Here we have some photos of the AHARS BBS equipment. Rob, VK5RG, may be seen operating the equipment in the right-most two photos.

Click on any of the images to view a larger version!

Back to AHARS Home Page

The Adelaide Hills Amateur Radio Society (AHARS) meets monthly at Blackwood in the Adelaide Hills. The Society membership at July 2000 was over 100. For many years AHARS has made monetary donations to other Radio Clubs in South Australia, to assist in the installation and upgrade of their voice and packet repeaters. Over $1,000.00 has been donated to the South Australian Amateur Radio community. In addition to a technical lecture programme and two social dinners, AHARS convenes a major amateur and electronics equipment sale each year at the Westbourne Park Community Centre.

In 1997, a group of members suggested that the Society establish its own repeater for general use. Following discussions with other groups, it was decided to establish a PACTOR BBS, which could be used by Amateurs throughout Australia for interconnection to the AX25 Packet Radio Network. At the time, PACTOR forwarding and mail box facilities were available from only a few dedicated private operators, with no institutional (Radio Club) support for this activity. Meetings between a number of Packet Gateway operators and the Society revealed great support for a dedicated High Frequency BBS. It was considered that with Internet backup, the existing gateway and forwarding facilities were quite adequate for all current requirements.

The initial aim was to provide a facility for outback travellers and Australian stations, out of reach of the VHF/UHF AX25 network, with particular attention to Intermediate Class Licensees. With the opening of further High Frequency bands to this group of Amateurs, this parameter has been reconsidered, and the system is now available to all Australian amateurs on the main High Frequency bands.

A sub-Committee

An initial approach to the Committee of AHARS resulted in formal approval being given for a major BBS facility to be constructed. A sub-committee was established to oversee the project. A number of meetings, with guests from associated groups such as the South Australian Packet Users' Group (SAPUG), Packet forwarding operators, BBS SYSOPs, etc. was held over the next two years.

Why use PACTOR?

Of the operating modes available, the chosen mode would be that with the maximum speed and the minimum cost. We have advanced well beyond morse code for digital communications. Radio Teletype is subject to selective fading and with no error correction, it was not favoured. The first error correction mode for HF was AMTOR (a derivation of the Commercially used SITOR), which was very advanced in early days, as an extension of the Baudot Code, with mail-box facilities, error correction (ARQ). This mode has no facilities for the transmission and reception of anything but plain text and numerals.

The next choice following this was PACTOR, which has 200 baud capabilities, ARQ, and forward error correction (FEC). It also has the facility for text and data file transfers, similar to that of Packet. Although the speed of 200 bauds is adequate, a number of manufacturers have developed "Company Specific" modes such as G-TOR, PACTOR II and CLOVER, which are capable of higher speeds. These modes require more expensive equipment, and there is no software available with these advanced modes, to enable the use of simple modems. PACTOR modems are available from several suppliers, and usually include 1200 baud Packet plus a few other options. The price is reasonable.

There is also, however, software available which can be used with a simple modem, similar to those used some years ago for RTTY. Remember the "clank " of the Creed 7B, Teletype Corp. Model 15, 19 etc., and the Seimens Mode1 100? If readers wish to try PACTOR using the earlier modems such as the ETI730, ST5, ST6 and DT600, the step to PACTOR, is as simple as installing a programme called "Terman93" by HB9JNX (from his home page on the Internet) or "BMKMULTY" from G4BMK, and modifying the PTT, receive data and transmit data circuits.

Unattended Operation

This aspect was very important. The establishment of such a station, at an existing licensee's residence, precludes the use of any other High Frequency receiving or transmitting equipment at that location. Both the host licensee's equipment and the BBS will at some time clash in normal operation, with possible damage to equipment. Such conflict could be tolerated in the development of the BBS. However, the permanent location at a member's home seemed most unlikely. A further parameter here is to have a UHF path to the AX25 network.

