Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Coaxial Cable

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

billhuntersemail(at)gmail
Guest

Posted: Wed Feb 22, 2017 12:01 pm Post subject: Coaxial Cable

Hi All,

 

I am replacing the coaxial cables for my transponder, ADS-B, Nav, and Comm antennas.

 

What kind of coaxial cable, set of crimp tools, and ends do you all recommend?

 

..

 

THANKS!!!

 

Bill  Hunter

ceengland7(at)gmail.com
Guest

Posted: Wed Feb 22, 2017 2:32 pm Post subject: Coaxial Cable

On 2/22/2017 1:56 PM, William Hunter       wrote:

     

      	  Quote: 	
		                         <![endif]-->   <![endif]-->                

Hi All,         

          

I am replacing the coaxial cables for my             transponder, ADS-B, Nav, and Comm antennas.         

          

What kind of coaxial cable, set of crimp             tools, and ends do you all recommend?         

          

..         

          

THANKS!!!         

          

Bill  Hunter         

          

          

          

        

     	
     Are they bad? UV damaged insulation? Cut? Pinched? "If it ain't     broke, don't fix it." (It might get broke.   )

     

     If you just gotta do it, RG400 is 'better' than RG58 stranded (good     enough). But never forget; better is the enemy of good enough. Look     at prices. Look at ease of field maintenance if you can get to a     consumer electronics store on a weekend for RG58 crimp connectors,     but can't get RG400 crimp connectors until Tuesday.

     

     Look at B&C

     http://www.bandc.aero/aircraft-electrical-tools.aspx

      or Stein

     http://www.steinair.com/product-category/tools/crimpers/

     for tools

     

     Coax & BNC connectors, as well.

     

     Charlie

billhuntersemail(at)gmail
Guest

Posted: Wed Feb 22, 2017 5:48 pm Post subject: Coaxial Cable

 	  Quote: 	
		   If you just gotta do it,

 
	


Yep…when ya gotta…ya just gotta…

 

This is a new install of transponder and ADS-B.

 

Thanks for the advice.  I definitely need to measure out the EXACT length of cable that I need (plus a little bit more for mama and the kids) as the RG400 is kinda pricey.  Hmmm, I guess the higher number of RG’s means the more money it costs?!?!?  I was hoping for more like an RG4.

 

Anyhoo, thanks for the advice.

 

..

 

Cheers!!!

 

Bill  Hunter

 

 

 



 

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

Sent: Wednesday, February 22, 2017 2:31 PM

To: aeroelectric-list(at)matronics.com

Subject: Re: Coaxial Cable

 

On 2/22/2017 1:56 PM, William Hunter wrote:

 	  Quote: 	
		  

Hi All,

 

I am replacing the coaxial cables for my transponder, ADS-B, Nav, and Comm antennas.

 

What kind of coaxial cable, set of crimp tools, and ends do you all recommend?

 

..

 

THANKS!!!

 

Bill  Hunter

 

 

 

 	


Are they bad? UV damaged insulation? Cut? Pinched? "If it ain't broke, don't fix it." (It might get broke.   )



If you just gotta do it, RG400 is 'better' than RG58 stranded (good enough). But never forget; better is the enemy of good enough. Look at prices. Look at ease of field maintenance if you can get to a consumer electronics store on a weekend for RG58 crimp connectors, but can't get RG400 crimp connectors until Tuesday.



Look at B&C

http://www.bandc.aero/aircraft-electrical-tools.aspx

 or Stein

http://www.steinair.com/product-category/tools/crimpers/

for tools



Coax & BNC connectors, as well.



Charlie

ceengland7(at)gmail.com
Guest

Posted: Wed Feb 22, 2017 9:08 pm Post subject: Coaxial Cable

My neighbor installs adsb's in certified a/c as a dealer/repair station. He uses RG58 coax exclusively. Check the specs.

 'Better is the enemy of good enough.'

 Charlie

 On Feb 22, 2017, at 7:56 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote: 	  Quote: 	
		   

 	  Quote: 	
		   If you just gotta do it,


	


 



Yepâ€¦when ya gottaâ€¦ya just gottaâ€¦



 



This is a new install of transponder and ADS-B.



 



Thanks for the advice.  I definitely need to measure out the EXACT length of cable that I need (plus a little bit more for mama and the kids) as the RG400 is kinda pricey.  Hmmm, I guess the higher number of RGâ€™s means the more money it costs?!?!?  I was hoping for more like an RG4.



