The QRM Eliminator to the Rescue
HTML-код
- Опубликовано: 22 ноя 2024
- I’ve covered the QRM Eliminator in other videos, but this is no simulation. I needed it to minimize the power line noise.
Remember, if you purchase a QRM Eliminator, you must not run more than 100W through it. I run a maximum of 100W, for 60m, and for the rest of the bands I am usually running 14 to 18W, to drive my amplifier.
I hope you enjoy this video and find it helpful. If you find my channel informative and entertaining, I hope you will consider joining my support group by clicking on: www.patreon.com/N4HNH There are 3 levels of support, including exclusive content.
Another great way to help support this channel is to click subscribe.
73, de N4HNH
I built one from a kit. Brilliant piece of kit. I live in a rural area with overhead power lines. Nothing the power company has done reduces the level of QRM. My main antenna is a "random" end fed with a 9:1 unun. My auxiliary antenna is 8 metres of wire at right angles to the main antenna. 73 de CT7AOX.
It seems that your power company is incompetent. That is sad. It took almost 2 years, but my power company finally fixed it. It is almost always dirty insulators or loose hardware (i.e. loose nuts, bolts, staples).
I use a GAP In-line DSP module. It has been crazy good at eliminating QRM. Bought it back in 2010 and have never regretted it.
i find setting the qrm eliminator up on am on a clear frequency helps a lot, then when you have the noise pulled donw right switch to ssb , done !
I too have the FTdx5000 and I usually have S5-S9 broadband noise. Thanks for this video because I was also thinking of giving one of these a try. 73
The 5000 has one of the lowest noise floors because it has low phase noise. But any sensitive receiver will receive atmospheric noise.
The QRM Eliminator can help with noise but especially pulse type noise, like noise from electric power poles.
The 5000 is still my favorite.
73, de N4HNH
Great video, I also wish manufactures would include this function as it works.
Hopefully I can catch this later and forward the link to 3 or 4 people
I got one of these. Works fairly well but it's very touchy. I have solar power inverter noise at S9+20 on much of HF. This does knock down some of the signal but removes more of the noise so overall it's a lot better SNR.
That type of noise is too much for just about any type of noise eliminator.
73, de N4HNH
The toys you have to play with
amazing
Paul, I do thank God for my blessings. I did go 20 years before purchasing a new base station. I saved for it. That is why I am so discriminating when it comes to a radio's capabilities. My money has to be spent wisely. Plus, I need a radio that can be effective when using simple wire antennas.
73, Doug
Doug.... I think you should do a shoot-out test of the various legacy and current QRM eliminators... I have the old Palomar unit. There is or was a kit by VK5TM and then there is the MFJ-1026 Noise Canceller, the Timewave ANC-4+ along with the current WiMo and GC units as well as those by BHI.
I only own the MFJ-1026 from your list. But they all operate from the same concept. There is nothing magical. The performance of my MFJ-1026 is no better or worse than the QRM Eliminator, except when it comes to reliability. I repaired my MFJ-1026 one too many times and I gave up on it. It costs four times as much as the QRM Eliminator did. But, typical MFJ. The only thing I have from MFJ that hasn’t failed prematurely is my dummy load and my MFJ-989C tuner.
73, de N4HNH
Good info - TNX. I went ahead and bought one off of Amazon. After that I started looking at the back of the FTDX10 and realized I don't have a TX-GRD or PTT on the back. Maybe some other way of hooking up. I'm a new ham and don't have a headset/footswitch yet. It's on the list, but one thing at a time with $$$.. Times like there where I'm wishing I had bought the 101D or IC-7610
There is a cable on eBay that plugs into the Linear port to pick up the TX signal for an amplifier. It has an RCA plug on the other end. I don’t have one to test but it might work. I use the Heil FS-2 footswitch. It definitely works.
73, de N4HNH
@@n4hnhradio Doug, you have just jumped right in solving problems to questions, and that clearly deserves reward. I've signed up for your top tier Patreon.
