Flex 5000A Software Defined Radio

Flex5k-Panafall on 20m

Two Weeks ago I stumbled across a good deal on a Flex Radio Systems Flex 5000A software defined radio, so I had to snatch it up!  I bought it used from a ham in Pennsylvania in excellent condition.  My particular model has the 2nd receiver installed which I really like.

I thought I would write up a bit of a blog post with my experiences and revelations regarding the Flex 5000A.

First off I should preface that I am not new to software defined radio.  I also own a awesome RF Space SDR-IQ HF software defined radio that I totally love.  My good friend Jeff N9IZ also owns a Flex 5000A and really enjoys it.  I have had the opportunity to use his Flex in the past, so I was somewhat familiar to the platform.

With all that being said, I still have learned a lot of new aspects about the Flex 5000A in past 2 weeks.  It seems like every time I go to use it, there is something else to discover and play with.  As a curious amateur radio operator this makes operating the Flex a blast and sometimes a frustrating venture indeed.


Installation of the Flex 5000A is not for someone that has little to no computer experience.  If you really like the idea of SDR and don’t know much about computers, then seek out a computer savvy Guru to help you out.  I have over 15 years of experience in the computer technology industry and even I found at times aspects of installing the Flex 5000A to be frustrating.  This is because of the Firewire 400 interface used to connect the Flex 5000A to your PC.  The Flex 5000A is very particular about Firewire card chipsets and the installation of its drivers.

You should also be using a good at least dual core PC with at least 2 GB of RAM.  I would recommend 4 to 8 GB of RAM actually and a good GPU (graphics card) will really work well for the Panadapter performance.

Firewire 400 (and Firewire in general) is now largely an outdated computer IO system.  USB 2.0 has largely surpassed Firewire 400/800 because of its commonplace with PCs, tablets, etc, not to mention the backward compatibility to older USB devices.  Firewire interfaces to have their positive strengths, in particular they don’t share interrupts like USB does and have dedicated bandwidth, but with USB 3.0 now out, that is the final nail in the coffin for Firewire 400.

The Flex 5000A is admittedly picky about what Firewire card you use. This can make installing the Flex 5000A a bear.  I went through 3 different Firewire cards each with a different chipset before I found a card that worked properly with the Flex 5000A.  The one that finally worked for me is a cheap StarTech.com branded 2+1 port Firewire PCI card with a VIA VT6307 chipset.  I paid about $20 for it from Amazon.com.

Install the Firewire card first, and let your PC find it and install the Windows driver for the card.  Then you will need to install the Flex 5000A driver with the radio disconnected from the PC.  DO NOT plug in the flex until the driver is properly installed and working.  You will need to restart your PC after the driver is installed.  The Flex 5000A software driver is written well and if the Firewire card is good, it will work just fine.  It even asks to set a Windows software restore point which is particularly good since installing drivers improperly can cause the dreaded Blue-Screen-Of-Death (BSOD).

After your computer restarts you will then be able to connect your Flex 5000A to your PC and all your cables (antenna, ground, speakers, mic, etc) and install PowerSDR, the interface that the Flex 5000A uses to control the radio.  PowerSDR is a very well written application and the interface looks great.  I am running the latest version of PowerSDR version 2.6.4.  When installing the latest version of PowerSDR it will also check the firmware of the Flex 5000A to see if it needs updating and update it for you.

When you launch PowerSDR for the first time there is a brief wait while it copies and backs up the internal settings for the Flex 5000A to your PC and also runs a self optimization routine.  It only will do this during this first time start up of PowerSDR and subsequent restarts of the application will not go through this.

Then before you actually start the radio you will need to go through the settings for the audio mixer for your microphone and speakers, and then lastly set your options in the antenna selector screen.

Whew! Then you can start your Flex 5000A in PowerSDR and use your Flex!




PowerSDR 2.6.4 is very well written and has a really nice graphical interface.  You can even skin the interface to make it look different if you care about such things.  I am using an all black skin but there are others out there that change the color of the application, buttons, and text.  This can be nice for people that have trouble with their vision (there is a high contrast skin that comes with the installer for PowerSDR even).

Flex5k-Panafall on 20mPowerSDR 2.6.4 on 20m running my the “IK3VIG Black” skin.  I am using the “Panafall” display.  A true thing of beauty!

The receiver on the Flex 5000A is simply awesome.  It is probably one of the best, if not the best receiver in an amateur radio that I have ever used.  The ability to pick out weak stations and reject strong interfering stations is very powerful with the Flex’s receiver using preset filtering or custom filters set in the software.  The Tracking Notch Filter function that was introduced in PowerSDR 2.x is very useful.  You can set several of these notch filters and have them stay on certain segments of the band that you are using.  For example, if you have some RF interference caused by some noisy electrical appliance that always seems to be at a given frequency, you can set the Tracking Notch Filter that interference and it will remember always that position notching out the interference.

PowerSDR TNFPowerSDR 2.6.4 with the Tracking Notch Filter enabled (note the green vertical bar in the panadapter at the top of the interface).

Every time I start PowerSDR I find that I learn something new.  There are so many features that I cannot list them all here, it would just take too long.