 



Anyhoo, thanks for the advice.



 



..



 



Cheers!!!



 



Bill  Hunter



 

 

 



 



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

Sent: Wednesday, February 22, 2017 2:31 PM

To: aeroelectric-list(at)matronics.com

Subject: Re: Coaxial Cable



 

On 2/22/2017 1:56 PM, William Hunter wrote:

 	  Quote: 	
		  

Hi All,



 



I   am replacing the coaxial cables for my transponder, ADS-B, Nav, and Comm antennas.



 



What kind of coaxial cable, set of crimp tools, and ends do you all recommend?



 



..



 



THANKS!!!



 



Bill  Hunter



 



 



 



 

	


Are they bad? UV damaged insulation? Cut? Pinched? "If it ain't broke, don't fix it." (It might get broke.   )



If you just gotta do it, RG400 is 'better' than RG58 stranded (good enough). But never forget; better is the enemy of good enough. Look at prices. Look at ease of field maintenance if you can get to a consumer electronics store on a weekend for RG58 crimp connectors, but can't get RG400 crimp connectors until Tuesday.



Look at B&C

http://www.bandc.aero/aircraft-electrical-tools.aspx

 or Stein

http://www.steinair.com/product-category/tools/crimpers/

for tools



Coax & BNC connectors, as well.



Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Feb 23, 2017 8:44 am Post subject: Coaxial Cable

At 07:41 PM 2/22/2017, you wrote:

  	  Quote: 	
		   > If you just gotta do it,

  

 Yep…when ya gotta…ya just gotta…

  

 This is a new install of transponder and ADS-B.

  

 Thanks for the advice.  I definitely need to measure out the EXACT length of cable that I need (plus a little bit more for mama and the kids) as the RG400 is kinda pricey.  Hmmm, I guess the higher number of RG’s means the more money it costs?!?!?  I was hoping for more like an RG4.

  

 Anyhoo, thanks for the advice.

  	


  There's a new kid on the coax block with materials

  similar to RG58 but with some modifications that

  improve leakage (100% shield) and loss (2/3 that

  of RG58).



  I use in on my ham radio antennas both fixed

  an mobile. There are companies that will supply

  select lengths with connectors already installed

  for very reasonable prices. Case in point:



  http://tinyurl.com/zfxz7m7



  If it were my airplane . . .



 

 

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Feb 23, 2017 9:29 am Post subject: Coaxial Cable

At 10:40 AM 2/23/2017, you wrote:

  	  Quote: 	
		  At 07:41 PM 2/22/2017, you wrote:

  	  Quote: 	
		   > If you just gotta do it,

  

 Yep…when ya gotta…ya just gotta…

  

 This is a new install of transponder and ADS-B.

  

 Thanks for the advice.  I definitely need to measure out the EXACT length of cable that I need (plus a little bit more for mama and the kids) as the RG400 is kinda pricey.  Hmmm, I guess the higher number of RG’s means the more money it costs?!?!?  I was hoping for more like an RG4.

  

 Anyhoo, thanks for the advice.

  	


  There's a new kid on the coax block with materials

  similar to RG58 but with some modifications that

  improve leakage (100% shield) and loss (2/3 that

  of RG58).



  I use in on my ham radio antennas both fixed

  an mobile. There are companies that will supply

  select lengths with connectors already installed

  for very reasonable prices. Case in point:



  http://tinyurl.com/zfxz7m7



  If it were my airplane . . . 	


   P.S. Forgot to mention, LMR-195 is compatible

   with the legacy line of connectors and tooling

   for RG-58/400/141 coaxes. But the last time

   I needed a couple of 195 coaxes, I ordered one

   with connectors already installed and long enough

   to cut in two.  Only needed to install two connectors

   myself.



 

 

   Bob . . .

donjohnston

Joined: 13 Dec 2009
Posts: 231

Posted: Thu Feb 23, 2017 6:03 pm Post subject: Re: Coaxial Cable

 	  billhuntersemail(at)gmail wrote: 	
		  What kind of coaxial cable, set of crimp tools, and ends do you all recommend? 	




I pulled RG400 throughout. It costs a bit more, but unless you want to do it again...



As for the connectors, that's dependent on the equipment.  I've got some BNC and some TNC.  Just get good quality connectors and use a good crimper.  



