Season's Greetings! Merry Christmas, and welcome to the 9th issue of WyrePak Newsletter. It's becoming increasingly difficult to fill the pages with interesting topics on the subject of Packet Radio these days, which is why we appreciate it so much when we receive articles from members. This edition is just four pages long, and whilst I promise to try to keep to our thrice-yearly publication dates, you may find that to keep the content relevant, the newsletter may be a bit shorter than previously. Any suggestions, articles or simply requests for information around which we can construct an article, are always very welcome.
All future meetings will take place at Brinton's Chain Wire Club, Zortech Avenue, Oldington, Kidderminster DY11 7DY. The decision was made rather hurriedly on the night of 19th August, when members arrived at the Sutton Arms to find the lounge noisy, busy and already smoke-filled. The last meeting there was made difficult by the over-loud piped music too. A quick trip to the Chain Wire Club by the Secretary revealed that the Club Room was available, and so the whole meeting re-convened there!
The Chain Wire Club is also used by the Kidderminster and District ARS and provides a quiet, smoke-free room with bar facilities. The Stewards kindly let us have the room free of charge, as long as we buy a drink and clear the glasses afterwards. The Club also has a large area to the side and rear, ideal for antenna erection and other outdoor packet activity.
For directions, type the postcode or "Zortech Avenue" into Multimap (www.multimap.com) - from Kidderminster, turn right off the Kidderminster - Stourport dual carriageway at the second set of lights, and follow the signs to the Golf Centre. Avoid the Golf Club entrance and follow the sign to the Chain Wire Club. The room we use is to the left of the stage, just past the bar.
Meetings are being held on the third Tuesday of every second month. The dates for 2004 will therefore be 17 February, 20 April, 15 June, 17 August, 21 September (AGM) and 16 November. These are subject to change, but a reminder will be broadcast via the List Server to all members in advance of each meeting to confirm.
Members are now able to distribute a private message to all other members by simply logging on to the BBS, typing "SP LSTSRV" and entering a subject and message in the normal way. The message will then be sent to all other WyrePak members as private mail.
If any member does NOT wish to receive mail from the List Server, please let G4SPZ or G8PZT know.
In order to minimise costs and improve service, members are encouraged to advise the Secretary of their e-mail address in order that the Newsletter can be distributed by electronic means. Currently, members receiving their Newsletter through the post only get a monochrome copy, to save printing costs, but it is available in glorious Technicolor by e-mail. A text-only version is usually available on the KDARS website at www.kidder.thersgb.net
August 2003 - Nine of the Group's 15 members, many of whom are also joint Fourpak or KDARS members, attended the first meeting to be held at the Chain Wire Club. G4SPZ, G0EWH, G8PZT, G0HHH, G0HTF, G8UAE, G7JWL, G0MBG and G3KFD made this the best-attended meeting yet and all agreed that the new venue offered a far more conducive environment for the meetings.
September 2003 - the Annual General Meeting on the 23rd was held at the Chain Wire Club, attended by seven members. Formal minutes have been prepared and will be distributed at next year's AGM, but if any member would like a copy in advance, please drop a Packet message to G4SPZ @ GB7PZT. Jim G0HTF stood down as Chairman, Phil G4SPZ was elected to the posts of both Chairman and Secretary, Brian G0MBG took on the role of Vice-Chairman, and Richard G0EWH remains as Treasurer.
October 2003 - the gang of 6 members gathered and a lively discussion took place on the future scope of the Group and Voice over IP technologies. This is reported elsewhere in this issue. Discussions on the technical side included the 4-metre port antenna, WAP access to the BBS and Forward Error Correction.
December 2003 - Paula invited all members to her QTH on December 16th for an informal social gathering, which in the end was attended by G0EWH, G4SPZ and G8PZT. Seasonal refreshments of a mince-pie-and-alcohol kind were consumed... see the Developments section for late-breaking facts.
The intention of this section of the Newsletter is to summarise the relevant information, which is made available at the WyrePak meetings. I have tried to avoid duplication and to omit items which are out-of-date, whilst providing readers with a good impression of what happens in a typical three or four month period. Contributions to the Newsletter are still invited, please contact G4SPZ - Ed.
Time-outs are thankfully no longer a problem. Paula reported that she had fixed two separate possible causes of node and BBS time-outs. Noise on the RF side could be one cause - in several parts of Kidderminster, severe noise is audible at times, which moves in frequency within the 2-metre band. Paula intends to try some DF equipment to locate the source.
Problems with the link to TJZ in the west were due to an IP address change. By now, this should have been rectified.
Richard G0EWH had e-mailed the sysop of GB7BHM mentioning the immense signal strength and wide deviation, which was still causing problems to some KIDDER users on 144.800MHz.
