[Lowfer] RF Noise Canceller

[wa3tts at verizon.net]

Hi All:  I managed to find my copy of the Phase-X noise canceller schematic and figure out how to use dropbox again, its been a couple years....see link below for the schematic...

https://www.dropbox.com/s/tufhocewo2eso9l/QRMX-PHS.jpg?dl=0


I recall doing a test with my NanoVNA and a 0 degree splitter along with a 20 dB pad to lower the VNA output before splitting to drive the two ports on the Phase-X.  I was able to see the phase move about
with the phase control pot and recall the RF input loss was about 8dB, basically the same as my ANC-4 noise canceller.  The gain fell off after 40meters with the Phase-X.  It did work OK on 630m, althougth I needed to
use 475 kHz bridge-T diplexers on both inputs to manage the overload from the two very nearby AM 50KW stations at my location.  I do not recall if I tried to use it on 137 or 185 kHz bands.
I did use a BN73-202 core.  There may be better toriod cores for 185 and 137 kHz, maybe a FT50-W core that has u > 10,000.   It's on my list of things to get  back to some day....

I think the Phase-X is a worthwhile kit but I would have liked to see it usable in the mid and upper HF bands.  It seems fine for medium frequencies. If I get some time in the next week or two I will try doing the NanoVNA test again in the LF range.  Certainly more affordable than the Timewave ANC-4 or the MFJ equivalent....
One issue with any of the phase cancellers is it being hard to tell which way your combined antennas are "pointing" with the electrical phase manipulation.  I found it useful with my pair of EWE antennas to build some single band 90 degree 50 ohm "T" phase shifters ( 90 deg. plus and minus, etc) and use them on the antenna feedline near the receiver.  With the fixed phase shifters I could plug the 90 degree phase changes into EZ-NEC with the antenna info and get some pattern plots to see the predicted directional changes. Then compare to what the antennas were doing. using 630m wspr2 signals since the transmitting station locations are easily determined.
Hopefully in a couple years I will have time to play with this LF rx antenna phasing thing....
Have fun with it.
73, Mike wa3tts

-----Original Message-----
From: John Bruce McCreath <weazle at hurontel.on.ca>
To: Discussion of the Lowfer (US, European, & UK) and MedFer bands <lowfer at mailman.qth.net>
Sent: Wed, Dec 28, 2022 7:34 pm
Subject: Re: [Lowfer] RF Noise Canceller


Hi Tom…..thanks for the link to the noise canceller site.  I took a quick look at it,
and was disappointed that none of the pictures came thru, just the text.  I’ll give
it a couple of tries later, as it may have been a temporary glitch.

Your comments on the toroid vs binocular core back up what I’ve discovered
myself while toying with antenna matching, etc.  Huge improvement in all the
cases I tried.

Tnx & 73, J.B., VE3EAR


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