A must read

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  • Updated 5 years ago
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  • A post from Steve at Flex
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Ken basically has it right.  The FLEX-6000 was born out of a government project we did that involved direct sampling.  At the time in 2010 we all believed (as Elecraft has publicly stated) that it would not be possible to build a direct sampling receiver with as much dynamic range as a superhet or direct conversion radio.  When we did the government project, Gerald worked a lot on the numbers and RF architecture and we discussed how to get the best dynamic range out of a direct sampling receiver.  We were able to use a very early sample of an Analog Devices ADC in that project and found that we were getting better dynamic range than even Analog was reporting, largely because of how we selected key parameters.  Gerald realized that we could build a better direct sampling radio than anything we'd built before.

Once we realized it was possible to build a direct sampling radio, all the "what if..." conversations started.  What could we do if we did this?  What would someone do with that?  Would it be better if we did this or that?  At the time, PowerSDR was the de facto standard in SDR, but we were keenly aware of the limitations of the architecture.  Namely that it would not work well in the IoT (Internet of Things) age, remote would be a kludge, the more data we wanted to process the more powerful computer you would have to buy, etc.  It's just not scalable.  At the time, the HPSDR team had built a working direct sampling receiver and we looked over their architecture and considered it.  It also had the critical flaw of having to have a fat communications pipe to the computer.  We decided putting the processor in the radio was the way to go.  

We contacted Intel, Freescale, Texas Instruments, Xilinx and Altera and had meetings with each to discuss what technologies we could use to build the compute engine in the radio.  We briefly discussed doing everything in an FPGA, but this was quickly ruled out because it takes roughly 10x to build the same thing in an FPGA as you can build in a processor.  Our Avnet/Xilinx FAE at the time put it very matter-of-factly when she said something like: "FPGAs are hard.  You wouldn't use them if you had any other way of doing it."  But to do direct sampling, an FPGA was required.  At this point we knew that we were going to be marrying an FPGA and a processor.  All the while that we are making these decisions about the hardware, I'm thinking about how the software will work and building the architecture for that in my head.  

FPGAs can have what are called "soft processors" which are processors that are actually built in the fabric of the FPGA.  We have used these before and they can be handy, but there is a key problem: all of them are limited to about 100-150MHz of clock speed.  We knew that this wouldn't cut it.  Several of the FPGAs have what are called "hard processors" which are processors that are part of the silicon and they run at native speeds, in the 750-1500MHz range.  Xilinx previously had used PowerPC, but now was promoting a new family called Zynq which included an ARM processor.  The world has largely abandoned PowerPC and MIPS and settled on ARM for embedded licensed processors.  We liked the ARM architecture and the toolset and toolchain were rich -- we were sure that ARM would be around for a while.  But Zynq was expensive and and brand new.

We talked with Intel who had a line of embedded processors and we liked those OK, but there seemed to be a lot of interface work required with them.  We moved to talking with Freescale and TI because each had DSP processors which we felt would give us a lot more power since we were going to be doing DSP.  TI was a full generation ahead of Freescale at the time so we got serious about TI.  TI had better raw compute power and we really liked where they were going so we picked TI.  We also had a good relationship with TI and felt like that would help us.  All the while that Gerald and I were visiting with these companies, we would walk out of the meetings and talk about what we could do for ham radio with each solution.

We ended up picking Xilinx and TI for the computing parts.  At this point, I had a pretty good idea what the software architecture was going to look like and so Eric and I started talking about the software architecture in detail.  Our codename for the radio was MICROBURST and SmartSDR's codename was SMOOTHLAKE.  Eventually, SMOOTHLAKE got the name SmartSDR and I think it was from Klaus, DK7XL, our EU representative.  

The path we picked was filled with peril and we received advice that we could easily kill the company with the decision we had made.  We knew that if we could do this, we would advance the technology in ham radio in one huge leap.  Gerald asked the team if we were committed to making this radio happen.  This is one of those moments where someone looks you in the eye and you know that this is a real commitment -- if we failed, there would be grave financial consequences for us and our employees.  Everyone made a commitment and we got to work.

Gerald started working on the hardware design and picked other key parts including the DAC, the Codec, power supplies, etc.  As I recall, Eric and I started coding before we had hardware.  Gerald did most of the PCB design and layout and I did some of the mind-numbing layout work on the ADC, DAC and DDR3 memory.  At some point we got a working PCB and we started the effort to bring up the processor.  Hardest. Thing. Ever.  I'll spare you the details, but Eric and I spent about 3-4 months bringing up the processor.  I am so much smarter now than I was then.  

