I have given a few agents calls, but it seems difficult to weed out those undesirable characteristics over a phone conversation.

@Ethan Summers  that was my entire point... desperation time is 72 hours or so before they are going to lose it.... 90% of the ones I bought were 48 hours .. that's when reality sets in.sending letters within days of the initial NOD  ( notice of default is what we call them here) your just one of hundreds.. so its just slinging mud on the wall)  and with default a fraction of what they were 10 years ago... not as many fish in the barrel. 

The wifi would also have to be installed in the basement, which can only be accessed through one of the tenants units, so wifi is also undesirable. 

Seriously, grime and dust and dirt can make a place feel pretty undesirable - you don't even always notice it when it's there, but you will notice it when it's gone because the place will just look, feel, and smell nicer.- On that same note, one of the other most important things is also to make the place feel light and bright.

If the area is in a geographically undesireable area or blighted neighborhood that is slowly declining which many communities in the Country are it may not be a very good investment.

Normal life changes for family units still apply, but vacancy is less than 10% and due to waiting lists, quickly rented if new vouchers are authorized.It's the landlord's responsibility to screen tenants, you can certainly have quality tenants in Sec 8, if you preceive this group as being undesirable, it's not the socio-economic factor as much as the lack of due diligence by the owner/manager.

Which one of yall got thrown down in the mud by bobby off Lizard Lick towing?

I wouldn't do that all the time, but had already gone through 5 LOI's that morning (1 of which closed) and then promptly dropped my folder in a mud-puddle losing my remaining copies.The 92% figure helps me with perspective, thank you.

And it we are, on none rent control unit, can we just raise the rent really high so the undesired tenants would go away?

Just find the most crime ridden,  undesirable area with frigid storms in the winter and mosquitos the size of small birds in the summer and invest there.