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bob.kravis(at)gmail.com
Guest

Posted: Thu Jul 29, 2010 10:47 am Post subject: Handheld radio to external antenna connections?

Hi,I followed the suggestions I found in the archives and purchased an ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will mount via its belt clip into a custom bracket between the forward edge of the seat and the floor plate (aluminum diamond plate) in my Firefly.  The antenna will be mounted through the floor plate and extend below and back through the belly fabric.  That's the plan. There were no instructions sent from Aircraft Spruce (part #11-04517) and the support tech was not very helpful in how to wire it up.  The ICOM support guy said most of the antennae come with a coax cable and BNC female that you just pug in to the radio.  Mine doesn't.  Now the antenna has a knurled aluminum shouldered spacer, through the center of which, the SS antenna rod runs.  There are nuts at each end which squeeze the assembly together.  There is no provision for electrical connection.  I will have to fabricate a cable with a BNC connector.

 1. What is the correct cable connection? Does the insulated center wire go to the antenna rod end and the sheath go to the aluminum floor plate or what?  It does not appear that the antenna rod is electrically isolated from the mounting hole in the floor plate so I don't see how that would work? Google searches for antenna connections have not been fruitful.

 2. I have the adapter for the handheld and will be installing a small panel with audio and mic jacks.  There is some very expensive cabling available to wire this up but what is really needed to get a clean, ignition noise free signal?

 Thanks for your input.

Bob

E008BK at  9NC8

  [quote][b]

russkinne(at)mac.com
Guest

Posted: Thu Jul 29, 2010 11:01 am Post subject: Handheld radio to external antenna connections?

BobI'd suggest first asking ICOM about this



On Jul 29, 2010, at 2:46 PM, Bob Kravis wrote:

 	  Quote: 	
		  Hi,I followed the suggestions I found in the archives and purchased an ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will mount via its belt clip into a custom bracket between the forward edge of the seat and the floor plate (aluminum diamond plate) in my Firefly.  The antenna will be mounted through the floor plate and extend below and back through the belly fabric.  That's the plan. There were no instructions sent from Aircraft Spruce (part #11-04517) and the support tech was not very helpful in how to wire it up.  The ICOM support guy said most of the antennae come with a coax cable and BNC female that you just pug in to the radio.  Mine doesn't.  Now the antenna has a knurled aluminum shouldered spacer, through the center of which, the SS antenna rod runs.  There are nuts at each end which squeeze the assembly together.  There is no provision for electrical connection.  I will have to fabricate a cable with a BNC connector.

 1. What is the correct cable connection? Does the insulated center wire go to the antenna rod end and the sheath go to the aluminum floor plate or what?  It does not appear that the antenna rod is electrically isolated from the mounting hole in the floor plate so I don't see how that would work? Google searches for antenna connections have not been fruitful.

 2. I have the adapter for the handheld and will be installing a small panel with audio and mic jacks.  There is some very expensive cabling available to wire this up but what is really needed to get a clean, ignition noise free signal?

 Thanks for your input.

Bob

E008BK at  9NC8

  	  Quote: 	
		  



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bob.kravis(at)gmail.com
Guest

Posted: Thu Jul 29, 2010 11:35 am Post subject: Handheld radio to external antenna connections?

I did Russ, they sent a generic email as I quoted.  I'll try calling them.  Thanks, bk



On Thu, Jul 29, 2010 at 3:00 PM, russ kinne <russkinne(at)mac.com (russkinne(at)mac.com)> wrote:

 [quote] BobI'd suggest first asking ICOM about this



On Jul 29, 2010, at 2:46 PM, Bob Kravis wrote:

 	  Quote: 	
		  Hi,I followed the suggestions I found in the archives and purchased an ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will mount via its belt clip into a custom bracket between the forward edge of the seat and the floor plate (aluminum diamond plate) in my Firefly.  The antenna will be mounted through the floor plate and extend below and back through the belly fabric.  That's the plan. There were no instructions sent from Aircraft Spruce (part #11-04517) and the support tech was not very helpful in how to wire it up.  The ICOM support guy said most of the antennae come with a coax cable and BNC female that you just pug in to the radio.  Mine doesn't.  Now the antenna has a knurled aluminum shouldered spacer, through the center of which, the SS antenna rod runs.  There are nuts at each end which squeeze the assembly together.  There is no provision for electrical connection.  I will have to fabricate a cable with a BNC connector.

  1. What is the correct cable connection? Does the insulated center wire go to the antenna rod end and the sheath go to the aluminum floor plate or what?  It does not appear that the antenna rod is electrically isolated from the mounting hole in the floor plate so I don't see how that would work? Google searches for antenna connections have not been fruitful.

  2. I have the adapter for the handheld and will be installing a small panel with audio and mic jacks.  There is some very expensive cabling available to wire this up but what is really needed to get a clean, ignition noise free signal?

