[Elecraft] Anyone using a DXE NCC-1 with K3?

Fri Mar 27 12:42:13 EDT 2015

 Thanks, Bob, for your concise description of how you use your NCC-1 with your K3---it is very helpful to me as I am almost confused by all the choices of configuration---a lot more ways to set it up than I thought.

My situation is that I plan (at least initially) to use only 1 un-amplified noise antenna into the B input of the NCC-1 along with a DXE Receiver Guard (high RF limiter to protect both rig and NCC-1 during xmit) since my transmit antenna is a mere 20 feet or so from my operating desk.  

I'll see how that works and then add a second noise/receive antenna to the A input.  Both noise antennas will be simple vertical wires or short indoor dipoles here in our small rented condo; maybe one will be longer and bent around corners and windows out to the back balcony.  I can't really put the noise antennas outside the shack as our windows and back balcony are screened in with fiberglass in a frame that the owner installed that I would be very reluctant to mess with.  At least my xmit antenna is outdoors and a bit higher up.  While I am on a multiband inverted U dipole now I am almost finished building a really fine magnetic loop as mentioned in my earlier post; it will probably be an improvement over the inv. U to start with and its high Q will undoubtedly help with the RFI hash before I put the NCC-1 to work, too (fingers crossed).  Ultimately I will also employ a second and third STL (mag loop) as noise/receive antennas for diversity reception and better noise nulling once I am able to put them in place.  But that may a lot more tricky than I imagine if I will have to constantly re-tune them as well as the main transmitting loop---so we'll see how it goes with the simpler vertical wires first.

I got the big box from DXE yesterday and lo and behold, the NCC-1 is almost the same size and heft as my loaded K3/100! I still need to make up some RG58 jumpers so I can hook it all up but I will try to do so  tomorrow during the WPX (been delayed with other stuff all week so am not ready to get it up and running just yet).  I want to make sure I hook it up correctly and your reply has certainly given me a clearer picture of how to accomplish that now.  

Since my noise antenna(s) will not be active I will set the internal dip switch to external power for the noise antennas and keep power from being applied to that port completely.

Also, since I run QRO most of the time (and my STL will be set up to handle 650 watts from my KPA) I will make sure that the TX control line is plugged into the K3's PTT jack and that the BNC receiver Guard is correctly placed ahead of both the NCC-1  and K3 RX input.

I considered spring for one of DXE's sequencers but as I am already over budget on this shebang I decided to go with the less expensive Receiver Guard initially.  Hopefully this will suffice with no further gear inline required---but if anyone here thinks that is still unwise please speak up ASAP* as I want to try to get this going sometime Saturday during the WPX---I'll need it with the current noise on most of the bands here.   

(*If I AM running the risk of damaging my receiver/NCC I will not use it at all during QRO operation until I can eventually get a sequencer in line, too)

Fingers crossed and hoping that I will be OK with what I have now so I can start enjoying this fine piece of gear right away.

Thank you again, Bob for helping me out; it is very much appreciated.  I can't wait to watch the noise diminish on my P3, too.

