Love/Hate my Flex 6400M

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  • Praise
  • Updated 3 months ago
I have had my 6400M for about month and enjoyed using on most occasions.

Lets start with some why I love the radio.
Excellent user interface for most modes of operation.
Great noise reduction once I learned the right combination of controls.
Easy remote set-up - Gave a demo at the Cascades Amateur Radio Society  meeting this week  
Works very easily with SSB and DIGITAL modes

Lets go why I hate this radio.
Has excellent QSK if do not use the internal ATU
The ATU prevents QSK from working properly
Pulled a ticket and received a fast response from Flex
They were aware of this and suggested that I attach a separate receive  antenna to radio
There is an inherent design flaw which should not be there
If I turn off the internal ATU and use an external ATU, QSK works,  but this dose not correct the design issue.  I do not think Flex has given careful thought to CW operator.
I am not speed demon on CW (around 15WPM) but I would like to be able to use the tools in radio without them being in conflict with one another.  
I guess I will use my Elecraft for my CW  operations with a ATU that doesn't interfere with the QSK and a cw decoder that helps catch a missed letter in a call sign.

If I didn't work CW, I would really love this radio.

Leo NK8L
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Leo Nessing

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Posted 3 months ago

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Photo of Al / NN4ZZ

Al / NN4ZZ

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Hi Leo & Bill,
There is another post with a pretty good list of “opportunities” to improve CW operation. Many of them have been on the idea list for 4 or 5 years, so it doesn’t look like CW has been a priority. Here is the link:

https://community.flexradio.com/flexr...

I’m a CW only OP and hoping CW will get some attention eventually. Depending on how you operate ( casual CW, QSK, contesting, etc) you might give SSDR a grade of B or C currently. But with some work it could be an A+

Regards, Al / NN4ZZ
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Dan Trainor

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I am curious, what is the symptom when using CW QSK with ATU?  Thanks, dan
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Leo Nessing

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The problem is the ATU does not allow the QSK to take effect.  At 15WPM there is a minimum delay of 93ms with the relay clicking and at 100WPM a delay of13.  As you move the CW speed the time delay follows but will not go to 0 for noise free QSK.  As stated Flex corresponded with me and admitted the situation.  If I don't use the ATU I get 0 delay for true QSK.  
If you look at NN4ZZ reply you will see this has been an on going problem.
Leo NK8L
(Edited)
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Dan Trainor

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Thanks for the information.  I use the Internal ATU.  And I must have fast (near 10-20 ms) QSK break-in.  Is this failure under warrantee?  This is totally unacceptable, this radio is going back for repair.  Thanks, dan
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Paul Burton

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I'm not sure what problems you all are having on CW.  I'm mainly a cw op (up to 30 wpm) using a 6300 at v.2.xx and TenTec Centurion tube-type amp,,keyed from the Flex front panel jack.  It works perfectly with fairly full break-in but needing a bit of delay for the amp switching.  Since I'm using a SteppIR antenna I don't generally need the ATU, but I've had no problem using it.  Is this just the 6400 or V 3.xx - or what?  I give Flex an A+ for CW.  CWX works fine but I don't often use it.

73, Paul 
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Leo Nessing

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Try operating true QSK with your radio with the internal ATU on.  It will not happen.  Again Flex is aware of the "problem" .  I run bare foot when I operate CW and I am spoiled using QSK with my Elecraft and my previous Ten-Tec radios.  QSK is a silent 0 delay system, even in the Flex, if you do not use the internal ATU.
Leo NK8L
(Edited)
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Dan Trainor

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But I use the internal tuner.  How can an internal tuner adversely affect QSK?  This is ridiculous.  dan
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Mark - WS7M

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I have to disagree.

I am 95% a CW operator.  I don't use full break in nor do I use the internal ATU and in those conditions this radio does the best CW I've ever had.

I do agree that the ATU should work.  I think Flex will come up with a fix.   The cool thing about these radios is virtually everything is controlled by the FPGA so it may just be a matter of flipping a few registers in that beast and everything will be good to go.  (hopefully)

As far as the Elecraft radios, I have heard they are very good CW radios.  I don't own one as I am addicted to my pan adapters and even if the CW was much better as you say I feel I can get by with the CW in the Flex.

Also in my case my Flex is mounted some 30 feet away in a utility closet.  I can't hear anything so at my op position using my paddle it is 100% quiet.  In fact it is so quiet that the full QSK does bother me so I run with a little delay.
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Leo Nessing

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Another Flex flag waver.  You take what I said and turned it to satisfy your personal way of operating.  If you read the comments by NN4ZZ you will see that this was a known problem by Flex for a number of years.
Read my entire statement no just a portion.  For CW operators who enjoy true QSK with zero delay, and no clicking relays, this is like buying a new car with a manual transmission  and every time the clutch is stepped on the car stops.
The reply I received from Flex shows that they have known about this for some time and to tell me that I should have to use a separate receive antenna so the ATU would not affect the QSK is condescending.  This is an obvious design flaw.   

LEO NK8L 
(Edited)