Thank you! I just want to help everyone I can to enjoy their radio more.
73, de N4HNH
Great video got one on order. Thanks. N9WZL 73S.
Mine did not come with a manual. Be sure to connect the PTT line from the QRM Eliminator to TX Gnd from your transceiver, or use a Heil FS-2 footswitch. The FS-2 can key your radio and provide the TX Gnd for the QRM Eliminator. The FS-2 keying line plugs into an adapter cable for your transceiver type. You need to order the cable. If you aren’t using the TX Gnd from your transceiver to key a linear amplifier, you can use it to provide the PTT for the QRM Eliminator.
Also, be sure that you don’t run over 100W through the QRM Eliminator.
73, de N4HNH
Hi OM, excellente video. Can yu tell me what type of antenna you use for the noise? I am using a QRM elliminator like this with to dipole antenna quiet similar both ones, but I cant achieve the performances you do!! Thank, Marcelo LU3DAH from Argentina.
It shouldn’t matter what antenna you are using to receive the noise, as long as it can receive the same noise as the main antenna. I was using my OCF dipole when I made the video.
The important thing to do is use the gain knobs to match the amount of signal/noise coming in on both antennas and then rotate the phase knob to null out the noise. With this unit, try setting the phase knob at 12:00 before you adjust the gain knobs. Then tweak the phase knob to cancel the noise.
Note that these devices work best against pulse noise, like from a power pole. Nothing can cancel broad noise from digital sources.
Thanks for the video. Have you tried nulling power line noise at higher frequencies like 50.11 MHz 6 metre band? Not sure why the QRM Eliminator specified upper limit frequency is 30 MHz.
I’ve never tried to use it on 6m.
I was once told with these you want the noise antenna to hear the noise without hearing the signals. Any signal the noise antenna hears will also be canceled out. Id be afraid your endfed will have too much signal gain.
That’s misinformation. It can electrically rotate the receive pattern, similar to rotating a beam. That is a secondary purpose. It can do that when there is no noise to cancel.
It’s just changing the phase angle between signals from the two antennas. It can be used to boost or cut (cancel).
Remember too that the goal is S/N ratio, not high S-meter deflection.
@n4hnhradio well I ordered one lol. I am starting down the powerline noise worm hole. I get it on 10 and 12 meters. Your videos are a huge help!!!
My power line noise is also worst on 10 and 12, but extends to 17, 20, 30, 40, and 80. It’s just worst on 10 and 12.
Be sure to connect a PTT to the QRM Eliminator. I show the connection in one of the videos in the QRM Eliminator playlist. The PTT signals the QRM Eliminator to protect itself when you transmit.
I have the FT2000 and the VRF means the QRM eliminator doesn't do enough to warrant the messing about trying to fit it on my desk near the radio. Now on the 897 oy does it come into its own.this gives new lease of life to yhe radio.Great videos my friend. Keep safe de M0JFE
I use VRF and mu-Tuning to minimize interference up and down the band. I also use it to combat noise, as I've shown in numerous videos. But VRF doesn't cancel out pulse type noise. It isn't designed for that. VRF can work against QRN. It can even help against interference from a strong signal out of band. But it can't cancel repetitive noise spikes, such as those from a power pole. That is the job of a noise blanker. But, by the time the noise blanker detects the noise, the noise is already in your receiver. Also, a noise blanker can introduce distortion and it degrades selectivity. The QRM Eliminator cancels the noise before it ever gets to your radio, thus your noise blanker isn't needed.
73, de N4HNH
@@n4hnhradio couldn't agree more your video and explanation is one of the better tutorials on here. Your electrical supply in the USA is slightly different to UK we don't have transformers on poles we have sub stations and its fed underground .Lamp post ie street lighting can cause issues we are surrounded by all kinds of noise just need different tools to combat it.
Like you I tutor/ mentor people and do what I can I'm also a ARRL member and the contrast of the magazines to the UK ones Just keeps ideas flowing lucky me in my XYL free zone I can have all my toys out without any complaints.
It would be nice to have underground power. Our problem is loose hardware, dirty insulators, and blown lightning arrestors. Transformers don't usually cause the noise but they rarely fail. The engineer who deals with RFI told me that in 30 years of being a lineman and now the RFI engineer, he has only known of a couple of transformers to ever just fail on their own. Our problem is the arcing from one piece of hardware to the other, primarily caused by low humidity (dry air).
73, Doug
The power line noise in France is intolerable. One would be lucky to find a QTH without this noise. I'm facing S6 without filters. A friend of mine is facing S8 in a totally different village. I live in the sticks it's been like this since i setup the radio here. I tried a noise canceller but it only works when you have the gain on it right down. It's better than nothing.
I've ordered 50 ferrites and some type 43 toroids to wind some baluns and ununs.
I was playing with it earlier and built a garden loop around 50M in circumference. It seemed to work better as an aux than using my noisiest vertical.
I think experimentation with the aux ant is key. However I'm considering trying to run a live mains wire next to the aux antenna and see if that helps. The problem is it's so violent and so random I don;t think it's the easiest noise to cancel.
Today was very noisy. It was sunny today but we have had weeks of rain. All of the ground is still wet this evening. I just went for a walk and especially in the forest we are saturated. I'm wondering if the problems comes from them putting cables underground lower down the hill. Here they are above the ground. I might try putting mu earthing cable to the aux antenna as an experiment. Seems the noise is really bad in certain places I drive by. We also have a hydro electric station with turbines not far from here.
I’m sorry to hear that. A phase cancellation device might be your best hope. Make sure you rule out other noise sources too, such as wireless phone chargers, plasma TV, LED lights, food sealers, etc.
Should I put this before or after the ant tuner? I am thinking rig-QRM eliminator-ant tuner.
Place it between the radio and the antenna tuner, or between the radio and the linear amplifier, if you use a linear amplifier. The auxiliary (noise receive antenna) will usually connect directly to the QRM Eliminator. I use an OCF dipole for my auxiliary antenna because it receives well on most bands.
Another great video!!!
Thank you Luciano! 73, de Doug
What about using a Beverage Antenna for the Aux Antenna?
You could connect a beverage antenna, but it would defeat the purpose of having a QRM Eliminator. It’s important that the Auxiliary antenna receives the same noise pulses as the main antenna, so the cancellation circuit has something to work with.
If you are wanting to use the QRM Eliminator to create a steerable RX array, it’s best to use two of the same type antenna, installed perpendicular to one another.
Hi Doug I get s9+20 noise spikes on 20m through 10m every 100khz,from 8pm every night when the neighbour 4 doors down turn on their garden lights.would this sort that noise out? Thankyou for all you do.Regards,Andy
I don’t know for sure, Andy! It works best against power line noise. Those garden lamps have proven to be a nuisance for many hams. I don’t have any near me or I would test it for you. It might be worth a $50 experiment though. If it cannot eliminate the noise, you could use it to electrically rotate your receive direction. If you have two dipoles, oriented perpendicular, their lobes and nulls are opposite. Set the signal level for the main antenna and the auxiliary antenna the same and use the Phase control to electrically move the lobes and nulls.
73, de N4HNH
Hello. I bought one of these to use my ft-710. I’m lost as to where to plug in the rca cable on the back of the 710. Any help would be amazing! Thanks!
You will need an adapter that provides a PTT signal from the 8-pin Tuner/Linear port. Check eBay. I bought one for my FTdx10 on eBay.
@@n4hnhradio thank you so much! I actually bought my 710 over the 7300 after watching all your videos about them. Love it!
You chose wisely. Much better specs. Newer technology though, to be fair to ICOM.
This cable should work: www.ebay.com/itm/325343335857?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=XiWLQ3BWQI-&sssrc=4429486&ssuid=_vRUbW8STJ6&var=&widget_ver=artemis&media=COPY
@@n4hnhradio ordered. Thank you!
