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Reviews For: MFJ-815B

Category: SWR & Wattmeters & Dummy Loads

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Review Summary For : MFJ-815B
Reviews: 11MSRP: 80
Peak reading wattmeter
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
KF7WAG Rating: 2013-10-27
Works fine for me Time Owned: more than 12 months.
I have read so many complaints from cheap Amateurs on here who r Getting wrong readings, I noticed I Get lower readings Then what my radio Is putting out If I use lower Grade coax, If I use higher Grade coax It shows closer To what my radio Is putting out, All u Amateurs buy cheap low Grade coax Then u wonder y Things don't work right, cause ur Tight wads, Go buy some real coax cheapies
K2OWK Rating: 2011-01-15
Good meter Time Owned: 0 to 3 months.
I bought this meter a few weeks ago from the Eham classified. It works as it is suppose to. I like it because it covers the band thru 6 meters, and is accurate enough for tuning any antenna. It is not a Bird, but it is also a bunch less money. I like the dual meter and the ability to switch between average and peak. I know the peak reading is not a true peak, but it damps the meter and lets it go to a peak referance close to the real peak power out. I would recommend this meter if you can buy it for a good price.
K6XN Rating: 2011-01-12
GREAT PRICE PERFORMER Time Owned: more than 12 months.
I purchased my MFJ-815B used for $35.00 and I am very pleased with its performance. It is close enough in accuracy to my Bird 43 that it is useful and adds value for tuning and monitoring SWR. I dont always need laboratory accuracy. If I need accuracy I use my calibrated Bird Wattmeter. The MFJ-815B is a bargain price performer and it has performed adequately for Field Day and portable operations. It adds value, the price is right and I for one am a happy I purchased it.
KQ9J Rating: 2008-11-30
Useful little meter Time Owned: more than 12 months.
Had one for about 10 years now and added another a short time ago (used..I don't think they are worth it for the new price). Readings are approximate at best. Now I have calibrated them against my PalStar and they are more accuracte. Good for portable operation or I use them with my other extra radios at home. Just not my main unit anymore. You will not get a true PEP reading as these have no independent power supply. I changed a couple caps in the forward high section of one of these so the PEP reading more closely approximates the Palstar. If you have a friend with a good meter check the calibration. They are easy to adjust.
AI4WM Rating: 2008-10-04
Easy to use and comparable with similar meters of this type Time Owned: more than 12 months.
Bought mine used so I had a quick and easy way to measure SWR without switching my W-4 or Siltronix back and forth as well as for EMCOM and Field Day. The meter has 2 ranges 30 watts or 300 watts forward and 30 watts reflected. It measures Peak or Average power. I found this meter to be a bit less accurate than my others when checked against them or my URM-120, however for 90% or more of the applications in amateur radio this meter will do the job,
As with all the MFJ meters I've seen this has provision for illuminating the meter via an optional 12VDC power supply.
W3RPM Rating: 2008-06-12
Good enough for government work. Time Owned: 0 to 3 months.
Got this at a HamFest for $30.

Hooked it up and keyed up. The forward needle barely moved on it's 300 watt scale. The reflected power meter read 20watts on the 60 watt scale.

That didn't seem quite right.

Took it apart and discovered the circuit board was silkscreened where wiring connected to it. Sure enough, the pad that said "FPWR" was connected to the Reflected meter, and the pad that said "RPWR" was connected to the forward meter. It all looked like factory soldering unless someone decided to swap the wires and then clean up the board.

It seems as though MFJ could use a little quality control or a quick test before their products leave the door.

couple minutes with the soldering iron and it's readings are similar to those of my Bird 43 wattmeter. Some minor adjustment and it should be good to go.
K5ADF Rating: 2006-07-16
Does not work on 6m Time Owned: more than 12 months.
I unfortunately bought a MFJ815B for the 6m side of my ICOM 756Pro. It simply does not work. The power out and swr readings are so far off as to be worthless. The 756Pro put out 100 watts FM and the meter registered 25 watts! I don't trust the SWR reading at all. I replaced this "mighty fine junk" with a Palstar WM150 and am much happier now. It agrees with my 756Pro as to what is being transmitted in both power and SWR. My advice is to go with the Palstar. Anyone want a worthless MFJ815B?
KB9BPF Rating: 2006-07-16
Mine works Time Owned: more than 12 months.
No doubt the Palstar WM150 is a much better meter for only a few bucks more, as is the Daiwa CN-101L, however my MFJ-815B has not disappointed me either. While the Palstar's readings track that of my Bird 43 the MFJ's do deviate a bit, but since most ham measurements are relative-indication oriented, the MFJ does OK. I must add that I've never tried to use mine on 6M, only 30 MHz and below.

I wouldn't buy another one of these new, or even a Daiwa for HF use, for that matter. If you're going to spend that kind of money spend an extra couple bucks and get the Palstar. If you really need accuracy, get N8LP's LP-100.
W4VD Rating: 2006-04-16
Only if you get it cheap Time Owned: more than 12 months.
I would only get on of these if the price was low,

As far as the fellow having troulbe with the meter causing an swr problem I think that may be happening to me, I just took mine out the junkbox to use on 6 meters last week, it's supposed to go to 60mhz.

The indicated SWR on my 4 ele yagi is 1.4 to 1, but the rig is cutting back to about 60 watts when it does 100 into the dummy load not connected at all to that meter,

Buyer beware
W0ZPT Rating: 2003-02-23
Mighty Fine Junk Time Owned: more than 12 months.
I purchased my MFJ 815-B used a while back and no wonder the original owner parted with it! The meter itself was causing a mismatch in my feedline! I've had good luck with other MFJ products, but not this one.