Today's Message Index:
----------------------
1. 05:07 AM - Re: Antenna placement. (LessDragProd@aol.com)
2. 05:28 AM - RADIO SCREAM (Robert Riegner)
3. 06:01 AM - Re: RADIO SCREAM (Paul McAllister)
4. 07:10 AM - Re: RADIO SCREAM (Doug McNutt)
5. 09:13 AM - Re: RADIO SCREAM (David Lloyd)
6. 10:41 AM - Re: RADIO SCREAM (John Rippengal)
7. 11:11 AM - Re: RADIO SCREAM (Robert Riegner)
8. 11:13 AM - Re: RADIO SCREAM (Robert Riegner)
9. 04:22 PM - Re: RADIO SCREAM (David Lloyd)
Message 1
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| Subject: | Re: Antenna placement. |
--> Avionics-List message posted by: LessDragProd@aol.com
Simple. It's designed to work as part of the total aircraft airframe.
I'm not the expert. Talk to Bob Archer. Bob knows antennas on aircraft
from empirical data he helped obtain as an antenna designer at TRW.
Or ask Lectric Bob about Bob Archer. He knows Bob Archer.
Jim Ayers
Less drag Products, Inc.
In a message dated 08/25/2004 11:32:53 PM Pacific Daylight Time,
Ron@Koyich.com writes:
Wow! Big claim.
A pair of balanced blades works pretty well - JUST to be argumentative,
how is the Archer antenna better, Jim?
Ron
Message 2
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--> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
1980 172N SKYHAWK II....2-TKM Slide-in replacements were installed a couple
of years ago[Which by the way have worked flawless till now] The last 6
months or so i have been getting tremendous squealing or feedback when Ptt
is pushed. Radios have been switched top for bottom with no change. headsets
have been changed, different PTT's have been used. Radios were sent back to
factory and nothing found.Radios receive loud and clear.Cleaned all radio
contacts and antenna contacts, reinstalled everything and checked on the
ground with handheld[engine not running],everything sounded fine.Started
plane,taxied,took off, and radios were unusable again. Transponder light
lites[sometimes] and vor needles move when PTT is pushed.Problem is only
with transmittion and when PTT is pushed, static and squeal are so bad it's
hard to stand on the headset. If i remember correctly, radio volume control
does nothing to increase or decrease noise.It's like the Bremuda Triangle in
there!!!
BOB RIEGNER
N60846
1980 172N SKYHAWKII
RADIO SQUEAL
Message 3
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| Subject: | Re: RADIO SCREAM |
--> Avionics-List message posted by: "Paul McAllister" <paul.mcallister@qia.net>
Hi Bob,
Did you happen to change headsets recently? I had the same problem and it
turned out to be RF breaking into my headsets and causing audio feedback
when I transmitted.
Paul
Message 4
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| Subject: | Re: RADIO SCREAM |
--> Avionics-List message posted by: Doug McNutt <douglist@macnauchtan.com>
At 08:25 -0400 8/26/04, Robert Riegner wrote:
>The last 6 months or so i have been getting tremendous squealing or feedback
when Ptt
>is pushed.
It might not be feedback. Check for variation in tone with engine speed or landing
lights. A bad diode in an alternator can be confused with feedback oscillation.
--
--> Halloween == Oct 31 == Dec 25 == Christmas <--
Message 5
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| Subject: | Re: RADIO SCREAM |
--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
Bob,
Was anything done or changed in your audio panel unit? Most audio boxes do
a lot of isolation of one comm. from the other when TX'ing. If this
isolation fails then comm. RF energy can leak to the other comm. and cause
the headset scream that you mention. If you turn one radio off, do you
still get the noise in the headset when the PTT is pressed?
You may have a common ground for the panel bus or other that has a loose
connection or a broken wire causing a ground loop that is active during
TX'ing because of the higher current going to the comm. unit.
If anything in your antenna coax, connectors, antenna is not right, grounds,
feeds, etc., the TX'ing comm. will radiate RF that could blast into the 2nd
comm.
Let us all know what you find.....?
David
----- Original Message -----
From: "Robert Riegner" <rade66@msn.com>
Subject: Avionics-List: RADIO SCREAM
> --> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
>
> 1980 172N SKYHAWK II....2-TKM Slide-in replacements were installed a
couple
> of years ago[Which by the way have worked flawless till now] The last 6
> months or so i have been getting tremendous squealing or feedback when Ptt
> is pushed. Radios have been switched top for bottom with no change.
headsets
> have been changed, different PTT's have been used. Radios were sent back
to
> factory and nothing found.Radios receive loud and clear.Cleaned all radio
> contacts and antenna contacts, reinstalled everything and checked on the
> ground with handheld[engine not running],everything sounded fine.Started
> plane,taxied,took off, and radios were unusable again. Transponder light
> lites[sometimes] and vor needles move when PTT is pushed.Problem is only
> with transmittion and when PTT is pushed, static and squeal are so bad
it's
> hard to stand on the headset. If i remember correctly, radio volume
control
> does nothing to increase or decrease noise.It's like the Bremuda Triangle
in
> there!!!