And check every single connector you put on!

art(at)zemon.name
Guest

Posted: Thu Feb 23, 2017 9:07 pm Post subject: Coaxial Cable

Folks,

I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 

Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58.Â 

I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.

At those distances, does RG400 vs RG58 matter? How do I evaluate it?

And then there is theÂ LMR-195 that Bob just showed us. How does that fit in?

Thanks,

Â  Â  -- Art Z.



-- 

https://CheerfulCurmudgeon.com/"If I am not for myself, who is for me? And if I am only for myself, what am I? And if not now, when?" Hillel

donvansanten(at)gmail.com
Guest

Posted: Thu Feb 23, 2017 10:40 pm Post subject: Coaxial Cable

After Bob posted the info on the LMR-195 I looked for additional information. One thing that seems a little strange is that it is solid core. It is also said to be flexible. It was my understanding that solid core cable is less flexible than multi strand cable. Any one know the minimum bend radius for LMR-195?Don.

On Feb 23, 2017 21:14, "Art Zemon" <art(at)zemon.name (art(at)zemon.name)> wrote: 	  Quote: 	
		  Folks,

I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 

Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58.Â 

I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.

At those distances, does RG400 vs RG58 matter? How do I evaluate it?

And then there is theÂ LMR-195 that Bob just showed us. How does that fit in?

Thanks,

Â  Â  -- Art Z.



-- 

https://CheerfulCurmudgeon.com/"If I am not for myself, who is for me? And if I am only for myself, what am I? And if not now, when?" Hillel

arcticarrow(at)gmail.com
Guest

Posted: Thu Feb 23, 2017 11:03 pm Post subject: Coaxial Cable

Iâ€™ve got to submit my two cents worth on the conversation about coax.  As an A&P IA what I hate the most is having to do something over because I did it wrong.  Typically coax is under the floor boards or above the head liner.  Most times it goes places where its hard to get at and left there.  The extra money for the best is soon forgotten but the frustration for replacement just goes on and on.

The radio shop in our area, which is very busy, urges RG400.  The installation money is all the same to me.



Bernie 	  Quote: 	
		  On Feb 23, 2017, at 9:36 PM, don van santen <donvansanten(at)gmail.com (donvansanten(at)gmail.com)> wrote:

After Bob posted the info on the LMR-195 I looked for additional information. One thing that seems a little strange is that it is solid core. It is also said to be flexible. It was my understanding that solid core cable is less flexible than multi strand cable. Any one know the minimum bend radius for LMR-195?Don.



On Feb 23, 2017 21:14, "Art Zemon" <art(at)zemon.name (art(at)zemon.name)> wrote: 	  Quote: 	
		  Folks,



I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 



Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58. 



I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.



At those distances, does RG400 vs RG58 matter? How do I evaluate it?



And then there is the LMR-195 that Bob just showed us. How does that fit in?



Thanks,

    -- Art Z.

-- https://CheerfulCurmudgeon.com/"If I am not for myself, who is for me? And if I am only for myself, what am I? And if not now, when?" Hillel

ceengland7(at)gmail.com
Guest

Posted: Fri Feb 24, 2017 6:10 am Post subject: Coaxial Cable

Here are links to cable specs for RG58a/u (stranded; note that RG58 can be had with solid center conductor, so beware when ordering), and RG400. I picked this site/brand to get both sets of specs in the same format.http://www.awcwire.com/part.aspx?partname=m17/28-rg58



http://www.awcwire.com/part.aspx?partname=m17/128-rg400



Relevant data:

400's center conductor is 0.0384" vs 58's 0.0355"

dielectric (center insulation) is the same dia, but 400 has marginally better properties; relevant only at the extreme high end of design use: capacitance of 400 is 29.4pF/ft, vs 58's 30.8pF/ft

test freq of 400 is 12.4 GHz, vs 58's 1 GHz (but we use the cable at a max of ~1 GHz)



400's loss at 1 GHz is 14.7 dB/100ft; 58's is 22.6 dB/100ft (unfortunately, I had to pull this spec from other sources; it doesn't show up in the linked pages)



Doing the math, for a 10 foot run (more than enough to mount the antenna on the belly of most planes), 400's loss would be 1.47dB vs 58's 2.26dB. For those that don't know, dB's are a logarithmic measurement. 0.79dB of difference is so small that it could get lost in the noise of connector quality, installation technique, phase of the moon...Â 

At comm & nav frequencies (~100 MHz; 1/10 thefrequency), the spread would be even smaller.

