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Reviews For: MFJ-868 SWR/ WATTMETER

Category: SWR & Wattmeters & Dummy Loads

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Review Summary For : MFJ-868 SWR/ WATTMETER
Reviews: 34MSRP: 139.95
Product is in production
More Info: http://MFJENTERPRISES
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
KK4JJM Rating: 2022-09-18
Great Meter. Poor Quality Control and LEDs Time Owned: 3 to 6 months.
Bought meter and found loose nut/bolt on coax connector. Tightened same. Within 3 weeks the 2 LEDs burned out. Replaced them with blue LEDs and now all is well. The large screen helps old eyes.
W4MKC Rating: 2021-06-20
Nice addition to the shack Time Owned: 3 to 6 months.
I bought this meter, because I have a difficult time reading small cross needle meters. This meter clears all that up. I really like this meter. I can read it fast, and I find it quite accurate. I use it about 4 hrs daily, and the lamps are still working, and this giant meter grows on me more each day. One of the best station components I've added to date.
W2NER Rating: 2019-04-12
Great meter Time Owned: 6 to 12 months.
I have a few meters, one being a Bird and the other a LP-100. Both are extremely accurate. So, when I got my brand new MFJ-868 (because I like analog meters) I tested it. It was dead on accurate using the bird or the LP-100. So, who ever says their meter sucks or had to calibrate it, this is because of one of two thing, you got a meter that was aligned poorly (easily fixed) or your just clueless!! I checked AVG and PEP and they are both dead on.
N8OPS Rating: 2017-12-30
I have the newer model Time Owned: 0 to 3 months.
I have the MFJ-869 but there isn't a listing for it here. But this is my opinion. It's still "mighty fine junk" and for some reason I keep falling for it. Just trash all the way around- intermittent on average power, extremely generous readings on peak power. Very poor fit and finish. Can this company just go out of business- please?

Sent it back. I'm done with MFJ.
PE1HZG Rating: 2017-07-22
Good meter Time Owned: more than 12 months.
I found that the peak meter would overshoot with SSB in peak signals, giving peak readings that are more than a bit optimistic.

To fix, I added a resistor 47K betweek the emitter of Q1 and the join of R11, pin 3 of U3, pin13 of U1.
This is easy to do by lifting the emitter leg of Q1 and put the resistor in series. Peak reading is not affected and the meter is a lot more stable.
W7KNX Rating: 2017-02-16
Excellent Time Owned: more than 12 months.
I have three of these in the shack, one on each radio that has an amplifier. I initially tried it because I wanted a large display that was easy to read at a glance and I prefer single needle meters. Very happy with them.
NA1ME Rating: 2015-08-01
Easy to read, but recalibrate if possible Time Owned: 0 to 3 months.
Like others, I was attracted to this SWR/wattmeter because of its huge, easy to read face. Out of the box, though, wattmeter accuracy wasn't as good as it could be. I inserted the MFJ and a Bird 43 between my 100W TX and a dummy load. 160M up through 15M the MFJ read 10% lower, and on 12M and 10M it was 20% lower. Therefore, on 20M, I tweaked the internal 20W and 200W pots so that the MJF now agreed with the Bird wattmeter (meaning, of course, that the MFJ was probably around +/- 5% accurate at this point). Tweaking was done full scale on the 20W scale, half scale on the 200W scale. As MFJ says itself, accuracy is indeed better half to full scale, as opposed to below half scale. But overall accuracy even at QRP, and across all the bands, appeared to much greater than it was out of the box. This is no expensive piece of high grade test equipment, but it does provide reasonable accuracy (after tweaking), and again it's great to be able to read TX output easily.
K9ILL Rating: 2015-06-27
I LOVE Mine Time Owned: 0 to 3 months.
I was supprised to see how well my 868b worked. I checked it with my Bird 43 meter and it was right on. The HUGE meter is awesome.
N7BOO Rating: 2014-12-25
Meter Calibration Time Owned: more than 12 months.
The reason I gave a rating of 3 was not meant to imply that the MFJ meter is a piece of junk.

First keep in mind just what you're purchasing, a run of the mill SWR/Wattmeter, not a lab grade device that is calibrated and re-calibrated on a schedule to insure accuracy.

You can't, nor should you always expect less expensive meters like the MFJ, Diawa, and many others, to perform accurately.

Over a year ago I purchased a couple of MFJ SWR/wattmeters, when they arrived the first thing I did was to check them, one was within specification, however, the second one was so far out of calibration it was totally useless.

