Official Position on Adaptive Predistortion

Wayne

We stand behind you, that way when we turn around to run we will be in Front!

Wayne

Because it costs more, is not mandated by the FCC and is not recognizable by the human ears, all this equates to waste of time, money and resources, with no RETURN ON INVESTMENT!

Wayne

Give me a break they wouldnt even spend extra to put a standard compatible mic jack on the M models, and used cheap power poles so they wouldnt have to provide fuses, what makes you think their going to do something that costs them money when most of the competition are not doing it either.

W2PP

Gerald:
    I agree with your approach to prioritization.  Fine.  But, you've over looked one very very important element, that is, OLD issues that seem to never be addressed.  Given your scheme for prioritization then things like ANF, NB and D STAR will NEVER be addressed.  These issues will be orphaned, and already have been.  

     It is not reasonable in the 21st century to sell a radio with ANF NB and D Star features that do not work at all or work very poorly.  These are foundational, and should be addressed forth with.  Leaving these issues for YEARS unaddressed is completely unacceptable.  

     I hope you will reconsider these issues.  I hope you will comment as has been requested repeatedly.

Thank you
Peter

Gene - K3GC

AC2IQ has a most interesting QRZ web site.  About mid way down is instructions for a ADP mod for the 6500.
I don't have the knowledge to know whether or not it is workable but it does look fairly simple to apply at low cost.
I have not seen any mention of it anywhere on this community but it is intriguing. 
Anybody have any experience with this mod?

Bill -VA3WTB

Gene, I think it is a spoof.
The Flex needs no mods. It needs to be added to SSDR software.

Gene - K3GC

Thanks Paul
Rob W1AEX referred me to AC2IQ.  It looks entirely credible to me - most certainly not a spoof.

I am very leery when it comes to making a hardware mod to the 6500.  Not because I distrust the author but because of the effect on possible resale down the line.
Also, being "chicken" I would to see some other brave soul do it first.:).

Bill -VA3WTB

The Flex already has the taps inside. Flex has stated that everything will be be done inside the radio and the software will be implemented. So no black box need. This was planned for when the 6xxx radios were designed.

Bill -VA3WTB

I don't believe they used power poles to avoid inline fuses. With the fuse inside, the power to the radio was done correctly.

Gene - K3GC

I wonder how many sales have been lost to Anan for this issue alone.  I know they make a lot of mileage over this one issue.  It sounds a lot sexier than it  truly is in the real world.
The flex transmitter puts out a very clean signal indeed but. . . . 

K2CB Eric Dobrowansky

It is not a spoof. He is a very knowledgeable design engineer who has designed and built things others can only dream about. Dave had a complete home brew pre-distortion rig on the air long before ANAN software had APD. There was a picture of it on his page at one time.

Seeing it on the air (on our SDR receivers) for the first time years ago, was quite a memorable event. 50db over S9 on 75m ssb, and not hearing a thing on the opposite sideband.

I know of one Flex 5000, and one 6500 on the air with his design. As good as ADP on the ANAN. And via hardware, so no ADP software needed.

K2CB Eric Dobrowansky

Please tell us, where inside is said tap? If not outside already, it will require some sort of mod. So another words, it will never happen. ****, for that matter, all the things we’ve been waiting for the past 4-5 years, will probably never happen!

Bill -VA3WTB

Incorrect, Gerald said everything is all in the radio as is. Keep in mind Flex may not use the exact way Anan does it,,but the same result.

One reason Flex has not been in such a hurry to implement this is the demand has not been there, and Flex already transmits the cleanest in the market apart from the Anan with APD turned on.

The early Anans really needed it because they were really dirty. But now with the Anan 7000 it could do just fine without it as they have cleaned things up a lot.

Lee - N2LEE

Gene, I spent 20 years in product marketing and development and here is a little lesson in product marketing.

- Change the Discussion in your favor
- Build up your strength, play down your competition

ADP is a the biggest card Anan has to play. So they make it a big deal because it's their only strength. 

Chasing the feature check box game is a no win situation. Flex has a strategy and right, wrong or indifferent they need to stick to it. 

K2CB Eric Dobrowansky

Bill, there are other non-APD transceivers that are just as clean; if not cleaner. Especially the Icom 50v PA radios, such as the 7700 and 7800. They are far ahead of the Flex in tx signal cleanliness. Obviously, comparing a 50v PA to a 14v PA is like comparing apples to oranges. But even the 7600 with its 14v PA is on par wirh the 6500. I'd be more than happy to do an a/b/c comparison on the air. I truly question the statement that the 6000 series was designed for APD from the start. Show me a schematic diagram and prove me wrong....... I don't recall Gerald making that statement directly. I seem to recall someone quoting Steve in one fashion or another, but even that was a vague statement. Something to the effect that it might be possible using the RXA input with software steering, similar to how it is done on the ANAN radios. Stating that it was designed from the start sounds like a huge stretch of the imagination. In not here to bash Flex in any way. I still own two 6000 series transceivers. And as Mike W can attest, even with my dissatisfaction in regards to Flex's speed of development, or lack thereof, I still recently recomnended my good ftiend to purchsse a 6400 and Maestro combo..... but the Flex Kool-Aid is getting a little strong lately, and a reality check is once again in order.

Bill -VA3WTB

K2CB, you should know by now I always do home work before posting.
And bye the way.. the schematic diagram is not for our eyes,,did you know that?

This is a posting From Flex on the subject.

Is the current Flex Radio 6700 capable of running a pure signal type mode with only a change to the current version of the SmartSDR software.
The answer is yes, it is only software for the FLEX-6700 and FLEX-6500 since both have an internal feedback tap from the power bridge.  

When we designed the FLEX-6000 we had adaptive predistortion in mind so we included a tap from the transmitter that feeds back into the receiver. This gives us simultaneous access to the desired and actual transmit spectrum in the FPGA so that we can implement linearizarion. We also have sensors for temperature, voltage and load match of the PA as these can be used to improve linearizarion. The work that needs to be done for the FLEX-6000 is to experiment with algorithms and input sources to determine what gets us the most **** for the buck and then finalize the implementation. 

Bill -VA3WTB

I don't believe the Icoms are access of 40db down,,our Flexes are.

Richard McClelland, AA5S

Obviously some marketing points to be gained, if nothing else.  I want to know when APD will be available for the Flex 1500 :-)  Not.

Bill -VA3WTB

I have not read were anyone has put APD down on the community. The reason for APD is so people stop spattering on top of other stations from other Freq. A clean signal to allow more stations to enjoy the band. This is all very good indeed.The Flex 6xxx radios causing problems to other stations is not the norm and most Flexes I see are clean, so the need for APD has not come to the top. And with the harmonic trap in the Flex amp witch makes it among the cleanest transmitters in our hobby is a big step ahead.

We all would like to see APD, but to me it is not a deal breaker.

I notice that no other companies are even considering it. At least Flex has it planned.

K2CB Eric Dobrowansky

Bill, I know the schematic is "not for our eyes".  On the same token, how can one so sure it was "designed from the start" without actually seeing said schematic? 

As the old saying goes - trust, but verify.  I'd like to believe the statements you quoted, but based on past experience, I would prefer to verify.

Bill -VA3WTB

Because Flex says it is,,simple...

Wayne

You want to buy some stuff Bill its all in pristine shape cause I say so no verification needed oh those broken knobs they are not broken thats the new style cause i said so.

Bill -VA3WTB

Because both of you are saying Gerald is not truthful and misleading you is were I pull the plug,,that's over the line.
I have never known Gerald or Steve lie to people the way both of you say they have.

Gene - K3GC

I find the APD discussion to be interpreting and informative but I think it needs to toned down a bit.  lively discussion is great, anger and name calling not so much.
Please let's remember this is just a hobby from which we can all learn.

KY6LA_Howard

APD would be fabulous if it could be applied to digital modes. 

Unfortunately the current implementation works best for analog modes such as SSB where the benefit is mainly to other local stations not hearing your splatter... while its a good practice most people will not be aware of it.


I heard Warren Pratt's NR0V original presentation (I posted it above) at Friedrichshafen in 2014 and his most recent update for version 2.0 of APD at the Friedrichshafen SDR Academy in 2018.  It was quite exciting to listen to his progress but the big elephant in the room for me is Digital


Most Digital modes are by definition non linear. 

So adding additional non-linearity to fix the spurious response is very difficult.  If one were able to develop an algorithm to do so for say FT8 then the elimination of spurious signals would likely have significant improvements for the people trying to copy your signal  - Hence very exciting if it were possible....which it likely is..

Ultimately this, like most of Warren's work, is a science project.

Wayne

I never said not truthful i said trust but verify which is how i do everything and is required and proven each day in todays world when i was growing up it did not apply but now it does the world has changed.

Bill -VA3WTB

Wayne,,it is verified, Steve answered the question asked,,,nothing more needed.

KC2QMA_John

As it is Flex radios are already some of the cleanest radios on the market. So lets see… If the 6000 series radio has extremely low IMD at the rated 100W output and you connect a legal limit amp to it then run the radios power at let say 10w to 50w to get lets say 1000w output from the liner then it should be even cleaner with a ton of power.

Or just run the radio standalone with less than 100W and you will have a cleaner signal.

Now in the future the 6000 series will have the APD feature enabled and it will only get better.

As for me I keep my power as low as necessary and make sure my SWR is almost flat to make contacts so I don't every worry about having a dirty signal.

I’m just glad to have one of the finest and "Cleanest" radios on the market today!

Varistor

As actual test data shows, Flex radios are not any different than similar DUCs: http://www.ab4oj.com/sdr/flex/6700notes.pdf http://www.ab4oj.com/icom/ic7610/7610notes.pdf Cleaner transmitters are good for everyone, particularly during major contests when the bands are wall to wall full of stations.

Mark K1LSB

The 6700 test in that link was conducted 4 years ago using SSDR V1.3.8.  You're comparing those results to the ICOM 7600 tested only a month ago.  And generally speaking, the 6700 2-tone TX IMD numbers are still several dB better than the IC-7610.  I'd be interested in seeing the same tests run again on the 6700 running a current version of SSDR.