  Thanks for your input.

Bob

E008BK at  9NC8

 

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[b]

bob.kravis(at)gmail.com
Guest

Posted: Thu Jul 29, 2010 11:53 am Post subject: Handheld radio to external antenna connections?

I called ICOM and was told that as suspected the center wire of the sheathed wire goes to the antenna rod.  But, the sheath (copper braid) termination was uncertain.  They suggested I track the mfr. down for advice.  I went back to the AS catalog and see that the knurled spacers are Delrin, not anodized aluminum as previously thought.  So there is insulation between the antenna rod and the floor plate.  ICOM also said that the load across the antenna port on the handheld must be 50 ohms or greater, else you overheat the transmitter output and cook it!  Now I wonder if I need to put a resistor (5 watt?) between the antenna and the floor plate? I'll post back when I get an answer. bk



On Thu, Jul 29, 2010 at 3:35 PM, Bob Kravis <bob.kravis(at)gmail.com (bob.kravis(at)gmail.com)> wrote:

[quote] I did Russ, they sent a generic email as I quoted.  I'll try calling them.  Thanks, bk

On Thu, Jul 29, 2010 at 3:00 PM, russ kinne <russkinne(at)mac.com (russkinne(at)mac.com)> wrote:

   	  Quote: 	
		   BobI'd suggest first asking ICOM about this



On Jul 29, 2010, at 2:46 PM, Bob Kravis wrote:

 	  Quote: 	
		  Hi,I followed the suggestions I found in the archives and purchased an ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will mount via its belt clip into a custom bracket between the forward edge of the seat and the floor plate (aluminum diamond plate) in my Firefly.  The antenna will be mounted through the floor plate and extend below and back through the belly fabric.  That's the plan. There were no instructions sent from Aircraft Spruce (part #11-04517) and the support tech was not very helpful in how to wire it up.  The ICOM support guy said most of the antennae come with a coax cable and BNC female that you just pug in to the radio.  Mine doesn't.  Now the antenna has a knurled aluminum shouldered spacer, through the center of which, the SS antenna rod runs.  There are nuts at each end which squeeze the assembly together.  There is no provision for electrical connection.  I will have to fabricate a cable with a BNC connector.

   1. What is the correct cable connection? Does the insulated center wire go to the antenna rod end and the sheath go to the aluminum floor plate or what?  It does not appear that the antenna rod is electrically isolated from the mounting hole in the floor plate so I don't see how that would work? Google searches for antenna connections have not been fruitful.

   2. I have the adapter for the handheld and will be installing a small panel with audio and mic jacks.  There is some very expensive cabling available to wire this up but what is really needed to get a clean, ignition noise free signal?

   Thanks for your input.

Bob

E008BK at  9NC8

 

 	  Quote: 	
		  



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[b]

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Thu Jul 29, 2010 3:19 pm Post subject: Handheld radio to external antenna connections?

Bob, the 50 ohm spec is supplied by using the right coax cable. Go to your local Radio Shack and you may be able to buy a cable ready made and only fabricate a ground plane for the antenna.



Rick Girard

 

On Thu, Jul 29, 2010 at 2:53 PM, Bob Kravis <bob.kravis(at)gmail.com (bob.kravis(at)gmail.com)> wrote:

[quote] I called ICOM and was told that as suspected the center wire of the sheathed wire goes to the antenna rod.  But, the sheath (copper braid) termination was uncertain.  They suggested I track the mfr. down for advice.  I went back to the AS catalog and see that the knurled spacers are Delrin, not anodized aluminum as previously thought.  So there is insulation between the antenna rod and the floor plate.  ICOM also said that the load across the antenna port on the handheld must be 50 ohms or greater, else you overheat the transmitter output and cook it!  Now I wonder if I need to put a resistor (5 watt?) between the antenna and the floor plate? I'll post back when I get an answer.  bk

On Thu, Jul 29, 2010 at 3:35 PM, Bob Kravis <bob.kravis(at)gmail.com (bob.kravis(at)gmail.com)> wrote:

  	  Quote: 	
		   I did Russ, they sent a generic email as I quoted.  I'll try calling them.  Thanks, bk

On Thu, Jul 29, 2010 at 3:00 PM, russ kinne <russkinne(at)mac.com (russkinne(at)mac.com)> wrote:

    	  Quote: 	
		   BobI'd suggest first asking ICOM about this



On Jul 29, 2010, at 2:46 PM, Bob Kravis wrote:

 	  Quote: 	
		  Hi,I followed the suggestions I found in the archives and purchased an ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will mount via its belt clip into a custom bracket between the forward edge of the seat and the floor plate (aluminum diamond plate) in my Firefly.  The antenna will be mounted through the floor plate and extend below and back through the belly fabric.  That's the plan. There were no instructions sent from Aircraft Spruce (part #11-04517) and the support tech was not very helpful in how to wire it up.  The ICOM support guy said most of the antennae come with a coax cable and BNC female that you just pug in to the radio.  Mine doesn't.  Now the antenna has a knurled aluminum shouldered spacer, through the center of which, the SS antenna rod runs.  There are nuts at each end which squeeze the assembly together.  There is no provision for electrical connection.  I will have to fabricate a cable with a BNC connector.

