Operating the MFJ-993B auto tuner remotely on the LAN

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I plan to experiment with wire antennas some so I purchased the 6400 without the optional antenna tuner and instead purchased the MFJ-993B auto tuner.  I think I should have read the MFJ manual deeper before purchasing.  I have the 6400 at the back of the house close to the antenna feed and operate using smartSDR from my radio shack in the front of the house connected to rig by ethernet.  I read that the MFJ tuner auto tunes with any transmit signal  and assumed that meant could be used remotely. But now in reading more closely it is important not to ever have it "auto tuning" with more than 10 to 20 watts. There is a tune button not he MFJ unit that is to be pressed before sending the lower power signal. Has anyone found a way to use the MFJ-993B tuner when operating remotely on the local area network with SmartSDR? They have a remote box, but it appears to be designed for a short serial connection to the tuner.
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Keith Mitchell

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Posted 3 weeks ago

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KF4HR

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Just adjust your Tune output slider on SmartSDR to an output level that is safe to use with the MFJ Tuner.  On start-up  [first] click on the Tune button and ensure the Tuner has adjusted to a low SWR before operating with higher power levels.  
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AB4RW

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That's kinda what I was thinking, just wasn't sure if understood his question, I use the Ldg and that's all I do.
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Jim Gilliam

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The Palstar which I am using remotely has memories and tunes to a frequency that is close to a memory channel. I just "spike" it for a second at full power and wiat for it to tune automatically. Then, resume operation. If the MFJ has memories it should operate the same way. Sorry you didn't buy the Palstar HF Auto. It is a keeper.


Jim, K6QE
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Mark - WS7M

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The 993B should also have memories.   

I do find with my 993B that sometimes I need to "reset" it with a power cycle for the tuning to work.  Could just be my unit.

But since you plan to have it remote, you might consider some kind of a web or network switch to cycle power on it.

I think virtually all tuners prefer to tune at less than max power.
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Keith Mitchell

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Okay, I think Jim is saying once I have some memory running stored in each band, the MFJ993B will jumped to the closest setting without my pressing the tune button. That being the case, I can certainly walk back and forth between the two rooms to store some settings. I was jumping to the conclusion I would have to do it every time I wanted the unit to do its job.  I'll have it hooked later today and see if that works. 
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Rick - N4RZ

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I also use the Palstar HF-Auto, but with the W1TR programs, the tuner will follow the radio frequency and is ready to go whenever you want to use it.  Note: on band changes you may have to wait up to ten seconds since this tuner does use a roller inductor, unlike the MFJ autotuners that use relays to switch capacitance and inductance values.  
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James Charlton

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Hi,
I use the MFJ 998 tuner (big brother to the 993) remotely with a 6600M and a Maestro and an Ameritron 1306 amp and it all works fine.  I set the "tune" power on the 6600m to 1 - 2 watts for each band.  Then, when I press the "Tune" button on the radio or the Maestro it drives the amp with 1 - 2 watts which causes the amp to put out between 20 and 40 watts which causes the tuner to tune.  Tuning to a new frequency takes a couple of seconds, tuning to a memory frequency takes well under a second.

I would not overpower the tuner when tuning.  If you do, at least on the 998 model, it will give a warning that you are overpowering it and go into bypass.  But it gets worse.  

With my setup, if I accidentally forget to push the "tune" button when changing bands or antennas, the amp tries to drive 1KW into the tuner which has not yet had time to operate.  The result is that the amp sees a high reflected power (SWR) and puts itself into bypass as protection.  Although not harmed, the amp must be reset manually at the amp (very annoying).  This all happens in a few mlliseconds.

I'm sure your set up is different, but my point is that while the tuner is tuning even from memory, the radio (or amp) may see high reflected power.  Besides protecting the tuner, tuning at low power also keeps whatever protective devices your equipment has from tripping.

Good luck, Jim Charlton   AD0AB  
    
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Keith Mitchell

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Thanks, James the correct use of the "auto" and tune buttons are still a bit ambiguous to me.  The manual states that if the auto is depressed  in the unit assumes a accessary cable specific to a transceiver is connected to force the transmitter into a lower power signal.  

