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Comm antenna placement

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Vern(at)teclabsinc.com
Guest

Posted: Mon May 14, 2007 7:37 am Post subject: Comm antenna placement

Hi All,  

   

I’m to the point of wanting to install antenna doublers in my airframe. The two options are placing one comm antenna under the rear seat and one on top of the tail cone behind the fiberglass top. Or two comm antennas under the rear seat. My aesthetic preference is for the two belly mounts. However, have those running with just belly mounted comm antennas had any problems with radio communication when talking to ground control, ATC or anyone else for that matter?   In searching the archives I’ve found some discussion but not an answer to this question.  

   

Thanks,  

   

Vern Smith (#324 tail cone on:)  

      [quote][b]

Tim Olson

Joined: 25 Jan 2007
Posts: 2872

Posted: Mon May 14, 2007 9:06 am Post subject: Comm antenna placement

Not even the slightest problems with communications with the dual-belly

antennas.



Tim Olson - RV-10 N104CD - Flying

do not archive

Vern W. Smith wrote:

 	  Quote: 	
		   Hi All,

 

  

 

 I’m to the point of wanting to install antenna doublers in my airframe. 

 The two options are placing one comm antenna under the rear seat and one 

 on top of the tail cone behind the fiberglass top. Or two comm antennas 

 under the rear seat. My aesthetic preference is for the two belly 

 mounts. However, have those running with just belly mounted comm 

 antennas had any problems with radio communication when talking to 

 ground control, ATC or anyone else for that matter?   In searching the 

 archives I’ve found some discussion but not an answer to this question.

 

  

 

 Thanks,

 

  

 

 Vern Smith (#324 tail cone on:)

billderou(at)yahoo.com
Guest

Posted: Mon May 14, 2007 11:18 am Post subject: Comm antenna placement

I have supervised antenna locations on two RV-10s and have measured VSWR with a thru-line wattmeter on all the COM antennas. I'll try not to get too windy, but:

   

  Start with the transponder antenna location as it transmits at very high power and has the

           most restrictions.

      Minimum 3 physical feet from transponder

      Max of 8.8 feet of RG400

      Minimum distance to COM antenna 30"

      Try to keep it somewhat away from the gear legs.

   

  Com antenna notes :

      Use RG-58 or RG-400

      Bent whip on belly hidden by gear legs and set 3" inside gear legs = VSWR 2.6 (poor-

            reflection from transmitter is bouncing off gear  legs and flows back into antenna and

            up into cable cancelling some of the transmitted wave energy)

      Bent whip on belly just aft of the baggage bulkhead = VSWR  1.8 (good) 

      Straight antenna located between gear legs approx 8" inside = VSWR 1.6 (exceptional)

            (Doesn't look as pretty but increase in range very noticeable. Additional feature is

             ability to measure the height of grass.)

      It is much better to locate the primary radio antenna away from the gear legs even

            considering the longer cable. Backup radio will work fine with the whip antenna

             located near the gear legs.

   

  GPS antenna notes:

     Easiest to locate. The GA56 antenna can be located underneath the windscreen or

     somewhere on the top of the fuselage. (Not aware of ground plane requirements here but

     someone else may have more information). It is an active antenna meaning it has an

     amplifier that is driven from voltage traveling down the coax center wire. Note that if

     you intend to get your G430 or G530 upgraded to WAAS the GA56 must be replaced

     and the minimum cable length is 8 feet - so the best initial location is probably on the

     upper fuselage just behind the baggage bulkhead. Locate away from the COM antennas.

   

   

  Have fun,

  Bill DeRouchey

  WTD Aviation  Technology

  N939SB, flying

   

   

   

   

  



Tim Olson <Tim(at)MyRV10.com> wrote:

  [quote]--> RV10-List message posted by: Tim Olson 



Not even the slightest problems with communications with the dual-belly

antennas.



Tim Olson - RV-10 N104CD - Flying

do not archive

Vern W. Smith wrote:

[quote] Hi All,

 

 

 

 I’m to the point of wanting to install antenna doublers in my airframe. 

