SmartSDR & FlexRadio 6X00 - Retraining the operator

FlexRadio Systems truly hit a home run with the 6000 series radios and SmartSDR.  Over the last year I've made close to 10,000 QSOs in contesting, DXing and general operating, spend hundreds of hours listening to the bands and integrating the radio into my station.

Count me as a very satisifed Flex-6700 owner!

But even with the experience of the last year, I have only scratched the surface of putting the full capabilities of the radio to work.  Utilizing the full capabilities of SmartSDR and the Flex-6000 series requires RETRAINING THE OPERATOR.  

The last week has seen some excellent conditions on 6m - the band has been open from California to stations across the US and into Asia with Japan and Taiwan appearing on the DXclusters.

So yesterday when I got home from the office, still needing to respond to the email backlog from my vacaction, I fired up SmartSDR and started monitoring 6m from my QTH in Woodside, California.

With a single panadaptor displayed by SmartSDR, I was watching 6m from about 50.025 MHz up to around 50.175 MHz allowing me to monitor the beacon, CW and Phone sections of the band.  Returning to my email, I tuned the  slice from time to time with the FlexControl as I saw stations appear on the band.

I also had SpotCollector running (the spot analyzer incorporated in DXLab) and began to see a number of new spots show up on JT65, much higher up in the band at 50.276 Mhz.  JT65 seemed like a perfect way of monitoring activity while I plowed through email.  Easily done - retune the radio, fire up WSJT and keep a eye open on both spots and WSJT.

About 30 minutes later I saw a JA station spotted by a station in the far north of California.  Email was promptly disregarded as I reached for my headset.  I started to reach for the mouse to retune the radio when a thought struck me...

There's plenty of JT65 activity and I'm going to lose my monitoring capability if I retune the "radio" to chase the JA.  But wait! I don't need to retune the "radio"!

Instead, I used the mouse to pull up a new panadaptor, create a slice and click on the spot - only to find slice A instantly retuned away from the JT65 frequency.  Doh!  SpotCollector and DXLab aren't FlexRadio 6000 aware and so retuned "VFO A" just as I'd instructed.

I quickly retuned slice A to 50.276 MHz,  manually tuned slice B to the reported frequency of the JA spot and set the mode to CW.  I muted slice A  (still sending audio as data via DAX to WSJT) and turned my attention to slice B.  I couldn't hear the JA - I could hear stations working him from a couple of hundred miles away - spotlight propagation (not uncommon on 6m).

With the headset on and monitoring the JA's frequency, I returned to email.  My hope was that propagation might begin to drop further south and west as the solar terminator approached.

A few emails later, I saw some SSB signals on the panadaptor and wondered whether these signals might be from Asia.  I reached for the FlexControl to tune the slice away from the JA, only to realize again, I don't need to retune the "radio"!

A couple of mouse clicks brought up a third slice, selected SSB mode, made the newly created slice C active and adjust the audio pan controls so that I could listen to one slice on each ear.

My 6m Radio

Now I was set!  I never heard the JA but I realized I was beginning to re-train myself to think about the Flex-6000 not as a "radio" but as the server it is!

I could never have begun to do all this with a conventional radio!

We have great hardware (the Flex-6000 series radios), great software (SmartSDR), but getting the best out of the radio requires upgrading and retraining the wetware - a.k.a. THE OPERATOR.

And this is just the beginning...


Contest Club California Peninsula - CCCP

About 6 months ago, a group of avid contesters here in the San Francisco Bay Area decided to form a new Contest Club.  Although the SF Bay Area is part of the territory of the Northern Californa Contest Club (NCCC - a 40+ year old venerable institution), we wanted something different:

  • Smaller
  • Competitive
  • Contest focused
  • Motivated members

We decided to form the club as an ARRL Affiliated Club in the Local category and participate in the ARRL Affiliated Club contests as well as other club focused contests like the California QSO Party.  The ARRL local club category allows 10 entries from club members and all members must live with a 35 mile radius circle on some geographic point.

We chose the center of the circle to be 0.5 miles of the end of runway 13L at Moffat Federal Field - a former Naval Air Station here in the Bay Area now operated by NASA for research purposes.

