WAPR News August 2004

by Andy Nemec, KB9ALN

Welcome to the Dog Days of Summer - the wet Dog Days. Hope you've been able to get some fun in between the raindrops.

Last issue, I was not able to put anything in the way of WAPR or packet radio info into the Badger State Smoke Signals. My schedule - and my life in general - has become very busy these days. The fact that there just isn't much packet activity to report on lately has made me consider making this column a quarterly feature. I've made no decision as of yet, and will be talking this over with a few other people before a decision is made one way or the other. I'll let you know what I decide in the next issue.

For now, on to news...

Manitowoc Node Stack Sold

As you know, Red N9GHE had a packet BBS and node stack in Manitowoc for years, and decided to retire a couple of years ago, and moved "Up North". His node stack has found a new home in Racine. Jim, KB9MMC has purchased it and is in the process of getting it on the air. No news yet on node aliases nor any other details, but will have more when I know it.

Algoma Nodes Off-Air

Anyone who has been watching the weather lately has likely come to the same conclusion that I have - it's been .... Whacky. In addition to a greater-than-average number of tornadoes, we've been flooded and blown around by wind and storms. The Algoma Nodestack was barely rescued from certain death in the nick of time by Rick, WB9RJB when he went to check on the status of his 146.805 voice repeater receive site in Algoma. Seems that it was no longer working, and he found that it had been hit by water rushing into the basement through a crack in the wall! The node stack shares the site (in a separate cabinet). While the remote receiver will need time to dry out and be repaired, it appears that the node stack may have been spared. He didn't have time to check it out when he was there, but says it didn't see much water at all. Thanks to Rick for the rescue from certain drowning

Rick does tell me that he may relocate both the receive site and the node stack. I will  update you on that if or when it happens. Update: It appears that everyone was very lucky on this. I just received a phone call from Rick that the site has been dried out and all of the equipment was spared! This is truly good news

News from the North

Leroy, N8WQG has been visiting my packet station and has been leaving me updates on the packet situation in the U.P. Which means that I must apologize for the lateness of my replies to him, of course. It seems that there is some good activity happening up there, along with the usual weak spots.

The great news is that a lot of the UP network is still alive and kicking. The folks up there have been using and, to a limited extent, expanding the network to relay weather spotting reports to the Marquette office of the National Weather Service. They have been completing some links (on a temporary basis) through a digipeater.

They're still having problems with the CMX nodes, however. These nodes link the U.P with nodes in Canada. There are weak links to that system of nodes, and Leroy tells me that he is trying to strengthen that link as well as other UHF links

That's about all of the news I have for this time out. Until next time, 73 from Andy.

Ham Implementation of 802.11 Packet Radio by Andy Nemec, KB9ALN

Our last feature consisted of a short introduction to 802.11 technology. While not an in-depth exploration, it was enough to give you an idea of what 802.11 is. This time out, we'll take a look at ham implementations of this technology, the hardware in a wireless network, and we'll compare it to what we use in the AX.25 world. Nothing Without a Network.

The whole point of having the ability to hook one computer up to another is to transfer files, E-Mail and engage in other activities, such as web browsing. Obviously, we can connect two computers together and do some of this stuff but unless the other computer is connected to some sort of network, we're not going to have much fun for very long.

Yes, technically, two computers do comprise a network. However, to be truly useful, more is better (to a point, we'll get to that later). Another factor is the proximity of one computer to the next. 802.11 technologies are short-range, for the most part. Therefore, some sort of network is needed to expand the effective range, and the usefulness of our 802.11 wireless card. In short, these devices are nothing if we operate a pair of them without some sort of network infrastructure

Looking at Network Hardware and Functions

What would an 802.11 network consist of, or look like? We already know about the wireless cards. One home computer with a wireless card can connect to another, of course. But what if you wish to make a network to serve multiple users, and want to connect to the internet as well? Here is a short introduction to some of the pieces of hardware that comprise a typical system, what they are, and what they do.

Wireless Access Point (WAP) A WAP can be a regular home computer with one or more wireless ethernet cards installed, but more often is a stand-alone box with a built-in wireless ethernet transceiver. In addition, it may also have a port to connect it to another network device, such as a router, dial-up or DSL modem.

The type of hardware is less important than the function it performs. It simply allows users to connect to each other or to another network. That network can be the internet or some other, segregated network. Router A router is a multi-port device (really a dedicated computer) that interconnects networks. Generally, it connects a number of smaller networks together, and/or to a larger one. Routers also join parts of the Internet together.

These days, a lot of people have had exposure to a router because they have their own home network. They generally have a bunch of RJ-45 connectors for ethernet cables. Wireless routers may have one or more. Most wireless routers are considered Wireless Access Points.

The Internet Backbone This is the collection of wires, fiber-optic cables, routers and other hardware that comprise the main "highway" that internet data travels on. It is very high-speed, in the gigabit-per-second range.

So, we now know that we need a wireless access point, routers to see to it that packets are sent to the right place, and a bunch of hardware, with or without wires, to transport our data. Surprisingly, this all looks remarkably similar to regular packet radio in a number of ways. Of course the hardware is different, but the functions that these hardware pieces perform are very close to what we've used in the past with AX.25 packet radio. Follow the analogies below to see what I mean.

Wireless Card = TNC and Radio This is a simple one to see. The wireless card has a radio in it, and it is controlled by firmware and a processor that formats information so that it can be more easily sent via radio. That's pretty much what a radio and TNC do. WAP/ Gateway/Router = Local VHF LAN node The Wireless Access Point (WAP) is the entry point into the network - whether it is more 802.11-equipped devices or the internet itself. That's what a typical VHF LAN node does with AX.25 packet radio. It provides an access point to a network of backbone nodes or users. While the VHF LAN node doesn't possess the advanced routing capabilities that a wireless router has, it does provide rudimentary routing services. When you connect to a VHF LAN node and issue the "N" command, you are returned a list of other nodes that it knows how to get to. The VHF LAN node has a "table" of nodes and paths it needs to use to connect up to them. This is what happens with a wireless access point or wireless router - it knows what's out there and how to get to it. Internet Backbone and Routers = Backbone Node Network The Internet may be a (mostly) wired medium, but it still needs to know how to get from one point to the next so that clients can use it. Same with AX.25 packet radio - without the wires, of course. Net/Rom nodes serve as transporters of your packet. In order to know how to get the packet from point A to point B, it has to know about itself - what makes up the network and how to get to other parts of it. Same with the internet - only it's more thorough and automatic than Net/Rom nodes are. It transports data packets and knows it's way around itself so that it can do this job. More is Better? You'd think that having more wireless access points, routers and the like would be better. This is not always so.

The same old radio channel usage issues come up with 802.11 technologies as with garden-variety AX.25 packet radio. The more "stations" (computers) that are on the network, the more usage a given channel sees. While the effect of this is somewhat mitigated by the use of spread-spectrum transmission methods, the number of users on a given channel still is a factor that affects data throughput.

This is especially apparent when you  consider that the general public is also allowed and encouraged to use this technology. While some of these wireless ethernet channels lie in the ham bands, Part 15 users are still allowed to use these channels. Not only do you have to deal with hams using this technology, but with the general public as well.

While we are allowed to use higher radiation power levels than the general public, that's little comfort when you're trying to use an already crowded channel. In order to minimize these problems, hams have come up with an rather simple way to help with these problems.

Most users of this band rely on vertically polarized antennas that come with the wireless card. Antenna connectors are a little difficult to find for most people, so unless they really see a need, they leave them as they are. In the rare case that a "general public" wireless ethernet user needs to increase range, they may use an external antenna. In order to effectively operate with other wireless users, they also use vertical antenna polarization.

Hams have decided that one way to peacefully co-exist with these users is to orient our antennas horizontally. Cross-polarization is not a perfect means of making what we regard as "interference" go away, it surely does help substantially. If you've ever tried using vertical polarization when using VHF SSB, you know that it works much better when everyone uses the same antenna polarization, in that case horizontal polarization.

