[ADTech]

Most likely, you have the RCA ANT3036 which should be appropriate to your area.

WOI is listed in the chart twice because they operate two transmitters in the Des Moines market. They operate their so-called "full power" signal on VHF 5. Because of problems they discovered post-transition with indoors reception and low-VHF, WOI applied for and received permission to operate a low-power fill-in translator in downtown Des Moines so their signal could be better received in the urban portion of the city with indoor antennas.

Many sets and converter boxes have, as part of the signal meter or diagnostic screen, information about the RF frequency or channel that is being received. Check yours for WOI's signal. RF 5 will be in the 80 MHz range while channel 50 will be up around 690 MHz. Each of these signals would be received by different sections of your all-channel antenna. RF 5 would be received by longer elements in the back of the antenna while RF 50 will be received by the narrower Yagi front end of the antenna.

Reception of channel 5 would be most likely affected by interference from electrical devices or from having the antenna too close to metal objects such as guttering, soffit, fascia, drip edge, metal plumbing pipes, electrical wiring, and other such objects that are either too close to the antenna or are causing an adverse reflection of the signal resulting in multi-path distortion of the signal.

Problems with reception of the UHF signals are usually due due to either trees or other objects in or near the line of sight or from the metal-related items above.

Your best bet would be two-fold:

1) Look at your line of sight towards the broadcast towers and observe whether there are obstructions that might be avoided by mounting the antenna elsewhere.

2) Move the antenna to that point ensuring you get some elevation (5' min) above the roof line. Don't drill any holes until you've tested reception in a given location.

Keep in mind that the most convenient or available location for an antenna sometimes doesn't necessarily correspond to the required signal strength and quality at any given spot. There's a very good reason that the old-time antenna professionals developed the skill called "walking the roof" with a test antenna and a signal meter.