Today's Message Index:
----------------------
1. 02:40 PM - Excessive noise on VHF radio when Transmitting (Hugh McKay)
2. 03:14 PM - Re: Excessive noise on VHF radio when Transmitting (Pete Christensen)
3. 04:00 PM - Re: Excessive noise on VHF radio when Transmitting (Robert Borger)
4. 04:13 PM - Re: Excessive noise on VHF radio when Transmitting (Hugh McKay)
5. 04:16 PM - Re: Excessive noise on VHF radio when Transmitting (Hugh McKay)
6. 07:40 PM - Re: Excessive noise on VHF radio when Transmitting (Guy Buchanan)
Message 1
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| Subject: | Excessive noise on VHF radio when Transmitting |
Gentlemen,
I have a noise problem on the VHF radio system in my plane when I
attempt to transmit. In fact The other day while flying through Class C
airspace the approach controller was telling me that my transmission was
broken and had so much noise he could hardly understand what I was
saying. I also hear the noise in my headphones when I transmit, not when
receiving.
I have visually checked all the ground connections on the plane and they
are clear of corrosion and are tight. While on the ground with the
engine not running the radio transmission is fine with no problems. The
problem only occurs when the engine is running. The noise sounds like
the frequency of the rotating generator on the back of the engine which
is a Rotax 912 UL. The audible frequency can be heard to vary with the
engine rpm. It is =9Cdirty=9D noise. My radio is a panel
mounted ICOM IC-A200. I also have two 10,000 mF capacitors connected in
parallel between the voltage regulator and ground as noise filters. I
have visually checked the two capacitors, and they seem to be in good
order (i.e. no swelling or distortion). The antenna is a Comant VHF CI
121 using a quarter wave ground plane. I have had no problems with this
system for ten years.
Here are the specifics:
Aircraft Allegro 2000 LSA
Engine Rotax 912 UL
TSN 741 hrs
Radio ICOM IC-A200
Antenna Comant VHF CI 121
Any and all advice as to how to identify what is causing the problem and
how to correct it would be appreciated.
Hugh G. McKay III, P.E.
N661WW
email hgmckay@bellsouth.net
Message 2
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| Subject: | Re: Excessive noise on VHF radio when Transmitting |
Do you have a cigarette lighter USB adapter plugged in? They can cause this.
Pete
> On Jun 14, 2016, at 4:39 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
>
> Gentlemen,
>
> I have a noise problem on the VHF radio system in my plane when I attempt t
o transmit. In fact The other day while flying through Class C airspace the a
pproach controller was telling me that my transmission was broken and had so
much noise he could hardly understand what I was saying. I also hear the no
ise in my headphones when I transmit, not when receiving.
>
> I have visually checked all the ground connections on the plane and they a
re clear of corrosion and are tight. While on the ground with the engine not
running the radio transmission is fine with no problems. The problem only o
ccurs when the engine is running. The noise sounds like the frequency of the
rotating generator on the back of the engine which is a Rotax 912 UL. The a
udible frequency can be heard to vary with the engine rpm. It is =9Cdi
rty=9D noise. My radio is a panel mounted ICOM IC-A200. I also have t
wo 10,000 mF capacitors connected in parallel between the voltage regulator a
nd ground as noise filters. I have visually checked the two capacitors, and t
hey seem to be in good order (i.e. no swelling or distortion). The antenna i
s a Comant VHF CI 121 using a quarter wave ground plane. I have had no probl
ems with this system for ten years.
>
> Here are the specifics:
> Aircraft Allegro 2000 LSA
> Engine Rotax 912 UL
> TSN 741 hrs
> Radio ICOM IC-A200
> Antenna Comant VHF CI 121
>
> Any and all advice as to how to identify what is causing the problem and h
ow to correct it would be appreciated.
>
> Hugh G. McKay III, P.E.
> N661WW
> email hgmckay@bellsouth.net
> <Hugh.vcf>
Message 3
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| Subject: | Re: Excessive noise on VHF radio when Transmitting |
Hugh,
Do you perchance have an ANR headset?
With my Lightspeed Zulu 2, if the ANR isn=99t operating, my
transmissions are hopelessly garbled and noisy. First sign that the
batteries in the ANR unit are dying is when the tower can=99t
understand my transmission due to the engine noise in the cockpit.
Another source of noise I=99ve run into is with some plug=in USB
power sources. Some seem OK others generate a lot of electrical noise.
