Many thanks for these detailed instructions. I've been postponing the setup attempt for months, wanting to keep from screwing up the Flex 5000. Now, no more excuses....


----- Original Message ----- From: "Brian Lloyd" <>
To: "FlexRadio reflector" <>
Cc: "Stelios Bounanos" <>
Sent: Friday, January 01, 2010 2:32 AM
Subject: Re: [Flexradio] fldigi & Flex 5000A; DDUtil

I have promised to write a how-to for configuring fldigi to work with
PowerSDR on the Windows platform for the fldigi folks. I run mine
without any problems whatsoever but then, I am still running XP. I
have no intention of even considering Windows 7 until Microsoft comes
out with SP1.

I can tell you how to configure VAC, VSPmgr, PowerSDR, and fldigi but
if anything is Win7 dependent/specific, I can't help with that. Also,
these instructions do not address using ddutil. If you want to do rig
control of an amplifier, rotator, or other external device in addition
to fldigi, you can add that later. For now follow these steps in order
to get fldigi and PowerSDR to play together. It is perfectly OK to add
ddutil into the mix later.

Here are the steps.

1. Download all the software pieces you need.

Here is a list of the software you are going to need:

a. PowerSDR (

b. the flex FireWire driver (

c. fldigi (
I am running the alpha version 3.13BK right now but you can run the
production version.

d. the PowerSDR rig description XML file for fldigi's RigCAT

e. VAC v4.09 (
You must purchase the release version. You MUST NOT run the demo version.

f. VSPmanager (

2. Install the Flex firewire driver.

I am not going to address which one because it depends on which
version of PowerSDR your are running. For the purposes of these
instructions you should assume that you are installing the latest
released version of the driver. Follow Flex's instructions. I use a
buffer size of 2048 and a sample rate of 96ksps.

3. Install PowerSDR.

Again, I assume you are installing the release version and it is
compatible with the driver you have installed. Make sure that the
sample rate and buffer size (Setup>Audio>Primary) match the driver.
(The new driver may automatically track the settings in PowerSDR. Even
so, verify they are set the same.)

4. Make sure that PowerSDR both transmits and receives. It should run normally.

5. Install VAC.

Follow the instructions provided with VAC. There are some differences
between installing with XP, Vista, and Win7 so be sure you read the
instructions, most notably in how to deal with unsigned drivers in
Vista and Win7.

NOTE: you MUST MUST MUST use the purchased-version of VAC 4.09. You
MUST NOT, MUST NOT, MUST NOT use the demo version!!!!! Go ahead and
buy it. It will work.

6. Open the VAC control program Control Panel and configure VAC.

You get to the VAC control panel from the Windows "Start" button under
"All Programs". Look for the "Virtual Audio Cable" menu item and then
select Control panel.

In the upper left hand corner of the control panel for VAC you want to
set it for 2 cables. I left all the other settings alone. Click the
'Set' and 'Restart' buttons. If you want to check, here is what I have
all the VAC parameters set for:

 SR 22050..48000, BPS 8..16, NC 1..2, Max inst 20, Ms per int 7,
Stream fmt "Cable Range", Volume control (unchecked), Connected source
lines "line", Clock corr% 100.000.

Once you click the Restart button you should see cable 1 and cable 2
appear in the lower section of the Virtual Audio Cable Control Panel
(if not sooner).

7. Now set up VSPmgr.

For now you will create a single port-pair that will be used for CAT
control of fldigi by PowerSDR. Both rig control and PTT will be
handled by this single port-pair.

Start the VSPmgr utility. It will show you your physical serial ports
and offer to create a virtual port pair. Make sure that your virtual
port pair starts above any possible physical serial port numbers. It
is possible for virtual ports to conflict with physical ports if the
physical ports are added later. In my case I created port pair
COM6/COM7 for communications between PowerSDR and fldigi. Most of the
examples use COM6/COM16 or COM7/COM17 but I discovered that some
programs, e.g. WSJT and WSPR, have problems with port numbers above 9.
Therefore by creating a port-pair where both com numbers are below 10
means that the configuration may be used later on to communicate with
these other programs.

