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WearStation

With today's technology, it is now possible to build a fully equipped ham radio station, complete with Internet connection, into your clothing.
Traditionally, many serious HF operators have regarded VHF as merely a step toward eventually "growing up" to HF.

However, higher frequencies make possible smaller size, and the resulting portability allows for a new kind of experience and lifestyle that is not possible with the cumbersome equipment of HF.

And attitudes are changing. Serious hams like Steve Roberts, N4RVE are exploring what it is like to have an amateur radio station on a human powered vehicle. Hams like N4RVE have demonstrated that one doesn't need to operate in HF to be a serious ham.

"WearStation"

When I say I have a fully-equipped ham radio station, what comes to mind might be a shack or radio room with workbenches, crammed with all manner of rigs, computers, and homemade interface devices linked in a maze of wiring to a network of antennas on the roof or in the backyard.

The last thing that would probably come to mind would be clothing, crammed with all manner of rigs, computers, and homemade interface devices, linked in a maze of wiring to a network of antennas on a hat, or in a vest or jacket.

I constructed WearStation to explore a new lifestyle, and I describe here both my station, and some of the new experiences that have arisen from wearing it.

WearStation has voice, video, and data capability. Voice capability includes the ability to make a full duplex crossband QSO (2m and 70cm using a Yaesu FT-530 with headset). Video capability includes AM ATV (439.25MHz, Communications Concepts, INC kit), FM ATV, and digital video. WearStation is also capable of full-duplex video communications (video transmitted on one frequency and received, at the same time, on another frequency), if desired. WearStation's radio teletype (RTTY) capability consists of standard Packet bulletin board system (PBBS), as well as Internet access via TCP/IP using KA9Q's Network Operating System (NOS) or AX25 within the Linux operating system. I've configured WearStation with disk partitions to run DOS 6.22, Windows 95, Linux 1.2.13, or 1.3.82. Most of the time I run Linux 1.3.82.

N1NLF Hat-Based Antenna

Over the years, I've experimented with different antenna locations. The belt-worn "rubber duck" antenna is lossy at best. (As Steven Finberg, W1GSL would be quick to point out, many rubber duck antennas are similar to dummy loads in their level of performance.) Furthermore, having the antenna right next to your body doesn't make for the best radiation pattern. There is some debate as to the possible harmful effects of low level RF exposure. Even if you don't believe it is harmful (or don't plan on having children), the RF that goes towards heating up the cells in your body is basically wasted energy. Thus it makes some degree of sense to get the antenna up high, where little or none of the energy is obstructed by the body. Antenna clips to attach an antenna to a baseball cap are quite popular, and get the antenna up where it is not blocked by the body (giving rise to a much more omnidirectional radiation pattern). However, antennas work much better with a well-defined ground plane. I found that a hat, lined with copper mesh, had a very much improved radiation pattern. Energy that would otherwise be wasted, heating up brain cells, is instead reflected off, and contributes to the improved reliability of the connection.

The whip antenna sticking out of my hat has drawn some attention and questions, though it blends in pretty well with the overall style of the rest of my clothing. However, as technology improves, all but the antenna of WearStation will disappear into the clothing, and we'll have voice, video, and data communications, as well as Internet access, all in a rig about the size of an ordinary pair of eyeglasses. But the antenna, out of desire for optimality, might still be sticking out of the hat. Perhaps this could be integrated into the hat in a more harmonious way such as hiding it inside a feather or the like.

Conformal Antennas

Originally, I'd sew antennas into my clothing (special jacket and pants I made), and found some configurations that worked quite well. New research on conformal antennas, together with conductive undergarments and the like, could point the way toward better connectivity for clothing-based ham radio stations. It would be nice to have the benefit of an omnidirectional radiation pattern without anything projecting out beyond the boundaries of normal clothing.

