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Weak and Static on Transmission

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bbradburry(at)bellsouth.n
Guest

Posted: Mon Jan 16, 2012 6:10 am Post subject: Weak and Static on Transmission

I have a GNS430W radio and Advanced Aircraft Electronics high gain antenna model 5T in my Lancair Legacy (fiberglass fuselage).  The antenna is mounted vertically behind the rear bulkhead on the right side of the fuselage.  Although I didn’t need that much length to reach the antenna, I made the coax the recommended 13 feet or so length. (right now I cant remember the exact length recommended).  This antenna is designed to be mounted inside plastic airplanes and doesn’t require a ground plane.  

   

I get a “weak and lots of static but usable” reports from radio checks and on occasion, while airborne, static gets so great that I can not hear approach at all.  I have had to make two NORDO landings at a Class C airport that is located under an overhanging Class B airspace due to the receiving static.  The controllers are beginning to take exception to this and I need to get this fixed!  :>)  

   

I have checked the SWR on the antenna and it was around 1.5 which I understand to be fine.  

   

Any ideas as to where I should begin my investigation on the source of this static?  

   

Bill B  

   

   

  

       [quote][b]

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Tue Jan 17, 2012 6:37 am Post subject: Weak and Static on Transmission

1/17/2012



Hello Bill Bradburry, You wrote:



1) "Although I didn't need that much length to reach the antenna, I made the 

coax the recommended 13 feet or so length."



It may not have a direct bearing on your "weak and lots of static but 

usable" problem, but it sounds like you are a bit confused about the antenna 

requirements of the GNS 430W.



The specific coax length that you referred to in your posting refers to the 

GPS antenna for the 430W. High quality coax such as RG400 is required.



Here is what AAE says about the cable length for one of their VHF comm 

antennas:



"Q. What cable length is recommended for the antenna ?

A. Any length can be used.  This antenna is impedance matched to 50 ohms to 

allow you to use any length required."



2) "Any ideas as to where I should begin my investigation on the source of 

this

static?"



You could narrow down the source of the problem a bit if you could borrow a 

GNS 430W from a fellow builder or shop and install it temporarily for 

testing. If the problem goes away the problem is inside your 430W box and 

not the aircraft installation.



'OC' Baker Says: "The best investment we can make is the time and effort to 

gather and understand knowledge."



PS: Pull out and reseat your 430W box before going to the bother of 

borrowing another unit -- the problem may just be a reseating or mis aligned 

pin condition.



=============================================================



Time: 06:10:00 AM PST US

From: "Bill Bradburry" <bbradburry(at)bellsouth.net>

Subject: Weak and Static on Transmission



 I have a GNS430W radio and Advanced Aircraft Electronics high gain antenna

model 5T in my Lancair Legacy (fiberglass fuselage).  The antenna is mounted

vertically behind the rear bulkhead on the right side of the fuselage.

Although I didn't need that much length to reach the antenna, I made the

coax the recommended 13 feet or so length. (right now I cant remember the

exact length recommended).  This antenna is designed to be mounted inside

plastic airplanes and doesn't require a ground plane.

I get a "weak and lots of static but usable" reports from radio checks and

on occasion, while airborne, static gets so great that I can not hear

approach at all.  I have had to make two NORDO landings at a Class C airport

that is located under an overhanging Class B airspace due to the receiving

static.  The controllers are beginning to take exception to this and I need

to get this fixed!  :>)

I have checked the SWR on the antenna and it was around 1.5 which I

understand to be fine.

Any ideas as to where I should begin my investigation on the source of this

static?

