Topband: New 160M high performance receiving antenna at W3LPL
Lee K7TJR
k7tjr at msn.com
Wed Feb 6 00:06:58 EST 2013
>The "Wullenwever" antenna was never a low-noise high performance antenna.
It was simply a system designed to find direction over a very wide frequency
range. The multitude of elements increased bandwidth, but the physical width
in wavelengths is the primary determinant of directivity.
While I will agree that the Wullenweber antenna was never designed to be a
low noise antenna, I fail to see why it is not. My copy of TM32-....... manual
on the US version shows some pretty good directivity specs. On the low band
starting at 2 MHZ the beamwidth was 11 degrees with the side lobes down a
minimum of 18dB. The maximum elevation was 30 degrees. Also the range
specified was 4000 nautical miles. And its outer element diameter was
1116 feet. The 48 low band elements were 35 feet tall with a 120 foot tall
reflecting screen. Each element had a 19dB gain semiconductor amplifier with
a 7 dB noise figure. I agree also that not all the 48 elements were active
however the ones that are in a given direction produce some outstanding specs.
So if I compare usual high performance low noise RX antennas to this large
antenna our directivity specs pale in comparison leading me to believe the RDF
of the "W" system surely would be greater than anything we could imagine with
our RX antennas. Nor does noise figure appear to be a concern.
Or is my thinking corrupt?
Lee K7TJR
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