Lions and Tigers and Bears – Oh My! – Serial Ports in the Complex Ham Software Setup

I’ve been amazed, and deeply frustrated, at the complexity of a full software defined radio software suite setup. I expect mine is tad bit more complex than some, but nothing extraordinary.

Behind the scenes two vital software utilities have to be fully fired up – VAC (Virtual Audio Cables) which manages audio connections “in the black box,” and a Serial Port Manager (I use VSP Manager which is further managed by DDUtil) which manages “Pairings” of virtual serial port assignments.

It is at the DDUTIL level that complexity is the greatest.

VAC – Virtual Audio Cables

Ok, inside your computer you don’t have the ability to “patch” audio to the various programs like you would if each “piece” of the Audio Chain were a separate physical component.  Unlike putting together a stereo rack where you can cable the tuner to the amp, the CD player to the Amp, the CDRom Burner to perhaps all, and those legacy Turntable & Tape Decks to the amp – or in cases where the tuner  acts as the “hub” they get hard cabled there… in the SDR software suite software has to patch the audio to where it needs to flow or return.

Eugene Muzychenko has created the needed software, his product being what 99% of radio amateurs working with this problem use.

The Wiki Page on VAC: http://en.wikipedia.org/wiki/Virtual_Audio_Cable

Eugene Muzychenko’s VAC page: http://software.muzychenko.net/eng/vac.htm

VAC is audiophile grade software, with oodles of configuration selections that arguably are best left alone or setup in known working configuration for our purposes.

Please note that the free demo version of VAC is unsuitable for anything other than setting up basic configurations.  Do not use it on the air as the Demo Message will raise havoc.  VAC is a 22 Euro or USD $30 investment that being rather unique should be planned as part of your setup costs to do complex SDR.  Actually you can buy VAC from the developer for $25.20 to $50.50 depending on the level of support you want.  He also has a number of resellers.

One reseller has a nice page explaining what this VAC thing is all about:  http://www.fox-magic.com/vac.php

In my case I have only one pair of VAC Cables setup, though technically I would benefit from a second set connected to the RX2 (technically third receiver) in the Flex-5000A.

VSP Manager

K5FR is the person behind the next two parts of the puzzle.  VSP Manager creates pairs of virtual serial ports.

VSP Manager is available on request from K5FR for non-commercial use.  Details are at:  http://k5fr.com/ddutilwiki/index.php?title=VSP_Manager

There are alternatives to VSP Manager, and various technical reasons bantered about why this or that Virtual Serial Port is better.

Working well and being highly compatible with the real gatekeeper – DDUtil – is reason enough for me to stick with VSP Manager.

DDUtil

Now we get to the “switchboard, Router & patch panel” hub of the whole setup.

DDUtil by K5FR is found at:  http://k5fr.com/DDUtil.htm and http://k5fr.com/ddutilwiki/index.php?title=Main_Page

In Steve K5FR’s own words:

…..DDUtil, which is short for Data Decoder UtilityDDUtil was designed to enhance the operating experience for Flex Radio users by providing advanced connectivity to peripheral equipment and Radio Control Programs (RCPs) not before available.

DDUtil provides the automation required to decode and present transmit frequency data to select frequency sensitive devices such as linear amplifiers, antenna controllers (SteppIR), antenna tuners, antenna band switchers, etc. DDUtil may be used in a stand-alone mode or with up to four (5) Radio Control Programs(RCPs) running simultaneously.

DDUtil automatically senses when a RCP is trying to communicate with PowerSDR and modifies it’s mode of operation accordingly.

AnXMLfile is used to provide the reference data needed for the BCDoutput data. A sample file is included with the distribution files to serve as a guide. This file may be created from scratch or modified from the sample provided and then saved with an appropriate user name. All file modification may be accomplished within the program or may be done in any XML file editor of the users choice. But, unless the user is familiar with XML file editing it is recommended that XML file modification be confined to DDUtil until proficiency is obtained. Please note that this file requires a specific format see the BCD Data File Format topic in Setup / Other Topics for details.

The initial release is designed for the Flex family of radios including the SDR-1000, Flex-5000, Flex-3000 and Flex-1500 series…..

The DDUtil Block Chart perhaps explains it best:  DDUtil Flow Chart  (also at http://k5fr.com/ddutilwiki/images/DDUtilFlow.pdf )

Setting up DDUtil is a bit of a fiddle unless you make time to read the Wiki and the excellent articles at the Flex-Radio Knowledge-Base.  I would roughly estimate that the time I didn’t invest reading first cost me 4 to 5 times as much time fiddling & fixing later.

