May_June_2022 - 29

A vehicular
antenna
mount that is
representative of
the importance
of clean solder.
The before picture
shows the center
connector barely
soldered to the pin
with a big blop of
solder and the wire
not sitting properly
in the grove.
Pilots have choices today, and Holland said, " that's what's awesome.
Everybody is getting more and more and more advanced. And,
of course, without the old VHF com, that's been in the cockpit for a
long time, and HF communications, which [they've] had across the
water, basically now they're getting other capabilities, and being
able to communicate mainly through CPDLC, SAT voice, which is
actually a very good product that we use instead of the HF, which
people really love because of the clarity of the call. "
Trouble Shooting
The pilot's choice of headset and/or microphone will have a considerable
impact on the overall operation of the system, explained
Jim Karpowitz, avionics support tech, Skycom Avionics, Inc.
" A poor microphone can make even the best of com radios sound
tinny or distorted. Improper mic positioning can cause inadequate
transmit audio volume - the 'loud' part of loud and clear. The mic
must be positioned close to the mouth and foam filters over the
mic will protect it from moisture and give a clean sounding audio
signal, " he said.
Keeping the plugs clean is important and Flitz or similar metal
cleaners should be used to keep oxidation off of the conducting
surface.
" If you are getting scratchy, tinny or insufficient audio, this is
a good starting spot for troubleshooting. Headset jacks should be
secure and properly insulated from the airframe with non-conducting
washers, " he continued.
Holland said common issues they see with VHF com are they're
weak and unreadable.
" Portions of the HF systems are in an unpressurized area. So as a
result, these boxes are pressurized to prevent them from internally
arcing back and forth. And they'll lose their pressurization. And,
as a result, they may have poor performance. So you can normally
have just weak reception, or garbled when you're trying to transmit, "
he said.
Cleanliness is another important aspect to be mindful of.
" Cleanliness and condition of connectors both in the tray and in
the radio are critical elements in proper function. Most connectors
are gold-plated, and conditioning compounds such as Stabilant 22
or DeOxit Gold are helpful in maintaining the critical connections
that make the radio work correctly, " said Karpowitz.
And corrosion can be a leading cause of issues, especially when
they lead to power issues.
" Power problems are often a root of malfunctioning avionics.
Poor crimps, resistive circuit breakers, corrosion, wandering system
voltage and bad grounds can all add up to a com system that will
not work and play well with others, " said Karpowitz.
Of course, other issues can be found with the users of the aircraft.
Wi-Fi issues, for example, can often be caused by there being simply
too many people on a network.
" All they know is they're frustrated. And, hey, look, it's not working
right. It's not working right. It's too slow. It's too slow. When,
really, there's nothing wrong with the system. And the reason why
I say there's nothing wrong with the system is that most of those
systems are shared networks. So you might have, let's just say,
eight people in the airplane. And you got someone in the back
that's streaming. Well, of course, that streaming's going to really
impact the performance of everybody else trying to utilize the
system, " said Holland
For satcoms, Holland said the issue of multiple users is multiplied.
" Satcoms, which is the equivalent of the ground-based systems,
are even worse. Because you're not only sharing the bandwidth with
your airplane, but you're sharing the bandwidth with everybody
that's within your range. And that's including boats. So if you're
over the water, the boats could be a problem as well, " he explained.
And some com problems may be externally induced by consumer-grade
devices operating in the cabin. Digital devices and USB
power supplies are particularly notorious for causing annoying
breakthrough squelch problems and other flaky operation in an
otherwise properly functioning system, explains Karpowitz.
" Very importantly, do not try to rectify squelch break issues
merely by turning the squelch up. If a com system is properly calibrated
and you get squelch break in the aircraft, the problem is
noise, and noise needs to be dealt with at the source, " he notes.
Karpowitz said to watch for obvious issues such as radios that
are not locked completely into the tray or antenna connectors that
are loose.
www.AviationPros.com 29
http://www.AviationPros.com
May_June_2022

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