[Elecraft] Off Topic RG-174

[Jim Wiley]

Well, according to the wire tables, the 26 gauge center conductor can 
safely handle about 350 to 400  milliamperes, depending on how you 
interpret the safety factors.  The center conductor is certainly not 
operating in "open air", so the best figure is probably the one used for 
wire in bundles. 


That works out to 10 watts or thereabouts, which strikes me as about 
right for RG-174.  Give or take a little room for SWR,  this sounds like 
a safe "rule of thumb" for  normal use.


At 1800 watts, I would stand waaaay back when power was applied!    Can 
you say "BOOOM"  ?


- Jim, KL7CC



Nick-WA5BDU wrote:
> Well, that shows that it ought to be OK from the voltage breakdown 
> perspective, but consider current carrying capability or self heating 
> of that little bitty center conductor too.  It might be limiting.
>
> If you allow it an amp, 50 watts.  Two amps, 200 watts.  At 100 watts 
> of course, 1.414 amps.  Probably OK, I'd think.  But I don't know that 
> I'd go much higher.
>
> 73--Nick, WA5BDU
>
>
> Don Wilhelm wrote:
>> Mike,
>>
>> My chart in the ARRL Handbook says RG-174 has a dielectric breakdown 
>> voltage of 300 volts RMS.  So in theory, it will handle 1800 watts at 
>> an SWR = 1.0 (less at higher SWR) - but I would not trust it at much 
>> over 25 watts myself.  I like to see a larger safety factor where 
>> transmission lines are concerned.  The ohmic losses may be great too, 
>> that all depends on the length and the SWR.
>>
>> 73,
>> Don W3FPR
>
>
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