    1. What is the correct cable connection? Does the insulated center wire go to the antenna rod end and the sheath go to the aluminum floor plate or what?  It does not appear that the antenna rod is electrically isolated from the mounting hole in the floor plate so I don't see how that would work? Google searches for antenna connections have not been fruitful.

    2. I have the adapter for the handheld and will be installing a small panel with audio and mic jacks.  There is some very expensive cabling available to wire this up but what is really needed to get a clean, ignition noise free signal?

    Thanks for your input.

Bob

E008BK at  9NC8

 

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[b]

_________________
The smallest miracle right in front of you is enough to make you happy....

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Thu Jul 29, 2010 4:03 pm Post subject: Handheld radio to external antenna connections?

At 07:19 PM 7/29/2010, Richard Girard wrote:

  	  Quote: 	
		  Bob, the 50 ohm spec is supplied by using the right coax cable. Go to your local Radio Shack and you may be able to buy a cable ready made and only fabricate a ground plane for the antenna. 	


 I know it doesn't help for your antenna, but I bought a cable and a female-female adapter from Radio Shack to mount the supplied rubber duck antenna remote from the radio (I24 also).  Works just  fine.



 I made my own headset adapter with the PTT button in the end of the control stick.



 -Dana

 

 --

  "Naked" means you ain't got no clothes on; "nekkid" means you ain't got no clothes on - and are up to somethin'.    [quote][b]

ceengland(at)bellsouth.ne
Guest

Posted: Thu Jul 29, 2010 4:50 pm Post subject: Handheld radio to external antenna connections?

On 7/29/2010 1:46 PM, Bob Kravis wrote:

 	  Quote: 	
		   Hi,

 I followed the suggestions I found in the archives and purchased an 

 ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio 

 will mount via its belt clip into a custom bracket between the forward 

 edge of the seat and the floor plate (aluminum diamond plate) in my 

 Firefly.  The antenna will be mounted through the floor plate and 

 extend below and back through the belly fabric.  That's the plan. 

 There were no instructions sent from Aircraft Spruce (part #11-04517) 

 and the support tech was not very helpful in how to wire it up.  The 

 ICOM support guy said most of the antennae come with a coax cable and 

 BNC female that you just pug in to the radio.  Mine doesn't.  Now the 

 antenna has a knurled aluminum shouldered spacer, through the center 

 of which, the SS antenna rod runs.  There are nuts at each end which 

 squeeze the assembly together.  There is no provision for electrical 

 connection.  I will have to fabricate a cable with a BNC connector.

 1. What is the correct cable connection? Does the insulated center 

 wire go to the antenna rod end and the sheath go to the aluminum floor 

 plate or what?  It does not appear that the antenna rod is 

 electrically isolated from the mounting hole in the floor plate so I 

 don't see how that would work? Google searches for antenna connections 

 have not been fruitful.

 2. I have the adapter for the handheld and will be installing a small 

 panel with audio and mic jacks.  There is some very expensive cabling 

 available to wire this up but what is really needed to get a clean, 

 ignition noise free signal?

 Thanks for your input.

 Bob

 E008BK at  9NC8

Hi Bob,
	




Before you actually hook anything up (you don't want to let the smoke 

out), I'd suggest prowling around the aeroelectric web site, & maybe 

signing up for the mailing list (also on the Matronics server).

The primary site is at

http://aeroelectric.com/



and you can search for antenna info within the site by just typing 

'antenna; into the search box. Here's a link to some of the articles & pics:

http://www.aeroelectric.com/Pictures/Antenna/



It's hard to tell from the tiny pic on the spruce site; does the fat end 

of the antenna have a threaded stud instead of an actual connector? If 

so, you might want to re-think using it if you don't have reasonably 

well developed electronic fabrication & soldering skills. FWIW, you can 

make a decent comm antenna from a basic Radio Shack CB antenna & 

adapter. See:

http://www.aeroelectric.com/Pictures/Antenna/DIY_Comm_Antenna.jpg

All you have to do to make a CB antenna into a VHF a/c comm antenna is 

cut it to around 21" long. Perfect tuning requires instruments, but 

perfect tuning isn't required to make it work.



The Icom should already have a BNC female mounted on the radio for the 

'rubber ducky', right? If you do something like the link above, all 

you'd need is a standard 50ohm (important!) BNC male to BNC male cable 

to hook them up. BTW, you can't measure that 50 ohms with an ohm meter. 