Setting up the port-pair is nothing more than selecting the desired
values for End 1 and End 2, COM6 and COM7 in this case, and clicking
the "Create Pair" button.

8. Set up PowerSDR to use VAC.

With PowerSDR running, click on "Setup", select the "Audio", and then
the "VAC" tabs to display the VAC setup page. Set the options as
listed here:

"Enable VAC" checked;
Driver: Windows WDM-KS
Input: Virtual Cable 2
Output: Virtual Cable 1
Auto Enable checked;
Buffer Size 512
Sample Rate 48000RX gain 0dB
TX gain -1dB

Leave the other boxes, i.e. Mono/Stereo, Latency Manual, and Direct
I/Q, unchecked.

(The check box for "Allow PTT override VAC for Phone" is a personal
preferences. I do not have it checked on mine because I don't want to
accidentally press PTT and have my mic go live when operating digital

9. Set up CAT in PowerSDR.

With the "PowerSDR Setup" window still open from step 8 above, click
on the "CAT Control" tab.

In the upper right of the window set "ID as:" to "PowerSDR".

Under "CAT Control" make sure the "Enable CAT" check box is unchecked.
You need to do this to be able to change the settings. Set the
following values:

Port: COM6
Baud 57600
Parity none
Data 8
Stop 1

After you have set the above values, check the "Enable CAT" box.

Click the "Apply" button at the bottom of the frame.

(Note: with a virtual serial port baud rate, parity, and number of
stop bits really has no meaning. I specify them here just to make sure
that no one is confused by an omission.)

Do not check the box "Enable PTT". That is for hardware PTT using a
separate serial port. Fldigi will use a CAT command to key and unkey
the Flex rather than RTS or DTR on a separate serial port.

Also, do not enable either of the RTTY offsets. If you do it will
cause the frequency display on the waterfall in fldigi to be
incorrect. Since fldigi does not adhere to a strict offset of 2125 Hz
for the mark tone in RTTY, the offset will just confuse things. It
also is meaningless in other modes, like PSK.

If you are a veteran RTTY op you will find that running digital modes
with fldigi is a bit of a departure because it doesn't use a fixed
offset. Rather you can select any station on the fldigi waterfall just
by clicking on it and you won't have to retune the rig. After a few
minutes of operating this way you will see the advantage and how it
reduces confusion.

10. Set the "sweet spot" for PowerSDR's click-tune.

One of the nice features of PowerSDR is the ability to use the mouse
to click on a signal that appears in the panadaptor or the waterfall
and have the radio tune to that frequency. Normally that would set the
VFO to the frequency represented by the cursor bar which works for SSB
(where the carrier should go) and CW (already has an offset for the
beat note) but does not work for digital modes because you would have
to displace the cursor by the proper amount from the signal. To make
this easier PowerSDR lets you specify a click-tune offset. I use 1500
Hz and then have fldigi normally use a 1500 Hz offset for normal
operation (1500 Hz "sweet spot"). This allows me to center the
PowerSDR frequency cursor on the middle of the digital signal I want
to receive, and have the signal appear at 1500 Hz in fldigi. In most
cases I can get close enough for good copy and the AFC in fldigi takes
care of the small error, if any (usually less than 10Hz). This makes
hopping around to see different signals very easy, much easier than
using the waterfall in fldigi. Here is how you set the digital mode
offset in PowerSDR:

From the PowerSDR Setup window click on the "General" tab. At the
lower left corner of the window you will see a box labeled "Click Tune
Offsets (Hz)". I set them to 1500Hz so that when I click on the center
of a digital signal, it will cause that signal to be centered at 1500
Hz in fldigi.

11. Make sure that PowerSDR is running. If not, click the PowerSDR
"Start" button.

This completes the configuration of PowerSDR to use fldigi. Now we
setup fldigi itself.