The initial solution to this aspect of our planning was simple. The Society agreed to fund, develop and service the equipment and then donate it to the South Australian Packet Users' Group (SAPUG) for installation alongside the AX25 Packet and Rose network equipment. This would be at the "Burley Griffin Building", co-sited with the Wireless Institute of Australia, SA and NT Division, (WIA), VK5WI. The plans of all three organisations were disrupted in 1998, when the Thebarton Council, amalgamated with the West Torrens Council, and sold the building. SAPUG moved to new premises, where there is restricted space for their equipment, and the WIA fragmented its facilities to other Radio Clubs. AHARS is examining options for an alternate site, following the successful completion of the project. Presently it remains situated at the writer's home, in the south-eastern suburbs of Adelaide.

The BBS operates on PACTOR under the AHARS callsign (VK5BAR); Morse code identification has been included in the close down message to indicate the exact location of the equipment, with the call sign of the host licensee.

EQUIPMENT FOR THE BBS

Initial estimates included the need for the items listed below. A fund raising activity was established, with the early donation by member Graham VK5GH of a modified Philips FM92 144MHz transceiver, which was raffled with many ticket books thrust into unwary faces at conventions, club meetings, etc.

Another, and ongoing, source was the donation of various unwanted items by Society members at general meetings. AHARS runs a large Garage sale for the general public each year, and a private sale night for members only. On normal meeting nights, members are encouraged to place surplus items on a rear bench. Buyers donate whatever their conscience suggests to the Society's Treasurer. In this way, members have shown continuing support for the project.

The following is a list, and the source, of the equipment in use:

The equipment has been assembled on a mobile equipment trolley, for ease of access during construction. It operates on 240 Volt 50Hz AC power. No provision has been made for operation during power failure. The purchase of a "Lap-top" computer, and substantial battery supply with charger, is considered unnecessary at this stage.

The antennas are mounted on TV antenna brackets clamped to the square tube verticals of a carport. Removal to another location would not be difficult. Handbooks, circuit modifications, backup software, are stored in drawers at the bottom of the trolley.

Back to AHARS Home Page

Modem Choice for the BBS

There was little choice. The programme required the use of a Kantronics KAM Plus modem, and one was purchased from Kevin Cavanaugh, (VK4SP), who understood what we were setting up.

The 1200 baud UHF link to VK5SPG was catered for with an MFJ1270B (TNC-2) purchased from SAPUG.

Both units have performed well in the project, however the KAM+ was difficult to set up, and recent power surges have caused some intermittent operation. The BBS presently survives on a borrowed KAM+, while the problem with the Society's modem is assessed.

Modem Choice (including Home Construction) for users.

When a potential user considers purchasing a Modem for use on PACTOR, a number of choices are evident.

Some modems (frequently called Multymode TNCs and other vaguely related names) are fitted for PACTOR only, while others give all H/F modes, including CW, RTTY, AMTOR, G-TOR, and Packet (VHF and HF). Most are expensive, but it is worth paying the high price if continuous operation on these specialised modes is intended.

For technical enthusiasts, a home brew modem, suitable for use with software available on the Internet, is a practical option. Suitable Printed Circuit Boards and construction information is available within Australia. In the October and November 1999 issues of QST, a comprehensive article covered this very suitable alternative. Modems used by RTTY enthusiasts in the 1960s to 1980s may also be modified to operate on PACTOR, with these programmes. The main consideration is the widening of the lowpass filters, location of a suitable point for RS-232 take off and the realignment for the appropriate Mark and Space tones. Cost savings may be considerable, depending on which approach is used.

Modems known to be easily modified for use with TERMAN93 (or "BMKMULTY", another suitable software package from G4BMK), include the following:

• ST5
• ST6
• DT600
• ETI 730
• AEA CP-1
• AEA MP-64

Home constructed and commercial Modems using PLL XR2211/XR2206 combinations have also been used successfully.

Some limited success using the World Chip Modem (AM7910), has been reported by associates. However internal timing properties appear to limit its usefulness in this application.

