Page 1 of 1

HF Coupler NG

PostPosted: 20 Jun 2009, 03:31
by MemphisBelle
Hi,

Why is an HF coupler pressurized? I guess it is because it works better when pressurized but can someone give me more details?

Re: HF Coupler NG

PostPosted: 20 Jun 2009, 10:05
by MemphisBelle
Pressurzed.. I mean vacuüm :roll:

Re: HF Coupler NG

PostPosted: 20 Jun 2009, 18:33
by sr79
A HF coupler is pressurized usually with nitrogen to (1) prevent high voltage arcing (2) prevents moisture to prevent corrosion (3) provides uniform cooling medium and one of various controls which provide access to preset channels. Hopes this answers your question.

Re: HF Coupler NG

PostPosted: 20 Jun 2009, 23:06
by MemphisBelle
Pressurized with nitrogen. Ok, thanks for your awnser!

Re: HF Coupler NG

PostPosted: 28 Jan 2010, 23:11
by Xpt
Hi there,
Here in Brazil, there have been several cases of failures in the system of HF only in flight, while on the ground it normally operates. It was found that the most common cause is the HF coupler, the loss of pressurization causes the failure when the aircraft is at cruising altitude.
sr79: can you provide the source of the information about the nitrogen? i would like to read more about this.
tks guys!

Re: HF Coupler NG

PostPosted: 29 Jan 2010, 19:19
by sr79
my source of information was the aircraft a.m.m. and also you can look in wikipedia.com

Re: HF Coupler NG

PostPosted: 30 Jan 2010, 08:31
by 737GR
the same info is given in the book "AIRCRAFT RADIO SYSTEMS" by POWELL