At 02:41 PM 8/25/98 EDT, TexasRF@aol.com wrote:
>
>It is appropriate at this point in the loss discussion to move from the
>theoretical to real world.
>
>In the real world, the matched line would be 200 ft of RG213/U coax, the
>balanced line would be 200ft of 600ohm line with two number 10 conductors
>spaced for Zo=600 ohms. The frequency would be 14 Mhz.
>
>I think under this more likely scenario the real point of using balanced
lines
>would be very apparent and will show that the matched line loss is even
higher
>than the unmatched line loss in this application .
>
>We have known for decades from charts in the ARRL handbook that SWR causes
>line losses to increase. No argument here, we know this to be true, and have
>proven it to ourselves numerous times, especially at vhf/uhf, where line
>losses are already higher.
>
>I look forward to seeing the comparison numbers per the above discussion.
Gerald got to the point much more clearly and directly than I did. There
is no "automatic" additional loss in the unmatched case, unless you
artificially make the feedline have the same loss as in the matched case.
What never made sense to me was the additional 7+ dB of loss that Steve
asserted was due to the mismatch alone -- all this has really been is a
discussion of why an unmatched transmission line will have more loss than a
matched one, when their inherent characteristics are the same.
73, Pete Smith N4ZR
n4zr@contesting.com
"That's WEST Virginia. Thanks and 73"
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