MFJ 828 SWR/Wattmeter.
For about a year I have been casting a wanton eye on this model from MFJ. For several years I have had a Leader LPM 885 wattmeter and SWR bridge. The real drawback to this unit is the power scale only goes to 1 KW.
However, the meter is large and easy to read, as watt meters go this one is fairly accurate with the readings.
After reading the specs on the 828 I decided to make the jump and own one and have it in my shack. The unit arrived from HRO in just about three days after ordering. I quickly got the box open, only to find another box that contained the MFJ box with the 828 and the needed wall wart.
The 828 is pretty straight forward and not a confusing menu, let’s turn it on and see what my thought are with the MFJ 828.
The first button I pushed was the mode button and made sure the unit was in the Automatic mode. In this mode it does not care what power you send to the wattmeter. The 828 automatically changes for you, so no risk of frying the meter by applying 1.5 kw to the 20 watt scale.
The menu is simple, meter range, Beep on/off/, ALARM SWR good feature to have in your station. Let’s see what I found out about this product the Pros and cons.
Right away I found out that the analog readings versus digital do not agree with one another. My tri-band Yagi at the bottom of the 14MHZ cw band is 1.3. This not only corresponds with my FT 5K meter, but also with my older wattmeter, my FT 2k and my antenna analyzer, all say 1.3. My THP amplifier also confirms this by showing thirty watts of reflected power. If one does the math, it is 1.33. On the MFJ it reads 54 watts reflected and an SWR of 1.54.
This is with 1500 watts to the antenna, so based on this we have an error. Naturally, the higher the reflected power the higher the SWR will be, thus MFJ is telling me that my SWR is 1.54 this is an error in the reading.
In regard to the frequency counter MFJ states +- 1KHZ and I found this to be correct. However, the counter does not read out Hz. So, what it does say if the transceiver is set to say 14.006.7 kHz it will read 14.007 and if it is below the half Khz mark then it will read 14.006. This one will get you well inside the ball park, but do not rely upon it for pinpoint accuracy.
How accurate is the wattmeter, about as accurate as any one on the market at this time. At 1500 watts to the antenna my THP HL 2.5 read on the analog meter 1500 watts, the MFJ was telling me that it was 1554 watts and thus the alarm sounded. I am going to try the calibration procedure in the manual and will follow up on this report in the next paragraph.
Not satisfied with the readings I was obtaining I checked the manual for the calibration procedure. With this you must remove the cover and find the control the instructions want you to adjust. They are well marked, have a small screwdriver or alignment tool handy.
Let’s take the frequency counter, as I mentioned it will read only kHz . Therefore, if you are higher then 500 HZ it will read the next digit. Say you are transmitting on 14.006.6 Khz the 828 will read 14.007. If you are transmitting on 14.006.4 Khz the 828 will read 14.006.
It is accurate to some degree, not precision accuracy as you might have with your transceiver. Oddly, the analog meters in the 828 agree with all my other swr measurements. The wattmeter agrees with my other meters, using twenty watts, 100, or 1500 as an input power.
The digital wattmeter gives a figure of precise measurement I used 1 kw the 828 told me 1038 watts. Not bad most wattmeters have a plus, or minus ten percent.
In summation, this is not a bad swr/wattmeter I will give it 4 stars out of 5.
Oh, the unit also offers an swr protect for your linear amp, this is a good feature for those that do not have the protection in your amps already. Since I do not need this feature, it was not checked since I do not have the cables needed for using this feature.
To be quite honest about it, I may offer this unit for sale and keep my older Leader meter. If someone is interested in a purchase contact me on the forum, or via k4lrx@att.net.
Bill K4LRX
