[Elecraft] Diversity receive versus QRM eliminators
This is a topic that interests me. I have a wrinkle to add. Qualifications: I am a generalist rag-chew HF phone operator / listener. I'm not seeking rare DX nor exploring weak signals in general nor a competitive operator. I'm currently running K3(-s) with a DXE NCC-2 and a 2 x 6 remote antenna switch. I also have an MFJ-1026 but have not done A / B testing comparing the 2 units. The 2 x 6 remote antenna switch allows me to select any of 6 for the Main / TX antenna and any of the 5 remaining as the RX / Noise antenna. Now to the wrinkle. Antenna modeling has shown me that Inverted Vee antennas favor Vertical Polarization off the ends and Horizontal Polarization on the broadsides. I have two Inverted Vees up for 40 meters. The apex of each is about 38'. They are a nominal quarter wavelength apart in spacing AND orthogonal to each other. That gives me the opportunity to take some advantage of polarization per direction / selection of antenna. In any event, that's the setup. I don't presently have any great findings to share. At it simplest, I can select one or the other singly to lessen noise bidirectionally. The noise canceling unit isn't necessary for that.just the difference in polarization of the two antennas used singly can be helpful. The orthogonal antennas do give me an additional variable to utilize as far as noise diminishing / signal enhancing. I've not had all this together for too long. I'm hoping the setup with various antennas will prove effective in many circumstances. I believe I have demonstrated that to my general satisfaction. Sometimes I've been able to bring out an otherwise unheard side of a QSO by adjusting. SSB is tricky to gauge Signal to Noise Ratio with signals jumping up and down as well as background noises such at lighting intervening. A visual display such as a spectrum scope helps, especially with overall background noise. People familiar with operating Noise Canceling units may suggest that there is little automatic about them. It often takes some work. If you have a single source noise and an appropriate antenna setup, they can be quite effective. Many think that antennas 'should be' as alike as possible in orientation and phase. Others offer differing viewpoints. I couple of times I have read that an Antenna Noise Canceling unit 'cannot' take out lightning static. In some circumstances I have been able to substantially diminish lightning static from beyond the horizon for a much-improved S/N ratio. It is not easy and far from for sure with any lightning storm but on some occasions, it can be done. Digitization of some aspects of Antenna Noise Canceling is hopefully not too far out in time. Direction determination with stationary (and unswitched) antennas.a great bonus should that happen. As ever, Dick - KA5KKT __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Gernot, Why ? Generally you need to make sure you are not overloading/destroying RXin K3. 73 Andy HB9CVQ -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of g...@gmx.net Sent: Montag, 29. Juni 2020 23:37 To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Diversity receive versus QRM eliminators Andy, mni tnx - good ideas! Will rewire my QRM box to the K3 RXIn out to avoid the extra PTT-relay clicks imposed by the QRM-box. It is the Wimo-QRM Eliminator. Not as Hi -end as the NCC-1 but a start. Just looked-up the DXE - now the NCC-2 is out and it now also has the same extra PTT switching as my cheap box! Why is this required, as I just learned the K3 can handle this smoothly? tnx 73 Gernot DF5RF Am 29.06.2020 um 22:51 schrieb hb9...