Vy 73,

Jeff, NH7RO

K3 #5528 P3 #1397 KPA500 #0250

> Date: Fri, 27 Mar 2015 00:11:03 -0600
> From: nw8l at whitemesa.com
> To: cathrowinternational at hotmail.com
> CC: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Anyone using a DXE NCC-1 with K3?
> 
> 
> I have local noise problems which come and go depending on time of day, 
> day of week etc. I didn't like the idea of having a noise cancelling 
> device in the high power transmit path, so picked up a DX Engineering 
> NCC-1 which is perfect for use with my K3, inserted between the antenna 
> OUT and antenna IN jacks. I have a horizontally polarized loop which I use 
> as the RX antenna on the K3 when I need to fight noise. A vertical doublet 
> antenna is used as the transmit antenna, which serves as the noise sense 
> antenna in receive when the NCC-1 is active.
> 
> To do this, the loop antenna goes to antenna port A on the NCC-1
> (receive antenna input), K3 antenna OUT (from the transmit antenna)
> goes to antenna port B on the NCC-1 (noise antenna input) and the
> output of the NCC-1 goes to the K3 antenna IN. K3 KEY OUT goes to NCC-1 
> T/R CTRL to put it in bypass when the K3 is keyed.
> 
> Now I have 3 choices:
> 
> 1. If I then select the RX antenna on the K3, the NCC-1 is inserted and I
> use the quieter loop antenna for receive while nulling noise with the 
> NCC-1 controls. 2. If I don't select the RX antenna on the K3, the NCC-1 
> is bypassed, and the transmit antenna is used for receive. 3. If I select 
> the RX antenna on the K3, but turn the NCC-1 OFF, then I receive on the 
> loop antenna, but the signal passes straight through the NCC-1 from 
> antenna port A to the output without modification (sometimes that's all 
> that's needed, it's much quieter than the vertical when it comes to the 
> nearby noise pollution sources).
> 
> The NCC-1 can provide a very deep null on the receive loop antenna for 
> vertically polarized noise which is "heard" better on the vertical. The 
> trick is to correctly balance the levels of the two antenna inputs on the 
> NCC-1. The balance and phase controls are very precise and repeatable, and 
> the phase control has a wide range. Having the P3 to look at helps in 
> identifying the noise and finding what can be a very sharp (but deep) 
> null.
> 
> There are complications. One is that when the NCC-1 is active I need to 
> disable full QSK on the K3 in CW mode so that the internal bypass relay in 
> the NCC-1 doesn't make a lot of noise as it follows the keying.
> 
> The other involves antenna tuners. I use a KAT500, and if a frequency 
> change causes it to recall new L and C settings then the NCC-1 phase 
> setting may need to be touched up because the phase of the noise signal 
> from the transmit antenna is changed (and the NCC-1 null can be very sharp 
> indeed).
> 
> But for me the benefits have far outweighed the costs.
> 
> Bob NW8L
> 
> On Sun, 22 Mar 2015, Jeff Cathrow wrote:
> 
> > Am contemplating a purchase of a DXE NCC-1 receiving antenna/noise phasing unit very soon (tomorrow, actually---so I will have it in time for the WPX next weekend) for use with my K3/P3/KPA500 and was wondering if anyone else in the group uses one and how they have it configured.  Apparently I will either need to run it via my RX antenna jack or else with a sequencing unit (or RTR-1A controller that DXE also sells) if I want to run it inline with my main antennas.
> >
> > My main usage will be for the reduction of RFI that I am often subject to here in our condo complex (plasma or LCD TVs, wall warts and other electronic RF garbage producers nearby).  I currently use an old JPS ANC-4 with its attached noise receiving whip that works fairly well---but could still be much better.  (I don't plan to buy the active antennas that DXE also sells with or without the NCC-1; at least not for any foreseeable future).
> >
> > I also use my Elecraft PR6 6M preamp affixed via the XVTR or RX antenna BNC jacks and am wondering if I can run the NCC-1 through it with or without the PR6 being on (I have it wired so that the PR6 activates only when I am on 6M, IIRC)---but I am getting older these days and am more easily confused/dyslexic when it comes to IN/OUT jacks than I used to.  Will it be fairly easy to run both together or will it require removing the PR6 if I want to run the NCC-1 through the RX ports?
> >
> > Any user comments or thoughts on the subject will be appreciated; I have seen a few YouTube videos on the NCC-1 and it looks like it can be very effective on QRN coming from one particular source (like my ANC-4 but even noticeably better).  It certainly will be fun to see the noise disappear or fall dramatically on my P3, too!
> >
> > 73, Jeff,  NH7RO
> >
> > K3/P3/KPA500
> >
> >
> >
> >
> >
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> >
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