There are resistance ohms and then there are impedance ohms (that vary 

with frequency). The number for the cable is the latter.



Last (or at least the last thing my fingers can type at the moment), the 

type of antenna you're contemplating needs a 'ground plane' to work 

efficiently and present the correct 'load' (impedance) to the transmit 

amplifier. That can be something as simple as 3 or 4 metal straps, tied 

to the cable's shield, radiating out at right angles from the base of 

the antenna. (The coax cable doesn't actually provide the load; it's 

just supposed to have the correct transmission line impedance to get the 

signal to the antenna.)



If you sign up for the aeroelectric list, address your question to 'Bob' 

(the guy who started the list), & ask for the instructions to use a 

cheap CB antenna for comm. The info is all on the web site, but finding 

your way around the site is challenging (at least for me).



If this isn't making sense, email me off-list with your phone # or ask 

for mine & I'll try to explain in more detail.



Charlie

zharvey(at)bentoncountyca
Guest

Posted: Thu Jul 29, 2010 5:39 pm Post subject: Handheld radio to external antenna connections?

Bob,  I installed the exact antenna in my Pietenpol and it worked great! 

Get the correct coax cable (I don't remember the number but I bought the one 

I needed from Radio Shack).  The center wire of the coax goes to the Knurled 

knob (it's not aluminum) and the sheath of the coax goes to the aluminum 

plate as a ground (make sure you clean the aluminum plate to get a good 

ground).  Try it, you'll like it.

Gene

Firestar KXP  N71RB



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

From: "Charlie England" <ceengland(at)bellsouth.net>

Sent: Thursday, July 29, 2010 7:49 PM

To: <kolb-list(at)matronics.com>

Subject: Re: Handheld radio to external antenna connections?



 	  Quote: 	
		   



 On 7/29/2010 1:46 PM, Bob Kravis wrote:

> Hi,

> I followed the suggestions I found in the archives and purchased an 

> ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will 

> mount via its belt clip into a custom bracket between the forward edge of 

> the seat and the floor plate (aluminum diamond plate) in my Firefly.  The 

> antenna will be mounted through the floor plate and extend below and back 

> through the belly fabric.  That's the plan. There were no instructions 

> sent from Aircraft Spruce (part #11-04517) and the support tech was not 

> very helpful in how to wire it up.  The ICOM support guy said most of the 

> antennae come with a coax cable and BNC female that you just pug in to 

> the radio.  Mine doesn't.  Now the antenna has a knurled aluminum 

> shouldered spacer, through the center of which, the SS antenna rod runs. 

> There are nuts at each end which squeeze the assembly together.  There is 

> no provision for electrical connection.  I will have to fabricate a cable 

> with a BNC connector.

> 1. What is the correct cable connection? Does the insulated center wire 

> go to the antenna rod end and the sheath go to the aluminum floor plate 

> or what?  It does not appear that the antenna rod is electrically 

> isolated from the mounting hole in the floor plate so I don't see how 

> that would work? Google searches for antenna connections have not been 

> fruitful.

> 2. I have the adapter for the handheld and will be installing a small 

> panel with audio and mic jacks.  There is some very expensive cabling 

> available to wire this up but what is really needed to get a clean, 

> ignition noise free signal?

> Thanks for your input.

> Bob

> E008BK at  9NC8

 Hi Bob,



 Before you actually hook anything up (you don't want to let the smoke 

 out), I'd suggest prowling around the aeroelectric web site, & maybe 

 signing up for the mailing list (also on the Matronics server).

 The primary site is at

 http://aeroelectric.com/



 and you can search for antenna info within the site by just typing 

 'antenna; into the search box. Here's a link to some of the articles & 

 pics:

 http://www.aeroelectric.com/Pictures/Antenna/



 It's hard to tell from the tiny pic on the spruce site; does the fat end 

 of the antenna have a threaded stud instead of an actual connector? If so, 

 you might want to re-think using it if you don't have reasonably well 

 developed electronic fabrication & soldering skills. FWIW, you can make a 

 decent comm antenna from a basic Radio Shack CB antenna & adapter. See:

 http://www.aeroelectric.com/Pictures/Antenna/DIY_Comm_Antenna.jpg

 All you have to do to make a CB antenna into a VHF a/c comm antenna is cut 

 it to around 21" long. Perfect tuning requires instruments, but perfect 

 tuning isn't required to make it work.



 The Icom should already have a BNC female mounted on the radio for the 

 'rubber ducky', right? If you do something like the link above, all you'd 

 need is a standard 50ohm (important!) BNC male to BNC male cable to hook 

 them up. BTW, you can't measure that 50 ohms with an ohm meter. There are 

 resistance ohms and then there are impedance ohms (that vary with 

 frequency). The number for the cable is the latter.



