Friday, September 03, 2010

QDFA Version 3 - Initial Impressions

OJ Sagdahl and I finished the new "monster" QDFA yesterday. It didn't become quite as monstrous as we hoped, since weather considerations made us reduce the height somewhat, from a theoretical 21.5 ft to around 20. The loops are set up in a "house" pattern rather than a delta or flag, with two 12-ft masts on the loop's ends. The bottom vertical element is roughly 1 meter above ground.

The increased height and shape has provided us with a 5-6 dB extra gain, compared to versions 1 and 2. And most important: The Max-Gain masts are much more sturdy than the angling rods we used last year. But also a lot heavier, so they require good support and guys.

One interesting observation of version 3 is that the sensitivity appears to be identical throughout the MW band, while version 1 and 2 were noticeably less sensitive below 1000 kHz.

No comments: