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ATU should not require retuning if only the mode is changed

Duane_AC5AA Member ✭✭✭
edited June 2020 in New Ideas
Since the last issue I had with the ATU was classified as "working as designed" and changed to an "Idea," I'll open this one as an idea because I suspect it will be a similar story.  Over the weekend I was on 6m playing in the VHF contest.  For fun, I'm tuning my G5RV, and the tuner found a match.  All is good until I move a few KHz and switch from SSB to CW.  Viola - the tuner is disengaged and I have to go through the tuning cycle again.  Just to make sure it wasn't my change in frequency that caused the retune, I left it on the same freq and just switched modes - yep, ATU turns off.  Here's another example of a change needed in the ATU algorithm.  I'm enjoying the 6500, otherwise, and finding other improvements that I will post in the future.  Nice radio!    73, Duane
8 votes

Open for Comments · Last Updated


  • K1UO Larry
    K1UO Larry Member ✭✭✭
    edited December 2017

    Hi Duane,  Actually the tuner is working as designed at the moment.    Persistence of the various LC settings for the ATU per Band/Mode is what we are waiting on to really make it complete.  


  • Duane_AC5AA
    Duane_AC5AA Member ✭✭✭
    edited May 2018
    By "persistence of the LC settings per Band/Mode" do you also mean to include the algorithm for determining when tuning is required?  That is what seems to be in error in both this instance and on the last ATU post I made.  So, for example, ATU action should be based on transmit frequency and antenna selection, not on which slice is in use, which mode, etc.  There are a number of fairly common instances in DXing and Contesting where there is no need to disengage/re-engage the ATU.   Just thinking out loud . . .
  • Robert -- N5IKD
    Robert -- N5IKD Member ✭✭
    edited May 2018
    The same with opening a new slice on a nearby frequency. This should not require a re-tune.
  • Duane_AC5AA
    Duane_AC5AA Member ✭✭✭
    edited December 2016
    Yes, that was the subject of my first post a few days back that I was alluding to at the start of this "idea."  Thanks, Robert.
  • Jay -- N0FB
    Jay -- N0FB Member ✭✭
    edited December 2019
    I should think that ANY change in frequency would evoke the ATU to perform, at least, a check of the current complex SWR (LC). This check occurs in the blink of an eye. Depending on what the engineers want to do after that, checking for a tuner memory setting, running a full tuning sequence, I leave to the smart folks at FRS.
  • Duane_AC5AA
    Duane_AC5AA Member ✭✭✭
    edited May 2018
    Hi Jay - the idea in this thread, or "idea", is that changing MODE should not automatically cause the ATU to disengage, requiring a re-engagement and retuning.   I think we're saying the same thing.  The important thing is that the ATU's operational algorithm should make efficient decisions.  Moving 1 KHz on almost any band will have very little difference in SWR, depending on the antenna, of course.  My purpose in listing these ideas is to help drive the development of the ATU algorithm so that it is efficient and effective.  Currently, disengaging the ATU because one changes modes on a slice is a very poor algorithm.  I understand this is the early first-pass at an implementation, and I'm hoping the development of the software addresses all of these issues.  There's no reason to recode a second or third time because of avoidable errors in the first design!
  • Jay -- N0FB
    Jay -- N0FB Member ✭✭
    edited December 2019
    I understand Duane.  I agree completely that a "Mode" change should not necessitate a change on the ATU.  I'm sure the current simplistic code running the tuner was put in place just to get the product out the door.  It will, just like SmartSDR software, mature and just get better and better.

    The purpose of my statement was concerning something earlier mentioned in the thread that "moving 'a little bit' in frequency should not cause a tuning cycle." That's where I think it is better to let the ATU make a quick L&C measurement and then decide for itself (when ATU Memory algorithms have been coded) whether to snap in a different combinations of capacitors/coils to give the optimum possible SWR.