Blue skies & tailwinds,
Bob Borger
Europa XS Tri, Rotax 914, Airmaster C/S Prop (75 hrs).
Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
3705 Lynchburg Dr.
Corinth, TX 76208-5331
Cel: 817-992-1117
rlborger@mac.com
On Jun 14, 2016, at 4:39 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
Gentlemen,
I have a noise problem on the VHF radio system in my plane when I
attempt to transmit. In fact The other day while flying through Class C
airspace the approach controller was telling me that my transmission was
broken and had so much noise he could hardly understand what I was
saying. I also hear the noise in my headphones when I transmit, not when
receiving.
I have visually checked all the ground connections on the plane and they
are clear of corrosion and are tight. While on the ground with the
engine not running the radio transmission is fine with no problems. The
problem only occurs when the engine is running. The noise sounds like
the frequency of the rotating generator on the back of the engine which
is a Rotax 912 UL. The audible frequency can be heard to vary with the
engine rpm. It is =9Cdirty=9D noise. My radio is a panel
mounted ICOM IC-A200. I also have two 10,000 mF capacitors connected in
parallel between the voltage regulator and ground as noise filters. I
have visually checked the two capacitors, and they seem to be in good
order (i.e. no swelling or distortion). The antenna is a Comant VHF CI
121 using a quarter wave ground plane. I have had no problems with this
system for ten years.
Here are the specifics:
Aircraft Allegro 2000 LSA
Engine Rotax 912 UL
TSN 741 hrs
Radio ICOM IC-A200
Antenna Comant VHF CI 121
Any and all advice as to how to identify what is causing the problem and
how to correct it would be appreciated.
Hugh G. McKay III, P.E.
N661WW
email hgmckay@bellsouth.net
<Hugh.vcf>
Message 4
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| Subject: | Re: Excessive noise on VHF radio when Transmitting |
Pete,
My GPS unit is powered for a cigarette lighter plug, but I have been
doing this for ten years w/o a problem.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay@bellsouth.net
http://www.wwegeo.com
From: Pete Christensen
Sent: Tuesday, June 14, 2016 6:13 PM
Subject: Re: RotaxEngines-List: Excessive noise on VHF radio when
Transmitting
Do you have a cigarette lighter USB adapter plugged in? They can cause
this.
Pete
On Jun 14, 2016, at 4:39 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
Gentlemen,
I have a noise problem on the VHF radio system in my plane when I
attempt to transmit. In fact The other day while flying through Class C
airspace the approach controller was telling me that my transmission was
broken and had so much noise he could hardly understand what I was
saying. I also hear the noise in my headphones when I transmit, not when
receiving.
I have visually checked all the ground connections on the plane and
they are clear of corrosion and are tight. While on the ground with the
engine not running the radio transmission is fine with no problems. The
problem only occurs when the engine is running. The noise sounds like
the frequency of the rotating generator on the back of the engine which
is a Rotax 912 UL. The audible frequency can be heard to vary with the
engine rpm. It is =9Cdirty=9D noise. My radio is a panel
mounted ICOM IC-A200. I also have two 10,000 mF capacitors connected in
parallel between the voltage regulator and ground as noise filters. I
have visually checked the two capacitors, and they seem to be in good
order (i.e. no swelling or distortion). The antenna is a Comant VHF CI
121 using a quarter wave ground plane. I have had no problems with this
system for ten years.
Here are the specifics:
Aircraft Allegro 2000 LSA
Engine Rotax 912 UL
TSN 741 hrs
Radio ICOM IC-A200
Antenna Comant VHF CI 121
Any and all advice as to how to identify what is causing the problem
and how to correct it would be appreciated.
Hugh G. McKay III, P.E.
N661WW
email hgmckay@bellsouth.net
<Hugh.vcf>
Message 5
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| Subject: | Re: Excessive noise on VHF radio when Transmitting |
Robert,
My head sets are not ANR headsets. My GPS is powered from a cigarette
lighter plug, but it is not a USB.
Hugh G. McKay III, P.E. Fellow, L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay@bellsouth.net
http://www.wwegeo.com
From: Robert Borger
Sent: Tuesday, June 14, 2016 6:59 PM
Subject: Re: RotaxEngines-List: Excessive noise on VHF radio when
Transmitting
Hugh,
Do you perchance have an ANR headset?