In 1997 Johnny Melvin, (G3LIV) introduced me to his "P-Par" modem, mentioned in the UK Amateur Press. His assistance led me and Norm Rosenzweig (VK5ZAH) to develop a printed circuit board for a dedicated RTTY/PACTOR modem, using parts which are readily available from suppliers in Adelaide. A useful feature of this modem is the use of strip LED indicators to facilitate tuning the incoming signal. Norm is able to manufacture the board on direct order. (see his web-site, listed below).

System Considerations.

The overall system was designed to give a connecting operator the impression he was connected to a "standard" Australian packet network BBS. The programme used in a number of BBSs is by F6FBB, under a variety of operating systems including LYNUX, Windows or DOS. The choice of software for the VK5BAR BBS was limited, with a programme "MSYS' developed by Michael Pechura, (WA8BXN) chosen. This allowed the connecting station access to a significant number of bulletins, and an ability to send and receive messages, when connected on HF. Additionally by using a "NODE" available on the programme, a further connection to the AX25 network, via a 440 MHz link, gave access to the BBS controlled by SAPUG. This meant that the field operator, using a laptop computer, sitting under a gum tree away from any other BBS, could be looking at the same screen as a VHF operator in Adelaide, if connected to the same BBS on 144MHz. From that point on, access to the total network, including the "Wormhole", the Internet through "NETlink" stations and the DX Cluster, etc., would be possible. This depends on the number of users and the reliability of the HF path.

Software Limitations

Although the sub-committee had spoken to some Australian licensees with success with MSYS, few, if any seemed to have utilised the "Scanning" properties of the programme. This was desired to ensure coverage of the vast continent, day and night, summer and winter, without the presence of an operator at VK5BAR. The few experienced with MSYS in HF BBSs , appeared to have used dual stations and PCs, when operation on more than one band was desired. We also found that whilst MSYS was designed for scanning on a Kenwood transceiver, and the Documentation indicated success with ICOM and Kenwood equipment, we encountered some time consuming difficulties. We finally combined software with a little hardware, to overcome this problem. The system now continually scans four frequencies, one in each of four bands, remaining on each frequency for 5 seconds.

It was necessary to modify the scanning sub-routine, (encouraged by the author in the MSYS documentation) for use with our ICOM 737-A transceiver. Joseph Kasser (ex G3ZCZ now VK5WU), author of many other software programmes, and Colin McCarthy (VK5EB), kindly spent many hours assisting with the development. A suitable piece of hardware, including a small scan timing unit, so necessary to this aspect of the project, was constructed.

This was necessary, due to the failure of the programme to recommence scanning after the completion of a QSO. The construction of a simple timer, to break the scan control line, and restore it some 10 seconds after the last PTT operation, was required. Although needing only a few components, this unit caused me more consternation, and wasted more time, than some of the main assembly. A "dead bug" construction on a piece of PCB worked well. However, when correctly and neatly constructed, it failed to work. A second and final attempt proved too much for me! If the unit had contained many stages, a logical approach would have located the source. However, as it was simply a combination of two 25 pin DIN connectors, a relay, a couple of diodes, and a 30,000 uF capacitor..........??

At this stage I decided to write this article.

Equipment Problems.

There were some problems. Those encountered were mainly in such items as cable connectors, position and tuning of the multiband antenna, etc. Interconnection of audio lines using 3.5mm plugs and sockets proved unreliable and these were changed to RCA line plugs and sockets.

The two multiband vertical antennas donated to the project were both without 80Metre resonators. These were unobtainable. A "Werner-Wulfe" vertical antenna was purchased to solve this problem. This antenna operates on the 5 main bands, and is adjusted for best SWR on the frequencies used by the BBS.

Location of the equipment in my home workshop, where I am constantly constructing, testing and operating other radio equipment, was a disaster during this stage. My 400Watts transmissions on 80 Metres one night, did some front end damage to the ICOM 737A. We opted to freight it to Melbourne for service, from where it was reported "no fault". On return, it performed well for a day or two, then failed again, even without being subject to excessive overload. This time we serviced the ICOM ourselves...a faulty switching diode in the front end had failed.

The ICOM 737A transceiver scans continuously, stopping on each of four frequencies for 5 seconds before moving on to the next. This causes a continuous selection of bands, and the operation of relays and the tuning motor. Although little information is available to predict the life of these components operation so far has been quite reliable.

This all proved that an isolated location was necessary. Shortly after these adventures, I sought support from AHARS to move the system to another location.

Back to AHARS Home Page

Radio Frequency Interference

When the system was first operating, it crashed many times, due to the Transmitter RF getting into the Computer, through all leads. The problem showed up as uninvited ASCII characters appearing on the Menu screen of the programme, when the BBS transmitter was operating.

The filtering required was quite conventional, using ferrite toroids, obtained from salvaged computers, power supplies and printers. The power leads were twisted through ferrite cores from Television tube "yokes". Data leads to all ports were wound around ferrite rings recovered from old computers, and "clamp on" ferrites used when available. Audio leads into each item were also fitted with toroids. Generally 6 to 10 turns around these toroids, was adequate.

As the system is mounted on a mobile equipment trolley, little effort was made to earth the unit, other than by the AC Mains, GPO earth. Fitting of a mains line filter, or the main power lead wound around an old TV yoke, may be necessary if further interference is experienced at another site.

Computer Considerations

An AT486 DX2-66 with 100MB hard drive, 1.2 and 1.4MB floppies, an SVGA monitor, and operating under DOS, was considered adequate. The use of four ports was demanded by the programme, if we wanted to use a Mouse. Suitable software for analysis and backup of programmes, files, etc. was also included.

Operating Frequencies

Our original intention was to serve all licensees who were authorised to use PACTOR. This meant using frequencies allocated to Intermediate Class licensees and consequently the early access to the BBS was restricted to the 3.5, 21 and 28MHz bands. With the recent authorisation of these licensees to also use other bands, the final setup is for scanning on 3.5, 7, 14, 21 and 28MHz bands.

The scanning routine allows listening for PACTOR calls to VK5BAR for 5 seconds on each frequency, before scanning to the next, etc. Thus a caller may have to wait up to approximately 20 seconds for a response, depending on the band chosen for the call. Once the call is detected, the transceiver "locks" on to the frequency, and following the completion of the "QSO", recommences the scan. It is therefore likely that a caller on one frequency may have an indeterminate period of waiting, if the BBS is being used by another station on another frequency. Other private HF BBSs have solved this problem by using two or more complete installations on separate frequencies. We considered the above approach to be adequate for the present system.

All frequencies used have been in the "FSK" sections, as published in the WIA Band Plans. Regrettably we suffer some interference from voice stations, particularly on the 3.5MHz band, with most stations moving away when they become aware of the purpose of the installation. There continues to be some rejection of digital techniques, and it reminds me of the difficulties we had when experimenting with SSB transmissions in the 1950s, before the usefulness of that mode, to amateurs generally, became evident.

Transmissions are SSB (Lower Sideband) with a Mark tone of 2095Hz. Frequencies in use at present, are :

3632kHz, 7035kHz, 14080kHz, 21075kHz, 28075kHz

i.e. on MARK frequencies of 3629.905, 7032.905, 14077.905, 21.072.905, and 28072.9 kHz.

It is not proposed at this stage to include 10, 18 or 24MHz in the group, but this can be arranged if there is any such demand.

Back to AHARS Home Page

Using the System

A station set up for PACTOR operation should set its transceiver to LSB on a VK5BAR frequency. A command, "C-VK5BAR" (or whatever your programme requires), should be sent. After a few calling cycles, VK5BAR will respond, in PACTOR, with a connect message, addressed to the calling station. Answer the prompts only, and do not 'turn' the transmission around, but follow the instructions sent to you by the BBS. A set of instructions on all the commands is available by typing "?" at the long line of prompts.

VK5BAR has Bulletins under a number of titles, and 100 in total, which may be read. Additionally you may send a message to another station, in a similar manner to a VHF etc., BBS. But as there is no "Telephone Book" held on VK5BAR, it is necessary to use the full hierarchical address. This takes the usual form, e.g. VK7DSB @ VK5SPG. #ADL.#AUS.OC.

The most useful facility is the ability to connect direct to VK5SPG and the AX25 network direct (including the Rose Network and the Wormhole), through a NODE command. VK5BAR during its "welcome" screen, mentions this, but at the end of the long Command line, a user should type in BLOCK letters "NODE". On receipt of this, VK5BAR will send a "NODE" message, and a short command line. At this point type "C1 VK5SPG" and a direct link to VK5SPG will be established. The screen facing the user now is the same as that facing a person connecting to VK5SPG on VHF or UHF.

From this point on, the normal BBS functions are available.

On sending a "B" or good "Bye" command, after use of VK5SPG, the connection will be cut VK5BAR. There is no provision for return to VK5BAR from VK5SPG, except by disconnection, and to again call VK5BAR on HF.

The following is a sample of the connect text and operating lines:
(Bold/enlarged/italics words are from the calling station)

[MSYS-1.20beta4-MHI$]
Hello Rob, Welcome to VK5BAR's MSYS BBS in Adelaide, SA

To connect to VK5SPG or VK5SPG-2 netrom node,
type NODE (in uppercase) then...
C1 VK5SPG or C1 VK5SPG-2

Msgs to the following catagories ('TO' fields) are present:
50MHZ  AFARN  APRSWX ATV    BBS    CARS   CONTST DEFENC EVENT  JOURNA
KWOOD  MANUAL NEWS   OC     PACKET SPACE  TECH   THANKS TST    UIVIEW
VHF    WIA    WICEN                                                  
To read the messages in a category, use   R category
To list the messages in a category, use   L category
VK5RG DE VK5BAR

Enter command: A,B,C,D,G,H,I,J,K,L,M,N,P,R,S,T,U,V,W,X,Y,?,* >

NODE

MSYS K Node in Adelaide, SA. [BBS at VK5BAR]
### CONNECTED TO NODE VK5BAR-7(VK5BAR)
Enter command: B,C,H,J,N?

C1 VK5SPG

Attempting to connect to VK5SPG
using Port 1 (UHF)
###LINK MADE
[FBB-7.00g-AB1FHMR$]
Hello Rob, Welcome to VK5SPG - Adelaide Central LAN BBS (439.050)

Your home BBS is registered as VK5SPG.#ADL.#SA.AUS.OC.
New Messages 185617 - 211283, There are 829 active.

Type ?  for help.


Mailbox Menu
------------
B: Bye              C: Conference     D: DOS Area       F: Facilities
K: Kill Mail        L: List Mail      O: Options        R: Read Mail
S: Send Mail       TH: News-Groups    !: System Info    ?: Help
VK5SPG BBS 31>

LL 5

*** : TO Field Filter is set to:- [ * ]

 Msg # Origin TSD  Size To     Route   From              -  Title -
211283 02-Jul B$   2031 FACTS  @WW     VK3LCW STRZELECKI
211282 02-Jul B$   1803 FACTS  @WW     VK3LCW GOULD
211281 02-Jul B$D  2093 STEAM  @WW     M1ACA  7+ BRINORTH.JPG 8/8
211280 02-Jul B$   2254 ATV    @VKNET  ZL1ABS AK ATV proposed STSP Repeater
211279 02-Jul B$   1626 ATV    @VKNET  ZL1ABS AK ATV email list
Mailbox Menu
------------
B: Bye              C: Conference     D: DOS Area       F: Facilities
K: Kill Mail        L: List Mail      O: Options        R: Read Mail
S: Send Mail       TH: News-Groups    !: System Info    ?: Help
VK5SPG BBS 31>

B

Connected time: 1mn 20s - Bye Rob, Thanks for using VK5SPG BBS

What we would do next time!