 Last (or at least the last thing my fingers can type at the moment), the 

 type of antenna you're contemplating needs a 'ground plane' to work 

 efficiently and present the correct 'load' (impedance) to the transmit 

 amplifier. That can be something as simple as 3 or 4 metal straps, tied to 

 the cable's shield, radiating out at right angles from the base of the 

 antenna. (The coax cable doesn't actually provide the load; it's just 

 supposed to have the correct transmission line impedance to get the signal 

 to the antenna.)



 If you sign up for the aeroelectric list, address your question to 'Bob' 

 (the guy who started the list), & ask for the instructions to use a cheap 

 CB antenna for comm. The info is all on the web site, but finding your way 

 around the site is challenging (at least for me).



 If this isn't making sense, email me off-list with your phone # or ask for 

 mine & I'll try to explain in more detail.



 Charlie

herbgh(at)nctc.com
Guest

Posted: Thu Jul 29, 2010 6:01 pm Post subject: Handheld radio to external antenna connections?

I do not see any reason why the airframe cannot be the ground plane?  Herb

At 08:41 PM 7/29/2010, you wrote:

 	  Quote: 	
		  

<zharvey(at)bentoncountycable.net>



Bob,  I installed the exact antenna in my Pietenpol and it worked 

great! Get the correct coax cable (I don't remember the number but I 

bought the one I needed from Radio Shack).  The center wire of the 

coax goes to the Knurled knob (it's not aluminum) and the sheath of 

the coax goes to the aluminum plate as a ground (make sure you clean 

the aluminum plate to get a good ground).  Try it, you'll like it.

Gene

Firestar KXP  N71RB



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

From: "Charlie England" <ceengland(at)bellsouth.net>

Sent: Thursday, July 29, 2010 7:49 PM

To: <kolb-list(at)matronics.com>

Subject: Re: Handheld radio to external antenna connections?



>

>

>On 7/29/2010 1:46 PM, Bob Kravis wrote:

>>Hi,

>>I followed the suggestions I found in the archives and purchased 

>>an ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The 

>>radio will mount via its belt clip into a custom bracket between 

>>the forward edge of the seat and the floor plate (aluminum diamond 

>>plate) in my Firefly.  The antenna will be mounted through the 

>>floor plate and extend below and back through the belly 

>>fabric.  That's the plan. There were no instructions sent from 

>>Aircraft Spruce (part #11-04517) and the support tech was not very 

>>helpful in how to wire it up.  The ICOM support guy said most of 

>>the antennae come with a coax cable and BNC female that you just 

>>pug in to the radio.  Mine doesn't.  Now the antenna has a knurled 

>>aluminum shouldered spacer, through the center of which, the SS 

>>antenna rod runs. There are nuts at each end which squeeze the 

>>assembly together.  There is no provision for electrical 

>>connection.  I will have to fabricate a cable with a BNC connector.

>>1. What is the correct cable connection? Does the insulated center 

>>wire go to the antenna rod end and the sheath go to the aluminum 

>>floor plate or what?  It does not appear that the antenna rod is 

>>electrically isolated from the mounting hole in the floor plate so 

>>I don't see how that would work? Google searches for antenna 

>>connections have not been fruitful.

>>2. I have the adapter for the handheld and will be installing a 

>>small panel with audio and mic jacks.  There is some very 

>>expensive cabling available to wire this up but what is really 

>>needed to get a clean, ignition noise free signal?

>>Thanks for your input.

>>Bob

>>E008BK at  9NC8

>Hi Bob,

>

>Before you actually hook anything up (you don't want to let the 

>smoke out), I'd suggest prowling around the aeroelectric web site, 

>& maybe signing up for the mailing list (also on the Matronics server).

>The primary site is at

>http://aeroelectric.com/

>

>and you can search for antenna info within the site by just typing 

>'antenna; into the search box. Here's a link to some of the articles & pics:

>http://www.aeroelectric.com/Pictures/Antenna/

>

>It's hard to tell from the tiny pic on the spruce site; does the 

>fat end of the antenna have a threaded stud instead of an actual 

>connector? If so, you might want to re-think using it if you don't 

>have reasonably well developed electronic fabrication & soldering 

>skills. FWIW, you can make a decent comm antenna from a basic Radio 

>Shack CB antenna & adapter. See:

>http://www.aeroelectric.com/Pictures/Antenna/DIY_Comm_Antenna.jpg

>All you have to do to make a CB antenna into a VHF a/c comm antenna 

>is cut it to around 21" long. Perfect tuning requires instruments, 

>but perfect tuning isn't required to make it work.