With my Lightspeed Zulu 2, if the ANR isn=99t operating, my
transmissions are hopelessly garbled and noisy. First sign that the
batteries in the ANR unit are dying is when the tower can=99t
understand my transmission due to the engine noise in the cockpit.
Another source of noise I=99ve run into is with some plug=in USB
power sources. Some seem OK others generate a lot of electrical noise.
Blue skies & tailwinds,
Bob Borger
Europa XS Tri, Rotax 914, Airmaster C/S Prop (75 hrs).
Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
3705 Lynchburg Dr.
Corinth, TX 76208-5331
Cel: 817-992-1117
rlborger@mac.com
On Jun 14, 2016, at 4:39 PM, Hugh McKay <hgmckay@bellsouth.net> wrote:
Gentlemen,
I have a noise problem on the VHF radio system in my plane when I
attempt to transmit. In fact The other day while flying through Class C
airspace the approach controller was telling me that my transmission was
broken and had so much noise he could hardly understand what I was
saying. I also hear the noise in my headphones when I transmit, not when
receiving.
I have visually checked all the ground connections on the plane and they
are clear of corrosion and are tight. While on the ground with the
engine not running the radio transmission is fine with no problems. The
problem only occurs when the engine is running. The noise sounds like
the frequency of the rotating generator on the back of the engine which
is a Rotax 912 UL. The audible frequency can be heard to vary with the
engine rpm. It is =9Cdirty=9D noise. My radio is a panel
mounted ICOM IC-A200. I also have two 10,000 mF capacitors connected in
parallel between the voltage regulator and ground as noise filters. I
have visually checked the two capacitors, and they seem to be in good
order (i.e. no swelling or distortion). The antenna is a Comant VHF CI
121 using a quarter wave ground plane. I have had no problems with this
system for ten years.
Here are the specifics:
Aircraft Allegro 2000 LSA
Engine Rotax 912 UL
TSN 741 hrs
Radio ICOM IC-A200
Antenna Comant VHF CI 121
Any and all advice as to how to identify what is causing the problem and
how to correct it would be appreciated.
Hugh G. McKay III, P.E.
N661WW
email hgmckay@bellsouth.net
<Hugh.vcf>
Message 6
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| Subject: | Re: Excessive noise on VHF radio when Transmitting |
Visually checking the antenna grounds isn't going to cut it. I'd refresh
them manually. I have to do this once a year at least. (Stainless bolt
on aluminum antenna base. Not great.)
2nd guess is pre-existing ground loop is now picking up charging noise
due to a weakness in the system elsewhere. (Grounds?) You gotta be
religious about ground loops.
*_Guy Buchanan_*
Assistant Scoutmaster Troop 680
760.809.6145
gebuchanan@cox.net<mailto:gebuchanan@cox.net>
www.troop680.org
On 6/14/2016 2:39 PM, Hugh McKay wrote:
> Gentlemen,
> I have a noise problem on the VHF radio system in my plane when I
> attempt to transmit. In fact The other day while flying through Class
> C airspace the approach controller was telling me that my transmission
> was broken and had so much noise he could hardly understand what I was
> saying. I also hear the noise in my headphones when I transmit, not
> when receiving.
> I have visually checked all the ground connections on the plane and
> they are clear of corrosion and are tight. While on the ground with
> the engine not running the radio transmission is fine with no
> problems. The problem only occurs when the engine is running. The
> noise sounds like the frequency of the rotating generator on the back
> of the engine which is a Rotax 912 UL. The audible frequency can be
> heard to vary with the engine rpm. It is dirty noise. My radio is a
> panel mounted ICOM IC-A200. I also have two 10,000 mF capacitors
> connected in parallel between the voltage regulator and ground as
> noise filters. I have visually checked the two capacitors, and they
> seem to be in good order (i.e. no swelling or distortion). The antenna
> is a Comant VHF CI 121 using a quarter wave ground plane._*I have had
> no problems with this system for ten years.*_
> _**_
> Here are the specifics:
> Aircraft Allegro 2000 LSA
> Engine Rotax 912 UL
> TSN 741 hrs
> Radio ICOM IC-A200
> Antenna Comant VHF CI 121
> Any and all advice as to how to identify what is causing the problem
> and how to correct it would be appreciated.
> Hugh G. McKay III, P.E.
> N661WW
> email hgmckay@bellsouth.net
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