For details about the Flex 5000A’s performance and features, check out the Flex Radio Systems website for more information.

Setting up and installing a Flex 5000A is a huge pain in the ass as I outlined earlier.  But once it’s set up you should be just fine.  It is really helpful if you have an experienced Flex Elmer like I had to help.  My good friend Jeff N9IZ was kind enough to come over to my shack and help me get things working properly.

I had problems with the balanced microphone input on the Flex 5000A.  There is no preamp on this input, so if you plan to use a balanced dynamic mic you will need a preamp of some sort to drive the microphone.  Some folks use a mixer or the famed W2IHY audio equipment with their microphones, so that would work.  The Flex 5000A has extensive transmit and receive audio controls including a 3 and 10 band  EQ so you really don’t need external audio equalization.  The Foster mic connector on the front of the Flex 5000A seems to work well and is cabled for a Yaesu style 8 pin microphone.  It seems out of place on the clean front of the Flex and is kind of ugly.  They should have put a Foster connector on the back I think.  This would keep with it’s hamsexy appearance!  There is also a 1/4″ headphone jack and the very cool red LED power button.

Flex 5k frontMy sexy Flex 5000A from the front side.  Check out the sweet blue LEDs inside!

The backside of the Flex 5000A has a myriad of connectors for every option that you can imagine with an HF radio.  First off there are 3 HF antenna connectors.  This makes this radio very FLEXable (pardon the pun) should you want to use different HF antennas.  There is a External reference input for a 10 MHz oscillator, line inputs, line outputs, AMP relay, transverter, antenna connector for the optional VHF module, etc.

Flex 5k backsideThe backside of the Flex 5000A and all it’s connectors.

I do have a few gripes using the Flex 5000A.  The AGC-T is supposed to be used like an RF gain control.  This works well, but it’s a little strange as it doesn’t adjust your receiver S-meter to show you the threshold like a traditional RF gain control does on a regular knob having transceiver.

I also would like the ability to “move” some of the control buttons in PowerSDR to make the GUI a little bit more intuitive to use.  The placement of some of the controls is a little annoying causing you to search a bit to find the button or slider to activate the function that you want to use.

The “edge” style S-meter is a little ugly.  I really would like them to make a nice looking graphical needle style S-meter option like they use on the Icom IC-7600/7700/7800.  I do however like the display in dBm above the S-meter.

There are constant updates and they even take feature requests for updates to PowerSDR and radio firmware.  So perhaps I can get that sexy designed S-meter after all…

Other than that I am loving the Flex 5000A!  I have made several contacts, including DX contacts with excellent results.  I always get great audio reports, as the Flex 5000A audio is one of the most outstanding features.  A lot of hams use the Flex for AM on 80m for rag-chewing because of the audio performance.

I also got the “FlexControl” with my Flex 5000A.  This is a USB connected external tuning knob that works perfectly with the Flex.  You plug this knob into the USB port on your PC, not on a port on the Flex.  There are 4 buttons that are mapped for specific functions (3 hardware buttons and the 4th button is on the encoder shaft of the tuning knob).  The tuning knob is really nice and has a great feel to it.  The flex control also works exclusively with PowerSDR even when you have other applications open on your computer and the window focus is not on PowerSDR.  This means that you can log, yet still tune your radio without clicking from application to application.  This is a must have for a Flex owner that is into contesting.

FlexControl_420x356The USB powered FlexControl.

Well that about wraps it up for now about the Flex 5000A.  I really enjoy using this new rig and making some good DX contacts on it.  I’m sure that I will have some more posts with some additional thoughts and discoveries to come.

A big thanks to Jeff N9IZ for helping me with my Flex 5000A.  He is the Flex-master! 😉

Have a Flex or other SDR?  Tell us about it!  Post a comment below!

73! de Nick N9SJA

4 thoughts on “Flex 5000A Software Defined Radio

  1. Great write up and I just bought a used Flex5000A and followed your instructions and all the software and
    the firewire card installed with no problems on a Win7 system

  2. Great read on your first full experience with Flex radio. Now I want to tell you how to make your flex the even bigger dream machine. Go to the web site of KE9NS and download Power SDR T8. The very least it does is give you a choice of meter types, including the one you said you would like to have. The T8 Power SDR is an enhanced version that changes a lot about the Flex 5000 and older flex radios, once they went to the 6000 series, they changed how they render the screen, so there is no way to enhance it. T8 also has 9 levels of band stacking, and they have an edit screen so you can change the options on any memory that is in the stack. There is also a DX Cluster built in, and way too much for me to cover it all.
    The last thing is the Hercules DJ board that adds hardware controls for many functions, and it is all customizable by you. There is a whole world of third party support for your flex, and you can read up on it on KE9NS’s web site.

    • I have been using the flex 5000a for 6 months with KE9NS, I own a flex 6400 and have not used it since the day I bought the 5000A. S / N ratio between the two radios clearly in favor of the 5000A. fantastic and complete KE9NS software, soon pasta with tomato and coffee will also do. Very poor ssdr and too many external programs

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