PAX ELECTRONIC DEVICES AFFECT DIRECTIONAL GYROS AND VOR NAV INDICATIONS.

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FIRST TIME: GOING FROM DEN-CLE LOST ALL DIRECTIONAL GYROS EXCEPT WHISKEY COMPASS. ADVISED ZAU. 10 MINS LATER; LOST VOR'S AND RMI'S. NOTIFIED ZAU AND DECLARED EMER. WX GOOD AT DEST (CLE). CONTINUED ON AND LANDED WITHOUT INCIDENT. DID NOT THINK TO HAVE FLT ATTENDANTS CHK CABIN FOR ELECTRONIC DEVICES. SECOND TIME: GOING FROM SAN-IAH; LOST REMAINING DIRECTIONAL GYRO (#2). #1 COMPASS COUPLER PLACARDED IN SAN NIGHT BEFORE; DID NOT LOSE VOR'S OR RMI'S AS DID FIRST TIME. DIRECTED FLT ATTENDANT TO SEARCH CABIN FOR 'RADIOS AND TELEPHONES;' FORGOT TO ASK HER FOR LAPTOP COMPUTERS; SHE RETURNED AND SAID SHE FOUND NOTHING. ADVISED ZAB LOST ALL DG'S BUT STILL HAD NAVS. WX AT IAH; LOW CEILING 800-1000 MSL WITH 2 MI VISIBILITY AND FOG. DID NOT DECLARE EMER. APCH GAVE ME TIMED TURNS. INTERCEPTED LOC FOR ILS. LANDED WITHOUT INCIDENT. THIRD TIME: GOING FROM DEN TO EWR. LOST ALL DG'S AT CRUISE ALT. TALKING TO ZAU; ODDS OF COINCIDENCES TOO GREAT. INSTRUCTED FLT ATTENDANT TO GO THROUGH CABIN AND INSTRUCT ALL PAX WITH RADIOS; LAPTOPS; ETC.; TO TURN THEM OFF. SHE RETURNED AND RPTED APPROX 25 PAX WITH RADIOS LISTENING TO FOOTBALL GAME AND ONE PAX USING LAPTOP. DID NOT RECOVER DG'S. AFTER 5 MINS; ASKED FLT ATTENDANT IF PAX STILL USING RADIOS. SHE CAME BACK AND RPTED 'YES.' I IMMEDIATELY MADE A PA FOR ALL PAX USING SUCH DEVICES TURN OFF ALL RADIOS DUE TO AFFECTING NAV EQUIP. LESS THAN 90 SECONDS PASSED; GYROS CORRECTED THEMSELVES TO PROPER HDG. 20 MINUTES MORE PASSED AND DIRECTIONAL GYROS BEGAN MOVING OFF CORRECT HDG BY AS MUCH AS 20-30 DEGS. PICKED UP MIKE AND MADE ANOTHER PA. TOLD PAX IF THEY DIDN'T TURN RADIOS OFF; I WOULD HAVE FLT ATTENDANT GO THROUGH CABIN AND CONFISCATE ALL RADIOS AND HOLD THEM UNTIL REACHING EWR; OUR DEST. LESS THAN 2 MINS PASSED AND GYROS SWING BACK TOWARD CORRECT HDG. NO FURTHER INCIDENT ENSUED. I THOUGHT I WAS THE ONLY CAPT EXPERIENCING THESE PROBS UNTIL I READ ARTICLE IN AVIATION PERIODICAL; ALSO IN LCL NEWSPAPER. I AM SUBMITTING THIS INFO IN HOPES THAT REMEDY CAN BE FOUND AS SOON AS POSSIBLE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE 3 INCIDENTS HAPPENED IN 3 DIFFERENT ACFT. HE WAS UNABLE TO EXPERIMENT TO PIN DOWN JUST WHICH ELECTRONIC DEVICES WERE CAUSING THE PROB.