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Odd ICOM IC-A200 Power/Ground Instructions

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Tim_Lewis(at)msm.umr.edu
Guest

Posted: Wed Jan 09, 2008 12:52 am Post subject: Odd ICOM IC-A200 Power/Ground Instructions

The ICOM IC-A200 (VHF Comm radio) installation instruction 

(http://www.aeroelectric.com/Installation_Data/Icom_ICA200_Installation_Manual.pdf) 

depicts a 10 amp breaker, and tells the installer to "Use 2 pairs of #18 

AWG wires for power and power grounding wiring."  This struck me as odd, 

since a single 18 AWG wire is normally used with a 10 amp breaker, and 

since the IC-A200 is rated to draw only 2.6 amps (during transmit).



I called ICOM tech support and spoke to Mike, who told me that I should 

indeed use two 18 AWG wires for power and two 18 AWG wires for ground, 

and that the two wires should be twisted together "to reduce 

interference".  He further recommended twisting the end of the two wires 

together, aided by solder, and crimping this assembly into the supplied 

Molex terminal.



I expressed some skepticism about the efficacy of twisting two 12V power 

wires together to reduce interference.  I was unable to elicit an 

explanation of the mechanism by which the alleged interference reduction 

was to be achieved.  I was also unable to elicit an explanation of why 

it should take two 18AWG wires in parallel to supply 2.6 Amps (peak) to 

a radio.  I elected not to engage Mike in a discussion of the 

advisability of crimping a connector to a soldered wire.



Does anybody have insight into reasoning or experience that lends 

credibility to the idea that two 18 AWG wires should be used for power 

(and two for ground) in an ICOM IC-A200 radio installation? 



Thanks,



Tim Lewis



-- 

Tim Lewis -- HEF (Manassas, VA)

RV-6A N47TD -- 975 hrs

RV-10 #40059 under construction

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hooverra(at)verizon.net
Guest

Posted: Wed Jan 09, 2008 3:43 am Post subject: Odd ICOM IC-A200 Power/Ground Instructions

Tim,

    My guess is that since the power uses 2 molex pins 14, R it is a 

mechanical thing (1 wire per pin) the twist and solder part is BS IMHO. 

The ground could be 4 18-20 ga to maintain 1 pin per crimp. these can go 

all the way to the ground point or joined to 1 or 2 wires, your choice. 

As far as I can see from a grounding point of view you are trying to 

maintain the signal ground at the same potential as the 

airframe/battery. The IR drop wants to be as low as possible to achieve 

this, lower than may be acceptable for the power leads. That said you 

may want all 4 wires to go to ground.

    I think that the mechanical issues and the redundant contacts at the 

card edge connector are the overriding concerns here. If there is 

another explanation based on physics it escapes me (possible).



-- 

Ralph C. Hoover

RV7A 

hooverra at verizon dot net

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gmcjetpilot

Joined: 04 Nov 2006
Posts: 170

Posted: Thu Jan 10, 2008 10:08 am Post subject: Odd ICOM IC-A200 Power/Ground Instructions

Tim the 18 awg and 10 amp fuse is the broad brush 

approach, one size fits all. Yes its overkill. You could 

use a smaller awg wire and fuse. Also sometimes 

people gang off of existing 10 amp CB's and therefore 

18 awg is the correct wire size. I used 5 amp and 

stayed with the 18 awg because I had it; A short run of 

20 awg would work fine. They're just covered their bases.

   

  Notice 13.8 volts spec? You can take some IR loss with 

a 14.3-14.5 volt buss.



The wire diagram clearly shows ONE power and ONE

ground with a daisy chain or jumpers. Sorry have no 

idea what he's talking about. TWIST? Really. May be 

this is new and it does help but I am stumped. I went 

with one wire for power and ground. George



  If you find a 100% answer why, email me please, thanks

   

  PS Its a great radio but instructions are lousy.

   

    

  >From: Tim Lewis <Tim_Lewis(at)msm.umr.edu (Tim_Lewis(at)msm.umr.edu)> 

 	  Quote: 	
		  Subject: Odd ICOM IC-A200 

Power/Ground Instructions 

 
	


 

 	  Quote: 	
		  The ICOM IC-A200 (VHF Comm radio) installation 

instruction  

   
	


  (http://www.aeroelectric.com/Installation_Data/Icom_ICA200_Installation_Manual.pdf)  

   

  >depicts a 10 amp breaker, and tells the installer to "Use 

 	  Quote: 	
		  2 pairs of #18  AWG wires for power and power 

grounding wiring."  This struck me as odd,  since a 

single 18 AWG wire is normally used with a 10 amp 

breaker, and  since the IC-A200 is rated to draw only 

2.6 amps (during transmit). 

 
	


 	  Quote: 	
		  I called ICOM tech support and spoke to Mike, who told  

me that I should indeed use two 18 AWG wires for 

power and two 18 AWG wires for ground, and that the 

two wires should be twisted together "to reduce 

interference".  He further recommended twisting the end 

of the two wires  together, aided by solder, and crimping 

this assembly into the supplied Molex terminal. 

 
	


 	  Quote: 	
		  I expressed some skepticism about the efficacy of 

twisting two 12V power  wires together to reduce 

interference.  I was unable to elicit an  explanation of 

the mechanism by which the alleged interference 

reduction  was to be achieved.  I was also unable to 

elicit an explanation of why  it should take two 18AWG 

wires in parallel to supply 2.6 Amps (peak) to 

a radio. I elected not to engage Mike in a discussion of 

the advisability of crimping a connector to a soldered wire.  

 
	


 	  Quote: 	
		  Does anybody have insight into reasoning or 

experience that lends credibility to the idea that two 18 

AWG wires should be used for power (and two for 

ground) in an ICOM IC-A200 radio installation?  

 
	


  >Thanks,  

 	  Quote: 	
		  Tim Lewis


	


        [quote][b]

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