Bill B

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Jan 17, 2012 8:08 am Post subject: Weak and Static on Transmission

 	  Quote: 	
		  	
 

 At 08:07 AM 1/16/2012, you wrote:



  . . . I get a “weak and lots of static but usable” reports from radio checks and on occasion, while airborne, static gets so great that I can not hear approach at all.  I have had to make two NORDO landings at a Class C airport that is located under an overhanging Class B airspace due to the receiving static.  The controllers are beginning to take exception to this and I need to get this fixed!  :>)



     Bob's points are well taken. I can expand by suggesting

     that you are committed to the classic "divide and conquer"

     ploy . . . you need to separate the potential for an antenna

     system problems from the radio's potential problems.



     It's difficult to sift the sands of potential problems

     without hearing the nature of the "static". If you were

     getting a signal report from a grey-bearded ham radio

     operator he would qualify the report with "weak to the point

     of inducing pop-corn noise", or succumbing to atmospheric

     noises like lightning crashes, or scratching noise reminiscent

     of a loose connection. Further, such noises heard by

     experienced ears could probably tell if it was in the

     RF or audio chain of your transmission system.



     But alas, I've never heard a cogent signal report from

     a tower operator and seldom from other pilots in their own

     airplanes.



     I'd recommend a series of experiments. Plug a

     hand held into the antenna system and get signal reports

     from other pilots. You can start on the ground but

     they should probably be airborne so that they can fly

     outbound and get some sense of signal strength along

     with judgement of audio quality. If it doesn't repeat

     on the ground, then you go flying too. If the other

     guy reports noises, do YOU hear any noises? Open the

     radio's squelch control and tune in stations some

     distance away. Does the complaining controller repeat

     the complaint while the hand-held is being used?



     If the antenna system seems okay, this leaves the

     radio. "Weak and static" suggests one or more issues

     combining to reduce power output and introduction

     of noises reminiscent of loose connections. Probably

     nothing you can do about it personally except to

     confirm poor performance by getting a measurement

     of output power during an SWR check. This takes a

     unique kind of instrument not often found in the

     OBAM aviation toolbox.

     



 [img]cid:.0[/img] 



  

     Also, check with someone else in another airplane or

     even on the ground who overhears both sides of your

     conversation with the controllers. Does that third party

     agree with the controller's assessment? Can they refine the

     description of "static"?  I assisted in a similar

     exercise many years ago where the builder left a

     tape recorder running with the mic in front of

     the Unicom receiver in his hangar. One could hear

     both sides of the conversation. In this case, both

     sides of the conversation were clear. We then did a

     frequency check on the airplane radio and found that

     it was at the high end of the spec . . . enough off

     center to be at the edge of the government's receiver

     bandwidth but still inside the bandwidth of the

     lower cost receiver in the hangar. Replacing one

     of the transmitter's crystals fixed the problem.

     In your modern, frequency synthesized radio, this

     is an exceedingly remote possibility.



     The point is that you need GOOD data that tests

     a host of possibilities. "Weak and static" from

     one observer is insufficient data.



     Bob . . .

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jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Wed Jan 18, 2012 9:30 am Post subject: Re: Weak and Static on Transmission

Just to make sure the obvious is not overlooked, are you sure that the location of the antenna is surrounded by fiberglass and not RF-opaque carbon fiber?

IIRC, the Legacy uses a lot of CF in the airframe.



John

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Wed Jan 18, 2012 8:22 pm Post subject: Weak and Static on Transmission

I'm surprised no one has brought up the obvious of likely P-static. Does 

the aircraft have any static wicks?



On 1/18/2012 10:30 AM, jonlaury wrote:

 	  Quote: 	
		   



 Just to make sure the obvious is not overlooked, are you sure that the location of the antenna is surrounded by fiberglass and not RF-opaque carbon fiber?

 IIRC, the Legacy uses a lot of CF in the airframe.



 John





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=364203#364203

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jan 19, 2012 6:08 am Post subject: Weak and Static on Transmission

At 11:30 AM 1/18/2012, you wrote:

 	  Quote: 	
		  



Just to make sure the obvious is not overlooked, are you sure that 

the location of the antenna is surrounded by fiberglass and not 

RF-opaque carbon fiber?

