MFJ-849 SWR Meter

[JimChagares]

I just purchased a Yaesu FT-991A and the MFJ-849 SWR meter. The readings I get for SWR and forward power on the radio's meter come nowhere close to matching the MFJ-849 SWR meter. Thoughts and suggestions are appreciated.

Jim

 

[jwt873]

Little more info..

How far out is the meter. (What is the actual difference you're seeing for Watts/SWR)? Do you have any devices (tuners etc) between the radio and the SWR meter? Are you making the readings with your radio's internal tuner on or off?

 

[JimChagares]

Little more info..

How far out is the meter. (What is the actual difference you're seeing for Watts/SWR)? Do you have any devices (tuners etc) between the radio and the SWR meter? Are you making the readings with your radio's internal tuner on or off?

Thank you for your reply. I only have the radio and the SWR meter (two-foot jumper cables). After your reply, I rechecked the differences and noted the readings. Seems with them so far apart I should just rely on the radio readings.

40 Meters 7.103 SWR
Tuner: SWR = Radio 1.3, Meter 5.0
No Tuner SWR = Radio 9, Meter 5.0

40 Meters: 7.103 Power
Tuner Power = Radio 100, Meter 15
No Tuner Power = Radio 10, Meter 32

20 Meters 14.196 SWR
Tuner SWR = Radio 1.2, Meter 2.5
No Tuner SWR = Radio 2.5, Meter 2.5

20 Meter 14.196 Power
Tuner Power = 100, Meter 80
No Tuner Power = 50 Meter 27

 

[prcguy]

Are you using the tuner inside the radio to tune the antenna? If so the SWR meter in the radio is before the tuner showing what the tuner inside the radio has tuned where the outboard MFJ SWR meter is showing the actual antenna SWR with no tuner in line and it would usually be higher if you used the internal tuner.

If you bypass the tuner inside the radio the SWR meter inside the radio should read closer to the external MFJ but not always the same because the internal SWR meter has a lot of stuff in line before it gets to the antenna connector on the back of the radio. The internal SWR meter could read a little higher or lower SWR in this case even though there is no tuner in line.

For power measurements the internal radio power meter and the external are both calibrated to read accurate only into a 50 ohm resistive load. If you used the internal tuner the internal radio power meter will read close to the correct power but the external meter seeing a crazy match can be off quite a bit.

Connect up a 50 ohm resistive load right at the MFJ meter, bypass the radio internal tuner and both the radio and external MFJ meter should read about the same power. If not something is broken and no doubt it would be the MFJ because that's what they do a lot.

 

[popnokick]

The steps to BYPASS the internal tuner on the 991A can be easily confused with the steps to ACTIVATE the AutoTuner. Refer to page 63 of the FT-991A Operating Manual to read how to determine that the internal tuner is in fact bypassed.

 

[JimChagares]

Are you using the tuner inside the radio to tune the antenna? If so the SWR meter in the radio is before the tuner showing what the tuner inside the radio has tuned where the outboard MFJ SWR meter is showing the actual antenna SWR with no tuner in line and it would usually be higher if you used the internal tuner.

If you bypass the tuner inside the radio the SWR meter inside the radio should read closer to the external MFJ but not always the same because the internal SWR meter has a lot of stuff in line before it gets to the antenna connector on the back of the radio. The internal SWR meter could read a little higher or lower SWR in this case even though there is no tuner in line.

For power measurements the internal radio power meter and the external are both calibrated to read accurate only into a 50 ohm resistive load. If you used the internal tuner the internal radio power meter will read close to the correct power but the external meter seeing a crazy match can be off quite a bit.

Connect up a 50 ohm resistive load right at the MFJ meter, bypass the radio internal tuner and both the radio and external MFJ meter should read about the same power. If not something is broken and no doubt it would be the MFJ because that's what they do a lot.

The steps to BYPASS the internal tuner on the 991A can be easily confused with the steps to ACTIVATE the AutoTuner. Refer to page 63 of the FT-991A Operating Manual to read how to determine that the internal tuner is in fact bypassed.

Thank you, that made the difference. I was trying to compare the readings with the tuner in the radio on.