Although it’s not designed for band noise on 40 or 75, wonder if it would help or wonder if it would cancel the desired signal your trying to copy.
Got one of these ordered as well as 3 friends
If you aren't trying to cancel noise, you can use it to null out signals. The trick is to use two antennas oriented such that one has lobes and nulls where the other does not. This allows you to use the cancellation technique to electrically rotate a receive array.
73, de N4HNH
I bought one last week in the ope of eliminationg some noise on 160 80 40 and 20 that cropped up in December. Was hoping it was LED Christmas lights. Alas, it was not.
Even phase cancellation type devices can’t minimize certain types of noise. They are most effective against pulse type noise.
Hello Dear OM, I have the same equipment as you, namely: the IC-705, and the QRM Eliminator. Alas, I am not a technician, just a novice, and I would like to know how to connect the PTT cable (on the QRM Eliminator), and where to connect it to the IC-705, and how to connect it. Can you help me with photos? I thank you in advance and present to you my best 73qro, from HB3YKB Patrick, Geneva, Swiss.
You will need to build/buy a cable that connects to the Send/ALC connection on the side of the IC-705. It is a 3.5mm male stereo connector. The middle (ring) connection of the 3.5mm won’t be used. The other end of the cable needs to be a RCA male. Wire from the pin of the RCA male to the tip of the 3.5mm plug on the radio end of the cable. The “ground” connection of the RCA male should be wired to the sleeve of the 3.5mm plug. The 3.5mm male plugs into the IC-705 Send/ALC port. The RCA male connector plugs into the PTT connection on the back of the QRM Eliminator.
Note that this same cable could be used to key a linear amplifier, when not being used with the QRM Eliminator. Note also that certain linear amplifiers require a 15-20ms delay of the PTT signal. This can be set in the menu of the IC-705. Some people prefer the added insurance of an amplifier interface, such as the MFJ ARB-704. But for just connecting a QRM Eliminator, you won’t need to set a delay and you shouldn’t need the ARB-704.
On the 101d you have a 3rd RX connector for this. Wonder if this is possible in firmware on some SDR radios. Its all 1s and 0s at some point in there right? Seems like a little code could do the mixing and phasing.
There might not be enough memory left in the FTdx101D/MP to accommodate the phasing routine in DSP. Furthermore, the DSP chip from Texas Instruments would need to provide for such functionality.
These phasers aren’t using DSP to accomplish what they do. There are discrete components involved (i.e. Op-amps, transistors, capacitors, etc.). I’m fairly certain that adding phase cancellation would need to be designed into a new transceiver.
73, de N4HNH
@@n4hnhradio Those phasers aren't part of a RX chain built on software either. Thinking about this more, I don't think it's possible in a hybrid SDR like the 101d. The 7300 or any other dual RX radio that's strictly SDR, maybe it's possible. Memory for this would be another issue that might stop that idea though.
It's a good idea. If they could showcase that right I think it would help sell radios.
The FTdx101D or MP could function with a phaser circuit. It has two traditional superheterodyne receivers ahead of the SDR stage. The phaser circuit would need to exist inside the front end of the receiver, prior to the first mixer. It could be inserted before the bandpass filter and the preselector, which would more closely match how it functions externally, before entering the receiver. But it might even be better to place it just ahead of the first mixer, allowing the bandpass filter and preselector to limit the amount of noise first. This could assist the phaser circuit, similar to how the DSP can do a better job if we reduce the noise in the front end of the receiver first.
73, de N4HNH
@@n4hnhradio I've had an MFJ one for a looong time. It's really a wonder this isn't in radios already. Not like it's new, and it works.
My MFJ worked well until I turned on my amplifier to 500W or more. RF in the shack, from common mode current reflection with an OCF dipole would blow the bulb fuse. But three times it also fried a transistor. So I abandoned the 1026. So far the QRM Eliminator has handled high power just fine.
How about a update?
Use it anymore?
In the scrap bin?
