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Reviews For: MFJ-856 Line Noise Meter w/ 3 Element Beam

Category: Tools & Test Equipment for the amateur radio work bench

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Review Summary For : MFJ-856 Line Noise Meter w/ 3 Element Beam
Reviews: 10MSRP: 150
Walk or drive around with this handheld, directional noise finder with 3 element beam and meter to search out foxes, leaky insulators, loose hardware and corroded ground lines quickly. Track the noise source right down to the pole, transformer, or insulator, or other source. Operates in the 135MHz region where activity is a minimum and radiation from corona and arcing is far mroe localized. 0.3 uV sensitivity and wide-range AGC for noise level meter.
Product is in production
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# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
NO9E Rating: 2020-11-02
A saviour for RFI issues Time Owned: more than 12 months.
This is an excellent device to locate RFI. No quality problems except the elements need to be screwed well or they may fall off. I use it all the time. Recently, my super quiet rural QTH became super noisy at night time. This device was called to help and it found noisy transformers.

Old review:
My neighborhood has a serious powerline noise. It is at S9 level when it is dry and warm. Sometimes the noise blanker helps, but it does not help with multiple noise sources. The MFJ-1026 is a big but incomplete help; it reduces the noise by 20 but not 40db.

I tried to find the sparcing poles with my HT and a beam. Made many miles with little effect as many noises were erratic. A sweep with my stationary 20m to 70cm quads identified several direction of noises but no poles. I called the power company twice, and just before they came, the noise magically disappeared. Out of embarrassment, I did not want to call them again without a strong culprit.

Enter MFJ-856. Very smart and light construction. Good sensitivity and a useful meter. I could point to many sparcing locations although the noise was not always localized and sometimes in the wrong direction. Not the fault of the device, as it had good directivity as measured with a signal generator. Just an indication of a complex problem.

After locating some sparcing poles, the crew from the power company came again. They had a 350 MHz sniffer that was better than mine, but it cost over $2000. They fixed 2 poles that I identified; the other few were quiet at that time. They were quite excited by my device.

It was interesting how they located sparcing poles. Whenever a pole had a guy, they rocked it. A change in noise indicated a problem in this but sometimes adjacent poles.

After a few weeks when it warmed up, noises came back again. The MFJ-856 found a nearly continuous noise along many poles, with the strongest coming from a pole next to me. The crew came, this time without their sniffer because it broke. They used mine instead. They found seven poles in a row sparcing. A fix was usually just tightening the screws although in one case a new grounding was need. After that, the bands became quiet again.

In a few days, new noise appeared but only at about S3 level and only in the afternoon. As measured by MFJ-856, they came from poles 300 ft or more away. It seems that nearly all 30-year old poles need to have their screws tightened. I hate to call the power company every few days, but they will be called again in a few months. And before they are called, I will do my homework.

A serious power line noise makes an expensive radio/amplifier useless. I consider the $150 investment in MFJ-856 an excellent one.

Just to snipe at MFJ, after a few weeks the device stopped working. I contemplated sending it back, but after opening and tapping on contacts it came back to life. Well, resoldering all joints should be a small problem as opposed to having bands useless.
K5GO Rating: 2019-04-15
Expect the worst and you will be pleased Time Owned: 0 to 3 months.
The good news is that the parts supplied included everything listed in the manual they said would be included.

The bad news is that all the parts required to assemble the antenna as pictured in the poorly written instruction sheet were not listed or included.

The manual says the parts included should consist of 2 nuts, 2 brass threaded rods and two aluminum brackets. No hardware or insulators were mentioned or listed or included to mount the driven element to the boom.

The instructions said to mount the driven element halves to the aluminum brackets using the nuts supplied. That is a bit difficult when there are no screws to use with the nuts.

I fabricated insulators using cut pieces of the body of a Bic pen and a file. The sleeves have to be about 5/16" OD and allow the 1/4" tubing to pass through.

The aluminum brackets are identical which means they are not right either since the driven element halves are offset by a half inch. They have to be reformed with pliers or replaced with something different.

No nuts were included to attach the aluminum brackets to the studs on the side of the Model 852 receiver. That threaded fastener is very small diameter. I have no idea what size or whether metric or not.

If all the parts had been there it would have been assembled in less than ten minutes.

I would recommend that MFJ pay someone to assemble each of their products that require some assembly using the manual and parts normally included and make the necessary corrections to the parts lists and manuals.

It does function and may be useful for finding sources of noise in a convenient way.
W6OU Rating: 2019-04-13
Works quite well Time Owned: more than 12 months.
I have tried tracking down local power-line noise with a hand-held 2M Yagi and a 2M HT in the AM mode. However, I got mixed results. I don't think the HT had a large enough dynamic range. The MFJ-856 with a 3-element Yagi does a much better job. The direction of noise peaks and nulls are easy to determine.
N2EIK Rating: 2018-01-07
Works if you work it. Time Owned: 0 to 3 months.
I strongly disagree with many of the bad reviews. aprt from any QC issues, I personally did not have any. I have 60+ db noise, 24/7. Comms in any mode is a chore. I called the power company, he showed up when I was not home and told my xyl there was "some cable tv leakage but no power line noise". My spectrum analyzer says different. It clearly shows low freq broadband noise and does not show any cable freq (200-1ghz) rfi. So I I guess I could have homebrewed something but I bit the bullet and ordered the 856. Easy to assemble. I went right out in the sub zero weather and damn near got frostbite but I found a string of 4 poles radiating emi/rfi.
Here are my recommendations.
As prior post/link discussed, relocate the receiver and add attenuators. I had some rg174 laying around, a few switches and resistors... Done deal, fairly easy to do and it needs them to pinpoint issues. I really dont think a balun and matching network is needed, the antenna is resonant at 137, I checked it and there is a balun inside the receiver.
The next step for me is to call the power company again and try to get them to be here when I am home. I can show him from my well equipped electronics bench and walk him through the paces.