    Its possible (although not probable) that a 1KHz change in frequency could be enough to require a different tuner setting...especially on lower frequencies (80/160 Meters).  Some antennas are very narrow banded, thus more frequent adjustments are necessary than on a wide banded antenna system. Flex can't make value judgements based on what is "likely" to be OK for everybody.  I'm sure they'll rely on empirical measurements made by their own tuner and then decide (via some sort of branching decision tree algorithm) the right course of action to take.

    This is not their first rodeo concerning antenna tuners with memory settings.  They'll do it right! 

  • Duane_AC5AA
    Duane_AC5AA Member ✭✭✭
    edited May 2018
    I guess I was taken by surprise when I found that a rig that had been on the market for two years had a poorly functioning ATU.  It has terrific range, and, knowing Gerald, I know his crew will get things in order.  I wanted to point out some items that need attention.  Thanks for your responses, Jay.
  • Gerald-K5SDR
    Gerald-K5SDR FlexRadio Employee ✭✭
    edited April 2019
    Duane, I agree that we need to make the ATU smarter.  Steve has entered a User Story so that we can take this into account in development.  Our FLEX-3000 works similarly to what you describe.  
  • Andrew O'Brien
    Andrew O'Brien Member ✭✭
    edited August 2014
    Please excuse the newbie ignorance , is the ATU in the 6500 (or 6300) supposed to have ability to "memorize" a match so that when one returns to a recently used frequency, the settings are recalled and use of the ATU button is NOT needed?   It seems that on my antenna, I have to use the ATU each time I move anywhere. Andy K3UK. 

  • Jon_KF2E
    Jon_KF2E Member ✭✭
    edited July 2018
    That's the way it is for now. As Gerald said, they know they need to do more work on the tuner.

  • Jim    W3IPO
    Jim W3IPO Member
    edited October 2014
    I am enjoying my new 6500, up from a 1500 several years ago.

    This is a newbie question(hope it was not answered in the forums somewhere).
    Here are my ATU questions:
    1. What are the criteria for the ATU to give a "fail"  flag and an "abort" flag.  Is it some value of SWR?

    2. Does transmitting after an ATU "failure" risk damage to the 6500.

    3. Does the ATU "abort" mean never transmit?  or does it mean the ATU did not work?

    4. When should it revert to an external manual antenna tuner?


  • Ken - NM9P
    Ken - NM9P Member ✭✭
    edited June 2020
    I previous threads, I have gotten the impression that eventually the ATU will be very "smart." i.e. remembering its settings not only for band and frequency, but also separately remembering settings for antennas on each antenna port, so that going to my 2nd transmitting antenna will not require a retune in the middle of a competitive contest run.  It will certainly be nice when that happens.  I know the capability is there in the hardware, but it is a matter of time and priorities in the engineering department.  . . . another Christmas "gift" we will get to unwrap someday!
  • DrTeeth
    DrTeeth Member ✭✭
    edited December 2018
    I have reserved my 6300 and will not be getting the ATU for a few reasons. The main one being that it is very expensive in the UK, more so considering the technical specs compared with an outboard one. It costs $496 in the UK. That includes our sales tax but the price is the price.

    But this thread bothers me.

    The reason for this is the decisions taken, and the reasoning behind them, that would let the ATU be released in such a basic state that it disengages with a mode change! I understand that improvements will come with further updates, but the initial bar for release should have been raised considerably. I hope this thinking does not affect other areas of software improvement. TBH, this 'feature' would be enough to return the ATU under our consumer laws as faulty and get a refund. Having read the above, I'd be tempted to get the ATU for about $100.

    What if the improvements come in v2 which will cost $199?

    73s de Guy G4DWV/4X1LT
  • Ken - NM9P
    Ken - NM9P Member ✭✭
    edited June 2020
    In V 1.3, in addition to the ATU needing to retune when the mode is changed, it needs to retune when the TX profile is changed.  So If I decide to change from my Rag-Chew profile to the DX profile because of band conditions, I need to retune all over again.  This is inconvenient and unnecessary.  The programming could change the decision point about antenna tuner off/on to a different place in the logic chain, requiring a frequency change rather than changes in other parameters.  

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