I use it when the power pole acts up. I don’t keep it hooked up when I don’t need it. My radio puts out 200W. I want to minimize the risk of transmitting through it with more than 100W.
Kinda like what flex and Apache calls diversity reception. Yeah the big 3 should implement this feature for sure.
That’s some nice line noise. I’ve dealt with lg&e quiet a bit. If you can take a handheld rig and find the general area, most times they’ll fix it quickly. Now I have a bad solar head on a street light. They have no idea how to fix it. So working with arrl and the FCC to help “power co.”understand. Make sure you tell them that you aren’t a cb operator. Haha
It is similar but not quite the same. Taking the signal from two separate receivers, connected to two separate antennas, with differing polarization and/or spaced sufficiently apart, and combining both signals in phase, helps minimize the effect of QSB.
Another thing we can do is vary the DSP filter width of one receiver versus the other and create an effect similar to surround-sound.
Devices like the QRM Eliminator allow us to take the signal/noise from one antenna (the auxiliary/noise antenna) and invert the phase. We then combine the inverted signal with the non-inverted signal from the main antenna. The narrow noise pulses will be heavily attenuated while the wider SSB signal is passed along. There will be a slight bit of attenuation of the SSB signal but not nearly as much attenuation as happened to the noise. So you get a much improved S/N ratio.
I think the next big thing for amateur radio is to add the phase inversion option for transceivers with two separate receivers.
73, de N4HNH
Wouldn't a beverage antenna be better provided you have the room?
Not necessarily. The beverage has lower gain and a high takeoff angle. I still want to pull out ghost stations.
@n4hnhradio OK then I guess I'll get one of these to use with my beverage then. I'll be able to hear about anything
I assume that you mean to use a QRM Eliminator with another antenna, not with the beverage. You shouldn’t need it with the beverage, unless the beverage is close enough to a power pole that it is receiving PLN. That would be unusual. BTW, I don’t recommend the Chinese model in this video. They are not consistently constructed. They often require some level of repair, right out of the box. Mine had two things wrong. I recommend the Timewave ANC-4.
@@n4hnhradio correct. Just wanted something to expirement with.
Congratulations on the video. Your device has 2 gain and one phase knobs. Others have 2 phase knobs and a gain knob. Can you tell what the difference is? Thanks
I seem to remember hearing that some were labeled incorrectly. It’s a common board that people can buy, install into an enclosure of their choice, and add the knobs. Apparently some have labeled the knobs incorrectly and/or wired the knobs incorrectly. Exercise caution regarding who you buy from.
Anyway, the device works on the principle of matching the gain of the main and the auxiliary antennas and then using the phase knob to put the noise pulses received by one antenna 180 degrees out of phase with the noise pulses received by the other antenna.
I hope this helps.
73, de N4HNH
@@n4hnhradio Hi. Thanks for the clarifications. I didn't know about the exchanges.
You’re welcome! If you are concerned about the quality of the Chinese versions on eBay, DX Engineering has one. I haven’t tried theirs myself, but I’ve heard good reports about it. It uses the same principle. It is the WiMo QRM Eliminator 26000.
73, de N4HNH
@@n4hnhradio Sinceramente, eu não me preocupo muito com produtos da China. Lá, no Brasil ou nos EUA, tem coisas boas e ruins. O meu aparelho é igual ao seu. Grato uma vez mais!
Fantástico! Então você já tem um como o meu. Deve ter dois ganhos e um controle de fase, não importa como é rotulado.
73, de N4HNH
Hello I needed to order the qrm eliminator second generation on ebay today. Could you tell me if I hook it up before the mfj 939 auto tuner or after the tuner. Also do I have to run an rca patch cord from the back of the radio ptt TX grid of my yaesu ftdx10 to the eliminator to transmit? I sm not going to use any linear Amp just barefoot. I SUPPOSE I would have to buy a second unit for my ic7300 too. Is there no tr relay in the qrm eliminator like there is with anc4 or the mfj1026?
