Highly recommend this antenna if you need help picking one out. I love it
ViewTV Outdoor Amplified Antenna - 150 Miles Range - 360° Rotation - Wireless Remote https://www.amazon.com/dp/B017JEF126?ref=yo_pop_ma_swf
I just bought this antenna from Amazon. Pretty cheap, but it works really well. We live about 75 miles west of charlotte and are able to pick up the NBC and CBS broadcasts from charlotte. Don't forget to get the suggested mount for it also.
ViewTV Outdoor Amplified Antenna - 150 Miles Range - 360° Rotation - Wireless Remote https://www.amazon.com/dp/B017JEF126/ref=cm_sw_r_cp_apip_kwe7yRfnc3UAo
1) The sort of companies/individuals that do TV antenna installations might not have a very good web presence. Try the Yelllow Pages. Try Craigslist. Try calling some of the local satellite TV installers to see if they can do it or know someone who can.
2) Amplified antennas and separate preamps are powered through the cable. You just have to find a place to put the power injector before the splitters. Otherwise you have to get special power passing splitters.
3) "They're in completely opposite directions." That's actually a good thing. Most antennas will receive a coherent signal off the back. The general strategy is to aim the antenna at the weakest signal and then get the stronger ones from behind. In your case you would aim the antenna at the Univision transmitter.
4) If you mean the proverbial "150 mile antenna" then assume crappy. Example:
If you get an actual TV installer (as opposed to a general handy person) then you are mostly paying for their expertise. You would want to provide them with a list of required channels and perhaps a list of less required but interesting channels. You should also tell them how many times you want the signal split. Then they are entirely responsible for deciding how to do that.
Here are some examples of band appropriate (UHF, VHF-high) antennas for the reception off the back suggestion:
Here are some semi-random preamp suggestions:
Ref: