INTRODUCTION

UTILIZATION OF THE COMPUTER

Although laptops don't offer the flexibility of easily adding additional ports, or new modems, or hardware upgrades, they DO offer some real advantages. The most obvious benefit is that they are PORTABLE!  It is easy to take your logging, automatic sending, antenna aiming and complete station control with you on a mountain top DXpedition or on a mobile "rover" operation. Compared to RFI generated by many desktops, laptops also are very clean and quiet.  And, they are becoming much more affordable.  So, here is how I utilized mine to help me make my time operating more productive and fun.

RADIO EQUIPMENT

SEQUENCER/INTERFACE BOX

The heart of my station is the little box I built that houses my Level Converter and my Sequencer, and serves as a junction box for:

• my automatic control lines (the serial port cable from the computer) and the manual control lines (the footswitch, front panel toggle switch)
• the audio input lines (from my headset microphone, and from the computer sound card  Line Output) and audio output line (to the XMTR microphone input)
• PTT line to the XMTR microphone jack to put the rig into XMIT
• the CW keying lines (input lines from the keyer and straight key and output line to the XMTR)
• all the miscellaneous relay and amplifier control lines
• the Level Converter output line to connect my rig to the computer

The "Level Converter" is a way to let your computer control your rig and/or obtain information from it.  It is not essential for control of the station, but was an added bonus, since my logging program, TRX-Manager, ALSO provides for the option of rig control.  And, since I wanted to utilize the automatic sending and control features offered by the computer programs, I had already committed myself to an interface box to connect to the Serial Port of my computer. So, it was a natural step to go ahead and incorporate a Level Converter into the station at the same time, and enjoy the luxury of having my logbook automatically filled out with the band, mode, frequency, etc. (plus many other functions)!

 The Level Converter I use was built using the MAX232 IC circuit, shown in the ARRL Handbook.  I purchased the PC board and parts from Far Circuits .  You also can purchase ready built interfaces from the manufacturers of your radio equipment (or a number of different independent manufacturers). One of the reasons I made my own level converter (rather than purchase one ready-made) was because I wanted to use only the two necessary lines from the serial port needed for rig control (RX and TX), and route the others to use for PTT, PTT INTERRUPT and CW KEYING.

The sequencer board I used was a printed circuit board kit (DEM model TRSK) from DownEast Microwave Inc.  The function of the sequencer is to sequentially turn on/off all the equipment and relays when switching between XMIT and RECV, so that nothing is damaged. I had been wanting to do this for decades, since it is the only "sure way" to keep form "hot switching" relays, blowing up preamps, etc. etc. - it certainly is nice to have it in place, and also a true pleasure to have software that can take advantage of it.  At my station, I use a Heil MC-5 boom mic in conjunction with a Radio Shack foot switch. I use an adapter plug from Heil than simply plugs into the front panel mic jack on my IC746, and provides 1/8" jacks for the input of the audio input and the PTT control line (both from my sequencer box).  In my case, the footswitch is one of the two manual methods to turn on the sequencer (the other method is a toggle switch built into the front of the sequencer box), and in turn, switch  over to XMIT.  The other way the sequencer is turned on is via the serial port of my computer.

Both TRX-Manager and VKE (or the two working together) have the option for separate PTT control lines, so the station can be put into transmit BEFORE any signals (either audio or CW) are sent to the XMTR.  Since the XMTR is never run in "VOX" or "BREAK IN" mode, it can only actually transmit a signal when it is turned on (in my situation, by the sequencer board).  However, even if you did not have a sequencer to insure the proper switching sequence, both computer programs  let you delay the start of your SSB or CW messages by whatever type of delay you feel is necessary for all your relays to close (the delay following the PTT signal coming from the computer).

If you have more than one Serial Port on your computer, you can simply use one port for each particular software application.  However, in case you only have one Serial Port (as on my Toshiba laptop) I have shown below how I set up the lines from a single Serial Port to control my station. You should remember that this convenience is only possible because both the programs I use were specially written to work together to share a single Serial Port.  An especially useful benefit for us laptop owners!
 

