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Why can't the tower hear me?

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SteveR

Joined: 10 Jan 2006
Posts: 226
Location: Aledo, TX

Posted: Sat Aug 02, 2008 12:06 pm Post subject: Why can't the tower hear me?

A little new information on this.  To refresh  everyone's memory, I have a handheld with a homemade external antenna (brass  brazing rod on the bottom of the nose, with a ground plane).  I have no  problems whatsoever communicating air to air, even up to 125 miles, and I have  flown into multiple class D areas with no trouble at all (KFTW - 118.3,  KAFW - 120.825, KDTO - 119.95, KADM - 118.5, and others).  Everyone reports  my signal as loud and clear, EXCEPT the tower at KOUN (118.0).

  

 This morning, I was flying out of KOUN again and  got some new information that might be helpful.  On the ground, they could  hear me very clearly on 121.6.  As soon as I switched to 118.0 though, they  said my transmission was garbled and unreadable (still on the ground, nothing  had changed but the frequency).

  

 So, I know I can transmit clearly on 118.3.   However, apparently it is not so clear on 118.0.  I can hear the tower  clearly on 118.0.  I've read that an antenna that receives well will also  transmit well...this makes me think the antenna is probably good.  Is it  possible that the digital tuner on my handheld is not tuning correctly?  I  know, I need to get another handheld in the plane to see if I have the same  problem.  My radio is a three year old Vertex Standard  VXA-150.

  

 Anyway, my primary question is, can anyone shed  light on why I am not able to transmit clearly on 118.0?  Where should I  look first to try and solve this problem?  I realize that  118.0 is at the very bottom of the aviation band, which made me think maybe  my antenna length is off just slightly.  I am going to measure that to  verify.  On that note, what is the exact length of the antenna with respect  to the ground plane that I should measure?  It is a brass rod sticking  through an aluminum plate with nylon spacers as insulators.  The brass rod  sticks up above the ground plane about 1/2" or so on top.  Could that small  unshielded portion cause a problem, or is it too small to be a factor, and only  the primary antenna length below the ground plane matters?

  

 Thanks for any help,

  

 Steve Ruse

 [quote]   ---

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ceengland(at)bellsouth.ne
Guest

Posted: Sat Aug 02, 2008 1:00 pm Post subject: Why can't the tower hear me?

Do you have the same problem approaching KOUN from the air on 118.0?



Have you tried air to air with a friend on 118.0 (far from KOUN)?



Have you tried going to an  uncontrolled field far away from KOUN with a 

friend who's got a known-good radio on 118.0, going to opposite ends of 

the field & talking to each other ground to ground?



Have you tried substituting a different handheld hooked to your antenna 

at KOUN?



I'm still betting on the tower having the problem, but obviously, that's 

a hard sell if you have arrogant jerks in the tower.



If you test your radio against other radios on 118.0 & it works ok, I'd 

try going further up the food chain. I've read somewhere that the FAA 

now has a phone number that allows you to bypass the chain of authority 

& go straight to the top when you have unresolvable issues with local 

personnel. Sorry I can't offer the number because I haven't had need to 

use it lately. (I typically avoid controlled fields.)



Charlie



Steve Ruse wrote:

[quote] A little new information on this.  To refresh everyone's memory, I have a handheld with a homemade external antenna (brass brazing rod on the bottom of the nose, with a ground plane).  I have no problems whatsoever communicating air to air, even up to 125 miles, and I have flown into multiple class D areas with no trouble at all (KFTW - 118.3, KAFW - 120.825, KDTO - 119.95, KADM - 118.5, and others).  Everyone reports my signal as loud and clear, EXCEPT the tower at KOUN (118.0).



 This morning, I was flying out of KOUN again and got some new information that might be helpful.  On the ground, they could hear me very clearly on 121.6.  As soon as I switched to 118.0 though, they said my transmission was garbled and unreadable (still on the ground, nothing had changed but the frequency).



 So, I know I can transmit clearly on 118.3.  However, apparently it is not so clear on 118.0.  I can hear the tower clearly on 118.0.  I've read that an antenna that receives well will also transmit well...this makes me think the antenna is probably good.  Is it possible that the digital tuner on my handheld is not tuning correctly?  I know, I need to get another handheld in the plane to see if I have the same problem.  My radio is a three year old Vertex Standard VXA-150.



 Anyway, my primary question is, can anyone shed light on why I am not able to transmit clearly on 118.0?  Where should I look first to try and solve this problem?  I realize that 118.0 is at the very bottom of the aviation band, which made me think maybe my antenna length is off just slightly.  I am going to measure that to verify.  On that note, what is the exact length of the antenna with respect to the ground plane that I should measure?  It is a brass rod sticking through an aluminum plate with nylon spacers as insulators.  The brass rod sticks up above the ground plane about 1/2" or so on top.  Could that small unshielded portion cause a problem, or is it too small to be a factor, and only the primary antenna length below the ground plane matters?



