> Steve,
> It goes without saying that transmitted voltage/power arriving
> back at the tuner due to a mismatch at the antenna gets absorbed by
> the tuner...except for the small portion that gets re-reflected
> back toward the antenna.
Hi Bob,
How can a reactance, or group of reactances, absorb and dissipate power? If
the tuner
really absorbs reflected power and dissipates it, shouldn't it get hot?
You have that backwards, the BULK of reflected power is returned to the
line at the tuner, with only a small portion absorbed by the small (as a
percentage of reactance values) resistive losses in the tuner.
I feed an open wire line that operates with a 20:1 SWR (thirty ohm load,
600 ohm line) with an Ameritron ATR-30 tuner or Johnson KW matchbox.
Neither tuner gets the slightest amount warm, and the antenna it feeds
constantly equals or beats people with two or three element yagis...even
some who run much more power than me... day after day.
"Match efficiency" is 18.14 % between the line and antenna, but:
1.) The tuner does not get hot.
2.) My signal is competitive with others with similar antennas and power.
3.) Current at the antenna terminals flowing into the antenna's 30 ohm
resistive impedance at resonance is 6.7 amperes with 1500 watts applied at
the tuner input (the antenna is a dipole with multiple reflectors that I
feed with open wire so I can use it on multiple bands).
Please tell me why my tuner, with 140 feet of 600 ohm line going straight
up from a doghouse up to the 30 ohm antenna feedpoint, does not get hot.
Why does the same 600 ohm line and tuner(s) deliver 1.3 amperes into 50
ohms (SWR 12:1) with only ~100 watts applied to the system? Why doesn't
something melt, if 80% of 1500 watts is absorbed in the tuner?
73 Tom
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