 The two options are placing one comm antenna under the rear seat and one 

 on top of the tail cone behind the fiberglass top. Or two comm antennas 

 under the rear seat. My aesthetic preference is for the two belly 

 mounts. However, have those running with just belly mounted comm 

 [quote][b]

Vern(at)teclabsinc.com
Guest

Posted: Tue May 15, 2007 10:34 am Post subject: Comm antenna placement

Tim and Bill,  

   

Thank you both for your feedback to my question. I picked up two antennas for belly mounting.  

   

Thanks,  

   

Vern (#324)  

Do not archive   

   

Two belly or no two belly that was the question:)        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Bill DeRouchey

 Sent: Monday, May 14, 2007 12:18 PM

 To: rv10-list(at)matronics.com

 Subject: Re: Comm antenna placement  

  

     

I have supervised antenna locations on two RV-10s and have measured VSWR with a thru-line wattmeter on all the COM antennas.   

    

   

    

Have fun,  

    

Bill DeRouchey  

    

WTD Aviation Technology  

    

N939SB, flying  

    

  

 

 Tim Olson <Tim(at)MyRV10.com> wrote:  

  [quote]  

--> RV10-List message posted by: Tim Olson 

 

 Not even the slightest problems with communications with the dual-belly

 antennas.

 

 Tim Olson - RV-10 N104CD - Flying

 do not archive

 

 

 

    	  Quote: 	
		   	
[b]

danbenua(at)yahoo.com
Guest

Posted: Tue May 15, 2007 10:50 am Post subject: Comm antenna placement

Hi All,

My RV-6A has one Com antenna on top and one on the bottom. 

There have been several times when I was on the ground and could 

not contact an off-field RCO or clearance delivery using the bottom 

antenna.  Switching to the top antenna solved the problem. 



Of course the antenna position is not the only variable.  The two 

antennas are of different models and connect to radios from different 

manufacturers.  Your mileage may vary, but on my -10 I'm putting

one up and one down.



- Dan Benua

#40001 "Finishing"



 	  Quote: 	
		        I'm to the point of wanting to install antenna doublers in my airframe.

      The two options are placing one comm antenna under the rear seat and one

      on top of the tail cone behind the fiberglass top. Or two comm antennas

      under the rear seat. My aesthetic preference is for the two belly

      mounts. However, have those running with just belly mounted comm

      antennas had any problems with radio communication when talking to

      ground control, ATC or anyone else for that matter?   In searching the

      archives I've found some discussion but not an answer to this question.

      

           

      Vern Smith (#324 tail cone on:)


	




 

Don't pick lemons.

See all the new 2007 cars at Yahoo! Autos.

http://autos.yahoo.com/new_cars.html

coop85(at)cableone.net
Guest

Posted: Tue May 15, 2007 6:52 pm Post subject: Comm antenna placement

Vern,  

      I took a little different route.  I put a bent whip antenna just aft of the baggage compartment, and a $7 copper foil antenna on the roof.  I figured I wasn’t out a thing to try it and it works great.  It also alleviated my concern of shadowing the antenna to tower while on the ground, although I haven’t had any issues with my belly mounted antenna which I use with the primary radio.  

   

Marcus  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Vern W. Smith

 Sent: Monday, May 14, 2007 10:37 AM

 To: rv10-list(at)matronics.com

 Subject: Comm antenna placement  

  

   

Hi All,  

   

I’m to the point of wanting to install antenna doublers in my airframe. The two options are placing one comm antenna under the rear seat and one on top of the tail cone behind the fiberglass top. Or two comm antennas under the rear seat. My aesthetic preference is for the two belly mounts. However, have those running with just belly mounted comm antennas had any problems with radio communication when talking to ground control, ATC or anyone else for that matter?   In searching the archives I’ve found some discussion but not an answer to this question.  

   

Thanks,  

   

Vern Smith (#324 tail cone on:)   	  Quote: 	
		    http://www.matronics.com/Navigator?RV10-List 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4

        [quote][b]

sam(at)fr8dog.net
Guest

Posted: Tue May 15, 2007 10:12 pm Post subject: Comm antenna placement

Where can I find information on the foil antenna?

Thanks,

Sam Marlow



Marcus Cooper wrote:

 	  Quote: 	
		  

 Vern,



 I took a little different route. I put a bent whip antenna just aft of 

 the baggage compartment, and a $7 copper foil antenna on the roof. I 

 figured I wasn’t out a thing to try it and it works great. It also 

 alleviated my concern of shadowing the antenna to tower while on the 

 ground, although I haven’t had any issues with my belly mounted 

 antenna which I use with the primary radio.