Biggest difference is the outer jacket material; 400 is rated to 200 C, while 58 is PVC rated to 85 C. Unless you're bonding it to your cylinder head, that shouldn't be a big factor.



Yes, 400 is 'better'. But is 58 good enough? There are planes flying with 58 that is still good after 40 years.....

Charlie

On Thu, Feb 23, 2017 at 10:52 PM, Art Zemon <art(at)zemon.name (art(at)zemon.name)> wrote:

 	  Quote: 	
		  Folks,

I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 

Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58.Â 

I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.

At those distances, does RG400 vs RG58 matter? How do I evaluate it?

And then there is theÂ LMR-195 that Bob just showed us. How does that fit in?

Thanks,

Â  Â  -- Art Z.



-- 

https://CheerfulCurmudgeon.com/"If I am not for myself, who is for me? And if I am only for myself, what am I? And if not now, when?" Hillel

alec(at)alecmyers.com
Guest

Posted: Fri Feb 24, 2017 7:01 am Post subject: Coaxial Cable

I've been following this discussion. Isn't it better to move away from PVC jacketed cables, for fire safety reasons? Who uses PVC wire vs 22759-16  ETFE insulated stuff?



 

On 24Feb2017, at 9:06 AM, Charlie England <ceengland7(at)gmail.com> wrote:



Here are links to cable specs for RG58a/u (stranded; note that RG58 can be had with solid center conductor, so beware when ordering), and RG400. I picked this site/brand to get both sets of specs in the same format.

http://www.awcwire.com/part.aspx?partname=m17/28-rg58



http://www.awcwire.com/part.aspx?partname=m17/128-rg400



Relevant data:

400's center conductor is 0.0384" vs 58's 0.0355"



dielectric (center insulation) is the same dia, but 400 has marginally better properties; relevant only at the extreme high end of design use: capacitance of 400 is 29.4pF/ft, vs 58's 30.8pF/ft



test freq of 400 is 12.4 GHz, vs 58's 1 GHz (but we use the cable at a max of ~1 GHz)



400's loss at 1 GHz is 14.7 dB/100ft; 58's is 22.6 dB/100ft (unfortunately, I had to pull this spec from other sources; it doesn't show up in the linked pages)



Doing the math, for a 10 foot run (more than enough to mount the antenna on the belly of most planes), 400's loss would be 1.47dB vs 58's 2.26dB. For those that don't know, dB's are a logarithmic measurement. 0.79dB of difference is so small that it could get lost in the noise of connector quality, installation technique, phase of the moon... 



At comm & nav frequencies (~100 MHz; 1/10 thefrequency), the spread would be even smaller.



Biggest difference is the outer jacket material; 400 is rated to 200 C, while 58 is PVC rated to 85 C. Unless you're bonding it to your cylinder head, that shouldn't be a big factor.



Yes, 400 is 'better'. But is 58 good enough? There are planes flying with 58 that is still good after 40 years.....



Charlie



On Thu, Feb 23, 2017 at 10:52 PM, Art Zemon <art(at)zemon.name> wrote:

Folks,



I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 



Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58. 



I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.



At those distances, does RG400 vs RG58 matter? How do I evaluate it?



And then there is the LMR-195 that Bob just showed us. How does that fit in?



Thanks,

    -- Art Z.



-- 

https://CheerfulCurmudgeon.com/



"If I am not for myself, who is for me? And if I am only for myself, what am I? And if not now, when?" Hillel

ceengland7(at)gmail.com
Guest

Posted: Fri Feb 24, 2017 8:02 am Post subject: Coaxial Cable

http://www.wikiwand.com/en/ETFE

       "Combustion of ETFE occurs in the same         way as a number of other fluoropolymers, in terms of releasing hydrofluoric         acid (HF). HF is extremely corrosive and toxic, and so         appropriate caution must be exercised."

       

       You decide.

       

       On 2/24/2017 8:59 AM, Alec Myers wrote:

     

      	  Quote: 	
		          	  Quote: 	
		  --> AeroElectric-List message posted by: Alec Myers <alec(at)alecmyers.com> (alec(at)alecmyers.com)



I've been following this discussion. Isn't it better to move away from PVC jacketed cables, for fire safety reasons? Who uses PVC wire vs 22759-16  ETFE insulated stuff?