>

>The Icom should already have a BNC female mounted on the radio for 

>the 'rubber ducky', right? If you do something like the link above, 

>all you'd need is a standard 50ohm (important!) BNC male to BNC 

>male cable to hook them up. BTW, you can't measure that 50 ohms 

>with an ohm meter. There are resistance ohms and then there are 

>impedance ohms (that vary with frequency). The number for the cable 

>is the latter.

>

>Last (or at least the last thing my fingers can type at the 

>moment), the type of antenna you're contemplating needs a 'ground 

>plane' to work efficiently and present the correct 'load' 

>(impedance) to the transmit amplifier. That can be something as 

>simple as 3 or 4 metal straps, tied to the cable's shield, 

>radiating out at right angles from the base of the antenna. (The 

>coax cable doesn't actually provide the load; it's just supposed to 

>have the correct transmission line impedance to get the signal to the antenna.)

>

>If you sign up for the aeroelectric list, address your question to 

>'Bob' (the guy who started the list), & ask for the instructions to 

>use a cheap CB antenna for comm. The info is all on the web site, 

>but finding your way around the site is challenging (at least for me).

>

>If this isn't making sense, email me off-list with your phone # or 

>ask for mine & I'll try to explain in more detail.

>

>Charlie

>

ceengland(at)bellsouth.ne
Guest

Posted: Thu Jul 29, 2010 6:31 pm Post subject: Handheld radio to external antenna connections?

On 7/29/2010 9:00 PM, Herb wrote:

 	  Quote: 	
		   



 I do not see any reason why the airframe cannot be the ground plane?  

 Herb

 At 08:41 PM 7/29/2010, you wrote:

> 

> <zharvey(at)bentoncountycable.net>

>

> Bob,  I installed the exact antenna in my Pietenpol and it worked 

> great! Get the correct coax cable (I don't remember the number but I 

> bought the one I needed from Radio Shack).  The center wire of the 

> coax goes to the Knurled knob (it's not aluminum) and the sheath of 

> the coax goes to the aluminum plate as a ground (make sure you clean 

> the aluminum plate to get a good ground).  Try it, you'll like it.

> Gene

> Firestar KXP  N71RB

>

> --------------------------------------------------

> From: "Charlie England" <ceengland(at)bellsouth.net>

> Sent: Thursday, July 29, 2010 7:49 PM

> To: <kolb-list(at)matronics.com>

> Subject: Re: Handheld radio to external antenna connections?

>

>> 

>> <ceengland(at)bellsouth.net>

>>

>> On 7/29/2010 1:46 PM, Bob Kravis wrote:

>>> Hi,

>>> I followed the suggestions I found in the archives and purchased an 

>>> ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio 

>>> will mount via its belt clip into a custom bracket between the 

>>> forward edge of the seat and the floor plate (aluminum diamond 

>>> plate) in my Firefly.  The antenna will be mounted through the 

>>> floor plate and extend below and back through the belly fabric.  

>>> That's the plan. There were no instructions sent from Aircraft 

>>> Spruce (part #11-04517) and the support tech was not very helpful 

>>> in how to wire it up.  The ICOM support guy said most of the 

>>> antennae come with a coax cable and BNC female that you just pug in 

>>> to the radio.  Mine doesn't.  Now the antenna has a knurled 

>>> aluminum shouldered spacer, through the center of which, the SS 

>>> antenna rod runs. There are nuts at each end which squeeze the 

>>> assembly together.  There is no provision for electrical 

>>> connection.  I will have to fabricate a cable with a BNC connector.

>>> 1. What is the correct cable connection? Does the insulated center 

>>> wire go to the antenna rod end and the sheath go to the aluminum 

>>> floor plate or what?  It does not appear that the antenna rod is 

>>> electrically isolated from the mounting hole in the floor plate so 

>>> I don't see how that would work? Google searches for antenna 

>>> connections have not been fruitful.

>>> 2. I have the adapter for the handheld and will be installing a 

>>> small panel with audio and mic jacks.  There is some very expensive 

>>> cabling available to wire this up but what is really needed to get 

>>> a clean, ignition noise free signal?

>>> Thanks for your input.

>>> Bob

>>> E008BK at  9NC8

>> Hi Bob,

>>

>> Before you actually hook anything up (you don't want to let the 

>> smoke out), I'd suggest prowling around the aeroelectric web site, & 

>> maybe signing up for the mailing list (also on the Matronics server).

>> The primary site is at

>> http://aeroelectric.com/

>>

>> and you can search for antenna info within the site by just typing 

>> 'antenna; into the search box. Here's a link to some of the articles 

>> & pics:

>> http://www.aeroelectric.com/Pictures/Antenna/

>>

>> It's hard to tell from the tiny pic on the spruce site; does the fat 

>> end of the antenna have a threaded stud instead of an actual 

>> connector? If so, you might want to re-think using it if you don't 

>> have reasonably well developed electronic fabrication & soldering 

>> skills. FWIW, you can make a decent comm antenna from a basic Radio 

>> Shack CB antenna & adapter. See:

>> http://www.aeroelectric.com/Pictures/Antenna/DIY_Comm_Antenna.jpg

>> All you have to do to make a CB antenna into a VHF a/c comm antenna 

>> is cut it to around 21" long. Perfect tuning requires instruments, 

>> but perfect tuning isn't required to make it work.