We gave our first all out effort in the ARRL 2013 November Sweepstakes - what a blast!  All our members took part with no flogging required!  Everyone was motivated and kept their Butt-in-the-Chair because we all realized that our score was going to make a meaningful impact on the team result.

Here's our logo...

Formal CCCP Logo - Hi-Res


We decided (a little tongue in cheek to be true!) to call the club Contest Club California Peninsula - you can click the link and go to our web site - which we are in the process of updating.

You will see us active in many contests!

We love to compete!

K6TU Control iPad app is available!

The K6TU Control iPad application is now available via the Apple™ App Store.  If you are already familiar with the app and what it does, you can click on the link below to view K6TU Control in the App Store.

Download K6TU Control from the Apple App Store

The genesis of K6TU Control began at the International DX Convention in Visalia, CA back in April 2013.  As in 2011, I had been asked to manage the get-on-the-air station for the convention and so had asked the good folks at FlexRadio Systems whether they would provide a Flex-6700 as the core of the station.  Not only did they agree but they also sent Steve Hicks N5AC and Jim Reese WD5IYT to keep an eye on the radio (and me!).

I was able to spend a lot of time talking SDR and development with Steve and Jim as we watched folks use the N6V station.

As a serious contester, I was keenly interested in the workflow of operating the Flex-6700.  As I wrote in my last post on this blog, computer controlling ANY radio brings with it the necessity of thinking about workflow - how to integrate computer control of the radio with the other tasks you need to perform in a contest, DXpedition environment or other situation where speed and efficiency are paramount. 

The idea behind the FlexControl had been to streamline contest workflow for the most frequent operation of the radio - tuning (either VFO or RIT).  What I really wanted was a way to control the other functions of the radio without needing a second keyboard and mouse.  As Jim, Steve and I talked the idea over, the idea of the iPad app was born.

Here's a screen shot of the main view of K6TU Control. 



K6TU Control shows a list of open slices on the left and then shows the full detail of the selected slice on the right.  A tap on the + button at the top of the Slices list will create a new slice with exactly the same configuration (frequency, mode, antenna, filter size) as the slice selected and displayed on the right.

Click this link for a full description of the application.

Although pictures are worth a thousand words, videos are priceless - so with great thanks to Mack W4AX, this video shows you some of the features in use.


K6TU Control requires iOS 7 and runs on all iPad models since the iPad II - you must have your iPad connected via WiFi to your home network and Flex-6000 series radio.  This application is intended to optimize workflow in conjunction with SmartSDR and a FlexControl.  As a consequence, no screen real estate is used for a pan adaptor display and the app does not support streaming audio from the radio.

The app allows you to create and save the radio configuration as a profile together with custom filter configurations.  Access these features via the Profile button at the bottom of the Slices list.

Here's a view of my contest operating position together with the iPad and FlexControl.


I couldn't have done the development of K6TU Control without the help of the folks at FlexRadio Systems and the folks on the alpha/beta test team who provided feedback on usability, operability on different iPad models as well as testing.  A sincere THANK YOU to all!

Of contesting & computer controlled radios

This is the first post in a series about using the FlexRadio 6700 as an all-out contesting radio. The FlexRadio 6000 series are state-of-the-art Direct Digital Sampling radios but they are different; no knobs, no direct controls and a computer required to operate the radio.  I'm hoping that these articles will provide both perspective and a resource for others interested in exploring the killer performance of this radio.

I made the transition to computer control of my ham station in 2003 after moving to my current QTH and having enough space to put up decent antennas and neighbors far enough away to make RFI mostly a thing of the past.  I started with a station built around a TS-B2000 - the no panel version of the TS-2000 with software control from the PC.  I won't describe this journey here as its document elsewhere in posts on this blog.

Computer control of a radio needs attention to two aspects:

  • Can you control ALL of the radio functions remotely?
  • How do you integrate the radio with your contesting workflow?

The computer control for most radios is via CAT and depending on the manufacturer, you may be stuck with control of a subset of the radio capabilities.  Happily with all the FlexRadio products, there is full control of all capabilities via an extended CAT command set for the radios before the 6000 and a full network API for the 6000 series.

It took precisely one contest with the FlexRadio 5000 for me to realize the importance of contest workflow.  The California QSO Party in 2009 was that contest and within the first 10 minutes, I realized the nightmare of a computer controlled radio when using the same computer for the logging software (in my case Writelog).  Note that it could have been a computer controlled Elecraft, Icom, Yaesu, Kenwood... anything!  Having to mouse the software in focus (accepting keyboard input, mouse commands) from the logging software to the radio and back again was time consuming and a mine field...  typing the wrong key strokes into the wrong window caused havoc.

By the end of the contest I had decided to build what became the FlexControl tuning knob.  This enabled me to command a limited set of the radio capabilies that I needed to access in a contest.  For the most part, I found that access to VFO tuning, RIT & XIT where the most needed.  The FlexControl allows many functions to be controlled thanks to the integration work done by Steve, K5FR with DDUtil.

With the prototypes of the FlexControl and the eventual product, I used my 5000 in many contests - all modes, CW, SSB and RTTY.  I placed well for a station with a single tower - several Call District 6 first places, a couple of records set in the Santa Clara Valley section and more importantly, I had a lot of fun!

When my 6700 arrived I was blown away by the performance of the radio.  Simply without peer!  The receiver is a joy to use and is very easy to listen to - important in a contest when after 48 hours, some radios begin to sound like they have a parott inside - and a raspy parrot at that!

To really leverage the radio, I wanted to take computer control to the limit.  I wanted a separate control panel that let me command all the radio capabilities without creating workflow issues.

Elecraft took an interesting approach to this problem with the K3/0 - this is a K3 chassis and front panel with all the controls... but no RF electronics inside.  Together with a pair of RemoteRig units, you can use a K3/0 to drive a remote K3.  The solution adds about $1200 to the cost of remote control but after a tower, antenna and amplifier, most hams won't bat an eye at that cost.  With decent Internet connectivity the solution works well.

I didn't want a control panel with knobs for controlling my 6700.  A couple of folks had suggested I build a FlexControl on steroids, more knobs, more switches etc.  But a physical device can't readily be configured for specific operating desires.  I wanted total FLEX-ibility!

Back in April this year, I was responsible for the N6V demonstration station at the Visalia International DX Convention.  FlexRadio had generously agreed to provide a 6700 for the station and sent Steve Hicks, N5AC and Jim Reese WD5IYT to help with the station.  During the weekend I spent many hours talking with Steve and Jim - in particular about contest workflow as SmartSDR was still in its early days.  We all agreed that a separate control surface as needed for contest operation.  It didn't take long for the idea of using an iPad as a "soft" control surface came up.

Driving back from Visalia I couldn't get the idea of the iPad app out of my head and after a couple of days back home, I decided to teach myself iPad application development and write one - K6TU Control coming to the app store soon!

The key takeway isn't the app.  The takeay is that contesting with a computer controlled radio - any radio - requires a seamless way of controlling it's operation that doesn't remove focus from the logging software.

It doesn't matter whether its a K3/0 or an iPad with FlexControl thrown in, you simply can't begin to optimize workflow without some independent method of controlling the radio.

Doing well in a contest, let alone winning, DEMANDS optimized workflow:

  • Cut down the number of key strokes
  • Minimize the extraneous information you send (e.g. cut out "please copy", repeating what you were just sent, eliminate unwanted characters in CW or RTTY like DE...  over the course of a contest these add up to HOURS of additional time).
  • Not having to think about controlling the radio - just do it!

For the first time since I began using a remote controlled radio in a contest, I have put the workflow issue of radio control behind me.


FlexRadio 6700 - Latest pre-release update

Kudos to Gerald and the team!  This last two weeks has seen huge progresss on all fronts - stability, features and performance. Radios are now shipping beyond the alpha and beta testers to those who indicated their willingness to take pre-release software.

I have to say things are looking pretty good!

More functionality of course means more to test - so between that and completing some new features on my Propagation as a Serivce web site, I've been busy and not really had time to sit down and compose a new post.  Hopefully this will make up for the delay...

Here's a screen shot of SmartSDR showing the panadaptor and the TX controls.


You can click on the image for a larger image but its easy to see the addition of the equalizer (for both TX and RX), plus the metering and microphone source select.