 

On 24Feb2017, at 9:06 AM, Charlie England <ceengland7(at)gmail.com> (ceengland7(at)gmail.com) wrote:



Here are links to cable specs for RG58a/u (stranded; note that RG58 can be had with solid center conductor, so beware when ordering), and RG400. I picked this site/brand to get both sets of specs in the same format.

http://www.awcwire.com/part.aspx?partname=m17/28-rg58



http://www.awcwire.com/part.aspx?partname=m17/128-rg400



Relevant data:

400's center conductor is 0.0384" vs 58's 0.0355"



dielectric (center insulation) is the same dia, but 400 has marginally better properties; relevant only at the extreme high end of design use: capacitance of 400 is 29.4pF/ft, vs 58's 30.8pF/ft



test freq of 400 is 12.4 GHz, vs 58's 1 GHz (but we use the cable at a max of ~1 GHz)



400's loss at 1 GHz is 14.7 dB/100ft; 58's is 22.6 dB/100ft (unfortunately, I had to pull this spec from other sources; it doesn't show up in the linked pages)



Doing the math, for a 10 foot run (more than enough to mount the antenna on the belly of most planes), 400's loss would be 1.47dB vs 58's 2.26dB. For those that don't know, dB's are a logarithmic measurement. 0.79dB of difference is so small that it could get lost in the noise of connector quality, installation technique, phase of the moon... 



At comm & nav frequencies (~100 MHz; 1/10 thefrequency), the spread would be even smaller.



Biggest difference is the outer jacket material; 400 is rated to 200 C, while 58 is PVC rated to 85 C. Unless you're bonding it to your cylinder head, that shouldn't be a big factor.



Yes, 400 is 'better'. But is 58 good enough? There are planes flying with 58 that is still good after 40 years.....



Charlie



On Thu, Feb 23, 2017 at 10:52 PM, Art Zemon <art(at)zemon.name> (art(at)zemon.name) wrote:

Folks,



I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 



Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58. 



I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.



At those distances, does RG400 vs RG58 matter? How do I evaluate it?



And then there is the LMR-195 that Bob just showed us. How does that fit in?



Thanks,

    -- Art Z.

Bob McC

Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

Posted: Fri Feb 24, 2017 8:04 am Post subject: Coaxial Cable

Charlie;   

I've followed your many posts and generally "good opinions" on many subjects over a lengthy period of time and respect those opinions and advice, but in this case I'm curious.   

Did you wire your bird with automotive PVC wire because it was "good enough" or did you use Tefzel insulated wire because that's what is recognized as "correct" current practice? Did you use "hardware store" hardware because it's probably "good enough" or did you use correct "AN hardware"? Did you use proper "braided hoses" (Aeroquip style) or did you use "good enough" rubber hoses?   

I'm a bit mystified why you seem to be advocating "good enough" RG-58 when "better" (by how much may be debatable) RG-400 is readily available for a small overall increase in $$$$. Wouldn't it seem that doing "the best we know how" be the most prudent "best" approach?? There is no labour difference, the fittings are essentially the same, the only actual "difference" might be a hundred dollars or so which in the overall scheme of things is peanuts for the average finished project? There's also "pride of workmanship" and the self satisfaction of doing it right as opposed to "good enough". Just my alternate view two cents worth.   

Respectfully   

Bob McC   

   

    [quote]    --------

_________________
Bob McC
Falco #908
(just starting)

alec(at)alecmyers.com
Guest

Posted: Fri Feb 24, 2017 8:30 am Post subject: Coaxial Cable

The noxious gases released are only one consideration - some others might be ease of initial flammability, tendency to spread fire along the cable, melting point, and probably some others I haven't thought of. I don't know how FEP-insulated RG-400 stacks up but I believe PVC is pretty bad in these respects. Noting that your coax doesn't carry any current, and a short circuit because the insulation has melted isn't a further ignition risk, I'm genuinely surprised that RG58 is still on the table.



On 24Feb2017, at 9:59 AM, Alec Myers <alec(at)alecmyers.com> wrote:



I've been following this discussion. Isn't it better to move away from PVC jacketed cables, for fire safety reasons? Who uses PVC wire vs 22759-16  ETFE insulated stuff?

