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New Dipole Ant

capture_002_07122013_131126

I removed the elements for 21MHz and 28MHz and used them as a single element. Since 15m+10m=25m, it should be resonant somewhere around 12MHz.

At 7026kHz, the measurement using a bridge tells that V1=2.569 V, V2=0.869 V, and V2delay=24.20 nS, which means Z=2.629+j8.624 ohm, and SWR=19.6.

capture_001_07122013_132532

Considering the cable length of 20m, Zant=14.861-j108.951 ohm.

At 10110kHz, V1=3.083 V, V2=5.222 V, and V2delay=4.40 nS, which gives Z=54.274+j131.008 ohm, and SWR=8.20, and Zant=29.910+j95.210 ohm.

At 14010kHz, V1=2.599 V, V2=2.495 V, V2delay=-9.40 nS, which gives Z=8.131-j30.425 ohm, and SWR=8.47, and Zant=5.906-j1.093 ohm.

capture_001_07122013_190606

For stub matching at 7026kHz, we need a 3490.4 mm cable and a 962.6mm short-circuited cable both 75 ohm to obtain Z=49.383+j0.774 ohm.

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I didn't know that

HPFLPF

I have been thinking that I need some audio filters when I listen to CW signals, because the sound seemed to be too wide-band. I was almost building a circuit, and I finally noticed that my rig has a built-in audio filter. Better late than never, right?