On-air reports have, without exception, had great comments on the audio quality - in many cases unsolicted which is always gratifying!  Adding some equalization to my different headsets has given me the option of "BBC Quality" for casual contacts or providing sharper audio for DXing or Contesting.

Also shipped with the last couple of updates has been the CAT control for SmartSDR.  This is started as a separate program and runs automatically.  Gone is the need to install a virtual serial port device driver (although it happily coexists with one) as it has a single ended virtual port driver included.  This means you have a single COM port which you can use to connect to sotfware requiring CAT control.

Thanks to Steve K5FR, there is also a new release of DDUtil available from Steve's web site.  This new version interfaces directly with the CAT control for SmartSDR and as before, allows multiple CAT programs to share the CAT control stream.  I've tested SmartSDR CAT with DxLab and Writelog.  I know that it also works with other programs including N1MM logger.

Having DDUtil able to talk to the 6700 and all my other equipment (amplifier, rotor, SteppIR controller etc) has me back to single button band change and a full legal limit automatic transceiver!  I'm really looking forward to getting on the air in a contest with this radio - it really has an amazing receiver!


FlexRadio 6700 - Initial QSO's

This last week I've been test flying the FlexRadio 6700 in a number of QSOs both on HF as well as 6m so I thought I'd give an update on the most recent experiences.

As a reminder I'm still using pre-release software together with the other alpha testers.  Functionality is quickly approaching the release 1.0 level and so on-air testing is now seriously underway.  

My installation is totally remote - all my radio equipment and antennas are located away from the house and controlled via Ethernet.  Audio is handled by a balanced audio link over a spare CAT6 Ethernet drop patched through from the radios to my office in the house.  The CAT6 cable has 4 pairs - two are used for stereo audio from the radio, one for microphone audio to the radio and the last for the PTT line.  For many years I used a homebrew set of balanced audio drivers but early this year, switched over to commercial components made by Radio Design Labs.  Much better fidelity and more audio drive (with gain controls brought to the front panel) make this link a considerable step up on my homebrew effort.

BrandoSince I never got round to training Brando to go and push buttons on command, I spent a lot of effort over the years in station automation.  With my Flex 5000, the CAT port from PowerSDR runs into DDUtil (courtesy of Steve, K5FR) which then handles the different components of the station - amplifiers, SteppIR antenna controller, rotor etc.

The current pre-release of the Flex 6700 software doesn't yet include CAT support (its coming soon!) so I have to go through a few extra steps to handle its operation until CAT is available.

So armed, I've made a fair number of phone QSO's over the last few days.  Mack W4AX (also one of the 6700 alpha testers) and I had a short 6700 to 6700 QSO on Sunday morning.  The bands weren't in good shape with an A index of 58 due to a sneaky CME hitting the Earth's magnetic field and creating a G2 class storm. The severe weather in the mid-West didn't help either - lots of lightning static made for a noisy band.

Mack's business brings him to Silicon Valley from time to time so we have had the pleasure of an eyeball QSO - I mention this because I know what Mack sounds like when he's in the same room - and he sounded just the same during our QSO on Sunday morning - natural and good audio!  I mention this because the TX equalizer we're using has a set response configured in the software - the controls for the equalizer are being externalized as I write this and will appear in SmartSDR shortly.

Late Sunday afternoon, I had a great QSO with Bob K8MLM in Woodbridge, VA.  I was testing on 20m just making sure I had my station control figured out and Bob called me.   Turned out Bob was running a Flex 5000 and so we had a great chat about FlexRadios in general and the 6700 in specific.  Bob was complimentary about the audio from the 6700 and with the bands in better state, gave me 59 once I'd kicked the amplifier in.

Last night (Monday) with the after effects of the geomagnetic storm abated, I checked on 6m before heading to dinner with my wife.  The band was alive and hopping up and down the West Coast and I made a couple of QSO's into British Columbia using the 6700 barefoot.  Tuning down to the CW portion of 6m, I heard WL7N in Ward Cove, AK - located in the sliver of Alaska just to the West of BC, Canada.  Of course, I hadn't hooked up the CW key line from my keyer to the 6700 so sadly a new grid square didn't make it to the log!

A note about SmartSDR and remote control...

Integrating the 6700 into my remote station so far has been very straight forward and easier than the Flex 5000.  In the case of the 5000, I have a computer sitting right next to the radio which runs PowerSDR.  I control that remote computer using UltraVNC over the Ethernet - works great and with plenty of bandiwdth between my home office and the radio, burining 50 Mbps on screen updates isn't an issue.  I can still use my FlexControl to tune the remote copy of PowerSDR as I use the Eltima Serial-to-Ethernet driver to remote my tuning knob.

Since SmartSDR connects to the radio over Ethernet, I run SmartSDR on the computer in the office.  Its a Mac Book Pro running Windows 7 under Parallels 8 for the Mac.  My FlexControl is plugged directly into the Mac and is assigned as a USB peripheral (via Parallels) to the Windows 7 VM.  The whole thing works seamlessly - tuning is smooth with no lag when I stop turning the FlexControl.

Ever time I turn on the 6700 I'm struck by the receiver performance - this radio has good ears!

Propagation Predictions - getting the big picture

Ask most Hams about Radio Propagation and they will tell you...

  • It's influenced by the Sun and its Solar Cycle
  • Impacted by the earth's geomagnetic field
  • When the Solar Flux Index is high and the geomagnetic indices are low, propagation will be better
  • Propagation varies with the time of day

and that's probably it.

You might also get the advice "listen around and you'll get an idea of propagation conditions".

If you are planning a serious effort in a contest, trying to work a new DXCC country or putting a plan together for a DXpedition, you really need to know how propagation varies by band through the day and how this impacts the signal you will lay down in different geographies.  I call this the Big Picture of Propagation - knowing for your station (antennas and output power), solar conditions and the time of year, how strong your signal will be - where and when!

Here's an example:


Fortunately there are software engines that incorporate many years of reasearch and observations into HF propagation and its influencing factors.  The "gold standard" of these is the VOACAP prediction software that was developed for the Voice of America to plan its transmitter and antenna requirements.  We can use the VOACAP engine to build out the big picture.

The big picture is only useful when it is representative of your station and the stations you expect to work. This means using antenna configurations and power levels that model what you have at your station and then selecting receive antennas you would expect at the receiving station.

Producing a prediction for a single band/hour combination isn't complicated once you have mastered the learning curve of VOACAP.  But doing this for all bands and all hours by hand is a LOT of work!  Trust me - I used to do this manually and it took the better part of half a day even once I got the hang of it.

The desire for the big picture on a regular basis drove me to design and implement my Propagation as a Service web site - K6TU.NET.  Using the service, I can produce a full set of predications in a few minutes - typically 3-4 minutes or less.  I use these predictions to plan my strategy for a contest weekend or for chasing specific DX stations - the big picture helps me understand what bands I should use when I want to work specific geographies.  This is really helpful in contests like the CQ WPX events where inter-contintental QSO's on 40m and below are worth 6 points!

The image above shows you a single GIF generated from each of the band/hour images you can see in an online gallery.  You can scroll through them quickly in a browser window to see the same effect.  I thought aggregating these all into one image was a good demonstration of the big picture.

I recently gave a presentation at the 2013 International DX Convention at Visalia, California on this topic -Propagation Predictions and DX Strategy - a PDF of the presentation is available via the link.  This presentation covers the use of the VOACAP Propagation Prediction software to generate the big picture and gives some do's and dont's for the process.

I got a lot requests to put the presentation on line so figured it would make a good post.


FlexRadio 6700 - LF reception

Where I live in the San Francisco Bay Area, we have a HOT RF spectrum especially in the AM band.  Using my 160m top loaded vertical as an antenna, the hotest AM radio signal is -8 dBm and there are many in the -10 to -12 dBm range.

One man's entertainment is another man's pollution; operating on 160m from my QTH benefited considerably from adding a high pass filter to cut off the energy coming from the AM band.  Every radio I've operated at this QTH has had increased noise level on the low bands (80 and below) without a BCB filter.

So I was naturally curious how the FlexRadio 6700 would work in this RF environment.

Out of the box, the natural antenna choice for initial receiver testing was the 160m vertical - it captures a lot of signal and functions as a receive antenna over a wide frequency range.  I connected the antenna directly to the 6700 - no in-line filters either in the direct antenna path or the RX filter loop.  This is a harsh real world test for any receiver.

Tuning around the different bands with the FlexRadio 6700 was a surprise!  I couldn't detect any BC band induced spurii even without the high pass filters.  160m had its fair share of QRM from local noise sources - I know what causes some of them (the ones on my own QTH) and others I have a fair idea (the variable speed pool pump in a new construction about a half mile away for example).  But that was it!

Another interesting test for any receiver is to see how its LF performance functions. Although we haven't got low frequency allocations at 137 KHz or 497 KHz yet, hopefully we will in the not too distant future.  I was curious to see how the 6700 would perform at those lower frequencies.

At LF, my 160m vertical is a very short antenna!  Despite that, I've been able to receive a lot of LF stations especially aviation non-directional beacons (NDB).  Most of these beacons serve as navigation aids for instrument approaches into airports.  Many of the US NDBs are being de-commissioned as GPS has rendered them obsolete.  But you can still hear multiple beacons in the LF spectrum from 200 to 400 KHz.

All the beacons have a callsign sent in CW or MCW and I quickly found a good directory mapping frequency, callsign etc to location compiled by William Hepburn of the LWCA - you can find the directory here.

Not withstanding the inefficient antenna I can hear beacons all over the Western states (Arizona, Utah, California, Idaha, Oregon, Washington - all logged) as well as many up in Canada.  I used Google maps to find some of the locations like NDB ZP at Sandspit, BC which I can regularly copy.

Here's a capture of SmartSDR tuned to WL (Williams Lake, BC) which Industry Canada shows on 0.385204 MHz running 500 watts into a 0.5 dBi antenna at 6 meters above the ground.  BTW, a couple of notes about this capture...  

  1. You can see that the radio is in WIDE mode - no bandpass filters selected in the receiver.
  2. The S meter calibration is accurate but ignore the level scale on the panadaptor as its not yet calibrated.


The clip is short - you can only listen to a beacon id so many times!

On the ham bands, the 6700 receiver truly shines!  As I've said before, the radio sounds very clear and its strong signal performance is excellent.  Even with the SteppIR as my primary HF antenna, I can monitor different bands to see if there is activity by using multiple slice receivers - of course a tribander or multi-band HF yagi would allow monitoring with optimum signal levels but wouldn't be as cosmetically friendly!

I'm looking forward to using the 6700 in a contest and also improving my low band receive antennas - the 160m vertical is noisy and this summer I plan to build a receive only 4 square.  That should help my 160m and 80m receiving conditions a lot!

FlexRadio 6700 - out of the box and how it sounds

I’ve been tracking personal milestones in my journey with the FlexRadio 6700:

  • Alpha hardware delivered ✓
  • Alpha software releases ✓
  • Production hardware delivered ✓

For anyone with experience in system development and manufacturing, committing the build of production hardware is no small decision – it simply has to be right!  Of course the science is in the “simply” – just like “oh, it’s a simple matter of programming” – wish I had a dollar for every time I’ve heard that!

So when I got the automated notice from FlexRadio that my production version of the 6700 had been shipped, I was even more excited that when the alpha was shipped…  first customer ship was approaching!

As soon as I got the email alert that the package had been delivered, I hustled home and started unpacking.  Here are some pictures…


FlexRadio ships double boxed – this is the inner box


 Inside – Microphone, Quickstart, GPS Antenna, Power & Ethernet cables

Everyone has seen pictures of the front and back of the radio so I won’t consume bits repeating them here…  but when you get a Signature Version of the 6700, be sure to have a look at the BOTTOM of the 6700.


Truly the Signature Version – K6TU 007!

The home for the production 6700 was ready to go and so I quickly cabled up the unit, installed the latest release of software and was ready for an on air test.

Cut to the chase – How does it sound?

The first real on-air-outing for the Flex 6700 was at Visalia and the N6V demonstration station which I wrote about in the last post.  We had used a Heil PR-781 microphone with no audio equalization and some on-air reports had noted that the audio sounded “muddy”.  Not a total surprise given the voice characteristics of the different operators.