 Thanks for any help,



 Steve Ruse

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SteveR

Joined: 10 Jan 2006
Posts: 226
Location: Aledo, TX

Posted: Sat Aug 02, 2008 7:54 pm Post subject: Why can't the tower hear me?

Charlie,



Thanks for the suggestions, those will definitely help narrow down the 

problem.  My plane is based on a small grass strip, and I typically avoid 

towered fields too, but sometimes they are necessary.  Unfortunately, the 

only one I have a problem with is right in my backyard.



Thanks for the tips, I'll post again when I find something.



Steve Ruse

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bobf(at)feldtman.com
Guest

Posted: Sun Aug 03, 2008 9:38 am Post subject: Why can't the tower hear me?

I just plugged in my handheld vertex into the extra antenna on my glastar - over Austin. Received the usual spark plugs ignition noise my Apollo GX65 hears; but when the approach transmitted, the intermodulation on the vertex was terrible. Vertex is Yaesu I believe, and my 2 meter ham radio goes nuts in certain parts of Houston (we call it RF alley) on I-59- so - intermod, usually affects received signals, but who knows maybe in these "cheap" little radios, other equipment on the field might also affect it. Do you have anything else "on" in the plane? I'd say it is not the antenna. best advice, you have already been given - test it with another plane or two on that frequency, and confirm it is okay before you get into it with the FAA. I do believe they have the worst radios on the aviation band however. I always have to turn the squelch "off" to hear them in my glastar - but the garmin in my 500B receives them well.

 bobf

W5RF



On Sat, Aug 2, 2008 at 3:02 PM, Steve Ruse <steve(at)wotelectronics.com (steve(at)wotelectronics.com)> wrote:

[quote]        A little new information on this.  To refresh  everyone's memory, I have a handheld with a homemade external antenna (brass  brazing rod on the bottom of the nose, with a ground plane).  I have no  problems whatsoever communicating air to air, even up to 125 miles, and I have  flown into multiple class D areas with no trouble at all (KFTW - 118.3,  KAFW - 120.825, KDTO - 119.95, KADM - 118.5, and others).  Everyone reports  my signal as loud and clear, EXCEPT the tower at KOUN (118.0).

  

 This morning, I was flying out of KOUN again and  got some new information that might be helpful.  On the ground, they could  hear me very clearly on 121.6.  As soon as I switched to 118.0 though, they  said my transmission was garbled and unreadable (still on the ground, nothing  had changed but the frequency).

  

 So, I know I can transmit clearly on 118.3.   However, apparently it is not so clear on 118.0.  I can hear the tower  clearly on 118.0.  I've read that an antenna that receives well will also  transmit well...this makes me think the antenna is probably good.  Is it  possible that the digital tuner on my handheld is not tuning correctly?  I  know, I need to get another handheld in the plane to see if I have the same  problem.  My radio is a three year old Vertex Standard  VXA-150.

  

 Anyway, my primary question is, can anyone shed  light on why I am not able to transmit clearly on 118.0?  Where should I  look first to try and solve this problem?  I realize that  118.0 is at the very bottom of the aviation band, which made me think maybe  my antenna length is off just slightly.  I am going to measure that to  verify.  On that note, what is the exact length of the antenna with respect  to the ground plane that I should measure?  It is a brass rod sticking  through an aluminum plate with nylon spacers as insulators.  The brass rod  sticks up above the ground plane about 1/2" or so on top.  Could that small  unshielded portion cause a problem, or is it too small to be a factor, and only  the primary antenna length below the ground plane matters?

  

 Thanks for any help,

  

 Steve Ruse

 [quote]   ---

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SteveR

Joined: 10 Jan 2006
Posts: 226
Location: Aledo, TX

Posted: Sun Aug 03, 2008 6:34 pm Post subject: Why can't the tower hear me?

My plane actually has no engine driven electrical  system, just a 12v battery that runs the radio, intercom and GPS.  My wires  are all shielded (including plug wires), and the plane has almost no electronics  so noise sources are minimal.

  

 Today, I did another test that sheds a lot of light  on the situation.  From 2,500', I called the tower from less than 6 miles  out.  My friend in his plane a few miles away reported that he could hear  me loud and clear, but the tower said I was garbled and unreadable.  To me,  that indicates that some combination of factors between my radio and theirs is  causing problems.  At what point should I try to address it with  them?  I doubt they will care about my problem if no one else is having  problems.

  

 Thanks for any tips.

