Wednesday, April 9, 2014

MFJ 259b Antenna Analyzer - An Update

Going over some previous post I see that a lot of people have read my little summary of the MFJ 259b. This is what I originally said: 

"The MJF 259b has finally arrived, it’s a fiddle though, you would have thought you’d get the power supply with it, but no, that has to be ordered separately, typical! So now I'm busily checking around the local hardware stores for an AC DC adapter with the right connector, it never comes easy does it? 

On surfing the web I came across a UK Amateur dealer who wanted £68 for the MFJ 99x accessory pack which includes the dip meter coil, carrying case and you guessed it the power adapter! Having checked out the web I can get a power adapter for £6.50, makes you wonder doesn't it? 

The other pain is that I knew it took rechargeable batteries, but I was rather taken back when I realised it needed 10! Removing the front cover to install the batteries requires the removal of 8 screws; you'd think MFJ would have come up with a simpler design? 

However I digress, last night I popped round to my next door neighbour and asked if by any chance he had a 12v power adapter, he did and blow me it fitted! So I was able to do a quick test to make sure all was working as it should, interestingly enough all my antennas were slightly out on the SWR readings, most likely from the recent storms, but over the weekend as a simple experiment I will borrow my Brother in Laws MFJ that I originally used to set them up to see how good the SWR matches are on both units, that could prove very interesting!!" 

I never did complete the last bit until much later, well it turned out that my MFJ wasn't too far off my brother in laws, I must admit I was expecting it to be way out.

Now that I've owned this piece of kit for some time and am a regular user I am probably now able to give a better report. The analyzer is actually a very useful especially if you are in to or going to make any sort of HF VHF antenna system. It's fairly easy to use with simple instructions, but if you get stuck just "google" and there are plenty of users out there who will help you.

However, in my humble my opinion it's not that well made, it's rather tinny, it doesn't feel very solid and to be frank feels rather cheap, but of course we owners know it don't come cheap; £300 plus I believe is the present asking price for a new one, so spare your blushes go 2nd hand if you can, believe me they are fairly easy to fix!

Mine does have some drawbacks, somewhere within the area of the coax connector there is an intermittent short, so whenever I connect up my coax cable to the connector I have to fiddle about to make sure I have a good connection otherwise I get a reading or +25 on the SWR. 

I've tried to find this short but it still is escaping me at the moment and it very annoying. More to the point it’s been there since new which doesn't exactly give me any comfort with MFJ products especially since they all seem very expensive! 

As a footnote I eventually found the issue and this is precisely the sort of thing I'm talking about when I say "cheap". The problem was a simple soldering connection of the inner (live) coax connector. The soldering looks and is quite frankly rubbish and once I'd done the fix correctly all was working how it should.

Something had obviously gone wrong when this analyzer was made up at the factory, look at the actual connection, the soldering is that bad the connection has failed.

I have extra bits I've made for the analyzer, I'm not going to purchase any bits of kit if a) I can make them and b) they are always far too expensive!

The loop coupler I use for measuring my homebrew traps; It’s dead easy to build and I strongly suggest you build rather than buy otherwise you may find yourself spending a large amount of money for what can be made in a jiffy at very little expense. 

If you have a good soldering gun you just take was some reasonably thick copper wire (about 6” in length) bend in a circle but keep ½” of each end straight. Take a male to male 259 connector and it’s a simple case of soldering one end of the wire to the centre pin and the other to the outside ring. So you finish up with a circle of Copper wire attached to the male to male 259.

The other piece of kit I made was a frequency counter lead out of some coax and with a PL259 connector at one end and the probe on the other. I used this for working out the frequency measurements on my K2, very useful and very cheap!

Overall, an essential piece of kit for the shack. 
Sometimes you'll get lucky and have one that has no issues and when they work correctly they are very good, but there are other analyzers out there at a cheaper price that do the exactly the same thing. 
In other words, "you pays yer money and takes yer choice!...Hope this helps.

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