The third "SAW" filter..

[daveg4otu]

ANV - yes I think we all appreciate the fact that the forum allows this discussion without the posts being pulled or censored....and for this I thank you.
Also must (at least for me ) thank  W&S for speedy repairs.

Equally, I believe that no-one here is wanting to run down  the reputation of what is after all a marvellous piece of  equipment.
 
Additionally , I agree with the point you are making that  the fault rate is  in fact very low  when compared to such as Xbox and others .

However-I believe the point being missed here is that  even 1 in 500 going  wrong is more than either AirNav or the customers  want to see....and so any reasoned discussion that may seek to establish  the causes of failure must surely   be beneficial to all.

I was not questioning  your (the company that is) level of QC - rather suggesting the possibility that of possibly  those who supply the components - a thing over which AN may have little direct control- may be where the root cause of SAW filter  problems lay.

Anyway - hopefully -  not too many more users will suffer the  LOS that has affected a few of us...and we can all get on with  enjoying using the gear.

:)

[AirNav Support]

We agree with that Dave and we are not happy about those returns.

Hence we did the change for the second batch and said we will fix any static issues for the first batch regardless of warranty period.

[flight checker]

Hi Dave,

I was not questioning  your (the company that is) level of QC - rather suggesting the possibility that of possibly  those who supply the components - a thing over which AN may have little direct control- may be where the root cause of SAW filter  problems lay.

"SAW" filters by their "nature" are sensitive to ESD, as compared to (for instance) "HELIX" filters, that, as an alternative will be found to form "Bandpasses" in a receivers front end for its "frequency range of interest", and to be an ideal application in the frequency range that transponders are supposed to operate. The increased "sensitivity" of the "SAWs" to ESD has to be taken care of by protective measures. If interested you may read about here for instance: http://www.epcos.com/inf/40/ds/ae/B3773.pdf. (> PAGE 6)

If intersted in "HELIX filter" fundamentals, have a look here:
http://www.rfcafe.com/references/electrical/helical-resonator.htm

"SAW filters" to be desribed here (just as an example):
http://www.saw-device.com/pdfs/what_is_a_saw_filter.pdf

So, as a conclusion, a SAW filters susceptibility to ESD finally is a question of how well it is protected against.

Helix filters, by their design, are not required to have additional protection.

Kind regards

Karl

[CoastGuardJon]

Hi Karl, thanks for those links, makes for some very interesting reading.

[flight checker]

You're welcome Jon,

Karl