Dress for the Occasion

WearStation is not one particular piece of clothing, but, rather, a wardrobe of `smart clothing'. (My wife often jokes that whenever she gets me new clothes, wires and such appear to grow out of them over time, and that it's getting harder and harder to find something in the closet that doesn't have any wires growing out of it.) A closet of `smart clothing' adds a new meaning to the term "dress for the occasion".

Typically I wear, somewhere on my body, a UNIX workstation (Pentium 90 or 100MHz 486) with 64M RAM and 1.2G hard drive, as well as custom-built processing hardware sufficient for handling full-motion, full-color digital video. Depending on desired functionality, however, a smaller computer may suffice, and could "disappear" into the clothing if desired. For example, a credit-card sized 386, sewn into a shirt, would suffice for simpler tasks such as reading mail (PBBS or Internet) while standing in line at the bank, or for station ID (character generation, etc.) over ATV.

Battery power is likewise varied on a day-to-day basis, depending on needs. For example, I use NiCads when I need to source large amounts of current (e.g. for use with electronic flash or the like), while lithium-ion batteries provide greater energy to weight ratio when the load is moderate. Over the years, lead-acid have proven to be the most forgiving of varied usage patterns.

Peeling Down

One of the reviewers of this article (David Stuben, N8HUL) asked an obvious question, regarding washing the clothing, getting dressed, undressed, etc. Currently, some care is required in washing the clothing; the wearable station isn't yet ready for a spin in the washing machine. (Much work remains to be done to truly integrate circuits into clothing.) I currently peel down (which takes a few minutes) and hand-wash items that have wiring imbedded in them, while wrapping the devices to which they're connected in towels at the side of the sink. (I've tried to minimize connectors and much of the apparatus is hard-wired.) Then I'm able to have a shower, go to sleep, and by morning, with the help of a fan or heater, all is dry.

In public buildings and the like, the trend toward individual rest rooms, showers, etc. (as opposed to the traditional men's or women's rooms) is a most welcome trend, offering more room to deal with some of the issues surrounding `peeling down'. However, many of the problems of peeling down will go away with miniaturization and true integration into regular clothing, making the `being connected' lifestyle much easier to live.

I/O

Interaction is through a one-handed "keyboard" (collection of pushbutton switches that can be operated while walking, running, etc.) and a computer screen over one or both eyes. In my early (1980) computer systems, I used a 1.5 inch CRT from a camera viewfinder. More recently (1990), I used a 0.6 inch CRT, as salvaged from a broken camcorder. I mounted the CRT above my eyeglasses, pointing down, and used a prism and lenses to form a virtual image of the screen in one eye (this looks like a large-screen TV located some distance away, overlayed on the real world). Alternatively, a surplus camcorder viewfinder (cost, approx $20) can be attached to a baseball cap, although it will then block one eye and impair real-world vision somewhat.

In addition to functioning as a computer screen (PBBS, Internet, WWW, etc.) the display also shows incoming ATV, and serves as a viewfinder for outgoing video. I am also able to `recall' previously recorded video, and, for example, run experiments pertaining to visual memory, computer-mediated reality, and the like.

High Speed N1NLF Gateways

My access to the Internet, within the Cambridge and Boston areas, is through the N1NLF gateways. These consist of a combination of both high-speed digital, as well as hybrid (e.g. partly analog) gateways to the Internet that I've installed on the rooftops of various buildings (including the tallest building in the city).

Winter Blues

A `WearStation' presents special difficulties, and raises many special needs such as miniaturization, reduction in power consumption, and increase in reliability (e.g. robustness and temperature stability). These problems surface as soon as one attempts to take radio out of the shack and into daily life. For example, In warm weather, a 1987 Georgia Radio Amateur Packet Enthusiasts Society (GRAPES87) WA4DSY 56kbps RF modem gives me reasonable Internet connectivity, but the Hamtronics transmit and receive converters I'm using with it tend to drift in extremely cold weather. On a typical cold day, for example (say, -20 deg. c), my bit rate is fine indoors, and fine when I step outside for a walk, until after a few minutes when my unit cools down. The bit rate falls steadily until it stops working altogether. I'd welcome comments from fellow amateurs who've managed to build a wintertime transmit/receive converter for use with the WA4DSY system. Crystal ovens are a good start, but I believe a redesign is in order.

