Adaptive pre distortion on a 6500

Bill -VA3WTB

This improvement is great, and I am happy many are working on it. They have implemented pure signal on the 6500 which we all know could be done anyways with the flex. No one is standing in the way of progress, and Flex sure isn't.

Lets keep having fun with this stuff. Because SSDR is by far the best SDR software out there, I would like it all done in the Flex domain. And I am willing to wait for it. I would not want to add another out board box to clutter the shack up more. And Steve says it won't be needed, that's good.

But lets keep pushing on and see what other things can be done. I still think it would be great to see pure signal on the Icom or maybe the KX3

Bill -VA3WTB

I was listening on 40M this morning to a couple guys talking about the pure signal on the flex. They said that getting it to work on the flex has been very hard work and nothing simple about it. It is working but not even close to being ready for prime time. They said that if it were simple to implement flex would have done it a long time ago. No truth to that as we all know.

Ed baker

NAH!!!!! The KX3 wants to go remote . but they are building theirs so it will fit on a wristwatch FYI :::::: The flex solution that Steve expounds is a in the box solution . Let me be clear that means there is no provisions for closing the loop to include the amplifier. Here is the difference. In the cell phone world (Where Pre or pure signal came from) there were no AMPLIFIERS to even consider .JUST many many users It's not -60 plus DB down in the box its into the noise level even with a external amplifier. OR Solid state amps that you can live with , less than clean amps that you can live with . That we all YES We all can live with .

Peter K1PGV

Anybody know K2WS who could contact him and actual get a clear, factual, account of what's up... in proper sentences that make sense?

Like I said before, I know he's a very clever guy, but that's all.  If nobody here is acquainted with him, I'll be happy to blindly send him an email and ask him "wazzup."

ETA: Not that I care that much about APD, as a feature it ranks just below the user-customizable clock, but I'm always curious to know what's going on.

Bill -VA3WTB

I am not an expert in this, I'm sure Steve has it all worked out, it was in the plans when they designed it. It will be interesting to see how it all unfolds don't you think?

KY6LA_Howard

I have had several discussions with Greg and Steve at Flex about Adaptive Predistortion [ADP] and how it might be implemented.   FYI ("Pure Signal" is a ANAN Product Name)

Flex obviously plans to get around to doing it but clearly ADP is still a low priority item as there has been little visible demand for it except from a few ADP Fanatics.

ADP helps with SSB.. it does not do that much, if anything for CW and likely can make things worse for some digital modes. So, not withstanding the experience of the digital cell phone industry, there is a lot of experimentation still to be done for the ham radio environment.

With the hardware taps inside the box, it is already possible to write software to do ADP in a 6000.. As much as Ed dismissed the possibility to have a third party write ADP for the 6000, the API is open and waiting for someone to do it... 

Using an external amplifier is a totally different issue as one would need a hardware box to sample the external amplifier's output and feed that back to the internal tap...  That is definitely going to require some hardware engineering to get it right without cause unforeseen consequences. In addition, different brands of amplifiers have very different non linear response characteristics, so I suspect that there will need to be much tweaking of the software parameters to customize any ADP hardware/software solution to work with a specific amp.

All in all ADP is a major and potentially very expensive Science Project

Ed baker

Yes Write ALAN A very positive move. and a great guy . OR AC2IQ OR Warren . Or John K2YN He has a auto version under covers. (ALL Fantastic individuals) And There are more out there PLAYING with their toys . Bill !!!!The plans did not include any external use . This really changed the dynamics of the application . AMPS were just not in the equation. I would really hope a Available hardware solution would be offered for a 6500 . It would be definitely 2 or 3 light years ahead of the curve. .AND I really think it could be built inside .

Ed baker

Howard It is truly beyond the scope of API . There is a necessity to have access to a processor and that is just the start. That is Also correct Some very intelligent guys worked on this for the past 10 years . The result I use every day on every band at every power level with exactly the same quality expected . Oh yes on a litany of amplifiers. Saying that only came true when Warren gave API auto function . Can an outside source make it for FLEX Absolutely . Right now I would say Flex has a garage full of headaches . Or 2.0 would have been there years ago. So to be fair the hardware approach a nice interim great accomplishment .

Bill -VA3WTB

Here is were I stand on this Howard. If ADP does not happen for the flex, I will be a little disappointed. But the Flex will always be a radio of choice with or without ADP simply because it is a wonderful radio. And I love many of the plans for it, sets it apart. And anything else not using SSDR, I'm not interested. SSDR rocks.