Thank you
Roy k1roy
You do need to connect a PTT line to the QRM Eliminator. I use a Heil FS-2 footswitch to key my radio. It has a RCA cable/plug that can be used to key a linear amplifier. Since I have the 10-pin mini-DIN cable from Elecraft that controls the Elecraft amplifier, the RCA plug is available for the QRM Eliminator.
There are cables available that connect to the 10-pin mini-DIN linear port on the back of the FTdx10 to provide only the PTT signal. I found one on eBay. It came from England. It can key an amplifier, in case I need to use my AL-80B backup amplifier. But it could be used to provide PTT for the QRM Eliminator, if you aren’t needing it for an amplifier.
You need to connect the QRM Eliminator between the radio and the tuner, so the main antenna going into the QRM Eliminator has an optimized signal to work with. You will need a second antenna connected to the auxiliary antenna connection on the back of the QRM Eliminator. This antenna needs to be able to receive the same noise as the main antenna.
73, Doug
Okay so if I get a Heil FS2 switch and I already have the pr 781 microphone that I'm using now on my ftdx 10 that is what we're perfectly work will one plug plugged into the connection on the Highland Mike and the ICA goes to the back of The qrm Eliminator? And that's all I need right?
Yes, with a Heil cable you get an XLR for the mic and and an adapter for the 1/4” from the FS-2 PTT line. Then plug the RCA cable to the back of the QRM Eliminator.
Thank you so much I will order fs2 switch from Heil then
Please let me know how it works out.
where would i connect the ptt to a yaesu FTdx10?
Pin 6 of the 8-pin modular plug is PTT and pin 7 is GND.
73, de N4HNH
@@n4hnhradio okay thank you very much for the info. Waiting for the Eliminator to arrive. The noise has been driving me insane.
For a QRM Eliminator, you connect to the Linear port on the back, not the modular plug on the front. You can order a cable on ebay that pligs into the Linear port and has a RCA plug for PTT.
This is the one I ordered: www.ebay.com/itm/254970401621?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=7qaf0C6WSW-&sssrc=2349624&ssuid=_vRUbW8STJ6&var=&widget_ver=artemis&media=COPY
I use an amplifier and didn’t want to tie up my Linear port. So I chose to use a Heil FS-2 footswitch to key the radio and I use its RCA plug for the QRM Eliminator.
73, Doug
@@n4hnhradio okay that's for the link. Appreciate it very much
Nice box. Bought one. Thanks for video. DE UN6GN! All the best!
I hope it helps with your noise. It can’t cancel wide spectrum noise, but does well with pulse type noise that happens at predictable intervals.
73, de N4HNH
Does The qrm Eliminator handle 100 Watts Peak or is it 100 W continuous
I don’t know, Roy. It didn’t come with any instructions. It’s made in China. I only read online that the maximum power allowed is 100W. It didn’t say PEP, AM, CW, etc.
If you watched my unboxing video, you saw that I had to reinstall the knobs. In a subsequent video I showed that I also had to tighten the power jack. I wish there was a better supplier. I have the MFJ-1026 but it isn’t even as good as this one, and it costs over $200.
I will admit that the inside of the QRM Eliminator looks solid. The issues I had were just sloppy finishing touches related to knob orientation and forgetting to tighten a nut.
I never run more than 100W SSB through mine. My amplifier outputs full power with less than 40W of drive from the transmitter, so that helps me stay well under the 100W limit. In fact, I usually drive my amp with 14 to 18W.
The QRM Eliminator does its job, so, for $50 to $60 shipped, I can tolerate reorienting the knobs and tightening a nut.