IIRC, the Legacy uses a lot of CF in the airframe.


	


    ???? Hmmm . . . didn't know that about the Legacy

    but I wondered when he made the reference to 'fiberglas'. I

    thought it curious that Lancair would use the carbon

    fiber in the IV and glass in the Legacy.



    Yeah, if the antenna is inside a carbon structure

    it's effectiveness is severely degraded.

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jan 19, 2012 6:12 am Post subject: Weak and Static on Transmission

At 10:18 PM 1/18/2012, you wrote:

 	  Quote: 	
		  



I'm surprised no one has brought up the obvious

of likely P-static. Does the aircraft have any static wicks?


	


    He didn't mention flying in precip and static

    wicks don't have anything to 'connect' to on

    a glass airplane. If it's a carbon fiber then

    wicks might be useful but my impression was that

    his poor signal reports were at low altitudes

    and probably slowed down for approach to landing

    and in clear weather. P-static wouldn't hurt

    a transmitted signal, only a received signal and

    he didn't mention not being able to hear . . .

    only be heard.



    This is why the differentiation between weak-signal

    static versus poor connection static is important.

    The presence of carbon would support the notion of

    it being the weak-signal variety.

   Bob . . .

bbradburry(at)bellsouth.n
Guest

Posted: Fri Jan 20, 2012 5:42 am Post subject: Weak and Static on Transmission

Well, to further clarify this problem.  I seem to be able to hear ok on the

ground while taxiing around the airport, but after I leave the airport the

reception gets really bad.  At first I thought it was a problem with the

approach frequency because that is where it would first start up.  It was a

loud hiss in the headphones so loud that I could not hear ATC.  In fact, I

have made two NORDO landings as a result on this loud hiss.  I sent my radio

back to have it checked out and nothing was found.  All this trouble is at

below 5000 ft and fine weather.  I am flying off my 40 hours (22 so far) and

am only flying in good weather.  These radio problems at a Class C airport

have made me afraid to fly.  ATC could take some action against me if it

continues.



Lancair has an all carbon Legacy available but this one is all fiberglass

with the exception of the horizontal stabilizer, which is carbon.  The

antenna is inside the fuselage about 4+feet forward of the stabilizer.

The bottom and rear half of the plane is in primer.  The rest of the plane

is bare fiberglass.  The primer ends just about at the location of the

antenna on the fuselage.  I don't know if this would have an effect on the

static on the plane or not.  I would have had to consider static wicks a

long time earlier in the build in order to install bonding wire.  It is too

late now AFAIK. 



Bill B

--

wschertz(at)comcast.net
Guest

Posted: Fri Jan 20, 2012 6:18 am Post subject: Weak and Static on Transmission

Bill,

Could this be interference from



1.    Your EFIS?

2.    Your electronic ignition at higher RPM?



I have an SL-30 with the antenna behind my rear seat bulkhead, and a SL-40 

with the antenna a homemade in the vertical stab.



SL-30 is noisy like you describe, but the -40 works fine.



I think it is the EFIS (was worse with Blue mountain, still present with 

Grand Rapids, but not as bad)



Bill Schertz

KIS Cruiser #4045

N343BS

Phase one testing Completed

--

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Fri Jan 20, 2012 11:47 am Post subject: Weak and Static on Transmission

Any chance that the kit has carbon material layered into the fiberglass for 

some reason like rigidity, or some other form of strength needed..?  Sure 

sounds like the antenna is being blocked.  Have you tried to temporary 

substitute a simple outside antenna..?  At least that would eliminate the 

radio system as being the cause....

Dave

___________________________________________________________



---

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Sat Jan 21, 2012 5:05 am Post subject: Weak and Static on Transmission

1/21/2012



Hello Bill Bradburry, You wrote: "These radio problems at a Class C airport

have made me afraid to fly."