Bear in mind this was alpha software hot off the press!  A scant 3 weeks later, the release I downloaded from FlexRadio for use with the production 6700 has the transmit equalizer operational! Hats off to the software team at FlexRadio – they are a great group of professional engineers!

As a contester, I usually operate with a headset and have been on a seemingly endless quest for one that is comfortable.  I have quite a collection as the real test is a 48 hour contest weekend that doesn’t end with neck ache (from the weight) or a head that feels like its in a vice.

RS60CFThe most comfortable headset I’ve found so far is the Radiosport RS60CF which I purchased from Arlan Communications.  It too has a microphone with a flat response which allows me to choose how I want to sound – BBC quality for casual ragchewing or something with “more punch” for contesting.

With the headset connected to the 6700, I turned on the Monitor, made sure the power level was at zero and hit the PTT.  It sounded very clean with the default profile from my own monitoring.  By the way, did I mention ZERO delay audio?  Testing using the Monitor function on PowerSDR requires a high sample rate and small buffers to minimize the delay between speaking and the audio in the monitor.  There is no delay audible in the 6700 – very nice.

With the 6700 connected to the antenna via my amplifier, I made a test tranmission to set the output power and then started tuning for someone to work. 

The first QSO was with an IT9 in central Italy.  With S8 signals both ways it was a pleasant QSO and got a “nice audio” response to my question about “how does it sound?”

First home QSO with the production 6700 – another milestone to mark DONE!

FlexRadio 6700 experience at N6V

The International DX Convention is held every April in Visalia, California.  In odd numbered years like 2013, a team of volunteers from the Northern California DX Club organizes the convention.  In 2011 and 2013 two friends of mine (John K6MM and Kevin K6TD) were the event co-chairs and asked me to be responsible for the Convention Special Event Station N6V.

A very well attended event, the Convention attracts heavy duty DX’ers and Contester’s from around the world so N6V isn’t a light weight station… legal limit and a good antenna are expected – as is really good radio!

N6V is fortunate to be well supported by a number of key vendors and I am personally very grateful to the following folks who helped me put on N6V in 2011 and 2013.

  • US Tower brings along a heavy duty mobile tower (55’)
  • SteppIR supplies and assembles the antenna on site (DB-18E)
  • M2 Antenna Systems supplied the rotor (Orion 2800) and cables
  • RF Concepts supplied an Alpha 9500
  • FlexRadio Systems supplies the radio (2011 was a FlexRadio 5000)

The 2011 station was a great success – it opened a lot of eyes since this was the first opportunity many people had to operate a FlexRadio transceiver.  Everything performed as expected and many contacts made around the world.

So when I was asked to assemble N6V for 2013 late summer last year… you can imagine what I wanted to do.  2013 N6V was just crying out for a FlexRadio 6000 series radio!

I called Gerald and Greg last October and told them what I was thinking – were they game for it?  But of COURSE was the swift reply.

My 2011 experience was good but had highlighted the challenges of assembling a high performance station in half a day.  We had integrated everything together on site for 2011 and this time planned to pre-integrate before the convention.

With the great cooperation of all the vendors we quickly had a plan in place.  Molly and Joe at RFConcepts agreed to ship the 9500 to Austin so that 9500 support could be integrated into SmartSDR.  FlexRadio already had a SteppIR at their offices in Austin together with the SDA100 controller to help integrate support for it into SmartSDR as well.

Think legal limit transceiver with a resonant antenna from 40 through 10m – no configuration required…  change band, change frequency and the amplifier and antenna follow the radio.

Here’s a block diagram of the 2013 N6V configuration.


We knew that timing would be tight – the FlexRadio 6700 is a sophisticated product and Gerald’s team was determined to build the best product possible.  Like making fine wine, building robust software that can be built on for the long term (as new features are added) can’t be rushed.  You have to get it right from the beginning.

We had agreed to arrive the day before the Convention opened so that we could assemble the station.  In addition to Greg and Don who manned the booth in the vendor area, Steve Hicks N5AC (VP of Engineering) and Jim Reese WD5IYT came to Visalia to assemble the station and look after the 6700.

