Air carrier first officer voiced concern regarding sfo tower frequency 120.5; claiming the transmiss...

Narrative:

It seems each time we are to contact sfo tower; the transmission quality is very poor coming from the tower frequency (120.5). The transmission that is received in the aircraft is very 'fuzzy' or soft and difficult to hear and process. It does not matter which controller is on the frequency; but the problem seems to be amplified with lower frequency voices. When the transmission begins; it is almost inaudible then gradually progresses in amplitude but is still 'fuzzy;' for lack of a better term. I have asked many pilots that I have flown with and almost all agree we have problems understanding controllers on that frequency. I don't know if a different mic is used or the transmitter is poor; but the quality has to be fixed. Additionally; this problem seems to be getting worse as controllers attempt to contact us on landing roll with the thrust reverser's in full reverse and instructions are given. It is at this time that the pilots have the highest decibel level of noise in the cockpit with the thrust reverser's in full reverse and if the controllers are trying to talk to us at the same time this poor audio quality is present; the problems are compounded. Additionally; this is a very high workload environment for the pilots (landing roll with full reverse) and answering instructions; particularly if not understood has to be secondary.

Original NASA ASRS Text

Title: Air carrier First Officer voiced concern regarding SFO Tower frequency 120.5; claiming the transmission quality is 'fuzzy' making Tower communications challenging especially during high noise 'reverser operation' periods.

Narrative: It seems each time we are to contact SFO Tower; the transmission quality is very poor coming from the Tower frequency (120.5). The transmission that is received in the aircraft is very 'fuzzy' or soft and difficult to hear and process. It does not matter which Controller is on the frequency; but the problem seems to be amplified with lower frequency voices. When the transmission begins; it is almost inaudible then gradually progresses in amplitude but is still 'fuzzy;' for lack of a better term. I have asked many pilots that I have flown with and almost all agree we have problems understanding Controllers on that frequency. I don't know if a different mic is used or the transmitter is poor; but the quality has to be fixed. Additionally; this problem seems to be getting worse as controllers attempt to contact us on landing roll with the thrust reverser's in full reverse and instructions are given. It is at this time that the pilots have the highest decibel level of noise in the cockpit with the thrust reverser's in full reverse and if the controllers are trying to talk to us at the same time this poor audio quality is present; the problems are compounded. Additionally; this is a very high workload environment for the pilots (landing roll with full reverse) and answering instructions; particularly if not understood has to be secondary.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1032219
Time
Date	201208
Local Time Of Day	0001-0600
Place
Locale Reference	SFO.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 280 Flight Crew Total 16000 Flight Crew Type 7500
Events
Anomaly	ATC Issue All Types

Air carrier first officer voiced concern regarding sfo tower frequency 120.5; claiming the transmission quality is 'fuzzy' making tower communications challenging especially during high noise 'reverser operation' periods.