Hi guys! I'm new here and have a question about my new MFJ-971 Antenna tuner I just connected up last night.
In learning to read the swing needles, I have a basic understanding of forward power and reflective power and the standing wave ratio where the needles cross. If I am posting this in the wrong place please forgive me.
So I set my antenna tuner to 6 watts first using the jumpers. Then I notice that before I have connected my homemade antenna to the 50 ohm coax from the tuner, the swing needles were already reading at about the 3rd hash down, say just over 100 milliwatts of forward power. Why is this when there is no antenna connected?
And then next when I take off the 50 ohm coax from the antenna out, the forward power needle drops by half.
So the question is, how can it be reading forward power without a closed circuit and just an open circuit transmission line on the coax?
Then once I do connect my homemade antenna circuit, do I deduct the forward voltage that it was already at before I connected the antenna, from where it is after the antenna is attached, to calculate forward power?
Thank you for helping out an RF Newbie..
In learning to read the swing needles, I have a basic understanding of forward power and reflective power and the standing wave ratio where the needles cross. If I am posting this in the wrong place please forgive me.
So I set my antenna tuner to 6 watts first using the jumpers. Then I notice that before I have connected my homemade antenna to the 50 ohm coax from the tuner, the swing needles were already reading at about the 3rd hash down, say just over 100 milliwatts of forward power. Why is this when there is no antenna connected?
And then next when I take off the 50 ohm coax from the antenna out, the forward power needle drops by half.
So the question is, how can it be reading forward power without a closed circuit and just an open circuit transmission line on the coax?
Then once I do connect my homemade antenna circuit, do I deduct the forward voltage that it was already at before I connected the antenna, from where it is after the antenna is attached, to calculate forward power?
Thank you for helping out an RF Newbie..
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