Enjoy! #FF-This hashtag mostly shows up on Fridays, which should give you a good indication of what one of the Fs means. The other stands for Follow, and the two combine to make the phrase Follow Friday.. Follow Friday is essentially a Twitter holiday with the aim of getting people to follow one another.
Technical. Original manufacturers part,390 Mhz frequency, 9-volt battery operated, part number 976LM a 977LM keypad is substituted per the manufacturers change, Color: Grey Works with all Liftmaster, Sears and Chamberlain garage door openers, utilizing the 390 Mhz frequency.echnical. Original manufacturers part,390 Mhz frequency, 9-volt battery operated, part number 976LM a 977LM keypad is substituted per the manufacturers change, Color: Grey Works with all Liftmaster, Sears and Chamberlain garage door openers, utilizing the 390 Mhz frequency.
In the case of a turboprop aircraft, SENER focuses on BPF tones generated by the turboprop engine covering the low and mid frequency range, the harmonics of the BPF tone, and possible false harmonics. Low frequencies for a turboprop aircraft range from 10 to 200-250 Hz and mid frequencies from 250 to 400-500 Hz. A statistical approach such as Statistical Energy Analysis is used to study frequencies higher than 500 Hz.