  

 Steve Ruse

 [quote]   ---

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bobf(at)feldtman.com
Guest

Posted: Sun Aug 03, 2008 6:54 pm Post subject: Why can't the tower hear me?

sounds like it is the tower's receiver.

bobf



On Sun, Aug 3, 2008 at 9:26 PM, Steve Ruse <steve(at)wotelectronics.com (steve(at)wotelectronics.com)> wrote:

 [quote]       My plane actually has no engine driven electrical  system, just a 12v battery that runs the radio, intercom and GPS.  My wires  are all shielded (including plug wires), and the plane has almost no electronics  so noise sources are minimal.

  

 Today, I did another test that sheds a lot of light  on the situation.  From 2,500', I called the tower from less than 6 miles  out.  My friend in his plane a few miles away reported that he could hear  me loud and clear, but the tower said I was garbled and unreadable.  To me,  that indicates that some combination of factors between my radio and theirs is  causing problems.  At what point should I try to address it with  them?  I doubt they will care about my problem if no one else is having  problems.

  

 Thanks for any tips.

  

 Steve Ruse

 [quote]   ---

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Dale Ensing

Joined: 11 Jan 2006
Posts: 571
Location: Aero Plantation Weddington NC

Posted: Mon Aug 04, 2008 4:47 am Post subject: Why can't the tower hear me?

No engine driven alternator or generator? How do  you keep the battery charged?

 Dale Ensing

 [quote]   ---

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_________________
Dale Ensing
RV-6A
Aero Plantation
Weddington NC

nuckolls.bob(at)cox.net
Guest

Posted: Mon Aug 04, 2008 5:30 am Post subject: Why can't the tower hear me?

At 09:26 PM 8/3/2008 -0500, you wrote:

 	  Quote: 	
		  My plane actually has no engine driven electrical system, just a 12v 

battery that runs the radio, intercom and GPS.  My wires are all shielded 

(including plug wires), and the plane has almost no electronics so noise 

sources are minimal.



Today, I did another test that sheds a lot of light on the 

situation.  From 2,500', I called the tower from less than 6 miles 

out.  My friend in his plane a few miles away reported that he could hear 

me loud and clear, but the tower said I was garbled and unreadable.  To 

me, that indicates that some combination of factors between my radio and 

theirs is causing problems.  At what point should I try to address it with 

them?  I doubt they will care about my problem if no one else is having 

problems.


	


     It's been suggested that you try another hand-held on the same antenna.

     Also, while still on the field you might try using the "rubber-ducky"

     antenna that comes with the radio. It would also be interesting to have

     a friend visit the tower (a gray-haired ol' ham operator that used to

     build his own stuff would be good) and see what your signal sounds like

     to him while you switch between the rubber duck, the ship's antenna and

     perhaps even another hand-held on its own rubber duck and the ship's

     antenna.



     I recall a trip to the practice area early one morning before I

     got my ticket. Some guy in a Pacer called the tower and was truly

     garbled to the point that I could barely understand him in the airplane.

     However, the tower guys could understand him better than I could from

     the quieter tower cab . . . they handled him like any other traffic.

     I was amazed that they did not at least suggest he have his radio

     looked at (I'll bet his REAL carbon mic was going bad). By the time

     I got back from the practice area, the guy had refueled and gone

     or I would have approached him. In fact, I cannot recall any time

     hearing a traffic controller complain about signals that I thought

     sucked for air. It's only when the pilot specifically asked about

     his radio that anyone offered much of an opinion and for the most

     part, controllers were exceedingly generous in their assessments.



     Years ago it was not uncommon for a multi-channel radio to

     have problems on every tenth step in the progression of frequency

     selections when one frequency control crystal of several dozen

     had gone bad. Modern radios use one crystal to stabilize a digital

     frequency synthesizer so if one frequency is off, ALL frequencies

     are off too. A quick check of your radio against a counter would

     be good. Any two-way radio shop in your area could do this test

     in about ten seconds.



     It's just possible that someone in the tower has a "thing" for

     you or your homebuilt . . . I've come to understand that the

     bell-curve is a fact of nature . . . it cannot be ignored. For

     every Mother Theresa there's GOT to be a Saddam Hussein.

     The best way to resolve the true nature of your difficulties

     is to get a third party involved . . . someone experienced in

     judging the quality of radio signals.



     If your third party approaches the tower folks with the notion

     that you need to conduct an experiment to resolve a problem

     they'd be hard pressed not to cooperate. Do a double-blind

     study of the four conditions I suggested above with your radio

     and one other radio and two different antennas. Just speak to

     condition A, B, C and D without letting anyone at the other

     end know what the details of any particular condition.



     Bob . . .

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