Flex-6500 cooling fan noise might be excessive

mikes3

Flex-6500 cooling fan noise: I REALLY LIKE my Flex-6500, first of all! (Thanks to the FLEX TEAM!) I have had two of the Flex-5000a units (-still have one), and the fan noise from the 6500 is comparatively "excessive," it seems! The exiting air that leaves the left side seems to be about the same as the ambient room temperature. I can feel NO heat buildup on any part of the radio. My suggestion, if this is technically LOGICAL, is to request that the fans be allowed to operate at a much lower speed than is now in place, UNTIL NEEDED. (The Flex-5000a units are inaudible by comparison.) Yes, allow them to ramp up as needed of course, but the just powered on radio, being COLD, should not require the cooling efforts that are now in place. (!!) Thank you; -Mike- KØJTA

Steve-N5AC

Mike, The air is actually pulled in to the fans on the sides of the radios and exits the radio at the rear. It takes a while for heat from the computing components to make it out this exit, but heat from the PA exits much quicker. Is it the low or high speed fan noise you are concerned about? Steve

mikes3

Hello, Steve; Yes, you are indeed CORRECT as to the flow-path of the air! (Intakes on the sides, exits somewhere else; -Rear, as you had mentioned.) I have no reference as to the speed setting of the fan(s), as the demands that I have impressed on my Flex-6500 are quite minimal. I run SSB only, so far. The heaviest usage is when I am NCS for the Sunday afternoon FLEX-NET on 20 meters. -Being that this is SSB, even this somewhat heavy work-load has not caused a shift of the perceived fan noise. I have no amp, so I just run the SELECTED 100 watts of power at all times. To answer your question, I am unable to define if the noise is being generated in a LOW or a HIGH fan-speed condition. My only reference is my two Flex-5000a units (I now have just one in-house). The 6500 is directly on top of the 5000. There is a one inch space between the two radios, so there is no air flow restriction. My fan noise is the same if I just apply DC power, then turn the 6500 ON, as opposed to a 1 to 2 hour NCS session. The Flex-5000a units are IMPERCEPTIBLE by comparison to the noise that I hear with the 6500! 73; Mike KØJTA

mikes3

I will add: Judging from the acoustics, I'd GUESS that the fan noise is NOT at a high power or speed setting. -Mike- KØJTA

mikes3

Tim had mentioned that the (two?) small fans that are inside the unit are barely able to be heard "outside the case" of the 6500. (From this newly recalled point, I am assuming that these two fans are NOT being heard by me...) Listening to the way the fans SOUND, I am willing to bet that the larger two fans at the front-sides of the Flex-6500 are the source of my noise. (Again, the fans are NOT turning at a full, or high rate, per the way they sound.) -Mike- KØJTA

Tim - W4TME

I would agree, what you are hearing are the side chassis fans.