The project was conceived at the time when PACTOR was overtaking AMTOR for use by High Frequency BBSs. Development of HF digital techniques (with error correction) has been rapid over the last few years, with Clover, G-Tor, and PACTOR II, evolving as significant and faster modes. The construction of Modems for these is not within the ability of "Home Brewers". Consequently, a user would need to spend a lot of money to use these modes. Another problem is that they are "company specific", which means that they may be used only for contacts with stations using the same brand of Modem. PACTOR was included in the hardware from a number of manufacturers, and as mentioned above, software for home construction was available.

The recent higher speed system, developed by the "inventors" of PACTOR, (SCS) has been PACTORII. The modems for this mode operate on the earlier PACTOR as well as PACTORII. The cost of importing one of these modems, plus the purchase of transceivers, Packet Modem, computer, etc. for the project, was questionable, and out of our reach financially.

The SCS Group have now developed a new Modem, PACTORII-e, which has adequate features to establish a BBS, using one of these units in conjunction with a computer. Presently a number of privately used "HF Gateways" are operating using these items. The cost is comparable with that expended on modems and software for this project.

It is possible, subject to the success of the present BBS, that AHARS may consider upgrading this area of the BBS, providing suitable funds are available.

Thanks to:

• AHARS Committee who have supported the project, following the enthusiastic approach of the sub-Committee.
• sub-Committee members, VK5EB, VK5NU, VK5XJT, VK5GMH , VK5RG
• SAPUG support via VK5ZAR
• Potential users VK5KDC, VK5KJJ, VK5AFO, VK5GH, VK5AKE
• Test stations, VK5EV, VK5AFO, VK5EB, VK5RV, VK5ZD
• Software assistance VK5WU, VK5EB, VK5XKN
• SYSOP. VK5EB
• Significant donations, VK5GH, VK5XJT, VK5TY
• Gateway operators who gave encouragement VK5UJ, VK5HB, VK5ATB
• AHARS members and friends who helped the fundraising projects.
• My very lovely wife, Carlein, for her continuing support, and hospitality to all the many visitors.

Documentation

During the construction, extensive effort was spent on ensuring that the documentation was kept up to date. Should it be necessary to hand the management of the project on to another group, little instruction for its maintenance and operation would be required.

It is difficult to imagine how much we rely on photocopier machines to help us assemble such service and installation information!

Bibliography

ETI 730
Tom Moffat (VK7TM) "Electronics Today International" March 1979 to September, 1979

ST6 RTTY Terminal
RSGB "teleprinter handbook" 1973, Pages 5.22 to 5.28

PACTOR Modem(Australian)
Norm Rosenzweig (VK5ZAH) http://george.mdt.net.au/~nrosie/pactor.html

VolksRTTY II: For RTTY,AMTOR and PACTOR
Terry Mayhan, (K7SZL), QST, Oct/Nov. 1999 (http://home.att.net/~k7szl/ Home page for construction information).

Kantronics
http://www.kantronics.com

MFJ Enterprises
http://www.mfjenterprises.com

Terman93
http://www.ife.ee.ethz.ch/~sailer/ham/ham.html#hfterm (check Terman93.zip)

AN93, Analog Modem
Johan Forrer, (KC7WW) ..QEX June 1994

BMKMULTY Software
Mike (G4BMK) E-Mail: [email protected]

SCS PacCom (PacComII-e)
http://www.SCS-PTC.COM

Clover, Fast data on HF Radio
CQ May 1992

Comparison Clover and PACTOR
CQ February 1994

PACTOR Comparisons: Apples v Oranges?
QST May 1996

A Comparison of HF Digital Protocols
QST July 1996

Factors in HF-ARQ System Throughput
"Communications Quarterly" Winter 1996