>
> BOB RIEGNER
> N60846
> 1980 172N SKYHAWKII
> RADIO SQUEAL
>
>
Message 6
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--> Avionics-List message posted by: "John Rippengal" <j.rippengal@cytanet.com.cy>
Sounds very much as though there is a lot of RF leaking into the cabin
causing feedback through your audio/intercom/headset. Check the coax
connection to the antenna particularly the outer sheathing for good
solid non-corroded connections both ends right through to the
radios. Could seem ok until the vibration of engine running causes
poor connection.
John
--> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
1980 172N SKYHAWK II....2-TKM Slide-in replacements were installed a
couple
of years ago[Which by the way have worked flawless till now] The last 6
months or so i have been getting tremendous squealing or feedback when
Ptt
is pushed. Radios have been switched top for bottom with no change.
headsets
have been changed, different PTT's have been used. Radios were sent back
to
factory and nothing found.Radios receive loud and clear.Cleaned all
radio
contacts and antenna contacts, reinstalled everything and checked on the
ground with handheld[engine not running],everything sounded fine.Started
plane,taxied,took off, and radios were unusable again. Transponder light
lites[sometimes] and vor needles move when PTT is pushed.Problem is only
with transmittion and when PTT is pushed, static and squeal are so bad
it's
hard to stand on the headset. If i remember correctly, radio volume
control
does nothing to increase or decrease noise.It's like the Bremuda
Triangle in
there!!!
BOB RIEGNER
N60846
1980 172N SKYHAWKII
RADIO SQUEAL
Message 7
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| Subject: | Re: RADIO SCREAM |
--> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
Thanks for all the great ideas guys.
David,
The stock[cessna] audio panel was replaced by an avionics tech.[
KMA24] The radios worked fine when the replace was done. The radio still
squeals when the second radio is turned off and PTT pushed.
Bob
>From: "David Lloyd" <skywagon@charter.net>
>Reply-To: avionics-list@matronics.com
>To: <avionics-list@matronics.com>
>Subject: Re: Avionics-List: RADIO SCREAM
>Date: Thu, 26 Aug 2004 09:10:12 -0700
>
>--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
>
>Bob,
>Was anything done or changed in your audio panel unit? Most audio boxes do
>a lot of isolation of one comm. from the other when TX'ing. If this
>isolation fails then comm. RF energy can leak to the other comm. and cause
>the headset scream that you mention. If you turn one radio off, do you
>still get the noise in the headset when the PTT is pressed?
>
>You may have a common ground for the panel bus or other that has a loose
>connection or a broken wire causing a ground loop that is active during
>TX'ing because of the higher current going to the comm. unit.
>
>If anything in your antenna coax, connectors, antenna is not right,
>grounds,
>feeds, etc., the TX'ing comm. will radiate RF that could blast into the 2nd
>comm.
>
>Let us all know what you find.....?
>David
>
>
>----- Original Message -----
>From: "Robert Riegner" <rade66@msn.com>
>To: <avionics-list@matronics.com>
>Subject: Avionics-List: RADIO SCREAM
>
>
> > --> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
> >
> > 1980 172N SKYHAWK II....2-TKM Slide-in replacements were installed a
>couple
> > of years ago[Which by the way have worked flawless till now] The last 6
> > months or so i have been getting tremendous squealing or feedback when
>Ptt
> > is pushed. Radios have been switched top for bottom with no change.
>headsets
> > have been changed, different PTT's have been used. Radios were sent back
>to
> > factory and nothing found.Radios receive loud and clear.Cleaned all
>radio
> > contacts and antenna contacts, reinstalled everything and checked on the
> > ground with handheld[engine not running],everything sounded fine.Started
> > plane,taxied,took off, and radios were unusable again. Transponder light
> > lites[sometimes] and vor needles move when PTT is pushed.Problem is only
> > with transmittion and when PTT is pushed, static and squeal are so bad
>it's
> > hard to stand on the headset. If i remember correctly, radio volume
>control
> > does nothing to increase or decrease noise.It's like the Bremuda
>Triangle
>in
> > there!!!