The Enemies of SDR Software – Latency and Conflicts

First of the two big enemies of “Radio in Computer” seem to be Latency – the delays introduced by hardware & software in audio streams, program functions, program-to-program data transfer, or between the SDR hardware (the “physical radio”) and the Computer (the “Software Radio”).

Tweaking in software design and optimizing components can make a huge reduction in induced Latency.

I’ve fought issues with software not in the SDR suite of programs dragging my system down – an early version of TeamViewer and various software update nag-ware programs have been the worse.  Adobe products and some Anti-Virus packages can be a problem as well.  Flex-Radio includes in its PowerSDR and Flex-Radio software a program simply called “Flex-Radio” which can be used to closely monitor system Latency.  The software will help you configure the software to optimize given your computer’s measured latency.

The second bugabo is the Conflicts can occur and are such a devil to sort out.  Things like various software fighting to access the same Serial Port, creating more than one Serial Port assigned the same number, fights between port assignments with expansion software, programs that are “just crabby” and don’t play well with others….  The list is fairly long and sticking with known compatible combinations can help you get up and running easily.

If you are like me and want to fiddle with other software while running the station – a browser, an editor to make notes, a call book lookup program, some space weather, weather, and time programs…. well it can be a fiddle sorting things out.  Several browsers seem to “bloat” while running the SDR suite and specially Safari for Windows seems to hog system resources upsetting the rest of the system.

I’m looking into replacing the several year old Dell Windows-XP dual core machine I am using with a new Windows-7 Multi-Core machine with its greater capabilities.  One of my Dayton 2012 goals was to talk with Neal K3NC  the PowerSDR Computer guru at the Flex-Radio booth, though Neal has had to take a pass for Dayton this year for health reasons.

How do you get enough physical ports to plug in all your stuff?

I faced this right away.  Most new machine have at best one or two serial ports.  Hardly enough to run a serial cable to each of the station components.  Presently I have serial cables to:

  • An SPE Expert 1KW Amp
  • A Palstar AT-Auto Antenna Tuner
  • A Begali CW Machine
  • A Green Heron RT-20 Rotor Control
  • An Array Solutions PowerMaster Watt & SWR Meter

And I want to reserve future ports for:

  • A computer controllable remote antenna switch
  • Power Control Hardware for the Flex-5000A Unit

So how does one hook up seven serial cables to a machine that came set up for two?

I bought a Serial Port Expansion Module that had formerly been used as part of a commercial Point-of-Sale setup.  This added eight assignable ports easily and with high reliability.

Word of warning, one has to again read the directions in assigning port numbers to the expansion unit so they neither conflict with existing port assignments or overlap your VSP Manager assignments.  Some of your software may require specific restrictions on post assignments you need to work around as well.

More esoteric deep in your machine USB and Serial ports can interact as well. Consider this an advanced subject!

What do you get for all this?

What do you get for braving all the “Lions and Tigers and Bears” of doing a full SDR software suite?  As it is easy to chronicle the woes of getting (and keeping) the software running, one forgets that their is some real joy to be gained in doing all this.

What you end up with is:

A DX Chasing “Machine” that has integrated rotor, amp, tuner and wattmeter displays & controls.  In my case the SPE Expert 1KW Amp, Palstar AT-Auto Antenna Tuner, Array Solutions PowerMaster SWR Meter and Green Heron RT-20 rotor controller are all integrated.

Quick switch between a QRO SSB setup to a digital mode station running JT65-HF or fldigi(Win) seamlessly.

Integrated logging (though I do have to manually add into my master log adi logs from auxiliary programs).

Receive performance rivaling top shelf dedicated monitoring receivers costing more than my entire station investment.

An “If you can Hear it, You CAN work it” capability – for a simple station I catch a lot on the air even when other area hams say the “bands are dead.”

What’s Next?

Other than the likely computer system update, the biggest forward change I see is to replace the Array Solutions RatPAK remote antenna switch with a configuration that can be controlled by the software.  I can either reconfigure feed lines to cover 160m-10m without an external antenna switch, or find a remote switch that can interface.  Looks like a Dayton 2012 “to do list” item to figure out what remote switch would work.

Through using the DDUtil suite I have learned that under certain circumstances my Flex-5000A’s power supply is underperforming, and that is on the upgrade list.

Remoting everything is up there.  Likely to wait until the Computer Update is done, this involves a small hardware hack of the Flex-5000A itself to allow remote power switch control.

Making use of a multi-antenna “diversity” listening configuration – as mentioned if I can hear the DX station I can usually work them, so further improving the stations “ears” only makes sense.  Power SDR has built-in features that I haven’t even begun to exploit when it comes to using the RX2 receiver and multiple antenna configurations.

All in all a lot of fun, easy to set up if you bite off small chunks at a time and read the instructions, and well worth the effort in results.

73

Steve
K9ZW

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