SERIAL  PORT LINE	DB-9  PIN #	DB-25 PIN #	COMPUTER PROGRAM	UTILIZATION	NOTES
DCD	1	8
RX	2	3	TRX-Manager	To Level Converter for Rig Control	1
TX*	3	2	TRX-Manager	To Level Converter for Rig Control	2
DTR*	4	20	TRX-Manager	CW Keying line output	3
SIG GND	5	7		Grounded	4
DSR	6	6	TRX-Manager and/or VKE	PTT Interrupt	5
RTS*	7	4	TRX-Manager, WSJT and/or VKE	PTT Control Line	6
CTS	8	5
RI	9	22

SERIAL PORT TABLE NOTES:

1.  Connected to the RX input of the Level Converter.
2.  Connected to the TX input of the Level Converter.  I used the circuit for the The output from the Level Converter is then sent via a 1/8" plug to my IC 746.
3. This is a +12 VDC signal from the computer to key the XMTR CW circuit.  I connect this line to the base of a 2N2222 transistor to provide isolation from the actual keying in the rig.  I also connect the transistor output in parallel with the output from my electronic keyer and straight key, so i can send however I want.
4. This is grounded to my rig and station ground.
5. This line needs to be +12 VDC go stop the computer programs from automatically sending.  I use a footswitch or a front panel switch on my interfaces box to ground the "PTTL" input on the DEM TRSK SEQUENCER.  This activates the sequencer board with the low (shorted to ground) and turns the station into transmit manually. I also use this same switch closure to ground to turn off another 2N2222 transistor, which in turn switches another 2N2222 ON.  The +12VDC signal from the second transistor (which comes on when I manually go into XMIT), goes back to the computer on this PTT INTERRUPT line to immediately stop the automatic sending of the computer programs, and tell them that I am now sending manually.
6. This line is a +12 VDC signal from the computer when the station is to be put into the XMIT mode from the computer (automatic mode).  I attach it directly to the "PTTH" input on the DEM TRSK SEQUENCER board, to turn it on and begin the automatic sequencing.  I also use this line from the computer to turn on a 2N2222 transistor, that in turn activates a small SPDT printed circuit board type relay.  When energized, this relay switches the microphone audio line going to the XMTR between  the audio cable from my headset microphone (where it is usually connected, in the relay "normally closed" position), and the attenuated computer audio "LINE OUTPUT".  Using this small relay makes it impossible to transmit manual messages from the mic at the same time as recorded messages from the computer.

A few IMPORTANT NOTES need to be added regarding the handling of the audio lines.  It is necessary to make sure that there are NO ground loops (which will introduce him into the XMTR).  As a first precaution, the computer LINE OUTPUT was attenuated after using an inexpensive 1:1 audio transformer to completely isolate it.  NOTE - the 'low side' of this transformer is NOT connected to chassis ground - only to the shield of the audio lead going to the computer sound card.  All the mono audio leads to and from the interface box were passed through 1/8" stereo (3 conductor) jacks and plugs, so the shields of the audio cables could be prevented from contacting the ground of the box. The shield on the headset mic is only grounded by connection to the shield on the output audio line actually going to the XMTR mic input (grounded only at the rig chassis).  And the shield on the line going to the computer is only grounded at the computer sound card end.  Keep all the audio lines as short as possible.  This arrangement has worked very well here - even when running the 8877 with the antenna pointed in the direction of the house.  If you have additional problems, it may be necessary to use optical couplers to avoid ground loops.

VKE - VOICE KEYER EXPRESS

The first step was to employ a very flexible and powerful voice keyer.  How many times is the band open when everybody  is sitting around monitoring?  Even just sending out a 15 CQ every few minutes can be very helpful in finding out if there is anything going on (especially when your nearest neighbor is in the next grid square).  I will never forget on of the first 2m meteor scatter QSL cards I received (back in the mid 1960's, from K0MQS) - it showed a mother cat leading her kittens home at night along the top of a wooden fence under the moonlight, and was captioned, "If you wanna get results, you gotta make calls!"  I wanted a voice keyer that I wouldn't outgrow - one that I could always use.  So, I chose VKE-VOICE KEYER EXPRESS for the following reasons:
 