12. Install fldigi. (This document assumes that you are running fldigi
on the same computer that is running PowerSDR so that means you have
installed the Windows version of fldigi.)

13. Install the RigCAT xml description file for PowerSDR.

On Windows fldigi keeps its configuration files in the fldigi.files
directory (folder) in the user's home directory, i.e. C:\Documents and
Settings\<username>\fldigi.files (assuming XP). In fldigi.file you
will find a folder named "rigs". Place the RigCAT description file for
PowerSDR, i.e. PowerSDR.xml, into the rigs folder.

14. Start fldigi to perform configuration. You may get an error
message because the audio input has not been selected. Just dismiss
any error messages. Click on the "Configure" menu item to perform the
configuration process for fldigi. It will offer you several options.
It doesn't matter where you start but you need only configure "Sound
Card" and "Rig Control" to get fldigi working with PowerSDR.

15. Click "Sound Card" to start the configuration of fldigi to use VAC
to communicate with PowerSDR.

The "Fldigi configuration" window will pop up with the "Audio" tab
selected. If the "Devices" sub-tab is not selected, select it.

Click the "PortAudio" selection button if it is not already selected.
For "Capture:" set "Virtual Cable 1". For "Playback:" set "Virtual
Cable 2.

The waterfall should come alive just as soon as you set the proper
virtual cables for input and output. In my case that didn't happen. I
found that I have had trouble with fldigi getting the sample rate
correct when in "Auto" or "Native" mode. If you see the following
error message, "PortAudio error: Invalid sample rate," click on the
"Settings" sub-tab and set both the Capture and Playback sample rates
to 48000 to match the setting for VAC in PowerSDR.

As long as you are at the "Settings" window for "Audio" you can check
the following:

For the sample rate converter ("Converter") set "Medium Sinc
Interpolator" if it isn't already set.

Corrections should all be set to zero.

16. Set up RigCAT to control PowerSDR and vice-versa.

Click the "Rig" tab at the top of the configuration window. Fldigi
supports several ways to communicate with your rig. We are going to
use RigCAT. (Hamlib works too but I am not going to cover that.)

Click on the "RigCAT" subtab to bring up the RigCAT configuration window.

Click the "Open" button next to the "Rig description file:" box. That
will let you select the proper rig description file. Navigate to the
rigs folder if not already there and select "PowerSDR.xml".

Below that are some timing settings for communication between fldigi
and PowerSDR. These are influenced by the speed of your computer. I
use the following:

Retries 3
Retry interval 50ms
Write delay 25ms

If you get error messages from fldigi about communications failure
with the rig, try increasing the Write delay and/or Retries. If you
notice that the response time is too long, i.e. frequency changes in
PowerSDR or fldigi take noticeably too long to be reflected in the
other program you can try reducing the delays.

In "Device:" select "COM7".

Click the radio button next to "CAT command for PTT".

Go back up to the top and click the check-box for "Use RigCAT".

Now click the "Initialize" followed by the "Save" buttons.

If rig control is working you should see the VFO frequency for
PowerSDR appear in the frequency display of fldigi. If you tune
PowerSDR, the frequency display of fldigi should automatically follow.
If you click the "T/R" button near the lower right side of the fldigi
screen, the Flex radio should key up. These two tests confirm that
RigCAT is working.

17. Set the "Sweet Spot" so that fldigi works properly with the
click-tune function of PowerSDR.

Click on the "Misc" tab at the top of the configuration window. Click
on the "Sweet Spot" sub-tab.

Set the CW value to the frequency of the CW note you use. Set "RTTY"
and "PSK et al." both to 1500.

Click the "Save" button.

18. Set the operator and QTH info.

Click on the "Operator" tab at the top of the configuration window and
fill in the information. When done, click the "Save" and "Close"

At this point, fldigi and PowerSDR are set up and should be working
together. There are quite a few other things that can be set up in
fldigi to suit your operating preferences but that is beyond the scope
of this document. Refer to the fldigi manual to see what all the other
functions do.

73 de Brian, WB6RQN/J79BPL

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