In the winter, I use a Kantronics 9612 TNC which can run at 19k2 or 9k6, together with a Tekk radio. The Kantronics TNCS work with the APRS (they're GPS ready in the widest sense). Of course, with a computer, GPS location information can be sent as ordinary data packets.

GPS doesn't work well within buildings, though. Instead, I use a number of IR beacons which I have placed in various locations around the building where I spend most of my time, and the apparatus picks up the signal so that it has some awareness of where I am. I recently tried the PacComm TNCs (nice small size - about the size of a package of cigarettes) but went back to using the Kantronics TNC as it seemed to perform better.

The 9612 also has the nice feature that it will ``slow down'' to 1200 bps for accessing PBBSs and traditional Internet gateways, using a standard HT (I often use a Yaesu FT-530). In fact, some of my earlier systems were 1200 bpsand these are still up and running as backups, in case the high-speed gateways should ever go down.

Getting Online: The Bare Essentials

Once the infrastructure is in place, all that is needed to get online in the simplest sense, is a small terminal, terminal node controller (TNC), and radio. The simplest way for a beginner to get online is with KA9Q's network operating system (NOS). Work is currently underway to build a small terminal and TNC into a pair of eyeglasses. This will make it possible to have a simplified WearStation (but without the video capability) as a base-level of functionality for occasions when one wants to travel light but stay "online". Such a system will be analogous to our clothing, while the video equipment is analogous to our outerwear, and would function like a vest or jacket. The "outerwear" would be added to the base-system, when video functionality is desired (stressing modularity).

Free-for-all

I am currently building other units to experiment with a small community of other WearStation users, each capable of functioning as a PBBS, digipeater, or true network node. Currently, my clothing can support several remote users logged into me simultaneously. One might imagine that if a large community of similarly-attired hams left their clothing turned on most of the time, packets could flow easily and effortlessly throughout the city, going from person to person in search of their destination. So long as any one user could connect to someone else on the net, it is hoped that there will be no need to connect to any of the existing N1NLF gateways, except for communications outside the community. If this experiment were extended to home-based and automotive-based systems using low power radios, hams could leave the radios running all the time, each being a node in a very dense network. This would make net access free and simple for all, without so much reliance on fixed gateways.

Further Work

Much has been learned from designing, building, and operating `WearStation'. Occasionally, in certain buildings, packets are lost, and a diversity system is one work-around. A diversity system might use spatial diversity (e.g. a plurality of gateways operating from different locations) or frequency diversity (gateways operating on a plurality of frequencies). Currently, work is underway to support simultaneous load-sharing across multiple radios under the Linux operating system. One might envision a small "antenna farm" on top of one's hat, serving multiple parallel Internet connections at the same time, in such a way that the connection is completely transparent to the wearer. If, for example, you step into the basement elevator and your 2m packets aren't finding their way out, load is automatically shifted over to the 70cm band (where packets tend to "find their way" out through small holes in the metal structures). If the Doppler shift at 10GHz is getting pretty bad, or the signal doesn't have line-of-sight view of a gateway, the load shifts back down to the VHF bands. Higher frequencies tend to behave much more like light, and don't have much penetrating capability but have a better chance of "finding" their way out of enclosures through small openings. Depending on the number of radios used, extremely reliable communication is possible in a variety of urban and indoor settings.

73

The design, construction, and use of WearStation has been a fascinating experiment in communications and connectivity. This article, for example, was typed on my clothing-based computer, then wirelessly sent to CQ-VHF through one of the N1NLF high-speed Internet gateways.

-By Steve Mann, N1NLF

Appeared as the feature article in CQ-VHF, January 1997

Thanks to Rosalind Picard; Steve Roberts, N4RVE; Faun Skyles; and David Stuben, N8HUL for helpful suggestions in preparation of this manuscript.