Wednesday, October 28, 2009

N6QQQ/R bench test results

The receiver and my uplink DVB-S modulator have arrived from Germany. With the DEMI 2330PATV, I'm able to get about 4 watts of DVB-S power output. When I started bench testing the repeater, however, it turned out that even with the amp's bias turned off, the DVB-S exciter alone was enough to be received by the receiver. Not too much of a surprise, given that the exciter and receiver were about 3 feet apart in the garage.

I made a YouTube video showing a complete round-trip - from my analog camera, through the MPEG encoder, modulated with DVB-S, amplified to 4 watts and transmitted with my 23 cm 14 dBd loop Yagi. Then received on the DVB-S receiver, modulated as 8VSB on 33 cm, amplified to about 15 watts, then attenuated by 20 dB and run through a rubber duck antenna. Then received on the loop Yagi on the roof, downconverted from there to TV channel 3, and then received on my portable ATSC TV.


The next step will be to start separating the up/downlink station and the repeater further and further apart. Hopefully, the last test will be with the repeater at its new home on the hill!

The next big demo will be at the K6BEN ATV luncheon on November 23rd. I'll schlep all of the gear for both the repeater and my uplink station over to Harry's Hofbrau and we'll try a full round-trip across the parking lot.

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