@hispeed.ch: > Hi All, > > I use in my K3S the RX in and RX out (RCA plugs) on the backside for > inserting the denoised signal from my DXE NCC-1 Phasing Box output plug. > This box has two channels, were one can do e.g. up to -180deg phase > reversal. CH A and B signals are finally send to an internal power > combiner and to K3S RX in. > > My have 2 selectable TX/RX antennas, 2x36m tuned doublet 160 to 6m @ > 24m center and a Steppir DB18E @ 18m. > RX signal come out safely from K3S RX (out) going to CH A NCC-1. > My QRM local noise pick-up ant is a 1m diameter ALA 1530 electronic mag. > loop (predominantly picking up local noise, no DX , horizontally > mounted in the attics, about -60dB decoupled from TX antennas) This > signal goes into CH B of NCC-1 By carefully equalizing/adjusting the > amplitudes CH1 /CH2 NCC-1 I then try do "Anti Phase". This will mostly > reduce the local noise on the used main antenna. > > The limitation is you can only effectively focus (phase) on one > single local QRM source. The unit NCC-1 is good up to around 17m Band. > It is hard to get more than 20dB S/N (about 2.5 S-Units) improvement. > > In some local noise cases, not being a point source (Line source : PLC > , VDSL etc. ) I am more successful using a LISN ( EMC , Line/Mains 50 > Ohm stabilization, decoupling network, 230V, 50 Hz) to safely replace > the signal from the mag. loop. > This procedure picks up the conducted noise on the mains in the > house/flat more in an integral way. This does not act as a "point source" > > Experiments with predominantly E-field ( small/short dipole antennas) > for local noise pick up are ongoing. > > 73 Andy > HB9CVQ, DK2VQ, AK4IG > https://www.qrz.com/db/HB9CVQ > > > -Original Message- > From: elecraft-boun...@mailman.qth.net > On Behalf Of donov...@starpower.net > Sent: Montag, 29. Juni 2020 19:51 > To: Elecraft Reflector > Subject: Re: [Elecraft] Diversity receive versus QRM eliminators > > Diversity is not helpful as a QRM eliminator. > > > Antennas with steerable nulls can be helpful, small loop antennas have > very deep nulls but also require a high gain, low noise figure preamp > and very careful attention to common mode rejection during > installation > > > 73 > Frank > W3LPL > > - Original Message - > > From: g...@gmx.net > To: "Elecraft Reflector" > Sent: Monday, June 29, 2020 5:18:30 PM > Subject: [Elecraft] Diversity receive versus QRM eliminators > > Hello all, > In a recent rush to eliminate urban noise I bought an QRM eliminator. > The working principle is to null out signals by shifting the phases of > two antennas (one main/tx and one rx). I can see the effect sometimes, > but it is not the holy grail for all types of QRM. I still don't get > rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit > better but maybe thats my inner impression to justify buying this thing. > Now, I do wonder how this differs from diversity receive, effectively > versus local QRM. > Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. > > Any thoughts or hints ? > tnx 73 Gernot DF5RF > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this email list: > http://www.qsl.net/donate.html Message delivered to > donov...@starpower.net > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message deliv
Re: [Elecraft] Diversity receive versus QRM eliminators
Andy, mni tnx - good ideas! Will rewire my QRM box to the K3 RXIn out to avoid the extra PTT-relay clicks imposed by the QRM-box. It is the Wimo-QRM Eliminator. Not as Hi -end as the NCC-1 but a start. Just looked-up the DXE - now the NCC-2 is out and it now also has the same extra PTT switching as my cheap box! Why is this required, as I just learned the K3 can handle this smoothly? tnx 73 Gernot DF5RF Am 29.06.2020 um 22:51 schrieb hb9...@hispeed.ch: Hi All, I use in my K3S the RX in and RX out (RCA plugs) on the backside for inserting the denoised signal from my DXE NCC-1 Phasing Box output plug. This box has two channels, were one can do e.g. up to -180deg phase reversal. CH A and B signals are finally send to an internal power combiner and to K3S RX in. My have 2 selectable TX/RX antennas, 2x36m tuned doublet 160 to 6m @ 24m center and a Steppir DB18E @ 18m. RX signal come out safely from K3S RX (out) going to CH A NCC-1. My QRM local noise pick-up ant is a 1m diameter ALA 1530 electronic mag. loop (predominantly picking up local noise, no DX , horizontally mounted in the attics, about -60dB decoupled from TX antennas) This signal goes into CH B of NCC-1 By carefully equalizing/adjusting the amplitudes CH1 /CH2 NCC-1 I then try do "Anti Phase". This will mostly reduce the local noise on the used main antenna. The limitation is you can only effectively focus (phase) on one single local QRM source. The unit NCC-1 is good up to around 17m Band. It is hard to get more than 20dB S/N (about 2.5 S-Units) improvement. In some local noise cases, not being a point source (Line source : PLC , VDSL etc. ) I am more successful using a LISN ( EMC , Line/Mains 50 Ohm stabilization, decoupling network, 230V, 50 Hz) to safely replace the signal from the mag. loop. This procedure picks up the conducted noise on the mains in the house/flat more in an integral way. This does not act as a "point source" Experiments with predominantly E-field ( small/short dipole antennas) for local noise pick up are ongoing. 