On 24Feb2017, at 9:06 AM, Charlie England <ceengland7(at)gmail.com> wrote:



Here are links to cable specs for RG58a/u (stranded; note that RG58 can be had with solid center conductor, so beware when ordering), and RG400. I picked this site/brand to get both sets of specs in the same format.

http://www.awcwire.com/part.aspx?partname=m17/28-rg58



http://www.awcwire.com/part.aspx?partname=m17/128-rg400



Relevant data:

400's center conductor is 0.0384" vs 58's 0.0355"



dielectric (center insulation) is the same dia, but 400 has marginally better properties; relevant only at the extreme high end of design use: capacitance of 400 is 29.4pF/ft, vs 58's 30.8pF/ft



test freq of 400 is 12.4 GHz, vs 58's 1 GHz (but we use the cable at a max of ~1 GHz)



400's loss at 1 GHz is 14.7 dB/100ft; 58's is 22.6 dB/100ft (unfortunately, I had to pull this spec from other sources; it doesn't show up in the linked pages)



Doing the math, for a 10 foot run (more than enough to mount the antenna on the belly of most planes), 400's loss would be 1.47dB vs 58's 2.26dB. For those that don't know, dB's are a logarithmic measurement. 0.79dB of difference is so small that it could get lost in the noise of connector quality, installation technique, phase of the moon... 



At comm & nav frequencies (~100 MHz; 1/10 thefrequency), the spread would be even smaller.



Biggest difference is the outer jacket material; 400 is rated to 200 C, while 58 is PVC rated to 85 C. Unless you're bonding it to your cylinder head, that shouldn't be a big factor.



Yes, 400 is 'better'. But is 58 good enough? There are planes flying with 58 that is still good after 40 years.....



Charlie



On Thu, Feb 23, 2017 at 10:52 PM, Art Zemon <art(at)zemon.name> wrote:

Folks,



I have been following this thread because I, too, am trying to decide which coax to buy for my plane. I'm a computer engineer; I shied away from EE in college and especially antenna design because... well... I heard that antenna designers were a special kind of crazy.. 



Seriously, though, if I understand correctly, in the context of an installation in a homebuilt airplane, the biggest difference between RG58 and RG400 seems to be that the RG400 is less loss-y. Yes? In other words, if an antenna puts a weak signal in one end of the coax, the signal that reaches the radio receiver will be stronger if the coax is RG400 than if it is RG58. 



I'm looking at 10 feet of coax from the GPS and comm antennas to the receivers, including service loops. I am looking at 20 feet for the VOR/GS antenna. The transponder antenna will be less than 10 feet.



At those distances, does RG400 vs RG58 matter? How do I evaluate it?



And then there is the LMR-195 that Bob just showed us. How does that fit in?



Thanks,

   -- Art Z.



-- 

https://CheerfulCurmudgeon.com/



"If I am not for myself, who is for me? And if I am only for myself, what am I? And if not now, when?" Hillel

ceengland7(at)gmail.com
Guest

Posted: Fri Feb 24, 2017 9:46 am Post subject: Coaxial Cable

I used tefzel wire for almost everything, because the cost difference really was negligible to get the tougher insulation, and I knew that I'd have big bundles carrying (in some cases) significant current and some really tight routing. Fire hazard wasn't a consideration; either product will produce toxic fumes. Around the engine, long term heat resistance *would* be a factor for me.



Yes, I use a/n hardware.Â 

Yes, I use a/n style (but not actual certified) hoses for oil lines. But for my water cooled engine's coolant lines, I'm using reinforced silicone fluid lines. Some have used a/n hoses & fittings for these lines, but they weigh a *lot* more and there's no evidence that they actually improve safety over quality silicone hoses *in that application*. (This ignores, of course, the massive difference in cost.) A/n hoses are 'better' than aluminum tubing, which is 'better' than tygon, yet early RV-x's are still flying with tygon brake lines, and the new kits still ship with aluminum brake lines. Either are 'good enough', though the aluminum is safer if the operator (the guy standing on the brakes constantly) isn't.

A lot of guys building RV-x's are replacing the $40 brass/nylon fuel selector (included in the price of the kit) with a $400+ Andair fuel selector. No doubt, the Andair is 'better'; it's got to be, for 10X the money, right? But is it, after factoring in weight, altered fittings needed, altered line routing, and expense? Thousands of RV's flying the brass valve prove that it's 'good enough', even if it isn't 'aircraft quality'. (Of course, the Andair isn't *certified* a/c quality either, but that doesn't deter devotees.)



