Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: MFJ-259B antenna analyzer always reads > 25 SWR  (Read 4607 times)
K2CMH
Member

Posts: 278




Ignore
« on: August 09, 2011, 12:54:48 PM »

I have an MFJ-259B antenna analyzer that is less than a year old that has started malfunctioning.
What is happening is that the 259B has started showing '> 25 SWR' all the time.  The analog meter
stays pegged at infinity.  When I sweep the frequency both the ohm meter and the R/X on the LCD
change as they should, but the SWR always stays at '> 25'.  I have tried it both on battery and
your wallwart.  The displayed voltage on startup using battery was around 15 volts.  I had a friend
bring over his 259B and test the same antenna I was trying to test and we got the reasonable readings
we were expecting.  Just to make sure, I took my 259B over to his house and put it on one of his
antennas and it still exhibited the same faulty behavior.  As one last test, I tried using the unit
with no antenna connected and still get the same behavior.  I'm at a loss as to what to try next.
Does anyone have any ideas as to what I could check for or try. 

I have contacted MFJ about this but am still waiting on their reply.  I was hoping that someone has
already run into something like this and had a quick-fix I could try.
Logged
KA4POL
Member

Posts: 2089




Ignore
« Reply #1 on: August 09, 2011, 09:24:13 PM »

I wouldn't bother. If it is under 12 months old go for their warranty. Your description sounds like loose connection. Opening the case might void the warranty, however. You also might contact the dealer.
73
Logged
AD5X
Member

Posts: 1436




Ignore
« Reply #2 on: August 10, 2011, 04:20:38 AM »

Open the case and check that the UHF connector center pin is soldered to the pc baord.  Sometimes the solder connection breaks, especially if it wasn't originally soldered properly.

Phil - AD5X
Logged
K2CMH
Member

Posts: 278




Ignore
« Reply #3 on: August 10, 2011, 05:35:18 AM »

>check that the UHF connector center pin is soldered to the pc baord.

I had thought about that, however, since the other functions of the 259 seem to work (such as the ohms, R, etc), I would think that if the center pin was not connected that those other functions would not work properly.
Logged
N7TEE
Member

Posts: 40




Ignore
« Reply #4 on: August 10, 2011, 08:18:35 PM »

K2CHM,

Have you checked the batteries in the unit or used a 12 volt wall wort on it?  Mine did the same thing as your's is doing.  Thought that you might try it first.

Dave
(N7TEE)
Logged
KA4POL
Member

Posts: 2089




Ignore
« Reply #5 on: August 10, 2011, 10:29:33 PM »

I have tried it both on battery and your wallwart.  The displayed voltage on startup using battery was around 15 volts. 

As he mentioned  Wink
Logged
W8JI
Member

Posts: 9296


WWW

Ignore
« Reply #6 on: August 11, 2011, 05:15:42 AM »

>check that the UHF connector center pin is soldered to the pc baord.

I had thought about that, however, since the other functions of the 259 seem to work (such as the ohms, R, etc), I would think that if the center pin was not connected that those other functions would not work properly.

He has a bad SWR detector diode probably.
Logged
KA2UUP
Member

Posts: 388




Ignore
« Reply #7 on: August 16, 2011, 10:39:02 AM »

I was using mine this weeknd and the same thing happened.  I discovered that the center pin of the patch cord I was using was not setting properly in the coaxial connector.  Check this out with another cord if you have one.   
Logged
K2CMH
Member

Posts: 278




Ignore
« Reply #8 on: August 16, 2011, 12:08:30 PM »

>I discovered that the center pin of the patch cord I was using was not setting properly

That is actually a very good idea and could most definitely account for the strange behavior that I have been seeing!
Logged
K8AXW
Member

Posts: 3958




Ignore
« Reply #9 on: August 17, 2011, 09:42:14 AM »

I saw a cartoon many years ago showing a ham with a piece of gear upside down on a work bench.  The soldering iron is hot, there are parts hanging out of the chassis and the guy has a very startled expression on his face as he holds up the power cord which he forgot to plug in the receptacle!

You ALWAYS check everything outside the box and if appropriate, into a dummy load FIRST!

Now, with that said, if you need to open MFJ box, look for bad solder joints or no solder at all.  I opened my MFJ analyzer immediately after receiving it, "just to see."  Big mistake!  I almost puked!
Logged
AA4HA
Member

Posts: 1581




Ignore
« Reply #10 on: August 22, 2011, 08:44:30 AM »

Now, with that said, if you need to open MFJ box, look for bad solder joints or no solder at all.  I opened my MFJ analyzer immediately after receiving it, "just to see."  Big mistake!  I almost puked!

I think they only hire "soldering school rejects", they must go through a list of folks who bought Heathkit gear 30 years ago and found those who still use acid core solder and a giant 250 watt iron for prospective employees. I do not buy MFJ gear but have fixed some stuff that was given to me for free.

We all need to write a joint (as in soldering joint) letter to MFJ and ask them to include a free soldering iron with each purchase.
Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
KJ4DKT
Member

Posts: 6




Ignore
« Reply #11 on: September 05, 2011, 09:43:22 AM »

If anyone compares employees of MFJ to TEN_TEC, you will immediately realize what is wrong with MFJ.  Mississippi has always and still is #50 in the US for education.  All of the combined IQs at MFJ do not exceed 10.  Enuff said.
Logged
KA4POL
Member

Posts: 2089




Ignore
« Reply #12 on: September 05, 2011, 12:37:47 PM »

And the other side are those customers who always want to pay less.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!