73 Andy HB9CVQ, DK2VQ, AK4IG https://www.qrz.com/db/HB9CVQ -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of donov...@starpower.net Sent: Montag, 29. Juni 2020 19:51 To: Elecraft Reflector Subject: Re: [Elecraft] Diversity receive versus QRM eliminators Diversity is not helpful as a QRM eliminator. Antennas with steerable nulls can be helpful, small loop antennas have very deep nulls but also require a high gain, low noise figure preamp and very careful attention to common mode rejection during installation 73 Frank W3LPL - Original Message - From: g...@gmx.net To: "Elecraft Reflector" Sent: Monday, June 29, 2020 5:18:30 PM Subject: [Elecraft] Diversity receive versus QRM eliminators Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to hb9...@hispeed.ch __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to g...@gmx.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
QRM eliminators can work surprisingy well at times and appear next to useles at others. It's rarely the unit, rather the situation. All of these similar units, of which the MFJ noise cancelling signal enhancer is but one operate by combining two essentially identical signals, the unwanted noise. With the phase of one 180 degree from the other and the amplitude matched total cancellation should occur, and it will, almost certainly. The difficulties are two fold. First is that whilst phase adjustment can be made over a reasonable range the amplitudes must be the same. That's not so easy and the noise antenna often needs to hear a lot more of the noise signal than you might think necessary. The second problem is that these units can only eliminate one noise source. If you are surrounded by plasma and switch mode devices removing one just leaves a bunch more. The problem here, other than amplitude matching is that all of the arriving noise signals from different sources have a different phase relationship between your main and noise antenna. So adjusting for one noise signal to have 180 degree relationship between main and noise antenna will make every other signal have a different phase relationship, the signals come from different directions and different distances so reach the two antennas at different times, and hence different phases. Cancelling one doesn't do much for the other. If you have one noise source coming from one direction and you can collect enough of it then the so-called QRM eliminators work rather well, until something shifts and the phase changes and your tweaking again. Of course once Wayne gets done with all the K4 trickery he will have time to develop the K-null that will eliminate all unwanted noise from all sources on all frequencies at all times at the push of a button. Join the queue :-) Martin, HS0ZED On 30/6/63 00:18, g...@gmx.net wrote: Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to hs0...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Good hint - tnx Frank. Will try a mini whip or small loop. 73 Gernot DF5RF Am 29.06.2020 um 19:47 schrieb donov...@starpower.net: Hi Alan, The MFJ works very well as a noise eliminator only if the noise antenna is very close to the noise source, so that the noise is much stronger than the desired signals. If the noise antenna is receiving about the same signals as the main antenna the noise elimination function cannot work... 73 Frank W3LPL - Original Message - From: "Alan - G4GNX" To: "Elecraft Reflector" Sent: Monday, June 29, 2020 5:43:24 PM Subject: Re: [Elecraft] Diversity receive versus QRM eliminators Hi Gernot. I use an LZ1AQ double mag loop (rotateable) to null out as much hash as possible. This feeds the RX Ant In input on the K3S. I also have an MFJ Noise eliminator which is also inline, using the LZ1AQ as the main (RX) antenna and I've tried a couple of antennas (including my HF vertical) as the 'noise' antenna and I don't find any noise suppression by phase elimination with the MFJ. I've yet to try a mini-whip antenna as the 'noise' antenna. I actually wonder if the MFJ unit is faulty, as I've heard that other people have at least noticed a small difference when using it. Once/if I get the MFJ untit to work, I may then buy one of the more expensive noise eliminators. 