>>>Can you tell me the difference between RG142 and RG400
>>>cable except that one has solid center conductor and the
>>>other stranded.
>>
>>bn: Why use either of these cables?
>
>Well, for one reason, the Bendix/King KLX-135A Installation Manual
>specifies that if the length of the coax is to be longer than 9 feet (as I
>recall), RG-142 or RG-400 is to be used.
>
>
>bn: The modern RG cables like 400 and 142 are still
>bn: small diameter cables and have losses comparable
>bn: to RG-58.
>
>NOT TRUE.
>RG58 has a nominal attenuation of 20db per 100 feet at 1GHz.
>RG142 has a nominal attenuation of 13db per 100 feet at 1GHz.
bn:
I stand corrected . . . but for a run of say 15' (very
long in a single engine airplane) we're talking
3db for RG58 versus 2db for RG142 . . . which is
still trivial. I encourage my readers to put the xponder
antenna as close to the instrument panel as they can.
Given that very few antennas are on the belly of any
airplane, a coax length of 5-6 feet is possible for
most airplanes . . . a GOOD thing to shoot for irrespective
of the kind of coax you use. Losses in this length
of coax are insignificant.
Bob . . .
////
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