I had to, like others on this forum, found it necessary to recalibrate the device before I could put it in service.

What can make it even more difficult for the average ham, comes down to 3 things:

1. Are you technically savvy enough to work on, repair, or calibrate this type of amateur radio gear if it's out of warranty?

2. Do you have the necessary test apparatus work on amateur radio gear and accessories?

3. Do you have the necessary schematics and procedures to repair, align, or re-calibrate the equipment?

Most often manufacturers of amateur transceivers and accessories do not include schematics, drawings, or calibration procedures with the item, without these documents, the average ham is going to be totally dependent on the manufacturer for service. Even individuals with years of electronics experience don't like the idea of attempting to work in the dark without the proper documents.

Burned Out Bulbs & LED's

About burned out light bulbs and LED lamps used for illumination, this is a fairly common complaint, and most often, when bulbs, or LED's fail, it due to using "Wall Warts", you know, those little unregulated power supplies that either come with the accessory, or that you purchased from the manufacture or dealer. DON'T USE THEM, THEY CAN'T BE TRUSTED. I've seen 12V wall warts with voltages of 18V or more, and they can and will quite often eventually damage bulbs and LEDs. When you turn the switch, they may be starting up with an excessive "no load voltage", well exceeding the voltage rating of the bulb or LED..

Yes, you can drop the voltage if you know how to do it, but I simply don't trust these little boogers PERIOD, invest your money in good regulated power supplies and quality DC outlet distribution strips with surge and reverse polarity protection.

Sorry for getting so windy, my intentions were meant to help.

NR7N Rating: 2014-11-29
NR7N Time Owned: 0 to 3 months.
I actually rate this meter at 4.5 but I will give it the nudge up.

First, this is actually a pretty good meter but the main problem is that it is not calibrated correctly. After calibration it is quite good. In fact, almost all diode detector based meters (95%+ of power/swr meters that hams use) are inaccurate to some degree. I include Daiwas, Diamonds Comets, etc. and even Bird wattmeters. The Bird is generally +/-5% and are more accurate then most because they have been calibrated against watt meters that actually measure the heat produced with the applied power. They are generally more rugged as well because of the environment they are desgined to work in. They are NOT a precision RF power measurement instrument so let's get that settled right now.

Almost any diode based meter can be calibrated within +/-10% if done with proper equipment. When I got my 868B I connected it up to a good dummy load and checked it for accuracy. The 20W range was pretty close but the 200W and 2000W ranges were off quite a bit (one high and one low). Again, this is not something special with MFJ as I just went through several new Daiwa meters that were actually worse.

Also check the directivity of the coupler for SWR measurements as my 868B read 1.5:1 into a known good high power load that was measured at 1.05:1. We'll get to that later.

My power measurement equipment consists of a HP 435B power meter and the corresponding thermcouple sensor (8481H) and a 500W Bird 30 dB attenuator (8325). A friend who has a metrology lab verified calibration of the 435B/8481H and gave me the exact attenuation of the Bird attenuator. In this way I have a calibrated measurement system.

The first thing to do with the 868B or any type of diode based power/SWR meter is to null the coupler when connected into a 50 ohm load. I ran 100W into the MFJ (set to read SWR) and adjusted the null capacitor on the coupler board for a minimum reading. The directivity on the MFJ coupler is quite good and it nulled right out. SWR can now be meaured accurately.

I then ran 20W (as referenced to the 435C/8481H/8325 with the MFJ in-line) into the 868B on the 20W range and adjusted the 20W pot for the correct reading. I did this at 200W on the 200W range and finally I ran 500W into the 868B on the 2KW scale (remember the Bird attenuator is rated for 500W). The MFJ is now calibrated and works great. it has good range to range tracking and seems relatively flat from 80 to 10M. I did not attempt to check at 160 or 6M as I don't currently operate those bands.

The construction looks adequate and the coupler assembly is well constructed and mechanically rigid. It is not a piece of junk.

Several other reviewers have complained about the meter light going out after a short period of time. A little diagnostic work found that the MFJ power supply was putting 13.8 VDC into a 12VDC bulb. The remedy was easy. I clipped the blue/white + VDC lead and inserted a 1W 39-ohm resistor. Make sure and put a piece of shrink tubing on each end before soldering. The voltage is now 10.7 VDC on the bulbs, they light the meter fine and should last forever.

The MFJ-868B is not worse then other meters on the market. It just needs to be calibrated correctly. Most of the competition's meters are just as initially inaccurate as well.