 

[tadpole207]

Hey ham nation- i also purchased a MFJ 849 SWR and power meter. All they sent was a power cable with 2 black lines- no white on either to know hot vs ground vs neutral. No green wire, so i imagine solid black is is hot, black with very light grey speckles is neutral and no ground. I see people hooking these up to batteries but the Tekpower supply has 2 tension wire mounts (red and black on front) Should the bare wires from the MFj-849 connect to the front of the tekpower supply? I really don’t want to connect it to a battery since its part of the shack and not mobile. See image:


reference to the black and white wire connectors on bottom left of the image (i did not receive the instruction guide, only the 1 page quick start guide here:
Nick

 

[ladn]

I think @prcguy has the right answer, but at the risk of being snarky, it's an MFJ product in the equation. Quality control isn't MFJ's strong suit and the OP might do well to compare it with another known good meter.

 

[tadpole207]

Have they always had QC issues or is this new? As a new ham, they are everywhere, online, print etc. You figure with the amount of $ they spend on advertising, they would have a good product, however you are not the first person to say that either. What brand of SWR meter would you recommend and i am looking at getting a tuner as well, and am scared to get the one i wanted as it is MFJ-969. Need it up to 6 meters

 

[popnokick]

As you shop for tuners read the specs carefully. Specifically in two areas: 1) Will this tuner handle 6M? and 2) Can I run full power (100W) in a digital / high duty cycle mode? There are significant differences in the lower cost tuners in these areas. Of course, by putting down more $$ you can solve any of these issues. Incidentally and back to vector antenna analyzers / SWR meters: I have an MFJ 223 digital antenna analyzer and its been a gem for more than six years now. However, the NanoVNA boxes are a fraction of the price and do the same thing (and more)... but have a steeper learning curve (and MUCH smaller screen).

 

[kc8jwt]

I think @prcguy has the right answer, but at the risk of being snarky, it's an MFJ product in the equation. Quality control isn't MFJ's strong suit and the OP might do well to compare it with another known good meter.

Our joke here locally is that MFJ stands for "Mighty Fine Junk".

I do have an MFJ Auto tuner and I will say that it works quite well for the 100W Alinco HF rig I use.

 

[tadpole207]

Thanks gents. I was looking at MFJ-969, TUNER, HF+6M, 300W, ROLLER, DL, XMTR, ANT SW. I wanted to stay away from auto tuners until i "learned" how to manually tune, and it seems that manual tuners in this price range can run more frequencies than auto's, as well as more power. Just an observation i have noted in the ones I am looking at.

I was initially going to get the MFJ MFJ-993B MFJ-993B, DUAL POWER AUTO TUNER, 300/150W, 1.8-30MHz but noticed it does not do 6m. Same with 929 MFJ-929, 200W AUTO TUNER, LCD/MTR, 1.8-30MHz even though all the great youtube channels that "contest" or "on the air"something or another, give rave reviews of both.

That being said, they have been in the game much longer than i have and their width of knowledge far surpasses mine; however i would bet that a lot of us newbies watch these channels in hopes of finding "the one" that does everything we need it to. Low and behold, i am learning the hard way, this just isn't possible.

So i still have this brand new Yaesu FTDX10 in a box waiting to get set up, and it comes back to the installation of the SWR meter. The tekpower i have in the picture above is strong enough to power it, but when i got the MFJ 849 SWR MFJ-849, WATTMETER, DIGITAL, HF/VHF/UHF, 200W in the mail the other day, it came with no instructions. I am figuring just on basic electronic training, that the 2 wires i have are positive and negative. Both are black. There is no ground. I can only find videos of people connecting it to a battery even though it is ran (or could be) inline with the radio they are using. So until i get that operational and able to trust its readings, i don't plan on plugging in the Yaesu yet.

And then when i finally get power to the SWR meter (https://smile.amazon.com/gp/product/B00L2K263Q/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1) and am comfortable of turning it on, i want to have a tuner i can understand and trust so that mag loop i have hanging works as advertised on the bands i need it to, with tuning of course. As some of you know, i am limited to my 3rd story apartment while we look for houses, and just had emergency back surgery at the beginning of April and go in for a 2 level reconstruction in July. I was hoping i would have all this figured out by now so while i am convalescing at home, i have something to play with...that i can touch within reach .....Also keep in mind i won't be installing anything as far as antennas go for quite awhile after July. Everything i have to do will be from my desk- tuning etc.

So ye with greater knowledge than I, how would you propose i tie the MFJ-849 meter in? It's own power source? Tied to the same power source as the radio? Should i get a 3rd power supply to run only the 849 and tuner when i get it?