73, de N4HNH
Wow it's even better than the $200 are actually now $250 I think mfj I think I'll buy one of these cheap qrm eliminators a for only $50 or so it's certainly worth the try and it looks like in your videos it looks beautiful I've got a fdtx 10 so I guess it plugs into the back where the transmitter ground connection is on the back of the radio so when I transmitted it won't pick up aref from the receive antenna I suppose
FTdx10 doesn’t have a dry contact for a PTT out. But, there are cables available for FTdx10 that connect to the Linear port and they have a RCA plug on the other end. These cables are normally used to provide the PTT signal for a linear amplifier. I found one on eBay. I don’t use it though. I use the cable from Elecraft, that provides PTT and band change data for my amplifier. I trigger the QRM Eliminator with the dry PTT contact from my Heil FS-2 footswitch that I also use to key my FTdx10. The FS-2 is designed to key the radio and amplifier with proper timing to ensure that that there is no damage to either.
73, de N4HNH
Agree 100%
Thankfully the power company finally made the necessary repairs, and the noise is gone. Now I can use the QRM Eliminator for its secondary role.
Hello DOUG N4HNH
I got a Yaesu FTDX 101 MP
QRM Eliminator is turned off can you transmit 200 watts ON it
another problem I would have with The qrm Eliminator
all my HF antennas come in the House to a big 2K a Ten Tec 229B manual Antenna tuner
on the back of my Big Ten Tec 229B antenna tuner I got a coax jumper running to antenna switch box
for two different Radios Yaesu FTDX 101 MP ICOM IC 7610
thank you
I subscribed to your RUclips channel you got some great videos
73
Roger, I’m not sure about running 200W with the QRM Eliminator off. There were no instructions with this thing. I just read online that it is limited to 100W. My MFJ-1026 is also limited to 100W. I assume that rating applies to when it is turned on. If I blow mine up, I will let you know.
73, de N4HNH
Great video , I get noise on 80m from telephone lines as it happens I’ve got a redundant phone line on my house I’m considering getting a qrm eliminator and connecting the telephone wire to it as a direct noise antenna , do you think this would work? , I’ve noticed the signal decreases with qrm eliminator on which isn’t a problem just out of interest does this offer the opportunity to use pre amps ? Thanks again for great videos 73 de 2e0nbk
Hi Nigel! The signal levels decrease on the S-meter because you are canceling noise that contributes to the S-meter readings. There is also a certain degree of attenuation through the device. The idea of this device is to improve the signal-to-noise ratio, not the S-meter reading.
I can’t say for certain that it will deal with phone line noise. It works best against pulse type noise. But it’s always worth a try. Noise is becoming more and more a problem these days, with all the modern electronics on the market.
73, Doug
@@n4hnhradio thank you for the reply , it definitely looks like a good tool for the radio tool box , thanks again
You’re very welcome, Nigel. It has helped me out. I still haven’t been able to get the power company to come fix the source of the noise. They are backlogged with few workers at the moment. Electric power takes precedence over RFI.
73, Doug
how to connect it with a external tuner, please help
Connect it between the radio and the tuner. The auxiliary antenna should connect directly to the QRM Eliminator. Be sure to connect the PTT so the QRM Eliminator grounds out during TX.
73, de N4HNH
@@n4hnhradio would that be, radio - QRM eliminator - Tuner? is that correct? there is a ptt at the back of the QRM, there is a red and black wire where do i connect that. I really appreciate this. de DV7MOV
thank you!
Yes from the radio to the QRM Eliminator to the tuner to the TX antenna. Connect the PTT on the back of the QRM Eliminator to the TX ground output of your transceiver, or use a footswitch. This prevents damage to the QRM Eliminator while you are transmitting.
73, de N4HNH
@@n4hnhradio thanks let me try. thank you!
You’re very welcome! 73, de N4HNH
I found better results if you use a small loop for Aux and set Gain 1 main antenna to zero, tune loop for max noise then start adjusting
Whatever works, right?
You R Great
Quite a bit of attenuation in the process, that gives the illusion of noise reduction. Not saying it doesn't help, but that's my pet peeve with these devices.
There is no illusion of noise cancellation. It reverses the phase of the signal from the noise antenna by 180 degrees and reinserts it into the signal path to the radio, along with the signal from the main antenna, thus cancelling the noise pulses.
The noise drops at a faster rate than the signal. That is why the signal-to-noise ratio improves.