I consider the following items to be mandatory equipment in my experimental 

amateur built airplane both during phase one testing and subsequently:



1) One of the readily available, portable, battery powered hand held VHF 

communications radios along with both its original rechargeable battery 

(recently recharged) and a spare fitted battery case filled with alkaline 

batteries.



2) An adapter that allows me to plug my headset into the portable radio.



3) A means to temporarily connect the antenna connection of the portable 

radio into one of the airplane's more capable antennae. Note that:



a) Actually using this temporary antenna connection is optional at the time 

of intended use and initial attempts at communication may be made using the 

antenna mounted on the portable radio itself.



b) Using this temporary antenna connection and the hand held radio for 

trouble shooting may aid in locating the source of your communication 

problem.



Following the above philosophy may take you out of the "afraid to fly 

category".



When you eventually solve this problem please let us know what the problem 

was -- thanks.



'OC' Baker Says: "The best investment we can make is the time and effort to 

gather and understand knowledge."



PS: You also wrote: "I sent my radio back to have it checked out and nothing 

was found."



A "ground checks OK" result does not guarantee that the connection between 

the radio and your airplane is also OK. Have you been able to borrow an 

identical radio and test it in your airplane?



===========================================================



Time: 05:42:24 AM PST US

From: "Bill Bradburry" <bbradburry(at)bellsouth.net>

Subject: RE: Re: Weak and Static on Transmission

Well, to further clarify this problem.  I seem to be able to hear ok on the

ground while taxiing around the airport, but after I leave the airport the

reception gets really bad.  At first I thought it was a problem with the

approach frequency because that is where it would first start up.  It was a

loud hiss in the headphones so loud that I could not hear ATC.  In fact, I

have made two NORDO landings as a result on this loud hiss.  I sent my radio

back to have it checked out and nothing was found.  All this trouble is at

below 5000 ft and fine weather.  I am flying off my 40 hours (22 so far) and

am only flying in good weather.  These radio problems at a Class C airport

have made me afraid to fly.  ATC could take some action against me if it

continues.



Lancair has an all carbon Legacy available but this one is all fiberglass

with the exception of the horizontal stabilizer, which is carbon.  The

antenna is inside the fuselage about 4+feet forward of the stabilizer.

The bottom and rear half of the plane is in primer.  The rest of the plane

is bare fiberglass.  The primer ends just about at the location of the

antenna on the fuselage.  I don't know if this would have an effect on the

static on the plane or not.  I would have had to consider static wicks a

long time earlier in the build in order to install bonding wire.  It is too

late now AFAIK.



Bill B

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jan 22, 2012 7:55 am Post subject: Weak and Static on Transmission

At 07:38 AM 1/20/2012, you wrote:

 	  Quote: 	
		  

<bbradburry(at)bellsouth.net>



Well, to further clarify this problem.  I seem to be able to hear ok on the

ground while taxiing around the airport, but after I leave the airport the

reception gets really bad.  At first I thought it was a problem with the

approach frequency because that is where it would first start up.  It was a

loud hiss in the headphones so loud that I could not hear ATC.  In fact, I

have made two NORDO landings as a result on this loud hiss.  I sent my radio

back to have it checked out and nothing was found.  All this trouble is at

below 5000 ft and fine weather.  I am flying off my 40 hours (22 so far) and

am only flying in good weather.  These radio problems at a Class C airport

have made me afraid to fly.  ATC could take some action against me if it

continues.


	


    This is the first time I've been aware that you were having

    problems both with hearing and talking. While the ground

    listeners complain of "static" you have described the extraneous

    audio as a "hiss". We may be talking of two different problems.

    I'm having trouble resolving a single noise source that would

    manifest in both what you hear and what is transmitted to the

    ground.



    Get a hand-held transceiver and use it to 'probe' around

    the airplane. Use tune the hand-held to an unused frequency,

    open the squelch and open the volume to get a low level of

    no-signal hiss common to all receivers. Then probe around

    the panel mounted goodies and wire harnesses with the

    hand-held's antenna. See if the no-signal hiss changes

    in level with the master switch on versus off. If it does

    change, turn off accessories and/or pull breakers/fuses to

    see if any one accessory produces a noticeable change

    in noise from the hand-held.



