the mod for the 209 analyzer uses off the shelf parts.  A 556 dual timer, and I have forgotten the other dual op amp chip.  Nearly the same circuit as in the april qst article.

Gathering parts to attempt the build after dayton.  If I can make it work, I plan to try the mfj swr meter mod bill mentions.
I will try if successful to get our club bo take it up as a project.
More as I go along.

Gary Lee
[log in to unmask]



On May 11, 2013, at 11:30 PM, Butch Bussen <[log in to unmask]> wrote:

> I boughtone of those and had a friend who said he'd modify it for me as 
> per the article in qst 4 or 5 years ago.  It appears to use a very 
> special chip and he still hasn't built it, guess I'll scratch that 
> one...
> 73
> Butch
> WA0VJR
> Node 3148
> Wallace, ks.
> 
> 
> On Sat, 11 May 2013, John Miller wrote:
> 
>> The 209 will go to VHF. I have one though it's not modified, because of what
>> you say I don't know anyone willing to modify it and I'm not comfortable
>> doing it.
>> ----- Original Message -----
>> From: "Colin McDonald" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Saturday, May 11, 2013 10:07 PM
>> Subject: Re: Audible SWR meters, Analyzers, and DXCC antenna
>> 
>> 
>>> an antenna analyzer is a device that transmits a tiny bit of RF into an
>>> antenna, and reads the reflected power, SWR and other variables depending
>>> on
>>> the unit.
>>> You don't tune them for anything other than frequency...it doesn't go in
>>> line with the radio or anything.  They are stand alone devices that
>>> connect
>>> directly to the antenna.
>>> Usually you select the band you want to check the antenna on, and use a
>>> VFO
>>> style dial to tune the frequency until you ssee a dip in the SWR...or a
>>> dip
>>> down to 50ohms or whatever measurement you are looking at.
>>> The high end ones are auto ranging and will show the min/max swr stuff as
>>> required.
>>> 
>>> So, there was one model, the MFJ 209 I think analyzer that was
>>> successfully
>>> modified using a freqmite CW output frequency counter, and a voltage
>>> controled oscelator.
>>> You turned the frequency knob with the VCO turned on and foundd the null
>>> and
>>> zero nulled the tone.  Then, you checked the frequency with the freq mite
>>> to
>>> see where the most resonant frequency occured.
>>> Unfortunately, this was only possible on the MFJ 209 antenna analyzer and
>>> it
>>> was a pretty invasive modification.  This analyzer still goes for a couple
>>> hundred bucks on the used market, and it's hard to find someone with the
>>> technical expertees to install the modification properly.
>>> Also, the MFJ 209 is difficult to find, and it only works for HF
>>> frequencies
>>> I believe.
>>> With tuners and HF being more forgiving, an antenna analyzer is really
>>> only
>>> particularly useful for tuning VHF/UHF antennas, and mobile antennas for
>>> max
>>> resonance.
>>> The newer MFJ 249, 259 and 269 analyzers work in a similar way to the 209,
>>> but they are unable to be modified using the original plan.  These
>>> analyzers
>>> will do VHF on the 249, and UHF as well on the 259 and 269 units.
>>> I believe I did hear that a 249 was modified, but there was something that
>>> was unstable or questionable about it.
>>> You also had to add more mods to the unit to switch the frequency counter
>>> to
>>> read VHF frequencies.
>>> So, the cat has been out of the bag for a good long while with regard to
>>> an
>>> accessible antenna analyzer.  The issue was that an analyzer is not a
>>> cheap
>>> piece of equipment, the original ham who did the mods stopped, and I think
>>> parts became difficult to aquire IE the freq mite.
>>> Also, with the updated analyzers the original plan doesn't work, so it
>>> kind
>>> of fizzled.
>>> I don't know anyone on list who actually had or has one of these units, or
>>> if anyone had them after the initial unit was modified.
>>> there are audio and text file instructions on how to do this entire mod if
>>> you can find a 209, a cw or voice frequency counter and can get in and
>>> make
>>> all the mods.  Or, you know someone who doesn't mind putting the time and
>>> expertees into it.
>>> I'm not sure if the HamPod technology could somehow be used with newer
>>> analyzer devices that provide a serial data output...perhaps.
>>> The issue of course, is that these newer units with data output are as
>>> expensive, or more so than a brand new ts590.  So not allot of people who
>>> may have the technical expertees and know how, can actually aford to
>>> either
>>> modify their own unit, or buy one to play with.  And, again, allot of guys
>>> say they'd love something like this, but if it's going to cost a grand or
>>> two, they will forgo the accessibility.
>>> At the end of the day, you can buy an MFJ 269 for 500 bucks and get a
>>> willing set of eyes to help for that once or twice a year you actually
>>> need
>>> the thing.
>>> How many here would pay $600 for a mostly accessible antenna analyzer?
>>> Because that was about how much the MFJ209 was with the mods done to it.
>>> The proof is in the pudding that no one wanted to and that is part of the
>>> reason why it didn't go anywhere originally.
>>> 
>>> I know lots  of guys would spend probably a couple hundred for something
>>> that was accessible and did the trick, but even a new unmodified antenna
>>> analyzer isn't cheap
>>> 
>>> Our ham club has an MFJ269 as part of the club's equipment and any member
>>> has access to it upon request for tuning mobile or vertical antennas etc.
>>> So, even hams who can see the thing are unwilling to lay out allot of cash
>>> for one.
>>> 
>>> 73
>>> Colin, V A6BKX
>> 
>>