I try to get my S-meter down to near zero before I enable any DSP. It makes the DSP do a better job. This device stops the noise before it is able to enter the receiver. That way the receiver doesn’t have to be bothered by it. The noise blanker is no longer necessary. Most DSP noise blankers can’t even completely stop the noise, and they can introduce distortion into the audio.
Attenuation is good for lower frequencies and sometimes good for 14MHz and up. There is no need to have a noise floor above S1; even S0.5.
73, de N4HNH
@@n4hnhradio Yes but it also attenuates the signal a lot, which makes things quieter. Look at the desired signal and it attenuates it quite a bit.
I fully understand how it works. I have the Timewave ANC-4. I am just saying that it's a lossy circuit.
All noise reduction devices attenuate. It is called insertion loss. Your coax has insertion loss. But, in the case of the noise canceling devices, you trade signal strength for S/N ratio. But, if you don’t like it, that is fine too. This device is for those who cannot enjoy their radio due to S9 or higher noise levels. It matters not to them if the station they can suddenly hear over the noise is reading S5. At S9 they couldn’t hear them.
I have no endorsement from any company so I don’t care if anyone watches the video and chooses not to purchase one. I hate to need one but sometimes I have no choice. If you already have the ANC-4 you don’t need to care.
@@n4hnhradio Yup. They attenuate a lot.
So does IPO and ATT. Attenuation can be good.
Or put it into a 1 VFO radio with two ANT ports!
I haven’t seen one of those since my FT-920. It is big enough that one could fit. But it works be a cinch to program this into the DSP of a dual-receiver rig.
If you're running a 200 watt transceiver you have to be careful of how much power goes through The qrm Eliminator
Indeed you must. Do not exceed 100W.
So it has to hook up to the back of the transceiver where it says transmitted ground correct? Also does it handle 100 W pep or is it 100 W continuous?
The JSP/Timewave ANC-4 is rated for 250w, though I don't recall the duty cycle of the rating.
Do you lose sensitivity
The s/n ratio seems greatly improved.
In a way yes. But you gain signal-to-noise ratio. I don't care if the S-meter reads zero, as long as I can hear the signal better. On 7 Megahertz and lower you don't need extra sensitivity. In fact, that's why you see me using IPO so often. Intercept Point Optimization attenuates while also improving the cross-modulation characteristic of the receiver.
The QRM eliminator removes noise before it ever enters your receiver. On the lower bands, I use the QRM Eliminator and IPO. Remember to always use IPO before enabling any amount of attenuation in the radio, since IPO improves selectivity.
73, de N4HNH
@@n4hnhradio great explanation
I get similar types of noise, but from other people's cheap wall warts, ect. 😮 We call it frying pan or sizzling bacon noise. 🙄
Wall warts can definitely be noisy. Fortunately, not all are noisy. My rule is not to bring anything electronic into my home that isn’t absolutely necessary. But I can’t stop my neighbors from doing so.
I had one did a great job (link enclosed) but when I connected it to the Alinco dx70 all cables set up as they should, on transmit I fried it! Unknown to me rather than just connecting the cable to the noise eliminator from DX70 enables the eliminator to be bypassed on transmit for it to work you need to cut a resistor inside the DX 70! Anyone know what componants I need to change?
ruclips.net/video/5tt6b6JFvA0/видео.htmlsi=J0raZPx2F1-SQ0Y9
I just bought one, will not swr with it inline useless
Did you hook up the PTT? You need to send it a PTT, so it doesn’t route your TX RF power through its receiver circuits. You can damage the device if you don’t provide a PTT input. It also affects the SWR.
You need to watch the rest of the videos in my QRM Eliminator playlist.
Provided a ptt it does not like a icom 706?.
If you have a high SWR, the PTT is probably not functioning. That will cause a high SWR. You need the RCA cable from the 706 to the PTT jack. Then make sure you enable PTT ground from the 706.
Have got a rca plug connected up it was ok until I transmitted.@@n4hnhradio