Radios

Articles and blogs about radio receivers and transmitters. Both commercial off the shelf radios and home made DIY experiments by Alexandru Csete OZ9AEC.

K1 TX Signal Tracing

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Yesterday I have done the transmitter signal tracing using my Velleman PCS500 pc-based oscilloscope. Here are the results: PRE (0.04-0.09) 0.025 V ATTN (0.02-0.05) 0.047 V OSC (0.01-0.04) 0.019 V MIX (0.1-0.2) 0.042 V BUF (1.5-2.0) 1.74 V TR1 (0.5-1.0) 0.66 V BPF (0.5-1.0) 0.78 V TR2 (0.5-1.0) 0.72 V TR3 (<0.01) 1.5 mV DRV … Read more

K1 Noise Blanker and Blown Final?

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I finished the KNB1 noise blanker today and installed it in the K1. When finished, I connected the K1 to my ATX-1080 set to the 40 meter band. I put the OHR WM-2 wattmeter and the T1 antenna tuner in between the K1 and the antenna. First I tried to put the T1 into bypass mode, but I wasn’t quite sure whether the yellow LED meant bypass on or tuner on… Later I found out that green led means tuner on, yellow led means bypass on.

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K1 Transmitter Alignments

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I was just about to panic when I first set the K1 into TUNE mode. I have hooked up the K1 to my variable power supply, set the current limiter to 1 amps (as instructed by the manual), turned the K1 on and set it into TUNE mode. The only thing that happened was that the K1 turned off and the current limitin led on my power supply was lighting up, meaning that the K1 wanted more current then it was given.

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Conclusion on the Filter Alignment

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I have tried to use my other dummy load on the FT-817. It did indeed reduce the signal strength in the K1 quite a lot. This may sound a bit strange but it is not. You know, the DL-1 dummy load kit from Elecraft is an open dummy load, meaning that it is not in an enclosure, thus the RF signal is radiated from it. My other dummy load, on the other hand, is built into a piece of cooling metal and looks much more radiation closed than the DL-1 does.

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