 Marcus



 ------------------------------------------------------------------------



 *From:* owner-rv10-list-server(at)matronics.com 

 [mailto:owner-rv10-list-server(at)matronics.com] *On Behalf Of *Vern W. Smith

 *Sent:* Monday, May 14, 2007 10:37 AM

 *To:* rv10-list(at)matronics.com

 *Subject:* Comm antenna placement



 Hi All,



 I’m to the point of wanting to install antenna doublers in my 

 airframe. The two options are placing one comm antenna under the rear 

 seat and one on top of the tail cone behind the fiberglass top. Or two 

 comm antennas under the rear seat. My aesthetic preference is for the 

 two belly mounts. However, have those running with just belly mounted 

 comm antennas had any problems with radio communication when talking 

 to ground control, ATC or anyone else for that matter? In searching 

 the archives I’ve found some discussion but not an answer to this 

 question.



 Thanks,



 Vern Smith (#324 tail cone on:)



 * *

 * *

 **

 **

 **

 **

 **

 **

 * *

 *

 *

ScooterF15

Joined: 19 Jun 2006
Posts: 136

Posted: Wed May 16, 2007 1:41 am Post subject: Comm antenna placement

There's a post at _http://forum.matronics.com_ (http://forum.matronics.com)  

in the  RV-10 list titled Low Drag VHF Antenna regarding the foil antenna I  

installed just aft of the passenger side door.

 

_http://forum.matronics.com/viewtopic.php?t=6664_ 

(http://forum.matronics.com/viewtopic.php?t=6664) 

 

-Jim

40134

 

(http://forum.matronics.com/viewtopic.phpt=6664&highlight=jsmcgrew&sid=e98a17dca7e4dd298739c55713db731d)  

 

 

 

In a message dated 5/16/2007 2:14:54 A.M. Eastern Daylight Time,  

sam(at)fr8dog.net writes:






Where  can I find information on the foil antenna?

Thanks,

Sam  Marlow



Marcus Cooper wrote:

 	  Quote: 	
		  

 Vern,



 I  took a little different route. I put a bent whip antenna just aft of 

  the baggage compartment, and a $7 copper foil antenna on the roof. I 

  figured I wasnâ€™t out a thing to try it and it works great. It also 

  alleviated my concern of shadowing the antenna to tower while on the 

  ground, although I havenâ€™t had any issues with my belly mounted 

  antenna which I use with the primary radio.



  Marcus



  ------------------------------------------------------------------------



  *From:* owner-rv10-list-server(at)matronics.com 

  [mailto:owner-rv10-list-server(at)matronics.com] *On Behalf Of *Vern W.  Smith

 *Sent:* Monday, May 14, 2007 10:37 AM

 *To:*  rv10-list(at)matronics.com

 *Subject:* Comm antenna  placement



 Hi All,



 Iâ€™m to the point of wanting  to install antenna doublers in my 

 airframe. The two options are  placing one comm antenna under the rear 

 seat and one on top of the  tail cone behind the fiberglass top. Or two 

 comm antennas under the  rear seat. My aesthetic preference is for the 

 two belly mounts.  However, have those running with just belly mounted 

 comm antennas had  any problems with radio communication when talking 

 to ground control,  ATC or anyone else for that matter? In searching 

 the archives Iâ€™ve  found some discussion but not an answer to this 

  question.



 Thanks,



 Vern Smith (#324 tail cone  on:)


	






Jim "Scooter"  McGrew

_http://www.mit.edu/~jsmcgrew_ (http://www.mit.edu/~jsmcgrew)  



************************************** See what's free at http://www.aol.com

coop85(at)cableone.net
Guest

Posted: Wed May 16, 2007 6:37 am Post subject: Comm antenna placement

I got the foil antenna from Van's.  The part number info is 



Comm Antenna

Part Number = AV ANTENNA, W'SCREEN

Price = $7.00



Here's a direct link:

http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1179326096-54-723&brow

se=avionics&product=lowdrag-antennas



Hope this helps,

Marcus



--

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Vern(at)teclabsinc.com
Guest

Posted: Thu May 17, 2007 6:27 am Post subject: Comm antenna placement

Marcus,  

   

Have you had a chance to compare the performance of the foil roof mount to your bent whip?  