The 4 metre antenna was taken down for inspection following a rise in SWR, and found to be completely unrepairable owing to water ingress and UV-induced degradation. Currently, only two local stations are believed to be regular 4 metre users, and the costs of replacing this antenna and increasing its height to 35 feet are being evaluated. However, service has been restored using a replacement antenna, and signals are reported to be very strong in Highley. Many other UK nodes no longer offer 4 metre ports. However, 4 metres offers excellent access to the node and BBS as the band is so quiet locally. Few commercial rigs provide 70MHz coverage but the AKD and modified PMR sets are available.
Paula has added a link to Melbourne, Australia on Port 37 of the node. KIDDER now has 37 ports and, due to the memory requirements, Paula is proposing to "split" the node into two halves on two separate networked computers. One will serve the RF ports and the other the Internet ports, although this is not currently a high priority as the system has been stable now for some time.
New links are shortly to be commissioned to nodes in Plymouth and Scotland.
144.800MHz is now closed to all but APRS traffic.
On a recent trip to Anglesey, Phil GW4SPZ/M was able to find a route using four node-hops across Wales as far as DRAGON, but could get no further. The link between DRAGON and Fourpak's ROCKET nodes is currently intermittent due, it is believed, to a damaged cable which links the two. The cable is routed along a railway line. DRAGON is a key link between Fourpak in England and Swansea University's nodes in Wales.
The List Server is being altered to prevent members having to re-subscribe. Phil G4SPZ has initially subscribed all members to the WYRPAK list, and Paula will try to modify the code to disable the re-subscribe requirement in the software. Don't forget that this server is available for any member to use, to circulate information, requests, appeals for help, requests for skeds etc. to all other WyrePak members. Simply log on to the BBS and send a private message to WYRPAK.
Richard G0EWH can provide further information on the 'KEY' ex-PMR radios for Packet which seem to be successfully convertible, and Paula G8PZT can supply EPROMS suitably blown for the amateur bands.
Some nodes outside the Fourpak network have changed to Linux operating systems in order to handle TCP/IP traffic more effectively. Unfortunately, the new software does not recognise aliases, and the node's full callsign needs to be typed in. TCP/IP traffic takes up quite a lot of airtime, and dramatically reduces the throughput of AX25 packets on the shared link.
The speed at which other nodes appear in (or disappear from) a node's "nodes table" depends on the software in use. With G8PZT's XROUTER software, a new node coming on air will appear in KIDDER's nodes table in a matter of minutes. With BPQ software, this can take several hours. It is therefore possible that a node can go off-air yet still appear in the nodes table at local BPQ nodes.
Users of WAP - or Wireless Access Protocol - mobile phones (sometimes known as "21/2G") can now access the BBS! Paula has created a WAP interface page on the website which provides users with a five line by 10 character screen on their mobile phones, permitting read-only access for private mail and bulletins. This is yet another example of the convergence of packet with more modern technologies. The website address for this service is http://g8pzt.ath.cx/bbs/cgi-bin/wap/menu.pz.
By the time you read this, Paula will have delivered a talk on Internet Linked Voice Repeaters and Gateways to the Kidderminster and District ARS on 4th November. See the item elsewhere on Voice over IP. If anyone would like details of gateway frequencies, locations and DTMF tone commands, please drop G4SPZ a packet message via the BBS. You can also access the dedicated Gateway website, at www.pzt.org.uk and click on the KidderLink button.
A tentative plan is being developed to set up a DX Cluster at GB7PZT. Many local users connect to the Cluster but the traffic has to go via the Fourpak network. A local Cluster fed via the broadband Internet connection would both speed up the process for users, and reduce packet network traffic. Any regular DX Cluster users are requested to contact Paula to express their interest.
FEC is a technique which reduces packet loss, reduces the retry rate and improves throughput on an AX25 packet channel. It is used primarily on inter-node links, where corruption of packets may occur due to noise, fading, static or low signal strength. Forward error correction is currently in use on links between KIDDER and the Fourpak nodes at MLVN, GLOS and GB7WE at Wenlock Edge.
The technique involves the insertion of 16 additional coded bytes of data into each packet. The receiving end can use the additional information to reconstruct a corrupted packet, instead of having to request the re-sending of the whole packet which may be up to 255 bytes long. The effect of reducing retries is a marked increase in channel throughput, despite the small additional "overhead" of the FEC coding data.
On local circuits, such as between users and nodes where the major cause of packet corruption is collisions with other stations' packets contending for channel time, FEC is unlikely to improve matters. Packet collisions tend to result in the total loss of the packet, rather than corruption of the data, simply because the receiver output becomes completely garbled. However, FEC may be useful where a user is working a distant node where signal strength is weak on an otherwise quiet channel.
Normal user interfaces and packet software do not support FEC, and a user interested in trying FEC would need to run XROUTER node software configured as a user. XROUTER will drive a TNC or BayCom modem, and behaves much like AGW so could potentially be used in conjunction with popular interface programs such as Winpack.
