Originally Posted by Steve347
Pros & Cons Of Combining Antennas For Directionality?
By this I am referring to identical antennas which obviously cover the same frequency ranges.
1. can pickup stations from different directions.
1. 3+dB loss per antenna due to the splitter/combiner? I am assuming using a regular splitter.
Not exactly true. When a 2-way splitter is used as a splitter, each output port is down 3 dB because the signal has been cut in half. To that, you must add the internal loss of the splitter, which is about 0.5 dB, which is why each output port is often marked 3.5 dB (loss).
When a splitter is used as a combiner, you are not dividing the signals in half you are combining, so you don't have the 3 dB loss. You do still have the internal loss of 0.5dB. However, since you have the same signals coming from each antenna in various strengths and phase relationships, they can help or hinder in ways that are impossible to predict giving gains or losses.
2. Phasing issues? I am assuming that this could be mitigated by using identical feed lines to the combiner?
Identical length feed lines are required when you have identical antennas aimed in the SAME direction for additional gain. However, when the antennas are aimed in DIFFERENT directions, the feed line lengths are irrelevant because some signals will already be out of phase. That is why you must try that method of combining to see if it will work for you, which it often doesn't.
If you don't have all the signals when combined that you had when the antennas were separate, that method of combining doesn't work for your location.
3. Pattern effects? What does this do to the individual/combined pattern? I am assuming that this may work well at or near 180 degrees (opposite directions). At what smaller angle would this become more of a detrimental issue?
Difficult to predict. According to ADTech, who works for Antennas Direct, the DB8e has the best chance of working when the panels are at right angles (90 deg apart), if not aimed in the same direction.
4. Is there or would there be an optimum vertical spacing depending on the horizontal angle between the antennas
Probably, but the only way you are going to find it is by the empirical method (trial and error).
If I had your problem, I would aim the 8200 at 115 deg for UHF and VHF. I would add a UHF antenna aimed at 286 deg for WUNC PBS and connect it to a separate tuner (converter box), with the output of the tuner connected to the aux input of the TV.