We now offer a VHF Retrofit kit that will clip right on a C2 or C4 antenna and will give it modest VHF performance (~ unity gain) on VHF channels 7-13. With noise margins on your high VHF stations in the low 30s, it will like do well on those stations, based on the TVFool plot.
However, the problem in Des Moines is WOI, one of about three dozen stations in the country that elected to remain on a low VHF allocation post-transition. Effective and efficient reception of a channel 5 signal usually requires antenna elements that are two to three times the length of the VHF Kit's elements. However, there are two things that make allow the C4 with VHF kit to do the job: 1) WOI transmits at about 14 kW from an 1800+ tower which, over the flat landscape in the area, gives them a coverage area of 70 -80 miles, and 2) WOI also operates a UHF translator from downtown whose signal might be receivable by a C4 in your location. The extra power on the VHF 5 channel is likely strong enough for the VHF-1's 35" dipole to pick up anyway, so you've got two opportunities to pick up WOI with a compact antenna, should you choose to go that route instead of the much larger all channel antenna suggested above.
Tech support for Antennas Direct
Last edited by ADTech; 08-20-2014 at 08:18 AM.