If the Auto button is "out" the unit waits for the user to press the tune button on the tuner before attempting to find a good match and leaves it up to the operator to send a  "low" wattage signal.  What I haven't found is whether if I leave the Auto button "out"  and have some  saved memories of good matches throughout a band.  Will the tuner select one of those memories automatically or does it only do that If I press the tune button on the tuner?


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Dwayne - NA6US

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Once your tuner has a set of stored frequencies, when you change frequency on the radio, first click the radio tune button before you transmit so your antenna tuner senses the change and adjusts its internal configuration in anticipation of full power from the radio.

This is a good habit to get into since radios and amps don't like any bad high power miss matches even if is only for a few seconds. 

My antenna tuner can sense and adjust on 5-25w so I have a transmit profile (No-Amp) set to tune at 5w without amp and a second transmit profile (With-Amp) set tune 1w with the amp. 

Better to adjust amp power up an profile change and lessen the risk of high power on a bad match as the antenna tuner is working to match.

Im working on a small project that sets TX Inhibit on the radio when I make large band/frequency changes to "force" me to remember to Tune.
(Edited)
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James Charlton

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I second that!
Basically, never tune at high power.
I am trying to devise a workaround to the pressing the "tune" button on the transceiver or Maestro (I don't know how the computer version works).  As careful as I try to be, I sometimes forget to tune after changing bands and the amp sees a surge of reflected power and goes into bypass.

I then get to run from my shack on the second floor to the basement to reset the amp and run back up again.
  Annoying, but probably good exercise.
Jim   AD0AB
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Dwayne - NA6US

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Let me know how you go with your program/hardware. I will post when I have something working. My approach is to monitor for large changes to TX frequency and enable hw lockout.
(Edited)
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John KB4DU

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Keith;

I use an MFJ 929 tuner wit the 6400, no amp. This tuner uses the same logic and interface as the 993, except it doesn't have the meter, No interface cable is used, but then the tuner needs power from a source besides the radio.

The MFJ manual isn't the best, it takes some reading and some experimentation to get the results desired.

Page 6 of the manual describes the sticky-tune feature, which I have turned on. All I do is click the Tune button in SmartSDR, with a tune power of 10 watts. This triggers the tuner to determine a match. If the frequency is close enough to a memorized frequency, the tuning is very quick. If the tuner has to hunt for a match, the process is a little longer ( and noisier). The only time I use the tune button on the tuner is when I want it to find a better match, below 1.7, which really isn't necessary since the Flex is quite happy at 1.7 or below.

Also, I changed the function of the tune button ( a menu setting) so that a short press forces a retune, rather than the default long press.

Hope this helps.
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Keith Mitchell

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Thanks, I'll give this a try in the morning. I have smartSDR on a laptop now so I can sit next to the tuner and 6400 to see how it operates. What you described should work fine if I take the time to spread a few memorized matches through out each band I operate.
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Norman Clanton

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My problem is similar, although somewhat different. I have an older LDG tuner (AT-1000), which works well, but retuning must be initiated by the press of a button on the tuner. I would like to figure out how to get a control signal from my Flex 6400 that I could used to trigger a relay to simulate the button push whenever I put the radio into the "Tune" mode from the Maestro. I am not presently using an amplifier, but the ability to do that would enable me to operate remotely. Any thoughts?


73, Norm KA1SG
(Edited)
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AB4RW

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I use the LDG1000PROII tuner on my 6400, I just have it set to auto tune and when I switch bands or different ends of band it auto tunes fine, works great whether I'm at desk or running remote. I just hit tune button on radio, works great! Not sure how old your tuner is. LDG has come out with a program that allows you to initiate a tune via computer, check out there website.
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Steve Potter

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I use my 6300 with a 993B, auto button OUT, and pressing Tune in SmartSDR prompts the 993B to commence a tune. If the Tune button is IN, then it expects the 993B tune button to be pressed (along with 10watts RF) to instigate a tune (except immediately after a power cycle when just presenting RF will cause a tune. This is when an radio interface is NOT present.
Steve