   

Vern (#324)        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Marcus Cooper

 Sent: Tuesday, May 15, 2007 7:52 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Comm antenna placement  

  

   

Vern,  

      I took a little different route.  I put a bent whip antenna just aft of the baggage compartment, and a $7 copper foil antenna on the roof.  I figured I wasn’t out a thing to try it and it works great.  It also alleviated my concern of shadowing the antenna to tower while on the ground, although I haven’t had any issues with my belly mounted antenna which I use with the primary radio.  

   

Marcus  

   [quote]http://www.matronics.com/Navigator?RV10-Listhttp://forums.matronics.com [b]

coop85(at)cableone.net
Guest

Posted: Thu May 17, 2007 4:32 pm Post subject: Comm antenna placement

Vern,  

     I use the whip primarily as it is tied to my Garmin 480 and the foil is connected to the SL-30.  I have never not been able to contact anyone on the SL-30 and therefore switch to the 480 and have used it intentionally numerous times to see how it works.  During initial testing I did a number of radio checks with the tower and it sounded like they couldn’t tell the difference (I wasn’t that far away though).  My primary mode is to use the bent whip setup as primary and get ATIS/talk to Unicom on the foil with great success.  

   

I figured worst case I’d have to add another whip antenna and I’d only be out $7 plus the coax to try it.  

   

Marcus  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Vern W. Smith

 Sent: Thursday, May 17, 2007 9:26 AM

 To: rv10-list(at)matronics.com

 Subject: RE: Comm antenna placement  

  

   

Marcus,  

   

Have you had a chance to compare the performance of the foil roof mount to your bent whip?  

   

Vern (#324)        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Marcus Cooper

 Sent: Tuesday, May 15, 2007 7:52 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Comm antenna placement  

  

   

Vern,  

      I took a little different route.  I put a bent whip antenna just aft of the baggage compartment, and a $7 copper foil antenna on the roof.  I figured I wasn’t out a thing to try it and it works great.  It also alleviated my concern of shadowing the antenna to tower while on the ground, although I haven’t had any issues with my belly mounted antenna which I use with the primary radio.  

   

Marcus  

    	  Quote: 	
		   	
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Vern(at)teclabsinc.com
Guest

Posted: Fri May 18, 2007 7:04 am Post subject: Comm antenna placement

Marcus,  

   

Thanks for sharing your findings. I know results are subjective without measuring equipment, but it is great when people are willing to say ‘hay this is what I did and these are my impressions.’ The way you use your setup sounds like it perfectly matches your needs.  

   

Vern Smith  

   

Do not archive  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Marcus Cooper

 Sent: Thursday, May 17, 2007 5:32 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Comm antenna placement  

  

   

Vern,  

     I use the whip primarily as it is tied to my Garmin 480 and the foil is connected to the SL-30.  I have never not been able to contact anyone on the SL-30 and therefore switch to the 480 and have used it intentionally numerous times to see how it works.  During initial testing I did a number of radio checks with the tower and it sounded like they couldn’t tell the difference (I wasn’t that far away though).  My primary mode is to use the bent whip setup as primary and get ATIS/talk to Unicom on the foil with great success.  

   

I figured worst case I’d have to add another whip antenna and I’d only be out $7 plus the coax to try it.  

   

Marcus  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Vern W. Smith

 Sent: Thursday, May 17, 2007 9:26 AM

 To: rv10-list(at)matronics.com

 Subject: RE: Comm antenna placement  

  

   

Marcus,  

   

Have you had a chance to compare the performance of the foil roof mount to your bent whip?  

   

Vern (#324)        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Marcus Cooper

 Sent: Tuesday, May 15, 2007 7:52 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Comm antenna placement  

  

   

Vern,  

      I took a little different route.  I put a bent whip antenna just aft of the baggage compartment, and a $7 copper foil antenna on the roof.  I figured I wasn’t out a thing to try it and it works great.  It also alleviated my concern of shadowing the antenna to tower while on the ground, although I haven’t had any issues with my belly mounted antenna which I use with the primary radio.  

   

Marcus  

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