The CLEO Relay facility is the absolute last item you unlock in Daybreak.
At first, you will get items for completing waves 3, 5 and 7. However, as you advance, you will stop receiving items for waves 3 and 5. I believe the last ten items must be completed in wave 7. Also note that you have to complete waves 3-7 to get credit for wave 7 -- just joining a game at the last minute will not get you credit for wave 7.
Once unlocked, you'll have to summon the Red Talon Trader via radio in your State of Decay base game and purchase this using your Daybreak Prestige. It will costs you 4000 prestige, but since you got this far in Daybreak that shouldn't be an issue. You'll also need a large outdoor slot to set this up on. ONce set up, achievement unlocked.
What this facility does is summon a CLEO drop for you (along with a zombie hoard to defend it) in your regular game for 500 prestige. The value of the items in this CLEO drop are worth @1000 prestige, so if you buy a lot of CLEO guns & ammo, it might be worth it to have this facility around. If not, scrap it right away.
NOTE: If this is the last item you unlock in Daybreak, then why is the TA Ratio so low? This is because when Daybreak was first released the achievement was bugged in a good way, and awarded to anyone who built any facility in their base if they had Daybreak installed. This has since been patched out, and now you have to slog though the entirety of Daybreak to unlock this.