Note Jim's words about a "good transmission line calculator" and take to heart
Dan's ,AC6LA, words:
"Think Twice Before Using a Web-Based Line Loss Calculator"
See his site here: https://ac6la.com/swrloss.html
Wes N7WS
On 12/4/2023 12:50 PM, Jim Brown wrote:
Clarifying a typo, "antenna tuners" like the KAT500 are networks that
transform the impedance presented by the transmission line to 50 ohms,
allowing the output stage to provide power to the line. This has NO effect on
loss in the line, which is determined solely by the match between the antenna
and the line, as Bob correctly states.
That said, line loss due to SWR is often wildly overestimated. For 60M, I'm
using an 80M dipole fed with about 160 ft of a good RG11, which looks like 5:1
VSWR at the transmitter. Taking line loss into account, VSWR at the antenna is
around 7:1. A good transmission line calculator shows the excess loss in the
line due to VSWR to be about 1 dB, which is a small fraction of an S-unit.
Using FT8, I've confirmed more than 70 countries on that band with 100W, and
can work EU almost any night from my QTH near San Francisco.
73, Jim K9YC
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