FlexRadio 6700 experience at N6V
FlexRadio 6700 - LF reception

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!


Stu, thanks for updating this blog for all the rest of us waiting for shipment. However I am concerned that you will get a notice from the FCC if your transmissions begin with the BBC News Radio Opening, even though FlexRadio audio quality richly deserves that opening.

Ed - on the money! Broadcasting, masquerading as a foreign radio station, playing music... that would be too much!

In my long since days back in the UK, a good response to "how's my audio?" was "BBC quality mate!".

I too received notice last night and I am anxiously waiting to see UPS come up the driveway in several weeks.
Looking forward to work you on air.
I appreciate your coments too.

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