At this point, Eric and I sequestered ourselves and wrote the core foundations of SmartSDR.   We spent hours at my house in the lab writing software and we would periodically call in and let everyone know what we were able to achieve.  Gerald was off designing the PA while we worked software magic.  Bob McGwier, N4HY, visited a couple of times for about a week at a time and helped us write DSP software.  We would literally get up at dawn, eat breakfast and then go into the lab and work, emerging only for food.  We had only one or two working prototypes at the time.  At one point we decided to pull a joke on Gerald.  I rigged a couple of 1/4W resistors to a 12V supply where they would sink about 5W and we taped it to the bench.  We called Gerald on FaceTime and Bob was supposed to tell Gerald what we had working.  At a key point, I flipped the switch and smoke came billowing out from under the prototype and Bob feigned despair that the prototype was destroyed to tease Gerald.  As it turns out, we had a communications issue and all that didn't make it to Gerald so he was spared the grief, but we all got a laugh out of it.  My bench still has a small black scar from the resistors ;-).  I don't know how many hours a week we were working, but it was a lot.  We would get to the point in the evening where the code we were writing didn't make sense and we would go to bed and get up the next day and do it over again.

From the beginning we knew many of the things the radio would be capable of based on the hardware and we did things in the hardware to make sure we could do as many things in the future as we could dream up.  To this day, we have a long list of fantastic things that we can do in the radio and the main thing standing in the way is writing the code.  We continue to add new ideas to that list and work on all the things on the list.  As the FLEX-6000 has continued to sell well, we continue to hire more engineers to execute that list faster and faster.  Now the ideas come from everywhere -- customers, advisers, employees, etc.  We work on key priorities and the best ideas based on an internal plan (much of which is shared with you in the roadmap).  

So there's essentially in the design process there is communications between the hardware designer knowing the available parts and the software architecture designer on what's possible.  The hardware guy might say "if I add this capability, could you use it?" or the software guy might say "is there any way you could give me thins kind of data?"  You work together to figure out what gets you the most value for the buck and the engineering investment and you go with that.

Designing and building the FLEX-6000 and SmartSDR with the team at FlexRadio has, without a doubt, been the most rewarding experience in my career.  I've never worked with a better team of people.  With the SmartSDR foundation, our engineers can visit with a customer at a hamfest, hear a great idea, say "I can do that" and then return home and make it a reality.  As an engineer it's extremely satisfying to be able to envision what a customer wants and be able to make that a reality.  The FLEX-6000 hardware platform is the most programmable platform we've ever had and we can do just about anything on it -- which is why we designed it the way we did.

Sorry for the novel!  I hope it gives you some insight into how we do this at FlexRadio.  It's probably different other places, but there are probably similarities. 
Photo of Bill -VA3WTB

Bill -VA3WTB

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Posted 5 years ago

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Photo of Kevin J. Mahoney

Kevin J. Mahoney

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The "back story" is much appreciated by me. Gives me a lot more insight into the people and product I have invested in. Very interesting as well. More of this as time goes on would be great
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Jim Bryce W5HFS

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Thank you very much for the birth of a great radio. We all will have even great appreciation for the knowledge and skill the entire Flex teams contributes.
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Mike - N1MD

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Thank you SO MUCH for sharing this with us! I knew a long time ago that I was doing the "right thing" when I signed on with SDR a la FlexRadio in 2009 with a Flex-3000. I never even blinked when I ordered my 6700 while you guys were at Dayton that first year. Your recounting of the collective journey the company embarked on is thrilling for me to read.
Thanks to you, the whole FlexRadio team and, of course, Gerald.
Mike, N1MD
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Al K0VM, Elmer

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Thanks BIll for a great story! And thanks to the TEAM for a great radio.!!

Al, K0VM
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Steve W6SDM

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Bill, thanks for passing that on.

Thanks so much for sharing that experience, Steve.  It doesn't matter that it's a novel - I read the whole thing, and I will probably do it again to make sure that I didn't miss anything.  The history of how this radio came about is intriguing.  The fact that there are capability that didn't exist until very recently really makes the investment in my 6300 more valuable - to me anyway. 

Sometimes we forget that for every accomplishment there's sacrifice - and risk.  I, for one, am really glad you made the sacrifice and took the risk.  The result is one of the most amazing radios I've ever owned.

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Paul Christensen, W9AC, Elmer

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Sounds like a great introduction for an inevitable book or documentary about Flex!    Hopefully, folks will read this an have a better understanding of what it takes to create a new product and advance the performance and features list of the Flex 6K.  

Paul, W9AC
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Roy - W5TKZ

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A job that continues to be done well. My hat is off to all the team.

Roy - W5TKZ
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Dale KB5VE

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Steve this is the most infromation we have recieved on this great leap forward in ham radio! I know the effort has been tremendous because all you computer code writer get in a zone and it is like you are in a different dimension and you are seeing light years ahead. Thank you for sharing this and we look forward to more of the same in the future. You are a member of a great group and we the end user sometimes fail to say thank you to the ones who build our high tech play perrties!
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Dave -- W7IWW

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Dreamers creating new realities!! That's the FlexRadio team. Thanks for taking the risks and sacrifices that allow me to have the most fun with ham radio since becoming a Ham in 1961. 
Dave W7IWW
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Jay -- N0FB, Elmer

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Thanks for giving us a glimpse into the making of a dream into a reality.  It takes a special set of people who can take a concept and turn it into a product.   The Flex 6000 has become the measure for which all Amateur Radio's are now measured.  

Thanks for your vision, talent and your hard work.
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Mike Whatley

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That piece should be lifted from this forum and be the cover story in the next issue of QEX. Or QST. The Flex team exhibits Innovation, risk, technical creativity and sheer "guts" all in this tale. Thanks for the look inside!

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Great story Bill.....  Thank you for sharing it with us....

Dennis, k0eoo
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Ernest - W4EG

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Like everyone else...

Thank you for the great under taking. 

In the late 90' early 2000 I read and article regarding FlexRadio and  the work that they were under taking to  create of this fantastic radio for the military.

I query some military friends, if they heard of a Flex radios? However, if they knew they were not talking or could not share the information, since it was classified. 

This perked my ears and mind and I had to buy their product: I purchased their early Flex 1000 which out performed the Kachina and the Ten Tec Pegasus.

My intuitions were right: I figured that eventually this amazing product would be declassified or change in some way to be use by the amateur radio community.

I can only guess that the items we like in our Flex-6x00 radio have many of the features we like added to our radios. Such as decoding all modes and others, which we don't know, but we see and hear their noise; scanning from on one stream to the other.

Eventually we'll find out all what those radio that Flex manufacture for the military are or where they were use for. 
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James Kennedy-WU5E

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Nice read. my friends in the DX family told me I was crazy buying a FLEX 6000 two years ago. A story when FT4TA came up the air. I setup the FLEX 6500 and zoomed in to I could find a opening the pile up. The operator answered me on the 3rd call, the ability zoom and the signals for DXer paramount! This radio kicks butt in pile up!



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Jim Bryce W5HFS

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Exactly my experience. Even though I've been licensed forever, I am totally all thumbs at contesting, DX, pileups, etc. But with the 6700 barefooted and with my Teledyne T-6 only 30 feet high in a low part of Austin, I'm frequently one of the first answered. They must like the sound, in fact sometimes they say just that.
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Jim, KJ3P

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Way, way back, when Collins serendipitously came up with the transceiver idea (instead of separate TX & RX), it was a turning point in ham radio equipment.

Flex's product is far from serendipitous...this story proves that the 6000 series was a result of good people making great decisions, yielding a ground-breaking product.

Years from now, this will be seen as a magical moment in radio design, and a major turning point for ham radio.

--Jim, KJ3P

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Kevin J. Mahoney

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I have many Heathkits and other "knob" radios. When I spend a day in the shack I like to try to make a contact of each one just to keep them active and to have a bit of fun.....however the 6300 is the most fun radio I have ever had. Your article reinforced why I purchased this product. 
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Michael - OZ1MDF

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So envious. I also want such an experience of teamwork and achievement :-)
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Ken - NM9P

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I commented on the post where this was originally, so I won't rehash my thoughts other than to say a big "thank you" for this insight into the process, and a bigger "Thank you" to all the team for all their hard work.  We understand a little better now, but I am sure that we really still have NO IDEA what all has gone into this project!


Ken - NM9P
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The committment of every one an Flex Radio and the ham users throughout the world shows!  Let's keep it going!
Photo of Jim K4JAF


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Really enjoyed this article from Steve.  Keep up the good work "FLEX" 
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Alan W4FBI

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Reminds me of a similar story. Another company risked it's entire future on one project, in the mid to late 80's. Boeing 747. Thanks for taking the risk - FLEX!!!
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THis sure is the chepest way to get a new radio several times a year.

I bet you guys are thankful that 'twas I who asked the original question, hi hi.
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Bill -VA3WTB

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Yes It was a good question Guy, but I wonder why Steve took so long to write such a gem?
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KY6LA - Howard, Elmer

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Amazing amount of work getsdonewhile waiting for. Wives on shopping trips.

That's why I carry an iPad to remote into my 6700. Made a lot of Q's sitting in shoe stores all over the world.
Photo of DrTeeth


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Why oh why won't the women leave us at home? I have a bad back so *cannot* go shopping. That is why I worry about having by back fixed next month - I will lose my 'get out of jail' card. I don't know why call it 'shopping', they should call it 'dithering' and 'not deciding'.
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KY6LA - Howard, Elmer

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It's a perfect example of the Random Walk

My life saver is ipad remote DXing via the 6700.
Photo of Jon  W1JDB


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My solution? Take my wife shopping for my stuff...oh wait she is a HAM too...
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Tim - W4TME, Customer Experience Manager

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Jon - I recommend taking her shopping here: http://cart.flexradio.com/