FlexRadio delivered!  We had a 6700 with support for CW (semi-break in at that time) and SSB with integrated support for the Alpha 9500 and SteppIR antenna!  The 6700 drove the Alpha 9500 to legal limit with about 40 watts or so of input power.

Some things to keep in mind…  this was alpha level software with support for receive (which I’d had for some weeks prior to Visalia) and transmit (which was hot off the press).  Alpha software in this case means that not all features were yet implemented and that not all the SmartSDR controls were hooked to the radio.  For example, in the release of the radio software we used at Visalia, the MIC Gain control wasn’t hooked into the radio – Steve and Jim preset the audio level and we used the power output control to keep within legal limits driving the amplifier.

We didn’t have any shortage of operators!  Here’s a picture we grabbed of some of them:



Radio Performance

To me as a contester and semi-serious DX’er, the proof of a radio is its receiver and how it is to operate (workflow and usability).  I expect a transmitter to transmit – do it cleanly, not get hot and bothered and sound good.  The receiver I expect to perform miracles – it has to handle weak signals right next to monster signals, have killer filters and have audio that I can listen to for hours on end.

I’ve used every major brand of radio in the 40 years I’ve been licensed and a large number of commercial service radios well beyond my check book.

The 6700 is the best receiver I have ever used.

It’s a FlexRadio Systems SDR so by now, while I don’t take them for granted, I expect the filters to be brick wall, no ringing and all the configurability at my finger tips.  Here’s a screen shot from SmartSDR of adjusting a SSB filter on the fly…


The filters perform!  You can pull signals out of a busy band that are really weak – even when parked next to a very strong station. 

It’s not “just” the filters, it’s also about dynamic range.

FlexRadio hasn’t released the dynamic range figure for the 6700 yet but from real world listening, it’s good – very good.  As an engineer and VC I deal with quantifiable objectives – so you may have some idea about how much it pains me to make a qualitative statement. 

The 6700 is simply the clearest radio I’ve heard.

During the CQ WPX SSB event in late March, I took some time during one of my break periods to compare my 5000 with the 6700.  The 5000 is a great transceiver with an awesome receiver –the 6700 just sounds clearer – same station, same noisy band conditions (40m at 9pm PDT) but clearer.  I don’t yet have a good explanation for this but when you use this radio, you will hear what I mean!

I’m really looking forward to using the 6700 in a contest.  I think it will be less fatiguing over a contest weekend and I’m guessing my QSO rate will benefit significantly.

Another comment about the receiver – it handles local high power stations VERY well!  Greg had a 6700 on the FlexRadio Systems booth that was hooked up to a broadband active antenna on the roof of the convention center… maybe 100’ from the tower with the SteppIR and legal limit from N6V.  Greg and Don often had that 6700 tuned to the same band as N6V was operating and only a few KHz away… monitoring a weak signal.  I’ve been at contest stations with brand X (X something other than FlexRadio) where you couldn’t do this because when the transmitter in brand X keyed up, the whole noise floor rose and obliterated the weak.


Transmit wise at Visalia the radio performed well and did its job quietly, no muss, no fuss.  We even had the GPSDO option installed and with the antenna taped to the sidewalk just outside the door, had solid lock.

For the most part we got good audio reports – we had a lot of different operators and a couple of different microphones.  Some operator’s voices together with a flat response studio microphone could have benefited from the TX equalizer but… that wasn’t implemented at the time of Visalia.

Over the course of the convention we made over 500 contacts – all of the QSOs that got logged will receive an N6V QSL card via the BURO.

Sincere thanks to US Tower, Steppir, M2, RF Concepts and especially FlexRadio Systems for their support of N6V.

My personal thanks also go to Gerald and FlexRadio Systems – they generously donated a FlexRadio 6700 as the major price for Sunday mornings wrap up event.  Another Gerald, K0JJ, won the certificate for the 6700 in the breakfast raffle draw.  He is going to be a VERY HAPPY Ham when his radio is shipped (after all the pre-orders!).

The FlexRadio 6700 made the day!

My Photo


Intense Brit, lived in Silicon Valley since 1984. Avid pilot, like digital photography, ham radio and a bunch of other stuff. Official Geek.

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