Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

MFJ 259b antenna analyzer giving false readings

M

mr_fx

Sr. Member
Oct 8, 2011
1,536
172
173
Kansas City
ok...so for some reason my MFJ 259b analyzer is giving weird readings...

I have tried different coax... it's telling me my beam is 3.5:1 swr or worse on all bands, the SWR dip is where it should be. but there is high reactance and a impedance mismatch

I have similar results on all antennas... even on the dummy load... hell my 80m vertical shows 8:1...
 

mr_fx said:
ok...so for some reason my MFJ 259b analyzer is giving weird readings...

I have tried different coax... it's telling me my beam is 3.5:1 swr or worse on all bands, the SWR dip is where it should be. but there is high reactance and a impedance mismatch

I have similar results on all antennas... even on the dummy load... hell my 80m vertical shows 8:1...
Click to expand...


Has it always been like this or just start suddenly? Are you near any high power broadcast transmitters especially AM stations? It is a well known fact that the MFJ-259B/269 is affected by nearby high RF fields.
 
AS CK posted HIGH RF fields do make the 259b go wacko.

Try using other functions of the 259b to see if they work correctly, sweep a piece of coax connected to a dummy load to see what type of readings it gives?

Process of elimination, try different functions of the analyzer see if they work correctly.
 
I have tried different pieces of coax I've tried to friend tennis I have tried a dummy load it still reads incorrectly even the dummy load is showing really odd numbers although not quite as severe
 
Have you tried dummy load directly to mfj meter? This may help to rule out any other factors other than the dummy load and the meter and whatever adapter is being used. That is one other thing, if you have an N-female that comes out of the mfj meter what type adapter are you using? N-male to SO-239?? If so, remove the adapter and clean it and then slowly reseat it and don't push down too hard. Just enough to get the tip seated. Then finger tighten the adapter. I have found this to be an issue with one I have used before. Might not work. But won't hurt to try. Hope you get it resolved. Good day.
 
This reading (8:1 SWR) may be the maximum such a meter will read.

If your comfortable taking the 259b cover off, do so and check the wire connection to the connector on top. Be sure and take the batteries out in this process.

Sometimes the wire can break or come un-soldered by twisting when screwing your coax onto the meter.

I added supper glue to the out side cover for my connector, and this seem to make sure the connector never twists.
 
  • Like
Reactions: 222DBFL
Marconi said:
This reading (8:1 SWR) may be the maximum such a meter will read.
Click to expand...

That meter will show SWR values to 31:1 at which point it indicates SWR >31:1

If your comfortable taking the 259b cover off, do so and check the wire connection to the connector on top. Be sure and take the batteries out in this process.

Sometimes the wire can break or come un-soldered by twisting when screwing your coax onto the meter.

I added supper glue to the out side cover for my connector, and this seem to make sure the connector never twists.
Click to expand...

Good points about the connector maybe having broken the PC board trace where it is connected.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ BJ radionut:
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ BJ radionut:
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.


      Top Bottom
      Back