I'd have to look at it again, but when I checked a few years ago there were fundamental differences in the design of the phase shifters in the Timewave and MFJ units. The MFJ unit has a superior circuit design in my recollection, but with the usual MFJ QC issues. I sold my MFJ-1026 because although it worked OK, it was a total pain to get properly adjusted. DX Engineering also has a superior version of the MFJ design, both in RF/electrical and QC terms. But, I have not used one.
I just purchased an MFJ-1026. It is working on some noises, but not others. I'm in the process of making a short continuously-loaded hamstick type antenna (but 8 ft tall) for 40 meters that I can hide in the shrubs, as I'm not able to get much more than a few S-units reduction on the noise that motivated me to buy the device. I noticed some improvement after placing a wire near my vertical, but the wire isn't picking up a signal strong enough to do much with. Hopefully the sensing antenna will improve on that.
Curiously, some of the noise is nulled at 9 on the phasing, and more noise starts to null right at the end of its range, which is problematick. Changing the position of the sensing antenna doesn't do a thing. Another odd thing is most noises don't have sharp nulls or peaks. The noise will just decrease slightly over half of the range. I think this could be from using a random length of wire that is picking up the same noise along the length of the wire, or maybe due to the noise being radiated from different circuits in the AC wiring.
Also, I am using RG-6 for the sensing antenna feed-line. After testing on a short length of RG-58 vs RG-6, the MFJ can't "hear" the signal on the 75 ohm line, but the transceiver can. It seems as though the MFJ doesn't like 75 ohm feed-line.
I also hear a mess of broadcast stations below about 6 MHz with it on, making it useless on 75 or 160 meters unless I install a high-pass filter inline.
Last edited by KE6KA; 04-24-2013 at 10:03 PM.
I used the same noise antenna as I use for the ANC-4. I saw NO CHANGE in the noise level whatsoever when playing with the MFJ controls. I also took it apart BEFORE powering it up and corrected many solder errors and bad solder joints. What components I could I measured and all was well. But the circuit just didn't work. On my test bench, I hooked up the output to my Spectrum Analyzer and used clip leads as source and noise antennas. I watched the output as I ran a Dremel tool nearby (lotsa noise). NO REDUCTION whatsoever! And this was a BRAND NEW UNIT, just out of the box from HRO.
That was $200 flushed away! I ran the same tests on the ANC-4 and it DID reduce the noise!
I used a MFJ-1025 for a while and had success with it. That's the same as the 1026 without the preamp. It can be very effective if you can get it to work but it requires some understanding and patience. It can only really work with one noise at time because different noises will have different phases and levels so it won't help much if you have multiple wide band noise sources.
It's best if you can position your noise antenna to receive the noise at as high a level as possible because you need to adjust the controls to get the noise levels equal on the two antennas and it's obviously better if you have noise to "burn" because then you end up balancing them by attenuating the noise antenna input rather than your main antenna input.
The one frustration I had with it is that it doesn't quite do a full 360 degree phase shift. There's a "hole" in the midde of the circle that it can't quite do. I frequently seem to be getting close to a null just as I ran out of range because the null point was in the hole. You can check if this is happening by reversing the inputs but don't transmit like that! I modifed it to install a phase reversal switch which solved that problem.
I was playing around with mine last night trying to see if I could null either WWV or WWVH. For some reason I could only null both of them at the same time. However, when I nulled out them out I could hear WWV's auroral scatter from the geomagnetic storm last night.