73, Alan. G4GNX -- Original Message -- From: g...@gmx.net To: "Elecraft Reflector" Sent: 29/06/2020 18:18:30 Subject: [Elecraft] Diversity receive versus QRM eliminators Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to g...@gmx.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Hi All, I use in my K3S the RX in and RX out (RCA plugs) on the backside for inserting the denoised signal from my DXE NCC-1 Phasing Box output plug. This box has two channels, were one can do e.g. up to -180deg phase reversal. CH A and B signals are finally send to an internal power combiner and to K3S RX in. My have 2 selectable TX/RX antennas, 2x36m tuned doublet 160 to 6m @ 24m center and a Steppir DB18E @ 18m. RX signal come out safely from K3S RX (out) going to CH A NCC-1. My QRM local noise pick-up ant is a 1m diameter ALA 1530 electronic mag. loop (predominantly picking up local noise, no DX , horizontally mounted in the attics, about -60dB decoupled from TX antennas) This signal goes into CH B of NCC-1 By carefully equalizing/adjusting the amplitudes CH1 /CH2 NCC-1 I then try do "Anti Phase". This will mostly reduce the local noise on the used main antenna. The limitation is you can only effectively focus (phase) on one single local QRM source. The unit NCC-1 is good up to around 17m Band. It is hard to get more than 20dB S/N (about 2.5 S-Units) improvement. In some local noise cases, not being a point source (Line source : PLC , VDSL etc. ) I am more successful using a LISN ( EMC , Line/Mains 50 Ohm stabilization, decoupling network, 230V, 50 Hz) to safely replace the signal from the mag. loop. This procedure picks up the conducted noise on the mains in the house/flat more in an integral way. This does not act as a "point source" Experiments with predominantly E-field ( small/short dipole antennas) for local noise pick up are ongoing. 73 Andy HB9CVQ, DK2VQ, AK4IG https://www.qrz.com/db/HB9CVQ -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of donov...@starpower.net Sent: Montag, 29. Juni 2020 19:51 To: Elecraft Reflector Subject: Re: [Elecraft] Diversity receive versus QRM eliminators Diversity is not helpful as a QRM eliminator. Antennas with steerable nulls can be helpful, small loop antennas have very deep nulls but also require a high gain, low noise figure preamp and very careful attention to common mode rejection during installation 73 Frank W3LPL - Original Message - From: g...@gmx.net To: "Elecraft Reflector" Sent: Monday, June 29, 2020 5:18:30 PM Subject: [Elecraft] Diversity receive versus QRM eliminators Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to hb9...@hispeed.ch __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Using something like the MFJ-1026 works well for me, BUT the 2 receceiving antennas must be similar to work well in my experience - i.e. 2 dipoles or 2 verticals with similar gain characteristics to get the most out of the little black box. Hank K4HYJ - Original Message - From: g...@gmx.net Date: 06/29/20 13:19 To: Elecraft Reflector (elecraft@mailman.qth.net) Subject: [Elecraft] Diversity receive versus QRM eliminators Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to h...@optilink.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
