Comm noise

"RST Engineering" wrote

Orval, you are chasing your tail. If it does it on BOTH radios, the
probability of a dual identical fault is practically zero, especially if
the noise on #1 correlates with the noise on #2.

Sure, go ahead and shotgun the thing and then come back in here lamenting
that you spent $X amus on the problem and it is still there.

I'm with you, on this point.

Do you have any ideas on what possible things to look at (to trouble-shoot
it) to figure out what the real problem is, yet?
--
Jim in NC

Sure. Does it do it with just the master switch on, sitting on the ground,
engine off. Engine on and idle. Engine on taxiing. Engine on runup.
Engine on takeoff roll. Engine on climbout...

What is the LEAST active thing the airplane is doing when it starts. Does
it always happen, say, ten minutes into the flight? Or does it do it on the
ground in the same ten minutes? Does it start in the air and continue after
landing?

An hour's logical troubleshooting can save dozens of hours shotgunning the
problem.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


"Morgans" wrote in message
...

"RST Engineering" wrote

Orval, you are chasing your tail. If it does it on BOTH radios, the
probability of a dual identical fault is practically zero, especially if
the noise on #1 correlates with the noise on #2.

Sure, go ahead and shotgun the thing and then come back in here lamenting
that you spent $X amus on the problem and it is still there.

I'm with you, on this point.

Do you have any ideas on what possible things to look at (to trouble-shoot
it) to figure out what the real problem is, yet?
--
Jim in NC

"RST Engineering" writes:

Orval, you are chasing your tail. If it does it on BOTH radios, the
probability of a dual identical fault is practically zero, especially if the
noise on #1 correlates with the noise on #2.



Do the two radios have separate antennas, or do they share a single point
of failure?


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Wouldn't taking a meter to the coax where it attaches to the radio
tray tell whether the cable and/or antenna has a problem?

On Sat, 30 Aug 2008 08:22:33 -0700, "RST Engineering"
wrote:

Sure. Does it do it with just the master switch on, sitting on the ground,
engine off. Engine on and idle. Engine on taxiing. Engine on runup.
Engine on takeoff roll. Engine on climbout...

What is the LEAST active thing the airplane is doing when it starts. Does
it always happen, say, ten minutes into the flight? Or does it do it on the
ground in the same ten minutes? Does it start in the air and continue after
landing?

An hour's logical troubleshooting can save dozens of hours shotgunning the
problem.

Jim

Have you ever seen two com radios sharing a single antenna? Tell me how you
do it without the transmitter of #1 blowing up the receiver of #2. Unless
you are talking about dual Genave A-200s/Escort 110s and the ilk that used
two antenna inputs, one for the transmitter and one for the receiver.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


"David Lesher" wrote in message
...
"RST Engineering" writes:


Do the two radios have separate antennas, or do they share a single point
of failure?


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

The odds of finding the problem that way lie somewhere between the odds of
winning an argument with an umpire and an argument with your wife.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


"Peter Clark" wrote in message
...

Wouldn't taking a meter to the coax where it attaches to the radio
tray tell whether the cable and/or antenna has a problem?

In article ,
"RST Engineering" wrote:

The odds of finding the problem that way lie somewhere between the odds of
winning an argument with an umpire and an argument with your wife.

I'll take my chances with the umpire.

"RST Engineering" writes:

Have you ever seen two com radios sharing a single antenna? Tell me how you
do it without the transmitter of #1 blowing up the receiver of #2. Unless
you are talking about dual Genave A-200s/Escort 110s and the ilk that used
two antenna inputs, one for the transmitter and one for the receiver.

I thought Nav antennas were typically shared. I mention this because I
have seen non-aircraft multi-antenna multi-front-end receivers where
weirdness on one antenna appeared to be on the other.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"David Lesher" wrote in message
...
"RST Engineering" writes:

Have you ever seen two com radios sharing a single antenna? Tell me how
you
do it without the transmitter of #1 blowing up the receiver of #2. Unless
you are talking about dual Genave A-200s/Escort 110s and the ilk that used
two antenna inputs, one for the transmitter and one for the receiver.

I thought Nav antennas were typically shared. I mention this because I
have seen non-aircraft multi-antenna multi-front-end receivers where
weirdness on one antenna appeared to be on the other.

A Nav only antenna doesn't transmit, which is why they can be shared easily.
It's possible to share comm antennas, but you need either a transmit switch
or duplexer of some type to protect the receiver.

First of all, the OP said it was his COM radio that was affected; NAV wasn't
mentioned.

Second, to use the correct terms, Nav antennas are isolated in a splitter
where a defect in one radio does not affect the other. Google "Wilkinson
splitter" for a technical description. "Shared" doesn't convey the full
effect of what has to happen; that implies that you just run both radios to
a single antenna without any isolation device in the path.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


"David Lesher" wrote in message
...

I thought Nav antennas were typically shared. I mention this because I
have seen non-aircraft multi-antenna multi-front-end receivers where
weirdness on one antenna appeared to be on the other.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433