Hello Foster006. I just moved from Joplin back east.
The local Radioshack manager told me that the digital scanner would be mail order only for Joplin. (He said that Joplin would not go digital.) The city technician told me back in 2003 that the city would upgrade to APCO 25 standards, but he didn't mention whether it would be digital or encrypted.)
For antennas and some electronic parts, some of us hams in Joplin have gone to B&B (4th & Grand) and bought some Radio Shack parts. This is strictly a closout store, but they did have some antennas, including a UHF beam (TV antenna). That might be helpful for you.
Local hams in Joplin like to purchase supplies from WB0W, Associated Radio, D&L Antenna, and/or Memphis Amateur Electronics. Each has a webpage and offers competitive pricing. (I know each of these people, as they regularly attend the Joplin Hamfest each year.)
If you need some specific electronic parts (e.g., EPROMs, antenna connectors, resistors, etc.), I can recommend a local engineering shop who often sells hams. Send a private message if you're interested. You might want to check out the Joplin Amateur Radio Club and come to one of their meetings. (I'm the newsletter editor.)
Hope this information helps. j c