Four part Urethane paint is 'better' than acrylic enamel (at ~10 times the cost). It's also quite capable of killing you, if sprayed without perfectly functioning protective gear. Yet lots of planes are still flying with decent looking enamel, 40 years later.

Honestly, if I were buying 10' of coax, I'd probably (well, I might) go ahead & order the 400; it's certainly prettier. But I've got a box of 58 on hand, and I'm pre-wiring for ELT, comm, nav, glideslope, xponder, GPS,spare GPS, both wingtips, etc with what I have on hand. Whatever I don't use can be easily removed to save weight. I wouldn't have done the same thing with 400, at up to $4/ft.Â 

You're right; a hundred dollars over the total cost of a project is 'peanuts'. You could say the same thing about a $.50 ATC fuse vs a $20 aircraft quality circuit breaker. Now multiply that (and the weight difference) times 30. Which is 'better'? Now extrapolate that over the dozens (hundreds?) of other decisions throughout the airframe.Â 



Everybody should make their own decisions based on valid data and their comfort levels, but they shouldn't make them based on paranoia or worse, bad data. The 58 is certainly good enough, and it *is* aircraft quality cable. If you want 'better', there's certainly nothing wrong with that.Â 

Charlie





On Fri, Feb 24, 2017 at 10:02 AM, Robert McCallum <robert.mccallum2(at)sympatico.ca (robert.mccallum2(at)sympatico.ca)> wrote:

[quote]              

Charlie;

   

I've followed your many posts and generally "good opinions" on many subjects over a lengthy period of time and respect those opinions and advice, but in this case I'm curious.

   

Did you wire your bird with automotive PVC wire because it was "good enough" or did you use Tefzel insulated wire because that's what is recognized as "correct" current practice? Did you use "hardware store" hardware because it's probably "good enough" or did you use correct "AN hardware"? Did you use proper "braided hoses" (Aeroquip style) or did you use "good enough" rubber hoses?

   

I'm a bit mystified why you seem to be advocating "good enough" RG-58 when "better" (by how much may be debatable) RG-400 is readily available for a small overall increase in $$$$. Wouldn't it seem that doing "the best we know how" be the most prudent "best" approach?? There is no labour difference, the fittings are essentially the same, the only actual "difference" might be a hundred dollars or so which in the overall scheme of things is peanuts for the average finished project? There's also "pride of workmanship" and the self satisfaction of doing it right as opposed to "good enough". Just my alternate view two cents worth.

   

Respectfully

   

Bob McC

   



   

 

   [quote]    --------

Kellym

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

Posted: Fri Feb 24, 2017 10:44 am Post subject: Coaxial Cable

If one uses the available information, RG-58 is and has been more than 

adequate for VHF applications for the past 50 years or so. In fact, much 

of that installed in aircraft 50 years ago is still doing a fine job.

The only application that gets a noticeable benefit from the expensive 

RG-400 is those devices operating in the Gigahertz frequency spectrum 

such as GPS and transponders and DME. Most Mode C transponders and DME 

will in fact operate satisfactorily, passing all required performance 

checks with RG-58 coax if the coax length isn't excessive.

The only case I can think of where RG-58 has needed to be removed and 

replaced with RG-400 is for certified WAAS GPS installations, where 

Garmin specifically upgraded their requirement due to their design 

needing a certain insertion loss for the proper performance. They could 

have used a different design that would have eliminated the need for 

coax entirely. (see the Dynon 2020 GPS as an example that meets ADS-B 

performance without coax).

Unlike the type certified advanced technology half million dollar 

production wonders, most amateur built aircraft are necessarily on a 

tight budget, and not spending $200-300 on unnecessary coax makes a 

difference. Using RG-400 for VHF com and nav antennas is huge overkill. 

Using RG-58 for those applications is not wrong, and makes the servicing 

in Timbuktu and 50 miles from Nowheresville substantially simpler. AFAIK 

Radio Shack and Fry's still don't stock RG-400 connectors. In fact, for 

under $15 one could carry a spare 10 or 20 ft RG-58 cable with BNC 

connectors installed.

JMHO.

Kelly

A&P/IA

EAA Tech Counselor



On 2/24/2017 12:01 AM, Bernie Willis wrote:

 	  Quote: 	
		   Iâ€™ve got to submit my two cents worth on the conversation about coax.

