Apr 7, 2008

Receiving Phasing System / Noise Cancelling Controller

DX-Engineering NCC-1

Finally the phasing control box has arrived !
Very surprised to see this unit is 4 times larger than I expected; it measures 24x24x11.5 cm ( or something like a foot x foot x a quarter of a foot, for that matter).
This is the size of a medium HF rig.

  • 300 kHz to 30 MHz (Switchable in two ranges; <5-10mhz>5-10 MHz)
  • 3rd order output intercept: 32dBm each input, +38dBm both outputs combined
  • Available phase rotation >360 degrees (between 500kHz and 15MHz)
Go check their website for the rest


Or better said, in what respect does this unit differ from its MFJ 1025/1026 counterpart?
  • Phase adjustable through more than 360 degrees (MFJ does much less)
  • Exceptional dynamic range (30dB more)
  • Low noise floor (that is usuallly not much of a problem on the Low-bands)
  • Provisions for optional high pass and band pass filters (see pics)
  • DC controls with smooth action. Expandable for remote or external control
  • Provides power and transmit muting for external active antennas
In a nutshell; after some years this is the natural follow-up of the MFJ.
The MFJ is definitely not bad, but it has some drawbacks in practise. Adjusting both input gain setings and finding the right phase are a bit tricky.
The new NCC-1 has no seperate input gain seetings per channel, but a 'balance pot' instead.
Next it has a switch for swapping the antenna inputs (changing receiving direction on the spot !).

Looking at its internals, especially the transformers, this smells like W8JI design:

Looks like 2N5109's under those heatsinks.

Extra options:
  • Provisions for the high pass and/or band filters
  • Accessory entry slot for future remote control etc.


You can use it for (local) noise cancelling or, produce a steerable 2 element phased vertical RX array.
And there are some more applications.

What will I do with this unit?

First test this unit at a friends location to get a feel how it compares to its MFJ 'predecessor'.

Next I will start building a second 160m reference vertical in my front yard.
This will be >0.10 wavelength away from the backyard version which allows for a very good steerable phased vertical system (sort of very poor mens 4-square). PA3FGA has proven again and again that his double 160m reference phased vertical system works very well, expecially during contesting.


Aurelio said...

Hi Mark,

Dit is precies wat we zochten voor de 2x sloper @ 4tue. Zelfs mute schakeling is voorhanden bij zenden? Ik ben heel benieuwd hoe dat kastje werkt in contest op 160m @4tue.

Gaaf ding!


Anonymous said...

Hi Mark!
Did you form any further conclusions about the DX Engineering NCC-1 Noise Reduction Unit? Given your experiences, would you purchase it again. What do you think?

Mark, PA5MW said...

Yes and no.
We have used the NCC-1 during a contest on two 160m full size slopers where it did work fb. I have tested and compared it at a friends house who already had a tweaked and fb working two phased RX verticals set-up and the MFJ-1026; the NCC-1 proved to be much better in respect.
But I'm still having trouble finding a suited location on or near my small home QTH for the second vertical. Perhaps it will be a front and backyard vertical set-up with 20mtrs distance in between as I have found no better alternative yet.
Hope to finalize that proposal before winter sets in. I sure will write an article on my findings afterwards.
About the NCC-1; I would sure purchase it again!
'73 Mark, PA5MW

Rune Øye said...

Hi Mark

I have just received my NCC-1 di you ever: "Hope to finalize that proposal before winter sets in. I sure will write an article on my findings afterwards."

73 Rune LA7THA

Mark, PA5MW said...

Hi Rune,
These last few years we are plagued by many local man-made interference noises.
Several tests showed that vertical antennas pickup way too many of these interferences from all around the neighborhood.
A single interference source can be successfully notched using the NCC-1, provided you have enough interference signal on the noise pick-up antenna.
The NCC-1, or any phasing box, cannot do much for multi interference sources; about 5 - 10dB reduction can be achieved.
Currently I have much more success using 50 - 80m long BOG antennas in ditches, even under water they work fb.

73 Mark, PA5MW
*Happy New Year*