Topband: NCC-2 NCC-1

[Jim Brown]

On 12/23/2024 6:07 AM, Andree DL8LAS via Topband wrote:
> Hey,do any of you use an NCC-2 or NCC-1 for antenna phasing or noise reduction?

Hi Andy,

I own two NCC-1 units (the second is a spare). It is my understanding 
that the NCC-2 differs only in the switching, providing for the main TX 
antenna to be used as one of the antennas. The phase shift it provides 
is most effective below 40M.

I made extensive measurements of my first NCC-1 as part of the research 
for my applications note on phasing a pair of VE3DO loops. It's on my 
website, k9yc.com/publish.htm  I have a pair of the loops spaced 5/8 
wave, aimed to EU, my most difficult direction, and confirmed, listening 
to the known headings to various stations, that it worked exactly as 
careful EZNEC modeling predicted.

Usefulness for noise cancellation is much trickier, depending entirely 
on the number of sources, their azimuth to you and antennas you can use 
for sensing and listening, and the physical breadth of the source. The 
whole practice of nulling a source is effective for a single azimuth 
heading at a time, and for sources whose radiating antennas (the wires 
connected to them) are small as a fraction of a wavelength. I've had 
little success with noise cancellation, thanks to the number and their 
azimuthal dispersion, but this is entirely dependent on our own 
individual situation.

BTW -- I had to measure the unit I bought to learn anything about it, 
and did that work in 2017. When I asked DXE a year or two earlier prior 
to purchase if it would be effective at 50 MHz, they didn't know.

73, Jim K9YC