>>

>> The Icom should already have a BNC female mounted on the radio for 

>> the 'rubber ducky', right? If you do something like the link above, 

>> all you'd need is a standard 50ohm (important!) BNC male to BNC male 

>> cable to hook them up. BTW, you can't measure that 50 ohms with an 

>> ohm meter. There are resistance ohms and then there are impedance 

>> ohms (that vary with frequency). The number for the cable is the 

>> latter.

>>

>> Last (or at least the last thing my fingers can type at the moment), 

>> the type of antenna you're contemplating needs a 'ground plane' to 

>> work efficiently and present the correct 'load' (impedance) to the 

>> transmit amplifier. That can be something as simple as 3 or 4 metal 

>> straps, tied to the cable's shield, radiating out at right angles 

>> from the base of the antenna. (The coax cable doesn't actually 

>> provide the load; it's just supposed to have the correct 

>> transmission line impedance to get the signal to the antenna.)

>>

>> If you sign up for the aeroelectric list, address your question to 

>> 'Bob' (the guy who started the list), & ask for the instructions to 

>> use a cheap CB antenna for comm. The info is all on the web site, 

>> but finding your way around the site is challenging (at least for me).

>>

>> If this isn't making sense, email me off-list with your phone # or 

>> ask for mine & I'll try to explain in more detail.

>>

>> Charlie

>>

Isn't inconsistent top/bottom posting fun?
	




"I do not see any reason why the airframe cannot be the ground plane?"

It can, if it's 'dense' enough; an aluminum skin works fine. A typical  

tube&fabric airframe is so open it's almost invisible to VHF frequencies.



Having said that, the antenna will work with no ground plane at all; 

just not as well. Like the rubber ducky that came on the radio, which 

actually has internal 'stuff' to compensate for the lack of a ground 

plane and the fact that it's too short. None of the 1/4 wave antennas 

that we are discussing have any of that 'stuff' built in. Each is 

effectively just a piece of heavy wire.



Charlie

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Jul 29, 2010 7:11 pm Post subject: Handheld radio to external antenna connections?

The name of the game is to cut the old msg(s), leaving only enough info so 

the reader will know where you are coming from.



Most folks don't do that, for some unexplained reason.



john h - Firm believer in keeping it simple.

mkIII



 > Isn't inconsistent top/bottom posting fun?

 	  Quote: 	
		  

 >
	


 	  Quote: 	
		   Charlie

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

zharvey(at)bentoncountyca
Guest

Posted: Thu Jul 29, 2010 11:29 pm Post subject: Handheld radio to external antenna connections?

Herb, you may be right, however I've had really good luck with a sheet 

(maybe the floor pan) of aluminum.

Gene  In HOT Tennessee

Firestar KXP  N71RB



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

From: "Herb" <herbgh(at)nctc.com>

Sent: Thursday, July 29, 2010 9:00 PM

To: <kolb-list(at)matronics.com>

Subject: Re: Handheld radio to external antenna connections?



 	  Quote: 	
		   



 I do not see any reason why the airframe cannot be the ground plane?  Herb

 At 08:41 PM 7/29/2010, you wrote:

>

><zharvey(at)bentoncountycable.net>

>

>Bob,  I installed the exact antenna in my Pietenpol and it worked great! 

>Get the correct coax cable (I don't remember the number but I bought the 

>one I needed from Radio Shack).  The center wire of the coax goes to the 

>Knurled knob (it's not aluminum) and the sheath of the coax goes to the 

>aluminum plate as a ground (make sure you clean the aluminum plate to get 

>a good ground).  Try it, you'll like it.

>Gene

>Firestar KXP  N71RB

>

>--------------------------------------------------

>From: "Charlie England" <ceengland(at)bellsouth.net>

>Sent: Thursday, July 29, 2010 7:49 PM

>To: <kolb-list(at)matronics.com>

>Subject: Re: Handheld radio to external antenna connections?

>

>>

>><ceengland(at)bellsouth.net>

>>

>>On 7/29/2010 1:46 PM, Bob Kravis wrote:

>>>Hi,

>>>I followed the suggestions I found in the archives and purchased an 

>>>ICOM-A24 and a Stainless Steel VHS Antenna - 45 degree.  The radio will 

>>>mount via its belt clip into a custom bracket between the forward edge 

>>>of the seat and the floor plate (aluminum diamond plate) in my Firefly. 