1. It is computer based, so it is easily transported on a laptop computer without the need for yet another box.
   
2. It has the option of simple message repeats (with adjustable listening time between transmissions).
3. It has the option of synchronized message repeats using 15, 30,60 or 120 second periods (ideal for meteor scatter or other schedules, or "random" CQing so you and your neighbors can all be transmitting in the same periods and not interfere with each other).  It simply uses the clock in your computer to keep the schedules in sync.
4. You can select from any number of .wav file messages you want to record onto your computer.  And since it is sending .wav files to the audio input of your transmitter, you can use it to automatically call on SSB, OR to send HSCW (high speed CW), or even regular CW ( I did this using .wav files with the CW message recorded using a 2 KHz audio tone for a very clean transmitted signal).
   
5. It is a Windows program, and works with all standard Windows compatible sound cards.
6. It offers the option to turn on the PTT line going to your transmitter (or sequencer board, if you are REALLY organized), so everything can have time to switch before the actual transmission begins (you set the number of milliseconds delay you want/need to have before it actually starts sending the recorded message).
7. It features a PTT INTERRUPT option to stop the automatic transmissions at any time through a switch closure (such as a footswitch or microphone PTT switch).  This provides the flexibility to instantly switch to manual transmissions (without having the automatic message continue to come on over top of you, or start up again after you try to go back to receive).  This is VERY slick for the "quick break" when a meteor comes along :-)

The next step was to find a full-featured and affordable logging program that would work well for a serious VHFer.  I finally selected TRX-MANAGER for the following reasons:

1. It automatically calculates distance and direction to the station you are logging, using all 6 digits of the grid square locator found on the CD you are using (if you are not using a CD, it just provides information based on whatever grid square information you enter manually into the logbook).  With a sharp antenna (such as used on VHF/UHF), I find this 6 character accuracy makes a real difference as to where you point (out to about 800 miles, anyway).
2. It features a built-in CW keyer (with the same PTT and PTT INTERRUPT functions as in VKE!), so you can automatically send CW in typing mode, stored message mode, standard simple repeat mode, or a synchronized timed schedule mode, using whatever kind of fixed timing sequence structure you want (ALL possible conventions are possible for meteor scatter, EME, tropo, etc., etc.).  This is the FIRST TIME I have ever had the capability of running a CW beacon that safely  automatically switches the station into XMIT first - before beginning the actual transmission.   It sure is neat!
3. It also can work IN CONJUNCTION with VKE, so all the controls and programs still only use a single simple serial port interface!  This is VERY attractive for those of us who want the ability to control the station with a laptop computer - we MUST keep it simple!
4. TRX-Manager offers many features.  It keeps track of things like the number of previous QSO's you have had, DXCC and GRID SQUARES, and shows you whether the station you are logging is a new one for you.   There are many other features I have not yet explored (such as automatic spotting on the Internet, packet cluster listings, automatic rotor control, scanning indicator frequencies, remote control of the rig via a telephone or UHF link, etc.).  Another convenient feature is that the logbook is kept in a standard Microsoft ACCESS file format, so custom reports can be easily generated through either ACCESS or EXCEL.  And, I was able to easily import my old logbook (from LogWindows, which never even showed me the grids of the stations I worked in its logbook).
5. It also can be used to control your rig, if it is one of the more modern rigs by Kneed, Icom, Yaesu, or Ten-Tec.  This means that the band, frequency mode,  signal report (yes, right off the rig's S meter!) is all automatically downloaded into your logbook, even if you rapidly jump back and forth between bands (like I have done in the VHF contests with my IC-746).  What a treat!  Of course, if you want to take full advantage of this function, you must provide a "Level Converter interface"  between your computer serial port and the rig (as is included in the "RIGblaster PRO" model from West Mountain Radio).
6. Compared to other logging-only programs, it is relatively small and efficient - even with all the rig control software built in!  This is an important consideration for those of us who want the ability to run it on a small laptop computer.