    You can use the hand-held as an airborne signal quality

    sniffer too. Use a headset with the hand held to listen

    to your own transmitted signals. You may have to take the

    antenna off the hand-held to avoid overloading the hand-held

    receiver. You don't need to talk on the ship's radio, just

    listen to your transmitted signal to characterize the noise.

    Is it the same "hiss" you hear in your received signals?



    In any case, carry the hand held to avoid the no-radio

    return to the airport. In fact, having the 'three musketeers

    of dark-panel ops' in your flight bag is good insurance

    for any flights:



www.aeroelectric.com/Pictures/Misc/Failure_Tolerance.pdf



    It was also suggested that you try a substitute antenna.

    I've fabricated test antennas that could be taped to the

    top or bottom surface of a wing and coax brought into

    the cockpit through the door gasket or some other pathway.



    But using the hand-held to characterize your transmitted

    and received signals personally takes ATC and others

    out of the loop. This is an especially good thing when

    they're unable/unwilling to join the discussion and

    offer their own observations/insights.

   Bob . . .

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Jan 22, 2012 10:54 am Post subject: Weak and Static on Transmission

Do you get the same static when you return from a flight?  Does the hiss go

away as the engine cools down?



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

bbradburry(at)bellsouth.n
Guest

Posted: Sun Jan 22, 2012 12:01 pm Post subject: Weak and Static on Transmission

Bob,



I have borrowed an ICOM A6 handheld that I could use to do the sniffing you

are describing, but I cant use it to transmit in the plane.  It seems that

the A6 comes with a headset adapter, but if you don't also buy the optional

PTT adapter as well, both mics will be open at the same time.



Do you suggest a good value handheld radio?  I need to buy one, but I am

concerned with the type of "gotchas" that ICOM seems to have.  It also will

not transmit they tell me if the external power is plugged in.



During this probing you describe, I should have everything in the panel

turned on for the first pass, then if I get a response, start turning

everything off one at a time till I find what causes the response??



This includes the radio??



Bill B



--

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Jan 22, 2012 2:15 pm Post subject: Weak and Static on Transmission

The adapter you describe is simply a NO (normally open) momentary switch

connected to a 1/8 in mono jack.  Both mikes only open if you push the PTT

switch on the radio.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

bbradburry(at)bellsouth.n
Guest

Posted: Sun Jan 22, 2012 3:42 pm Post subject: Weak and Static on Transmission

I wonder why the handheld mike is not turned off when the headset adapter is

plugged in?  That would solve the problem and you wouldn't need to buy an

"optional" part so that it will work.



I haven't noticed much of a problem with receiving when I am on the ground.

It also seems better when I get close to the airport and contact the tower.

At first, I thought the problem was with approach/departure freq because

that was where I had the most trouble.



Bill B



--

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Jan 23, 2012 10:07 am Post subject: Weak and Static on Transmission

The momentary switch is actually a remote PTT for the headset and doesn't

activate the built in mic.



What I was thinking is that you may have being having a problem with heat on

the spark plugs, voltage reg or rectifier.  I had it happen once with a

R-582 when the seal for the water jacked perforated and allowed the plugs to

foul at anything less than WOT. What was happening was water from the

cooling system was getting into the cylinders and fouling the resistor

plugs. At one point I was flying literally feet from the tower's antenna and

still had major TX/RX problems.



Now assuming that your problem is not heat originated what I would try is

unloading your buss in flight to see if any particular circuit could be

interfering with your radio.  The last test I would try is to use the

portable radio and shut down the master switch and the gen switch.