For further information contact Paula G8PZT @ GB7PZT.
Paula now runs a 70cms Internet-linked voice gateway using EchoLink software. This is on 434.500MHz FM and a move to 430.075MHz is planned. Signal strength is not high at present but this will be improved soon. Operating hours are limited as the NoV stipulates "attended operation". Reports would be welcomed to G8PZT. You can access the dedicated Gateway website, at www.pzt.org.uk and click on the KidderLink button.
The Bristol Channel 2-metre repeater GB3BC now has an EchoLink connection to the Internet. Try connecting to it via Paula's gateway - details of GB3BC's node ID number can be obtained from Paula.
Many of the most recent developments being undertaken and researched at G8PZT involve the connection of amateur radio systems to the Internet. This includes packet links to world-wide destinations, but also voice systems such as the Gateway mentioned above, and the planned 2m Internet-linked repeater GB3KD. The issue was debated at some length at the October WyrePak meeting.
Essentially, the question was asked: "Should WyrePak expand to support Paula's voice-over-IP activities?" Whilst it is true that some licensed amateurs consider the use of the Internet to carry amateur traffic to be against the true spirit of amateur radio, many others find the convergence of the various communications technologies offers an exciting future. The hobby is a very broad one these days, and there is room for the devotees of the numerous specialist modes as well as the traditional ones. That said, after a long, well-reasoned and lively debate, the consensus was that WyrePak should remain as a specialist Packet Support Group, and the development and support of Internet voice gateways and Internet-linked repeaters should be left to the newly-formed Kidderminster Repeater Group (KRG).
Any members interested in becoming involved in the work of the KRG should contact Paula, G8PZT @ GB7PZT.
This is a bricklayer's accident report, which was printed in the newsletter of the Australian equivalent of the New Zealand Workers' Compensation Board. This is a true story, allegedly, although it is remarkably similar to a sketch recorded years ago by Gerard Hoffnung at the Oxford Union...
Dear Sir:
I am writing in response to your request for additional information in Block 3 of the accident report form. I had put "bad planning" as the cause of my accident. You asked for a fuller explanation and I trust the following details will be sufficient:
I am a bricklayer by trade. On the day of the accident, I was working alone on the roof of a new six story building. When I completed my work, I found that I had some bricks left over which, when weighed later were found to be slightly in excess of 500 lbs. Rather than carry the bricks down by hand, I decided to lower them in a barrel by using a pulley, which was attached to the side of the building on the sixth floor. Securing the rope at ground level, I went up to the roof, swung the barrel out and loaded the bricks into it. Then I went down and untied the rope, holding it tightly to ensure a slow descent of the bricks.
You will note in Block 11 of the accident report form that I weigh 135lbs. Due to my surprise at being jerked off the ground so suddenly, I lost my presence of mind and forgot to let go of the rope. Needless to say, I proceeded at a rapid rate up the side of the building.
In the vicinity of the third floor, I met the barrel which was now proceeding downward at an equally impressive speed. This explained the fractured skull, minor abrasions and the broken collarbone, as listed in section 3 of the accident report form. Slowed only slightly, I continued my rapid ascent, not stopping until the fingers of my right hand were two knuckles deep into the pulley. Fortunately by this time I had regained my presence of mind and was able to hold tightly to the rope, in spite of the excruciating pain I was now beginning to experience.
At approximately the same time, however, the barrel of bricks hit the ground and the bottom fell out of the barrel. Now devoid of the weight of the bricks, that barrel weighed approximately 50 lbs. I refer you again to my weight. As you can imagine, I began a rapid descent, down the side of the building. In the vicinity of the third floor, I met the barrel coming up. This accounts for the two fractured ankles, broken tooth and several lacerations of my legs and lower body. Here my luck began to change slightly. The encounter with the barrel seemed to slow me enough to lessen my injuries when I fell into the pile of bricks and fortunately only three vertebrae were cracked.
I am sorry to report, however, as I lay there on the pile of bricks, in pain, unable to move, I again lost my composure and presence of mind and let go of the rope. Then I lay there watching the empty barrel begin its journey back down onto me. This explains the two broken legs. I hope this sufficiently answers your inquiry about the "Bad Planning" part of my report.
Well, that seems to be your lot this time, guys and gal. Thank you for your continuing support for WyrePak, G8PZT/GB7PZT and your local Packet network. Thanks to our contributors and don't forget, we're always looking for comments and contributions for the WyrePak Newsletter... please contact the editor, Phil G4SPZ at g4spz[at]aol.com or G4SPZ @ GB7PZT, 01299 403025 or pnharris[at]iee.org.
The Committee would like to wish all members and supporters, and their families, a very happy and peaceful Christmas and New Year.
WyrePak Newsletter is compiled, edited and published by Phil G4SPZ. This issue (c) 16.12.2003