VFR aircraft receiving TA's at 7500 ft has mode C altitude jump back and forth between 7500 and 8500...

Attributes
ACN	230098
Time
Date	199301
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : srq
State Reference	FL
Altitude	msl bound lower : 7500 msl bound upper : 8500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : tpa
Operator	general aviation : personal
Make Model Name	Small Aircraft
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	VFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 4 controller radar : 11
ASRS Report	230098
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other
Situations
Navigational Aid	Unspecified

Narrative:

Aircraft was tracking southeast to northwest 8 mi northeast of srq VOR level at 7500 ft. ARTS data block kept going to 8500 ft. ARTS went back and forth between 7500 and 8500 for about 15 mi of aircraft's flight.

Original NASA ASRS Text

Title: VFR ACFT RECEIVING TA'S AT 7500 FT HAS MODE C ALT JUMP BACK AND FORTH BTWN 7500 AND 8500 FT.

Narrative: ACFT WAS TRACKING SE TO NW 8 MI NE OF SRQ VOR LEVEL AT 7500 FT. ARTS DATA BLOCK KEPT GOING TO 8500 FT. ARTS WENT BACK AND FORTH BTWN 7500 AND 8500 FOR ABOUT 15 MI OF ACFT'S FLT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

VFR aircraft receiving TA's at 7500 ft has mode C altitude jump back and forth between 7500 and 8500 ft.