Noel

--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

ulflyer(at)verizon.net
Guest

Posted: Tue Jan 24, 2012 9:33 pm Post subject: Weak and Static on Transmission

What kind of engine, if 2-stroke and using a voltage regular what brand is it, also what brand/model hand held radio are you using?  I have almost the same identical problem.  



  When I first flying my new home built airplane it was fine, crystal clear both transmission and receiving.   However, something changed, now I can hardly understand transmissions.  I haven't yet been able to put my finger on what's changed and causing it.



 jerryb



 

 At 09:51 AM 1/22/2012, you wrote:

 [quote]--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>



 At 07:38 AM 1/20/2012, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Bill Bradburry" <bbradburry(at)bellsouth.net>



 Well, to further clarify this problem.  I seem to be able to hear ok on the

 ground while taxiing around the airport, but after I leave the airport the

 reception gets really bad.  At first I thought it was a problem with the

 approach frequency because that is where it would first start up.  It was a

 loud hiss in the headphones so loud that I could not hear ATC.  In fact, I

 have made two NORDO landings as a result on this loud hiss.  I sent my radio

 back to have it checked out and nothing was found.  All this trouble is at

 below 5000 ft and fine weather.  I am flying off my 40 hours (22 so far) and

 am only flying in good weather.  These radio problems at a Class C airport

 have made me afraid to fly.  ATC could take some action against me if it

 continues. 	


    This is the first time I've been aware that you were having

    problems both with hearing and talking. While the ground

    listeners complain of "static" you have described the extraneous

    audio as a "hiss". We may be talking of two different problems.

    I'm having trouble resolving a single noise source that would

    manifest in both what you hear and what is transmitted to the

    ground.



    Get a hand-held transceiver and use it to 'probe' around

    the airplane. Use tune the hand-held to an unused frequency,

    open the squelch and open the volume to get a low level of

    no-signal hiss common to all receivers. Then probe around

    the panel mounted goodies and wire harnesses with the

    hand-held's antenna. See if the no-signal hiss changes

    in level with the master switch on versus off. If it does

    change, turn off accessories and/or pull breakers/fuses to

    see if any one accessory produces a noticeable change

    in noise from the hand-held.



    You can use the hand-held as an airborne signal quality

    sniffer too. Use a headset with the hand held to listen

    to your own transmitted signals. You may have to take the

    antenna off the hand-held to avoid overloading the hand-held

    receiver. You don't need to talk on the ship's radio, just

    listen to your transmitted signal to characterize the noise.

    Is it the same "hiss" you hear in your received signals?



    In any case, carry the hand held to avoid the no-radio

    return to the airport. In fact, having the 'three musketeers

    of dark-panel ops' in your flight bag is good insurance

    for any flights:



  www.aeroelectric.com/Pictures/Misc/Failure_Tolerance.pdf



    It was also suggested that you try a substitute antenna.

    I've fabricated test antennas that could be taped to the

    top or bottom surface of a wing and coax brought into

    the cockpit through the door gasket or some other pathway.



    But using the hand-held to characterize your transmitted

    and received signals personally takes ATC and others

    out of the loop. This is an especially good thing when

    they're unable/unwilling to join the discussion and

    offer their own observations/insights.



 

   Bob . . .  



 

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 [b]

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Wed Jan 25, 2012 6:23 am Post subject: Re: Weak and Static on Transmission

 	  Quote: 	
		  When I first flying my new home built airplane it was fine, crystal clear both transmission and receiving. However, something changed, now I can hardly understand transmissions. I haven't yet been able to put my finger on what's changed and causing it.    jerryb 	


The vast majority of electrical problems are caused by bad connections.  I suggest that each connection be disassembled, mating surfaces cleaned, and fasteners tightened.

Joe

_________________
Joe Gores

bbradburry(at)bellsouth.n
Guest

Posted: Wed Jan 25, 2012 7:22 am Post subject: Weak and Static on Transmission

Jerryb,  

   

The engine is a Mazda Renesis rotary.  It is a 4 stroke engine but has no valves, so it is somewhat like a two stroke.  The voltage regulator is a Transpo V1200.  I am trying to use a ICOM IC-A6 handheld radio with little or no success.  

