Antenna questions

Sean, thanks, that is the exact Radio Shack model I was considering. It turns out the gain of this antenna isn't listed anywhere. The other Radio Shack models all seem to have some extra elements for picking up UHF, which doesn't help with FM, so I am inclined to stick with this barebones model.

I will probably do as you suggest and just try it.

Any thoughts on Wineguard and ChannelMaster antennas? I believe I can buy them with option to return.

Sean, you nailed this one down nicely!
Yes, I'd try the RS $22 one. You can fairly easily estimate relative gain by counting element count and geometry. If the others have significantly more elements than they'll probably have more gain.....
On a similar tack I just decided to relive my preteen years as a Ham by buying a 1957 Hallicrafters SX-100 receiver, and found on the net a couple of guys who sell "universal dipoles" using two long slinkies and a T connection and downlead! Amazing stuff. You simply string it up in your attic, and pull the slinky ends out to match wavemength. It'll go to 130 feet (gulp!), but works nicely at 15-16 feet for the SW bands normally used. For FM youd only need a few feet...hence normal dipoles. The point here is to confirm Sean's: height IS might. Even a lowly dipole, if set high enough, will offer great FM reception. Adding a few more elements (as in the $22 RS unit) simply makes it better. Don't worry too much about needing to spend more. DO use a good low-loss twin-lead instead of coax for a down-lead, though. I was surprised to hear from all the Hams that good foam twin-lead easily outperforms coax. Hmmm....
Have fun on the roof...I settled for the attic, as a couple of slinkies blowing in the wind could get a SWAT-team over to my house, I fear.

Twin lead is lower loss than coax so long as humidity remains low and it is not mounted up against or near metalic objects. Otherwise, the impedance is altered and the loss goes way up at that point. Having said that, foamed twin-lead is more stable and lower loss than the regular "el-cheapo" twin lead that uses only plastic as a dielectric. It is also slightly more expensive.

Bare in mind that what lowers the performance of coax so drastically is the use of impedance matching baluns or "transformers". These are the devices that allow one to use 75 ohm coax and adapt it to a "split terminal" ( 300 ohm ) connection. If you use one of these at the antenna and also need one for use at the tuner ( a lot of old tuners used screw or lug terminals with no provision for coax ), you are losing quite a bit of signal.

As to Ernie's comments about element count, that is "basically" true. One can change the spacing, diameter and length of said elements and alter not only the foward gain, but the front to back ratio and the bandwidth. Bandwidth is the amount of frequency coverage that one obtains with good gain & the proper impedance. That is why a TV / FM antenna can have a "million" elements yet not have that much gain i.e. it was designed for wider bandwidth ( low "Q" ) to cover the phenomenally wide TV broadcast spectrum than it was for higher gain in a more narrow ( like the FM band ) frequency range.

Gain, front to back ratio and bandwidth are all factors that APS has played with and why you pay so much for their products i.e. they are highly specialized designs. As such, it takes technology, "know-how" and R & D ( Research & Development ) to get things dialed in for optimum performance. Since time and knowledge typically equal money, they want to be compensated for their efforts : ) Sean
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that $22 RadioShaft antenna is working pretty well for me in my attic @60 miles out. It's probably only ~25' off the ground. I have one balun up top to convert the 300 ohm to 75 ohm RG-6 coax which the tuner accepts dirctly. I'm too afraid to mount it, or any antenna, outdoors anymore. Two really unfortunate lightning strikes have taught me how to compromise.

SEan, thanks for the refresher on Q. The Hallicrafters has SIX selectable bandwiths (0.5kHz for code up to ultra-wide for "phono"...HA!), and an amazing selectable Q-adjustable "notch" filter to move in to squash a strong adjacent broadcast. Results in amazing bimodal bandwidth curves! Didn't know they could do that in the 50s...and with tubes....
So the APS must be a lot of similar-length elements all stacked in a plane, as 88-108 megs is only a 20% change in frequency. Interesting. But isn't the Rat Shack also a tight-Q for FM (but with less gain, of course)? Gotrta get back to Radio Rwanda with its 10dB S/N ratio! Talk about low fi....