The nice thing is, the Flex just as it is right now has a small foot print and very clean, would ADP make it better? sure, but never a deal breaker for me, I'm happy with the performance.  On the other hand I have seen an Anan without ADP and they don't fair so well, so they really do need it.

That's how I stand on this. And we all know flex will not drop what they are doing to implement ADP. They will stick to the plan as they have set out. There just has not been a very large group asking for ADP. It seems strange to me some who do want it are not even Flex owners,,,funny.

I think ADP will be part of a package after V2 for purchase if anyone wants it. Till then I will gladly wait, no big deal.

Peter K1PGV

APD is primarily being used by Apache Labs (the makers of the Anan radios) as a marketing tool. How can they make their open source Hermes-based radio that runs open source PSDR stand out (and get Americans to pay them a lot of money for it)?  Answer: They point to, and actively promote, their only differentiating factor: What they call Pure Signal.

There are tons of nice features in all sorts of radios. Users will evaluate which features they care about, and vote with their wallets. I voted when I bought my Flex.

That doesn't mean I'm not curious about what K2WS has done. Which is how I got stuck in this thread in the first place. Since nobody's yet volunteered, I'm going to drop K2WS a line and ask him what's going on.

Peter
K1PGV

Ed baker

Don't procrastinate drop ALAN a e mail And Actually There are more differences than just pure signal. Both have there good points . SDR radios are fantastic . I did not start the thread to sell ANAN or Pre distortion or Bash Flex It was , and still is to praise ALAN for the 6500 Flex Pure signal or whatever you wish to call it operational. And if you, Anyone, really understood how difficult this task was or is you too would be praising his attempts. There would be no GEE WiZZ flex has it planned or ANAN does it better or the best reason Mine is already great . Yea sure. Possibly you would understand it is only as good as delivered . And only better as in HAVE . Hams actively pursuing innovation and demanding the best bounce for the buck drive the future

Bill -VA3WTB

Yes Congrats to Allan and all who worked on that project, while it is interesting I fail to see how flex owners can benefit from it, unless it is soon to be ready for all to use.
Peter I am with you, since this is with a flex 6500 maybe Allen will post an description of the work done and how everything connect, and how SSDR works with it. As this is about the ham community he should not have any problem sharing.

Stan VA7NF

Some notes:

Congratulations Ed:  ADP had disappeared from this forum for a while, you brought it back for a brief peak;

Be careful what you wish for:  Remember that a wide signal is a benefit to contesting.  The same feedback circuits that reduce splatter can be used to increase it to objectionable levels.  Just imagine how far I can keep other stations away from my running frequency with custom tailored key clicks and IMD. 

Oh yes:  FRS can you introduce a series of enhancements so I can add a tailored chirp or buzz to my CW so it is much more recognizable in a pile-up or to keep a run frequency.  (tongue only slightly in cheek)

Rick Hadley - W0FG

Yeah, that's the ticket...a tailored chirp so we can sound just like a Polish station from the 1960s!! ;-)

Ed baker

Actually ALAN reminded me with his 6500 and pre distortion. Yes I try to stay away from this forum . This occasion was a KUDO to ALAN . It brought out the usual snide comments and ignorance of some . Hopefully it did not diminish the True success of ALAN and his 6500 . I do care if Flex planned Pure signal. Promised , Lie or will offer it tomorrow. It is a fantastic system . And very few radios out there can duplicate this feat . I do know of one however that produces -60DB plus all day long without pure signal A story for another day. And to coin off one of the comments Designed with this in mind . As we go into the down cycle of dxing more and more hams will gravitate to local bands for entertainment. Good operating practices , Pure signal makes a good neighborhood

Peter K1PGV

OK, folks...  from the man himself.  Thus spake Alan K2WS:

I have built a hardware APD for use with the 6500.  It is strictly a personal project to learn how APD operates.  I was very impressed with AC2IQ’s demo of his hardware APD in the winter of 2013.  Dave was not willing to share his design schematics, so I did a lot of research and cooked up my own!   I have discussed the project with others on 75, but have not demonstrated it on the air… yet!  

My system does work, but there are a few loose ends I’m cleaning up.  Perhaps in a week or so my APD will be on the air.

It works by comparing the signal envelopes via separate log detectors, with a difference amp ;  the internal  0dBm Exciter signal in the 6500 with the external directional coupler’s signal ( barefoot or Linear Amplifier).  That  difference amp generates the error signal.  It drives the gain control port of a VCA which pre distorts the input signal and then drives the 6500’s 100w PA. 

It's always best to go directly to the source and no believe the noise in the system.

Many thanks to K2WS for taking the time to clarify what he's working on.  I admit that it does sound *very* interesting.

Peter
K1PGV

Bill -VA3WTB

Thanks  Peter, again great job Allen.
Ed reported it being on the air on 75M

Ed baker

Glad Alan let you know what is happening. The absolute important thing is ALAN discribed what he is doing with the 6500 not me .

The really neat part is that it is a variation of what is out there . Not AC2IQ not Warrens but ALAN's
How cool is that . Still Pure Signal or whatever
.

It's semantics my friend Lets see Demo , Testing

a difference???

I see it as a polite I'll show you later.

Lets see it was -58 down and yes on 75 TESTING Or was it a Demo Gee I dont know.

Look guys whatever you want to call it it's pretty good.

The results will be getting Better Long before that 2.0 BS WOW. OH did I mention a recording GEE WiZ I forgot that .Sorry BILL And any one else stop defending FLEX and wake up and smell the roses .

Ed baker

On another note : There is a transceiver out there Yes on the AIR Gee I have a good idea on that one too ,which not running Pure signal Blows the FLEX or anything else away on 3rd order IMD . With all implemented how does -80DBM sound boys . It's creative engineering my friends by HAMS . And Yes I Have been in QSO with him. ON 40 Demo or testing WHATEVER

Jim K4JAF

I think it may be a good time to put this thread to rest.. 

KY6LA_Howard

"I have discussed the project with others on 75, but have not demonstrated it on the air... yet! "

It will be interesting to hear how it does when Alan actually puts it on the AIr

Plus I would really like to understand how Ed Measured:

"IMD 3rd order -50 , -60 , -70DB , down." for a signal  "not demonstrated it on the air... yet! "

Ed baker

I actually like your comment also but for a far different reason . Trying to lessen the impact of using Pure signal WELL WELL And on the 6500 platform . Dont worry WAN And I,ve suggested that if you think that is sweet look at the CUDA project Another something to use as a comparison of GOOD BETTER . I guess Its the rest of the world that wants better ,cleaner, State of the art systems ALAN is 65 Air miles from one of my locations . And a regular QSO SORRY to disappoint you. He has shared this accomplishment with more than me. Measurement is easy ; Even the flex great gui gives you that opportunity. Just calibrate your display to give you the correct S9 and go from there Lets see I think Flex trusts you to do that . AND AND if the presented real world signal is strong enough to reveal the -50 -60 or lower and so on the 3 order IMD you too can measure. Some signals out there aren't even -20 DB The SSB ones that look like AM Is it the radio or the failure of the operator to adjust it correctly??? FYI Most of the manufacturers only use a single tone for that IMD number Yes it isn't that in the real word You weren't fooled were you Be careful when you say "it's good ." MY 6500 on it's best day wasn't the advertised number in the real world . and still isn't And I campaigned to have it provide that advertized proviso. And as a comparison my KX-3 is actually lower (Non Pure signal) I also agree with the previous post it is time to stop .

Peter K1PGV

Just another one of those days when I wish I was a mod on this forum.

/Thread

Peter
K1PGV

Bill -VA3WTB

Peter, you notice this **** only happens on the weekends?

Peter K1PGV

(actually LOL)  Now that you mention it...

Do you think that's because (a) the Flex staff isn't constantly monitoring the forum, (b) the weekends bring out more of the "special contributors", or (c) the weekends provide the opportunity for the "regular contributors" to drink more and then post more, followed by more drinking and more posting?

Peter
K1PGV

Bill -VA3WTB

I think when Tim is around he makes sure the threads keep on topic and the BS is controled before closing a thread.

Walt - KZ1F

Not for the radio they aren't. My guess is adp needs to be implemented in the radio, not control surface.

KY6LA_Howard

FreeDV is a Third Party Product inside the Radio

Bill -VA3WTB

I would not be surprised Steve has already been testing ADP in the lab to be sure things are set to go before they release it later.

KY6LA_Howard

ADP provides some benefits when transmitting barefoot.  But if you do not have some external box to sample an external AMP then the AMP will just reintroduce IMD.

I wonder if Flex will include an ADP sample tap in the new 4O3A amp?