I have the MFJ 1026, with the built in whip and it eliminated a local broadcast station from my overloaded Kenwood 450S. I use a Myantenna endfed for the Kenwood. 73 de Tom KB2SMS On 6/29/20 1:47 PM, donov...@starpower.net wrote: Hi Alan, The MFJ works very well as a noise eliminator only if the noise antenna is very close to the noise source, so that the noise is much stronger than the desired signals. If the noise antenna is receiving about the same signals as the main antenna the noise elimination function cannot work... 73 Frank W3LPL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Diversity is not helpful as a QRM eliminator. Antennas with steerable nulls can be helpful, small loop antennas have very deep nulls but also require a high gain, low noise figure preamp and very careful attention to common mode rejection during installation 73 Frank W3LPL - Original Message - From: g...@gmx.net To: "Elecraft Reflector" Sent: Monday, June 29, 2020 5:18:30 PM Subject: [Elecraft] Diversity receive versus QRM eliminators Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Hi Alan, The MFJ works very well as a noise eliminator only if the noise antenna is very close to the noise source, so that the noise is much stronger than the desired signals. If the noise antenna is receiving about the same signals as the main antenna the noise elimination function cannot work... 73 Frank W3LPL - Original Message - From: "Alan - G4GNX" To: "Elecraft Reflector" Sent: Monday, June 29, 2020 5:43:24 PM Subject: Re: [Elecraft] Diversity receive versus QRM eliminators Hi Gernot. I use an LZ1AQ double mag loop (rotateable) to null out as much hash as possible. This feeds the RX Ant In input on the K3S. I also have an MFJ Noise eliminator which is also inline, using the LZ1AQ as the main (RX) antenna and I've tried a couple of antennas (including my HF vertical) as the 'noise' antenna and I don't find any noise suppression by phase elimination with the MFJ. I've yet to try a mini-whip antenna as the 'noise' antenna. I actually wonder if the MFJ unit is faulty, as I've heard that other people have at least noticed a small difference when using it. Once/if I get the MFJ untit to work, I may then buy one of the more expensive noise eliminators. 73, Alan. G4GNX -- Original Message -- From: g...@gmx.net To: "Elecraft Reflector" Sent: 29/06/2020 18:18:30 Subject: [Elecraft] Diversity receive versus QRM eliminators >Hello all, >In a recent rush to eliminate urban noise I bought an QRM eliminator. >The working principle is to null out signals by shifting the phases of >two antennas (one main/tx and one rx). I can see the effect sometimes, >but it is not the holy grail for all types of QRM. I still don't get rid >of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better >but maybe thats my inner impression to justify buying this thing. >Now, I do wonder how this differs from diversity receive, effectively >versus local QRM. >Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. >Any thoughts or hints ? >tnx 73 Gernot DF5RF > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Diversity receive versus QRM eliminators
Hi Gernot. I use an LZ1AQ double mag loop (rotateable) to null out as much hash as possible. This feeds the RX Ant In input on the K3S. I also have an MFJ Noise eliminator which is also inline, using the LZ1AQ as the main (RX) antenna and I've tried a couple of antennas (including my HF vertical) as the 'noise' antenna and I don't find any noise suppression by phase elimination with the MFJ. I've yet to try a mini-whip antenna as the 'noise' antenna. I actually wonder if the MFJ unit is faulty, as I've heard that other people have at least noticed a small difference when using it. Once/if I get the MFJ untit to work, I may then buy one of the more expensive noise eliminators. 73, Alan. G4GNX -- Original Message -- From: g...@gmx.net To: "Elecraft Reflector" Sent: 29/06/2020 18:18:30 Subject: [Elecraft] Diversity receive versus QRM eliminators Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Diversity receive versus QRM eliminators
Hello all, In a recent rush to eliminate urban noise I bought an QRM eliminator. The working principle is to null out signals by shifting the phases of two antennas (one main/tx and one rx). I can see the effect sometimes, but it is not the holy grail for all types of QRM. I still don't get rid of the PSU/LED/plasmaish noise here, sometimes the S/N is a bit better but maybe thats my inner impression to justify buying this thing. Now, I do wonder how this differs from diversity receive, effectively versus local QRM. Note I have a 10m vertical as the 2nd ant, while the main ant is horizontal. Any thoughts or hints ? tnx 73 Gernot DF5RF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