Should i stick with my hunch on manual tuners, or should i pony up the extra $50 for the auto tuner? Am i needing another brand entirely to look at? @popnokick should i go with a nano analyzer before i get a tuner or do you recommend i use both at the same time? I was looking at Rigexpert but the cost at the moment puts it out of reach for me at the moment. Not sure they are any better than the Nano's you speak of. Many on the net i am on give great reviews on theirs.

I fear that me waiting for the perfect set up will keep me from getting on HF. I want to work it so badly, but I worry that i am going to burn up $1300 with a bad decision/connection. But i have just a few weeks left before I will pretty much be immobile for a month, and then PT and all that Jazz for the rest of the year, i wanted to be able to work HF and continue on this path that is pretty awesome.

Thank you all for letting me vent on my keyboard, and as much as I realize i sound like a complete noob, I am lol. Appreciate all the help.

 

[popnokick]

You'll probably need to contact MFJ directly about the power leads on that SWR meter, unless someone here comes up with an answer. Have you tried eHam.net reviews for it?
Don't confuse SWR analyzers with tuners... two very separate and different things. The SWR / analyzer will help determine where your antenna is resonant. A tuner may have an SWR meter as part of it, but that is not its primary function... which is to attempt to match your transmitter to your antenna and feed line.
Finally - if you're considering other alternatives for a tuner (good idea), check out LDG Electronics -
https://ldgelectronics.com
They have a very broad range of automatic and manual tuners, many which cover 6M and even at higher power levels with digital modes. I have a Z100 which covers 6M very well, but they recommend not exceeding 30W input with high duty cycle modes such as FT8, PSK, etc. Going up in price gets you not only 6M but also higher power ratings.

 

[tadpole207]

Again, thank you. It appears that the AT-200 https://ldgelectronics.com/products/desktop/at-200proii/ ill fit the bill for my immediate needs. I now need to get another power source, one that runs the radio (tek power in hand, 25a cont, 30a max) and one that runs both the tuner and SWR meter. I am assuming i can run these in parallel from different power sources, rather than serial, so if one blows, i don't burn up the entire setup.

Ill play around with swr meter hooked up to only the power supply and run a meter over the leads- eHam has limited reviews that i could find and all videos i found have them wired to a battery, and from the video, i cannot distinguish the black wires. I have emailed MFJ and await to hear back from them. Reversing polarity cannot be that bad right? lol..its only $250 compared to $1300 (still an ouchie)

 

[kc8jwt]

I was initially going to get the MFJ MFJ-993B MFJ-993B, DUAL POWER AUTO TUNER, 300/150W, 1.8-30MHz but noticed it does not do 6m. Same with 929 MFJ-929, 200W AUTO TUNER, LCD/MTR, 1.8-30MHz even though all the great youtube channels that "contest" or "on the air"something or another, give rave reviews of both.

I have the MFJ-993B and I can say that I really like it. I was confused at first about an HF and 6M Tuner, until I took a quick glance at the rig you are using and saw it only has one antenna output. I have an older Alinco DX-70 that does HF+6M, but my radio has an HF antenna port and a separate 6M port. I know that when I had my radio first sat up when I lived on the "farm", I had an HF wire through the tuner and then I had a 6M wire dipole cut simply for SSB. I didn't do anything else outside of the bandplan for SSB. A lot of our local guys had the MFJ-9406 SSB transceiver for 6M and we would a lot of times do our local 2M RACES net on Wednesday evening, and then a few of us would hop over on to 6M and ragchew for awhile after the 2M net. I had one of the MFJ 6M radios that I borrowed from another ham until I got my Alinco.

I had a manual tuner that I borrowed from another ham and it wasn't hard to learn how to do. What I did was when I set everything up, I went through frequencies that I knew that I would use and tune the radio with the manual tuner. Once I got the tuning correct, I wrote down the tuner settings for that frequency. When I wanted to go to a specific frequency or band, I would use those settings for my most common frequencies, and then tweak them for the different frequency in that band. In all truth, once you have your settings, a manual tuner can be just as quick as an automatic. I like the automatic one on mine because if it can't tune in a set amount of time, it beeps at me and tells me it can't tune and I can let off the key so that I am not transmitting with a high SWR.

I don't get to get on HF much because I live in a very tight lot in town and I don't have the room to put up a nice dipole wire to do HF, I've been looking at verticals to try to get me on HF here at home. In two weeks though, I go to Boy Scout camp and I'll take the rig, tuner, and wire out and put it up at the campsite to mess around with at night to see what I can do out in the middle of nowhere.