Channels 7 and 10 are transmitted via VHF. I'm in Fort Lauderdale using various tuners and antennas (indoor and outdoor). Both these stations are unquestionably the weakest and erratic of all the Miami stations. Even with an outdoor antenna I get only 50-60% signal strength for these stations. With indoor antennas my ability to receive these stations vary widely depending on weather and time of day. For me when the weather is bad I tend to pick up more stations, specifically the outliers in West Palm Beach.
Can you verify your antenna is VHF capable? You might want to buy cheap rabbit ears from Radio Shack and see if you can pull in these stations. I am willing to guess the problem is with your antenna, not your tuner. But since you also say you are getting phantom stations maybe something funky is going on with your tuner. You might want to consider getting a CECB, especially the Zenith one (available at Kmart). It's a nifty box for fine-tuning signal reception.
Finally, check out www.tvfool.com
. Put you address in there and look at the results. It will tell you what stations you should be getting. Since you say you are getting channels 8 and 9 I think something might be amiss with your tuner. These channel numbers are the *real* channel numbers for (virtual) channels 7 and 10 (, respectively) ... as you can see from the tvfool.com results. Sometimes when broadcasters are fiddling around with the digital broadcasts customer lose the virtual channel number and find that it has "moved" to the real channel number, and visa-versa. Channel 44.1 moved to channel 9.1 without warning. Channel 5-1 (NBC in West Palm Beach) seems to channel 55-3 nowadays. At any rate, after June 12 one hopes all this will settle down.
Good luck. Sorry I can't be much help.