, it doesn't work, I can try removing the reflector and sacrifice the gain to allow me to get a more symmetric reception pattern. Is all that more or less correct?
In regards to a VHF accessory, I will plan to try without first, and then if necessary, I can purchase one after the fact.
I have one more question. Reading about the antenna you have suggested, I don't see any mention of a pre-amp/amplification. In my case, I do plan
to split the signal in 2 and run it a significant distance (50-100 feet). My first question is if I will need active signal splitting or not. Second, am I OK trying the setup without a pre-amp/amplification or is there a pretty good chance I will need it no matter what. If I will need it, what would be the best way to determine how much amplification I need and the best option for my particular setup.
Thanks again!