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  #1  
Old 05-08-2019, 03:02 PM
n567vb n567vb is offline
 
Join Date: Feb 2008
Location: MN
Posts: 81
Default Ice on Antenna causing transmission lost?

Hi

I recently had a transmission issue with my comm radio while IMC. Based on the following, I'm guessing it was just ice on the comm antenna? Any other thoughts on what it could be?

RV-7, flying for seven years, no issues in the past with the radios. I went for a short IFR flight to stay current on a nice IFR day (2000 ft overcast), no rain, good visibility underneath. All was normal before entering IMC, I was able to contact clearance on the ground at my non towered home base. Took off and communicated back and forth with departure several times. A few minutes after entering the clouds, my transmissions starting getting intermittent and then stopped transmitting. No side tone in my headset and also tried switching to the passenger headset. Same issue. The controller could hear me trying to call, but couldn't hear me. I could receive him just fine. I acknowledged his directions using ident, and I returned to my home field. About a minute after clearing the clouds, I could transmit again. Temps on the ground were right about 40 degrees. There was no ice on the canopy, and I didn't see anything on the wings, but didn't get a could look. If there was anything, it was unnoticeable at quick glance.

I checked the antenna on the ground (it's mounted on the belly), no obvious issue that I could see. I cleaned the antenna (I was able to wipe some dirt off of it) and went up again later in VFR conditions, no issues and haven't been able to repeat the issue.

Based on the above, I figure it has to be something external/environmental, but icing seems to be the only explanation I can come up with.

Thanks
Vince
RV-7
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  #2  
Old 05-08-2019, 07:12 PM
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dlloyd3 dlloyd3 is offline
 
Join Date: Jun 2005
Location: Locust, NC
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No sidetone when transmitting indicates a problem inside the airplane, not an iced over antenna. No sidetone, no voice transmit but controller heard the carrier, could be loose wire or failing radio. Had plenty of ice but no communication difficulty due to it. Flying in heavy rain or snow will cause precipitation induced static, but that is easily recognized.
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Last edited by dlloyd3 : 05-08-2019 at 07:17 PM.
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  #3  
Old 05-08-2019, 08:56 PM
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N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
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Well... I had a friend who couldn't transmit after an encounter with ice.

When he landed he noticed the ice load snapped his antenna off. That doesn't sound like your issue.

If you have a Comant antenna, remove one screw at a time, give the hole a quick turn with your deburring tool, put dielectric grease on the screw and reinstall it. That solved a similar intermittent issue I had.
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Last edited by N941WR : 05-08-2019 at 09:02 PM.
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  #4  
Old 05-08-2019, 11:50 PM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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In my 6, ice always shows on the windscreen and have never seen it anywhere else when not also on the windscreen, excluding occassional pitot freezing. If it is an antenna issue, I would guess ti was related to static electricity. The moisture in the air increases the amount of static electricity produced from air friction on the body.

Larry
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  #5  
Old 05-09-2019, 12:21 PM
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RV8Squaz RV8Squaz is offline
 
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Location: Senoia, Georgia
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The no sidetone may be an issue. It's possible you just couldn't hear the sidetone over all of the static. BTW, this happens even on airliners. You just have to wait until you exit the clouds and the ice begins to sublimate. It makes communication near impossible sometimes.
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  #6  
Old 05-09-2019, 07:53 PM
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Bill.Peyton Bill.Peyton is offline
 
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Location: St. Louis, MO
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Static build upon airframe. Bet you don?t have static wicks!
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WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.
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  #7  
Old 05-10-2019, 03:50 AM
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FORANE FORANE is offline
 
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Location: East TN
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Google precipitation static; it's worst in the snow.
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Last edited by FORANE : 05-10-2019 at 04:12 AM.
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  #8  
Old 05-10-2019, 10:54 AM
n567vb n567vb is offline
 
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Location: MN
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I considered precip static, but wouldn't that affect all communications, not just transmissions? I was able to received ATC just fine
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  #9  
Old 05-10-2019, 11:33 AM
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larrynew larrynew is offline
 
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I've very occasionally had static while IMC. I have 2 radios with the secondary having the antenna on top of the fuselage. Switching to the upper antenna radio has always worked and the static on the primary radio with lower antenna goes away in a minute or two even when still IMC and always goes away when VMC.
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Last edited by larrynew : 05-10-2019 at 02:12 PM. Reason: -s
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  #10  
Old 05-10-2019, 11:49 AM
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Carl Froehlich Carl Froehlich is offline
 
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Location: Dogwood Airpark (VA42)
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Quote:
Originally Posted by n567vb View Post
I considered precip static, but wouldn't that affect all communications, not just transmissions? I was able to received ATC just fine
Typically it would affect reception but not transmission.

I suspect you have another issue to find other than static.

Carl

Last edited by Carl Froehlich : 05-12-2019 at 07:48 AM.
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