DSP PROGRAMS

The computer has also made it possible to take full advantage of weak signal reception.  This is especially valuable in EME communications, where signals are often quite weak.  I have used the computer to help make contacts on both 6m and 2m EME.

FFTDSP.  In the past, I have used the famous AF9Y FFTDSP software program to find weak signals, and employed an outboard narrow DSP audio CW filter (a TI TMS320C5X unit, operated via the serial port of my computer) to hear them.  However, a new program called SPECTRAN combines these two features and also uses any standard Windows-based sound card.

SPECTRAN.  For my situation, SPECTRAN offers a very exciting possibility, because it provides for  weak signal spotting AND DSP audio filtering through the use of my computer sound card - without tying up the use of my serial port.  That leaves my serial port free for TRX-Manager and VKE to control my rig and automatically import all the pertinent logging information.  However, because Spectran introduces a delay into the audio during processing, it is impossible to listen to the processed audio output when simply tuning across the band, or monitoring a CW side tone (or you own SSB signal) during XMIT.  In order to make the most effective use of this innovative program, it is advisable to build a simple interface box to switch the audio cables involved to the proper sound card ports.  At  my station, I use a small box housing a DPDT relay (controlled by a free jack on my SEQUENCER box) and a manual DPDT on/off switch to take the input lines from the XMTR audio input,  RCVR audio output, and headphones and properly route them to the computer sound care LINE INPUT and LINE OUTPUT jacks.

The relay in this little audio interface box assures that the headphones are always connected directly to the RCVR audio output during XMIT.  In addition, the LINE INPUT jack is automatically broken during XMIT, to avoid potential feedback problems. (A "momentary on" pushbutton switch was added to the box to provide an exception to this, in the event a "spot" function is desired).  On the other relay contacts, the headphones are switched to either the sound card LINE OUTPUT (on receive) or the RCVR audio output (on XMIT).  On receive, the RCVR audio output is always made available to the computer LINE INPUT (whether the box is manually switched on or off).  This allows the receiver audio to be used to display signals in the audio spectrum with SPECTRAN, even if the headphones are not listening to the processed audio (run through SPECTRAN, and available through the sound card LINE OUT).

The manual ON/OFF switch is NOT used to enable the relay, which is always tied to the station sequencer; instead, it switches the audio lines inside the box,  to create more of computer audio processing "IN/OUT" function as far as the headphones are concerned.  When the manual DPDT control on the box is switch OFF, the audio for the headphones is always connected to the RCVR audio output, and the LINE OUTPUT audio is always sent to the XMTR audio input (to allow VKE to automatically send audio messages).  When switched  ON, the headphones are subject to control by the relay action (connected to the RCVR audio output on XMIT and the sound card LINE OUTPUT on receive).

DIGITAL COMMUNICATION MODES.  As you can imagine from the above information, my SEQUENCER BOX (with its interfaces for the computer sound card audio lines, and PTT control via the serial port) immediately provides  provides full capability to operate any of the digital modes (PSK31, FSK441, JT6M, JT44. etc.)  Since I am primarily involved in weak signal VHF activities, I have become very active using JT44 mode.  Please see my JT44 web page for more information on this exciting tool!

INTERNET ALERTS

Especially when it comes to 6m, where propagation changes very quickly, it has been extremely helpful to be able to watch reports of what is going on at other locations and prepare accordingly if it appears that propagation is heading toward you.  I find the following Internet sources of information particularly valuable tools when operating 6m:

50 MHz PROPAGATION LOGGER
DX Monitor for the DX Summit
Chat Page on DXERS.INFO (also can display both of the above at once)
Near-Real-Time MUF Map

In summary, I have to say WHAT A JOY it has become to operate the station - without worrying about shorting out something or overloading a preamp, or hot switching the relays!  And immediately seeing what new countries and grid squares are needed and where to point for them!  And being able to finally automatically send CW in timed EME sequences!  Finally an immediately tangible benefit from computers that I could put to good home use!   The computer sure has made my life a lot easier, more fun, AND has helped me be more successful in making VHF contacts.  I hope you can find as much pleasure in the above programs as I have, and the above information and tips are helpful to you in making the most out of your equipment.

GL and DX!