Re: [amsat-bb] Re: 92 ohm line

[John Mock <kd6pag@xxxxxxx>]

	Another way is to run each line down the center element of two lengths
	of RG58 (or whatever's convenient).	

    If I run two pieces of RG-58 in parallel, I get 25 ohms.

    So would that mean...

    If I run 2 pieces of RG-58 in series, I get 100 ohms???

    I wonder!!!
				-- KD8KC

OK, here are the two cases, the first one mentioned

	    -----------------------------
    o-*-----|		RG58		 |----*--o
      |   --*----------------------------*-   |
      |  /  				   \  |  25
      |  |  ------------------------------ |  | ohms
       \-|--|		RG58 		 |-|--/
    o----*--*----------------------------*-*-----o


And the second, where the shields are soldered together on each end:

	   - --------------------------------
    0------|		RG58		    |-----0
	  *----------------------------------*
	  |				     |   100
	  |				     |   ohms
	  *----------------------------------*
    O------|		RG58 		    |-----O
	   - --------------------------------


	[ARRL Antenna Book (16th Ed.), p. 24-21]

And note that *i* didn't use the term 'in parallel' here.  I don't know what 
you would call which.

Of course, two lengths of RG59 gives about 150 ohms, as would two lengths
of TV twinlead in parallel might (but i'd be real concerned about proximity
effects in that case).

			-- KD6PAG  (Networking Old-Timer, "RF newbie")
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