>>>The antenna will be mounted through the floor plate and extend below and 

>>>back through the belly fabric.  That's the plan. There were no 

>>>instructions sent from Aircraft Spruce (part #11-04517) and the support 

>>>tech was not very helpful in how to wire it up.  The ICOM support guy 

>>>said most of the antennae come with a coax cable and BNC female that you 

>>>just pug in to the radio.  Mine doesn't.  Now the antenna has a knurled 

>>>aluminum shouldered spacer, through the center of which, the SS antenna 

>>>rod runs. There are nuts at each end which squeeze the assembly 

>>>together.  There is no provision for electrical connection.  I will have 

>>>to fabricate a cable with a BNC connector.

>>>1. What is the correct cable connection? Does the insulated center wire 

>>>go to the antenna rod end and the sheath go to the aluminum floor plate 

>>>or what?  It does not appear that the antenna rod is electrically 

>>>isolated from the mounting hole in the floor plate so I don't see how 

>>>that would work? Google searches for antenna connections have not been 

>>>fruitful.

>>>2. I have the adapter for the handheld and will be installing a small 

>>>panel with audio and mic jacks.  There is some very expensive cabling 

>>>available to wire this up but what is really needed to get a clean, 

>>>ignition noise free signal?

>>>Thanks for your input.

>>>Bob

>>>E008BK at  9NC8

>>Hi Bob,

>>

>>Before you actually hook anything up (you don't want to let the smoke 

>>out), I'd suggest prowling around the aeroelectric web site, & maybe 

>>signing up for the mailing list (also on the Matronics server).

>>The primary site is at

>>http://aeroelectric.com/

>>

>>and you can search for antenna info within the site by just typing 

>>'antenna; into the search box. Here's a link to some of the articles & 

>>pics:

>>http://www.aeroelectric.com/Pictures/Antenna/

>>

>>It's hard to tell from the tiny pic on the spruce site; does the fat end 

>>of the antenna have a threaded stud instead of an actual connector? If 

>>so, you might want to re-think using it if you don't have reasonably well 

>>developed electronic fabrication & soldering skills. FWIW, you can make a 

>>decent comm antenna from a basic Radio Shack CB antenna & adapter. See:

>>http://www.aeroelectric.com/Pictures/Antenna/DIY_Comm_Antenna.jpg

>>All you have to do to make a CB antenna into a VHF a/c comm antenna is 

>>cut it to around 21" long. Perfect tuning requires instruments, but 

>>perfect tuning isn't required to make it work.

>>

>>The Icom should already have a BNC female mounted on the radio for the 

>>'rubber ducky', right? If you do something like the link above, all you'd 

>>need is a standard 50ohm (important!) BNC male to BNC male cable to hook 

>>them up. BTW, you can't measure that 50 ohms with an ohm meter. There are 

>>resistance ohms and then there are impedance ohms (that vary with 

>>frequency). The number for the cable is the latter.

>>

>>Last (or at least the last thing my fingers can type at the moment), the 

>>type of antenna you're contemplating needs a 'ground plane' to work 

>>efficiently and present the correct 'load' (impedance) to the transmit 

>>amplifier. That can be something as simple as 3 or 4 metal straps, tied 

>>to the cable's shield, radiating out at right angles from the base of the 

>>antenna. (The coax cable doesn't actually provide the load; it's just 

>>supposed to have the correct transmission line impedance to get the 

>>signal to the antenna.)

>>

>>If you sign up for the aeroelectric list, address your question to 'Bob' 

>>(the guy who started the list), & ask for the instructions to use a cheap 

>>CB antenna for comm. The info is all on the web site, but finding your 

>>way around the site is challenging (at least for me).

>>

>>If this isn't making sense, email me off-list with your phone # or ask 

>>for mine & I'll try to explain in more detail.

>>

>>Charlie

>>

>>

>>

>

>

pj.ladd(at)btinternet.com
Guest

Posted: Fri Jul 30, 2010 2:59 am Post subject: Handheld radio to external antenna connections?

---

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Fri Jul 30, 2010 6:21 am Post subject: Handheld radio to external antenna connections?

Pat, Quoting, whether top or bottom, should be options you can set within your email program or your browser. Check and see in your program's help files or search for instructions on the web. Sometimes these may be forum settings, too. 



Rick Girard



On Fri, Jul 30, 2010 at 5:59 AM, Pat Ladd <pj.ladd(at)btinternet.com (pj.ladd(at)btinternet.com)> wrote:

[quote] --> Kolb-List message posted by: "Pat Ladd" <pj.ladd(at)btinternet.com (pj.ladd(at)btinternet.com)>

 

 

 ---

_________________
The smallest miracle right in front of you is enough to make you happy....

pj.ladd(at)btinternet.com
Guest

Posted: Fri Jul 30, 2010 8:40 am Post subject: Handheld radio to external antenna connections?

[quote] ---

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