  As an A&P IA what I hate the most is having to do something over

 because I did it wrong.  Typically coax is under the floor boards or

 above the head liner.  Most times it goes places where its hard to get

 at and left there.  The extra money for the best is soon forgotten but

 the frustration for replacement just goes on and on.



 The radio shop in our area, which is very busy, urges RG400.  The

 installation money is all the same to me.



 Bernie

> On Feb 23, 2017, at 9:36 PM, don van santen <donvansanten(at)gmail.com

> <mailto:donvansanten(at)gmail.com>> wrote:

>

> After Bob posted the info on the LMR-195 I looked for additional

> information. One thing that seems a little strange is that it is solid

> core. It is also said to be flexible. It was my understanding that

> solid core cable is less flexible than multi strand cable. Any one

> know the minimum bend radius for LMR-195?

> Don.

>

> On Feb 23, 2017 21:14, "Art Zemon" <art(at)zemon.name

> <mailto:art(at)zemon.name>> wrote:

>

>     Folks,

>

>     I have been following this thread because I, too, am trying to

>     decide which coax to buy for my plane. I'm a computer engineer; I

>     shied away from EE in college and especially antenna design

>     because... well... I heard that antenna designers were a special

>     kind of crazy.. 

>

>     Seriously, though, if I understand correctly, in the context of an

>     installation in a homebuilt airplane, the biggest difference

>     between RG58 and RG400 seems to be that the RG400 is less loss-y.

>     Yes? In other words, if an antenna puts a weak signal in one end

>     of the coax, the signal that reaches the radio receiver will be

>     stronger if the coax is RG400 than if it is RG58.

>

>     I'm looking at 10 feet of coax from the GPS and comm antennas to

>     the receivers, including service loops. I am looking at 20 feet

>     for the VOR/GS antenna. The transponder antenna will be less than

>     10 feet.

>

>     At those distances, does RG400 vs RG58 matter? How do I evaluate it?

>

>     And then there is the LMR-195 that Bob just showed us. How does

>     that fit in?

>

>     Thanks,

>         -- Art Z.

>

>     --

>     https://CheerfulCurmudgeon.com/ <https://cheerfulcurmudgeon.com/>

>

>     /"If I am not for myself, who is for me? And if I am only for

>     myself, what am I? And if not now, when?" Hillel/

>

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

Kellym

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

Posted: Fri Feb 24, 2017 10:45 am Post subject: Coaxial Cable

I'm with Charlie. There are huge differences with the other examples you 

cite, such as hardware store fasteners vs AN hardware.

The difference in performance and safety between RG58 and RG400 is 

minuscule for a very real price difference.

RG58 has been the accepted aircraft coax for at least 50 yrs. AFAIK 

RG400 didn't become recommended until after the turn of the century. 

Mainly over performance with WAAS GPS, not safety, not anything else 

that matters for other avionics.

I'll not argue Tefzel vs automotive wire. There is a huge durability 

difference there, as well as insulation thickness difference.

OTOH I have inspected many aircraft with RG58 installed 50-60 yrs ago 

and it is still performing fine. Unlike the general wiring that was used 

back then.



On 2/24/2017 9:02 AM, Robert McCallum wrote:

[quote] Charlie;



 I've followed your many posts and generally "good opinions" on many

 subjects over a lengthy period of time and respect those opinions and

 advice, but in this case I'm curious.



 Did you wire your bird with automotive PVC wire because it was "good

 enough" or did you use Tefzel insulated wire because that's what is

 recognized as "correct" current practice? Did you use "hardware store"

 hardware because it's probably "good enough" or did you use correct "AN

 hardware"? Did you use proper "braided hoses" (Aeroquip style) or did

 you use "good enough" rubber hoses?



 I'm a bit mystified why you seem to be advocating "good enough" RG-58

 when "better" (by how much may be debatable) RG-400 is readily available

 for a small overall increase in $$$$. Wouldn't it seem that doing "the

 best we know how" be the most prudent "best" approach?? There is no

 labour difference, the fittings are essentially the same, the only

 actual "difference" might be a hundred dollars or so which in the

 overall scheme of things is peanuts for the average finished project?

 There's also "pride of workmanship" and the self satisfaction of doing

 it right as opposed to "good enough". Just my alternate view two cents

 worth.



 Respectfully



 Bob McC



> --------

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

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum