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.


Specifications:
  • 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

Features:

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.



So?

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.



5 comments:

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!

73
Aurelio

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?
73
Lou
W1AAJ

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*