My problems are evolving as well.  I was previously getting “5 by 5” responses from the tower on radio checks.  Now it is “weak but usable”.  The first flights were uneventful as far as radio communications go.  I could hear them and they could hear me.  Not so much now.  As far as what has changed…well, I have been building on this plane for years!  

   

Bill B  

         

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of jerb

 Sent: Wednesday, January 25, 2012 12:30 AM

 To: aeroelectric-list(at)matronics.com

 Subject: RE: AeroElectric-List: Re: Weak and Static on Transmission  

  

   

What kind of engine, if 2-stroke and using a voltage regular what brand is it, also what brand/model hand held radio are you using?  I have almost the same identical problem.  

 

  When I first flying my new home built airplane it was fine, crystal clear both transmission and receiving.   However, something changed, now I can hardly understand transmissions.  I haven't yet been able to put my finger on what's changed and causing it.

 

 jerryb

 

 

 At 09:51 AM 1/22/2012, you wrote:

 

   

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 

 At 07:38 AM 1/20/2012, you wrote:

 

   

--> AeroElectric-List message posted by: "Bill Bradburry" <bbradburry(at)bellsouth.net>

 

 Well, to further clarify this problem.  I seem to be able to hear ok on the

 ground while taxiing around the airport, but after I leave the airport the

 reception gets really bad.  At first I thought it was a problem with the

 approach frequency because that is where it would first start up.  It was a

 loud hiss in the headphones so loud that I could not hear ATC.  In fact, I

 have made two NORDO landings as a result on this loud hiss.  I sent my radio

 back to have it checked out and nothing was found.  All this trouble is at

 below 5000 ft and fine weather.  I am flying off my 40 hours (22 so far) and

 am only flying in good weather.  These radio problems at a Class C airport

 have made me afraid to fly.  ATC could take some action against me if it

 continues.  



    This is the first time I've been aware that you were having

    problems both with hearing and talking. While the ground

    listeners complain of "static" you have described the extraneous

    audio as a "hiss". We may be talking of two different problems.

    I'm having trouble resolving a single noise source that would

    manifest in both what you hear and what is transmitted to the

    ground.

 

    Get a hand-held transceiver and use it to 'probe' around

    the airplane. Use tune the hand-held to an unused frequency,

    open the squelch and open the volume to get a low level of

    no-signal hiss common to all receivers. Then probe around

    the panel mounted goodies and wire harnesses with the

    hand-held's antenna. See if the no-signal hiss changes

    in level with the master switch on versus off. If it does

    change, turn off accessories and/or pull breakers/fuses to

    see if any one accessory produces a noticeable change

    in noise from the hand-held.

 

    You can use the hand-held as an airborne signal quality

    sniffer too. Use a headset with the hand held to listen

    to your own transmitted signals. You may have to take the

    antenna off the hand-held to avoid overloading the hand-held

    receiver. You don't need to talk on the ship's radio, just

    listen to your transmitted signal to characterize the noise.

    Is it the same "hiss" you hear in your received signals?

 

    In any case, carry the hand held to avoid the no-radio

    return to the airport. In fact, having the 'three musketeers

    of dark-panel ops' in your flight bag is good insurance

    for any flights:

 

 www.aeroelectric.com/Pictures/Misc/Failure_Tolerance.pdf

 

    It was also suggested that you try a substitute antenna.

    I've fabricated test antennas that could be taped to the

    top or bottom surface of a wing and coax brought into

    the cockpit through the door gasket or some other pathway.

 

    But using the hand-held to characterize your transmitted

    and received signals personally takes ATC and others

    out of the loop. This is an especially good thing when

    they're unable/unwilling to join the discussion and

    offer their own observations/insights.

 

 

   Bob . . .  

 

 

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