Re. FM Antennas: You might want to take a look at my fol. post which summarized the better AM and FM Antennas for Indoor and Outdoor use:
https://www.digitalhome.ca/forum/26-...ml#post2922681
For Outdoors and in Attic I recommend the fol. inexpensive TRUE OMNI Antenna from Stellar Labs 30-2430 which does NOT have Nulls like a typical Bi-Directional "FM Turnstile":
https://www.amazon.com/Stellar-Labs-...lhomconvert-20
My analysis of several "similar" Double-Hoop Antennas revealed that they are not quite Omni (duh...hoops are not complete Circles) with a Gain = -2.1 to +1.3 dBi, and fairly high SWR:
https://imageevent.com/holl_ands/omni/doublehoop
A TRUE OMNI alternative is the Vertical Dipole...however, it is only sensitive to Vertically Polarized Signals, which not all FM Stations are Transmitting, so I can't recommend it for general use [more suited for Low-Power FM Transmitters]:
https://www.amazon.com/Antenna-Outdo.../dp/B000F477AC [Commercial Vertical Stick Dipole]
https://imageevent.com/holl_ands/omni/verticaldipole [DIY Vertical Folded Dipole, Gain = 1.7 to 2.6 dBi]
And I've Analyzed an entire Zoo worth of other FM OMNI Antennas:
https://imageevent.com/holl_ands/omni
The BEST of which is the DIY FM Swept SGBH [but 16.2-ft Tall] with Gain = 4.5 to 7.5 dBi and low SWR:
https://imageevent.com/holl_ands/omn...tsweptsbghomni
IF you decide you want an Outdoor Directional FM Antenna (mounted on top of a ROTATOR), I also recommend using a Manual A/B Switch to select the TRUE OMNI for everyday listening (making it easy to change stations)....or to select the Directional FM Antenna and play around with the Rotator Controls.
Available Outdoor Directional FM Antennas are NOT very plentiful, which include the following:
https://www.amazon.com/dp/B01DWE9I9O [3-Element from Britta Products]
https://www.amazon.com/Element-Direc.../dp/B00HMXX9YW [4-Element from Stellar Labs, less expensive than Britta]
And numerous LARGE All-Band (Ch2-69) Antennas that also have some Gain in the FM Band....which need a HEAVY DUTY, i.e. Ham Quality ROTATOR.
I do NOT advise trying to SHARE the Coax Downlead with your TV Antenna....run a separate Coax. This avoids the extra LOSS (and NOT inexpensive COST) of a TV/FM Antenna Diplexer (i.e. Combiner) and Diplexer(s) to feed each drop. And even more importantly, it avoids sending the FM Signals THRU Mast-Mounted Amps and/or DistroAmps and/or Lossy RF Splitters.
Although it MIGHT improve FM Sensitivity by a couple dB, I also advise NOT passing FM Signals through either a Mast-Mounted Preamp or a DistroAmp. FM Tuners typically come with MULTIPLE RF Tuned Stages in order to suppress ALL Input RF Signals except those within the desired Channel Bandwidth (plus 1 or 2 Channel Bandwidths on either side) which "should" be less than 1 MHz Wide. The subsequent Multiple IF Filters (modern ones are Ceramic vice Wound Coil Type) provide even narrower Bandwidth to suppress Next Adjacent Channels...and perhaps also Adjacent Channel Interference. And fortuitously, the desired RF Signal only needs to be about 1 dB (more or less) Stronger than On-Channel Interference [i.e. "Capture Ratio" spec]. [BTW: Single Stage RF Tuned Stage in older TV Tuners only had about a 10-30 MHz Bandwidth (-3 dB) Filtering capability (more on higher channels)....and was eliminated in most later "Silicon" Tuners....cuz there was no way to fit it onto the Single Chip Implementation for the entire TV Processing Chain.]
When you send the entire UNIVERSE of RF Signals through a Wideband Amplifier [incl. Harmonics of signals at 1/2, 1/3, 1/4 etc of FM Band], Intermod ("Mixing") Products are generated throughout the FM Band....which can NOT be suppressed by the excellent Multi-Gang Tuners found in nearly all FM Tuners....cuz the DAMAGE has already been done....and CAN NOT be undone.
FYI: In an FM Tuner, there is a "Multi-Gang" bank of Variable Capacitors (Varactors in more modern Tuners, manual in old), where one of the "Gangs" is needed to tune the (typ. 10.7 MHz Higher Frequency) Oscillator. Hence my "most excellent" 1971 Kenwood KT7001 4-Gang Tuner had THREE Tuned RF Stages, each of which was progressively filtering out Frequencies other than the desired station:
http://www.fmtunerinfo.com