KE8AMR Rating: 2015-04-20
Don't bother Time Owned: 0 to 3 months.

I just installed an HF antenna here and have a major RFI problem which I believe to be power line related. I purchased one of these in the hopes that it would help me find it. When I received it, I went out hunting with my elmer. The meter is very erratic and doesn't seem to correlate with what I'm heading through the head phones. Also it kept locking up every couple minutes. The needle would peg to the right and the audio would stop. Turning it off and on would resolve it.

I called MFJ and they acted like it should be my responsibility to pull it apart and troubleshoot it. I did pull it apart and found that an air coil was shorted out on a capacitor. I fixed that which resolved the lockups, but it was still pretty much useless for direction finding.

I then invested in a Yaesu HT that will do AM and a proper directional antenna (Arrow). I found my pole in 15 minutes.

An HT that will do AM and a proper directional antenna will be about $100 more, but at the end of the day you still have an HT and VHF beam antenna you can use every day. And that's besides the fact you don't have to worry about buying a MFJ device that most likely won't function correctly on arrival.
NG0Z Rating: 2014-07-14
Crude but Effective Time Owned: 0 to 3 months.
If you sample my other reviews of MFJ/Ameritron gear you will see I am not a fan but this device appears to be the only reasonably-priced device of it's kind so I gave it a shot.

The design is rudimentary and the execution is crude and will likely need to be tightened and aligned with every use (or parts will be lost) but the MFJ-856 was instrumental (pun intended).

I was able to quickly locate an annoying RFI source next door and in fact it's directional properties were the key as I would not have guessed the source was where it was.

I'm not sure why 135 MHz was chosen as the unit is (undesirably) also a great AM Air Band receiver, but the unit seems to be well optimized to pinpoint sources of noise.

You will need to use something else to get close, like a handheld SW receiver, scanner tuned to VHF in AM mode, or by tuning your car radio to 530 AM on the broadcast band while driving around, but once you do that, pull out the MFJ-856 to pinpoint from there.

Good not great hence the "4"

73 de NG0Z

KB3BTO Rating: 2011-01-03
Works quite well. Time Owned: 0 to 3 months.
My MFJ-856 arrived today. I assembled the beam antenna, attached the MFJ-852 meter and used it to isolate the source of RFI that's been ruining my 10 meter operating - as if the lack of sunspots weren't enough - for the past 3 winters.
It was easy to assemble, operate, and enabled me to pinpoint the exact utility pole that's been causing my difficulties.
I purchased this as a last resort because I couldn't get the RFI to co-operate with visits from the utility company representative and was sick and tired of losing air time.
I do not regret my purchase and only wish that I had done it sooner. MFJ has saved the day. (Hey, that rhymes.)
K3PA Rating: 2010-07-08
Perhaps the lowest quality product every made? Time Owned: 0 to 3 months.
1) 4 different parts missing; markings on boom and elements to identify them missing.
2) Unreadable nth generation photocopied manual.
3) Took 4 phone calls to get missing parts; I was never in the support log any of those times. Wrong parts sent repeatedly.
4) Brackets to fit the Yagi to the receiver don't fit. Used symmetric brackets to fit an offset feed connection to save 2 cents on the right bracket.
5) Managers hearing the story actually thought it was funny. Eventual answer to bracket problem was to "just bend them around with pliers until they fit. It will look cockeyed, but thats just the way it is meant to be.".
6) $14M company wth no quality manager.

These people should be embarassed and ashamed. Martin clearly cares nothing for quality. Regardless of the low prices, there is no excuse for any of this, and we should NOT be supporting MFJ's shlocky methods in 2010.
ZENKI Rating: 2010-03-26
Great, needs amplifier Time Owned: 3 to 6 months.
I found this unit very useful.

It can be made better by using some kind of external audio amplifier. It makes peaking the noise much easier while mobile without having to concentrate on the S-meter. The professional RADAR Engineers unit has a speaker and it works well.

I fixed my MFJ by buying a small IPOD speaker set that is mounted on a 3.5mm plug. It simply plugs into the headphone jack. The audio from these 2 tiny speakers are good enough. It runs on 2 AA batteries. These speakers make finding noise very easy because its very easy to hear the noise peak. Far easier than looking at the meter.

What I have found incredible is how I can hear noise from one polarization and not on the other. Bottom line, when looking for noise rotate the yagi to both horizontal and vertical polarization.

Computers in my house even though they dont cause problems are very noisy, so are my cordless drill charges etc etc. Its amazing what you hear on this MFJ unit when you start sniffing around in your house. I found wideband hash from my central heating controller which sounded like band noise. Putting a ferrite on the controller cable reduced my band noise by 1 S unit.

Only criticism is that the Manual is not very clear about attaching the receiver to the Yagi. There is not a clear picture of how the receiver should mount to the boom. But hey, I mounted it and it seems OK. I am planning to add a BNC connector to the element so that I can belt mount the receiver or use a separate HT on my belt. I also want to attach a simple vertical whip on a MAG mount for quickly searching a area while mobile.

The quality is reasonable and no hint of poor components or the usual quality control complaints issues with MFJ products.

This would be a good tool for your radio clubs test arsenal.

WX3B Rating: 2008-01-09
Outstanding - a Must have Time Owned: 6 to 12 months.
I had been using MFJ's dipole noise meter with good results, and this takes it to a new level.

The yagi has excellent F/R and side directivity making it easier to locate (and eliminate) potential noise sources.

For anyone working with utility companies or neighbors, etc. this device is a great addition to your radio shack.


Jim WX3B