> >
> > BOB RIEGNER
> > N60846
> > 1980 172N SKYHAWKII
> > RADIO SQUEAL
> >
> >
>
>
Message 8
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| Subject: | Re: RADIO SCREAM |
--> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
HI PAUL,
HAVE USED 4 DIFFERENT AND ALL ARE THE SAME.
BOB
>From: "Paul McAllister" <paul.mcallister@qia.net>
>Reply-To: avionics-list@matronics.com
>To: <avionics-list@matronics.com>
>Subject: Re: Avionics-List: RADIO SCREAM
>Date: Thu, 26 Aug 2004 07:58:32 -0500
>
>--> Avionics-List message posted by: "Paul McAllister"
><paul.mcallister@qia.net>
>
>Hi Bob,
>
>Did you happen to change headsets recently? I had the same problem and it
>turned out to be RF breaking into my headsets and causing audio feedback
>when I transmitted.
>
>Paul
>
>
Message 9
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| Subject: | Re: RADIO SCREAM |
--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
Bob,
Do both radios squeal the same when turned on one at a time?
If they do then you can probably rule out an antenna or coax feed problem.
Any chance that you have a cabin speaker over head that is active when it
should only be supplying audio to the headphones. I once found feedback
from the speaker going back via the mike and setting up a feedback
squeal...but, that is rare. And, I think you said that they check out fine
as long as the engine is not running. Then, it has to be in the charging or
magneto system. Maybe a noise filter failed...
Let us know....
David
----- Original Message -----
From: "Robert Riegner" <rade66@msn.com>
Subject: Re: Avionics-List: RADIO SCREAM
> --> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
>
> Thanks for all the great ideas guys.
> David,
> The stock[cessna] audio panel was replaced by an avionics tech.[
> KMA24] The radios worked fine when the replace was done. The radio still
> squeals when the second radio is turned off and PTT pushed.
> Bob
>
>
> >From: "David Lloyd" <skywagon@charter.net>
> >Reply-To: avionics-list@matronics.com
> >To: <avionics-list@matronics.com>
> >Subject: Re: Avionics-List: RADIO SCREAM
> >Date: Thu, 26 Aug 2004 09:10:12 -0700
> >
> >--> Avionics-List message posted by: "David Lloyd" <skywagon@charter.net>
> >
> >Bob,
> >Was anything done or changed in your audio panel unit? Most audio boxes
do
> >a lot of isolation of one comm. from the other when TX'ing. If this
> >isolation fails then comm. RF energy can leak to the other comm. and
cause
> >the headset scream that you mention. If you turn one radio off, do you
> >still get the noise in the headset when the PTT is pressed?
> >
> >You may have a common ground for the panel bus or other that has a loose
> >connection or a broken wire causing a ground loop that is active during
> >TX'ing because of the higher current going to the comm. unit.
> >
> >If anything in your antenna coax, connectors, antenna is not right,
> >grounds,
> >feeds, etc., the TX'ing comm. will radiate RF that could blast into the
2nd
> >comm.
> >
> >Let us all know what you find.....?
> >David
> >
> >
> >----- Original Message -----
> >From: "Robert Riegner" <rade66@msn.com>
> >To: <avionics-list@matronics.com>
> >Subject: Avionics-List: RADIO SCREAM
> >
> >
> > > --> Avionics-List message posted by: "Robert Riegner" <rade66@msn.com>
> > >
> > > 1980 172N SKYHAWK II....2-TKM Slide-in replacements were installed a
> >couple
> > > of years ago[Which by the way have worked flawless till now] The last
6
> > > months or so i have been getting tremendous squealing or feedback when
> >Ptt
> > > is pushed. Radios have been switched top for bottom with no change.
> >headsets
> > > have been changed, different PTT's have been used. Radios were sent
back
> >to
> > > factory and nothing found.Radios receive loud and clear.Cleaned all
> >radio
> > > contacts and antenna contacts, reinstalled everything and checked on
the
> > > ground with handheld[engine not running],everything sounded
fine.Started
> > > plane,taxied,took off, and radios were unusable again. Transponder
light
> > > lites[sometimes] and vor needles move when PTT is pushed.Problem is
only
> > > with transmittion and when PTT is pushed, static and squeal are so bad
> >it's
> > > hard to stand on the headset. If i remember correctly, radio volume
> >control
> > > does nothing to increase or decrease noise.It's like the Bremuda
> >Triangle
> >in
> > > there!!!
> > >
> > > BOB RIEGNER
> > > N60846
> > > 1980 172N SKYHAWKII
> > > RADIO SQUEAL
> > >
> > >
> >
> >
>
>
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