And that's where we'll leave our discussion for this time. Next time, we'll look at some of the antennas used by hams in the 802.11 world. Until then, 73 from Andy.

Packet Radio IP Address Coordination Update

For those of you who may be new to packet radio, or just maybe have never investigated it, an IP address is a numerical address given to a computer that operates on the internet. IP addresses are also issued to computers owned by persons who wish to use TCP/IP protocols and services on conventional AX.25 packet radio. In our area, IP addresses start with 44.92 as the first two of four sets of numbers. One of my own IP addresses is, for example.

As some of you may know, I am also the IP address coordinator for the state of Wisconsin and the Upper Peninsula of Michigan. While this is not exactly a WAPR function, it is advantageous to be very close to WAPR as there is a lot of information that is used in both of my positions. However, I am writing in this article about IP coordination issues outside of the scope of WAPR, but with knowledge that WAPR is affected as well. This perspective has allowed me to have unique views of the current IP address coordination system as it relates to Packet Radio as we now know it.

One observation that I and many others have made is that conventional AX.25 packet, while usable and sparsely populated, seems to be slowly moving toward APRS as it's main use. Many operators have put their TNCs and radios in a closet, sold them, or just stopped using them. That's also true of many people who used to operate TCP/IP on conventional AX.25 packet radio.

Coincident with the "fade-out" of conventional AX.25 packet operation is an expected increase in 802.11 activity. As this is a system that utilizes TCP/IP, persons wishing to use this technology will need an IP address.

Which brings me to the current situation. While there are the occasional persons contacting me to obtain an IP address, very few people ever inform me that they are relinquishing their IP address(es). Of course, some of these folks have passed on and can't let me know they are gone. However, there are still many hams who are alive and well and have forgotten to let me know this. In some cases, they have even forgotten that they have an active IP address.

That means that there are many, many inactive IP addresses on the books that can be cleared, if I knew which ones were no longer being used. In the Milwaukee subnet for example, I am almost certain that nearly 75% of the currently listed addresses are inactive. I suspect that this holds true for a number of other subnets. Note that we aren't in danger of running out of IP addresses, but there are certain problems that could come up in the future that will require a re-working of the system. I'd like to stop potential problems before they even have a chance to develop.

As a result, the coming months will see me attempting to contact all of the current IP address holders and ask what their current status is. Are they active? Do they plan to be active? Are thy no longer interested in having an IP address assigned to them? These are the questions that need to be answered so that the IP address database can be "cleaned up".

I would like to reassure those current active IP address holders that they will not be asked to relinquish their addresses. In some cases, it may be necessary to change an IP address. This is done to conform to networking conventions in use on the internet. As any TCP/IP system (whether it be AX.25-based, 802.11-based or the Internet itself) requires an IP address, it only makes sense to assign these addresses in a logical, standardsbased manner

So don't worry - if I contact you in the coming months, it doesn't mean that you'll lose your IP address. I only drop or modify IP addresses if I get permission from the address holder, or I am reasonably certain that we will never hear from them again. Even if you plan to use an IP address far in the future, it is still OK to hang on to it.

In addition to long-term IP address assignments, I will also be designating certain blocks of IP addresses for "lease" (Dynamic IP address assignment). This means that if a person doesn't want to operate a full-time IP station, they can receive a temporary assignment of an address from a pool of addresses set aside specifically for that purpose. This is what happens when you dial in or connect to your ISP - you temporarily use an IP address until you are done with your internet activities. That address is assigned to another person, also temporarily, until they no longer need it.

From time-to-time, I'll be updating you on the progress of the clean-up, and may even ask for help locating certain people. I hope you can help me with some of this. If you are currently not using your assigned IP address and would like to relinquish it, please send me an E-Mail note letting me know this at: kb9aln(at)gbonline(dot)com

Until the next update, 73 from Andy.


Back to the WAPR Home Page and Index

Browse the News Archives