[Lowfer] Antenna Analyser Mod?

[Neil]

For what it’s worth, here is my experience with my modified MFJ 259B. 

Although my frequency reading sometimes jumps around when the antenna is reactive I have found that if I ignore the readout of the frequency and just listen to my receiver it works just fine. As long as I know I’m on 475 kHz by listening to the instrument, I can bring my antenna to resonance with a dip in the SWR.

I have also discovered that even if my dip is only 2 1/2 or 3 to 1, when I Actually transmit into the antenna, the SWR meter in the shack Gives me a much better SWR reading, and I can get it down to almost one to one sometimes.

When I hear the MFJ signal on my radio it has a warbling sound to it which I guess it is designed to do. It does help me identify what I’m listening to however. So I think that’s a good thing.

And that’s my two dollars worth for today.

73
Neil 
w0yse 

Sent from Neil's iPhone

> On Jan 12, 2018, at 12:37, N1BUG <paul at n1bug.com> wrote:
> 
> I haven't been following this thread, but information on the modifications I made to an MFJ-259B can be found here:
> 
> <http://blog.n1bug.com/2016/12/22/adding-630-and-2200-meters-to-the-mfj-259b/>
> 
> I didn't calculate the final inductance values but if you are handy with toroid calculations you can work them out from the core type and number of turns.
> 
> I have since discovered major issues with accuracy of the instrument at these frequencies when the load is reactive. Based on my experience I would not recommend a modified MFJ-259B for tuning transmitting antennas on LF or MF.
> 
> 73,
> Paul N1BUG
> 
> 
>> On 01/12/2018 01:46 PM, KD7JYK DM09 wrote:
>> "Hi, I did exactly that on my '259. Added 940mH to the lowest range. Yes
>> the oscillator now ranges from 250 to 550 kHz. But it is not stable at
>> all, typically wobbling +/- 2 or 3 kHz. So not reliable enough to tune
>> up an antenna at say 474kHz."
>> I'm not playing in the lower bands yet, so not TOO critical at the point
>> in time, my "immediate" (relatively) demand is to make an antenna for my
>> wife as close to centered on 660 KHz as possible.
>> For those that have done the mods to the 249, 259, et cetera, what kind
>> of ranges did you get from what L values?
>> Kurt
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