Revelations of a secret FlexRadio 6700 alpha tester
FlexRadio 6700 - out of the box and how it sounds

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!


While I have become very impatient over the process and the waiting for my Flex-6700 with GPS, with each new report I grow more confident that I made the right decision to make this "investment." [I learned this term from our dear democrat tax & spend politicians...When one wants something and wishes to justify an expenditure of funds, one refers to it as an "investment." Hi Hi]
Thanks...keep the info/reviews coming!
Daniel W3DCB

Thanks very much for the info on the convention and the use of the 6700. Please keep the 6700 details flowing our way. I just hope I get to use the 6700 before old age creeps further up on me. It has (and still is) been a long, long wait.
73s, have a good week

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