C550 POS AND HOLD ON RWY LOST COM WITH TWR BECAUSE OF BLIND SPOT.

Narrative

I WAS WORKING LCL CTL FOR RWYS 26R AND 26L AT HARTSFIELD INTL ARPT. GND CTL HAD TAXIED OUT A CITATION C550 TO RWY 26R FOR DEP. RWY 26R IS NORMALLY AN ARR RWY BUT WHEN TFC HAS SLOWED; WE ROUTINELY TAXI GA AND AIR CARGO ACFT TO IT BECAUSE ITS PROX TO AIR CARGO AND GA PARKING. THIS SAVED THE HASSLE OF TRYING TO CROSS 2 ACTIVE RWYS TO TAKE THEM TO RWY 26L; THE NORMAL DEP RWY. IT WAS TOWARD THE END OF THE ARR RUSH AND I STILL HAD A FEW ACFT ON FINAL FOR RWY 26R. I INSTRUCTED A B737 TO SIDESTEP TO RWY 26L TO LAND SO I COULD DEPART THE C550 OFF RWY 26R. AS SOON AS THE PREVIOUS ARR HAD PASSED; I TOLD THE C550 TO TAXI INTO POS AND HOLD ON RWY 26R. AS SOON AS THE ARR CLRED THE RWY; I ISSUED TKOF CLRNC TO THE C550. THERE WAS NO ACKNOWLEDGEMENT AND HE (THE C550) CONTINUED TO SIT THERE. WE HAVE HAD A PROB WITH A 'BLIND SPOT' ON THE LCL CTL FREQ AT THE APCH END OF RWY 26R. I TRIED THE CITATION A COUPLE MORE TIMES TO NO AVAIL. I HAD TO GO TO THE BACK OF THE TWR TO AN EMER XMITTER TO COM WITH THE C550. I FINALLY RE-ACHIEVED COM AND CLRED THE C550 FOR TKOF. WHEN HE FINALLY ROLLED; AN MD-80 WAS BEARING DOWN ON HIM ABOUT 2 MI OUT. FAA MAINT HAS KNOWN ABOUT THIS FOR QUITE SOME TIME. MOVING THE ANTENNAE WAS TRIED BUT FAILED TO ALLEVIATE THE PROB. IT CONTINUES TO HAPPEN. THIS IS AN UNSAFE SIT. ATC LCL NATCA HAS FILED AN UNSATISFACTORY CONDITION RPT AND OTHER NASA RPTS TO TRY TO GET SOMETHING DONE.