Wireless networking in the oncology ward

by Matthew Gast


One of my closest friends was recently diagnosed with leukemia. The inpatient portion of his chemotherapy regimen was short enough that provisions for cable-based network access would be silly, but long enough that any serious engineer would suffer from Internet withdrawl.




When I visited Nick in the hospital, I was quite surprised to see him working away on his laptop, using ssh to help troubleshoot a client's network problem. Although the hospital where he was being treated did not provide Internet access to patients, his room in the oncology ward was across the street from a university with an 802.11 network. Wireless networks are extremely flexible and excel at providing transient access to an amorphous user population. After being admitted to the hospital, he spoke with the IT director at the university, and arranged for permission to access the university's 802.11 network during treatment. No new infrastructure was required to support him, just a straightforward configuration of the university network.




To shoot across the street, Nick used a old Lucent Hermes-based card with the 10 dBi external antenna shown in the picture below. The connection was fairly reliable, but it did drop out occasionally. I suspect that the problem was due to the use of multiple pigtail connector conversions between the card and the antenna. The Lucent card uses an MC Card connector, which was converted to an SMA connector, which was then converted to a N connector before reaching the antenna. Each junction causes some reflection and reduces the antenna's effective gain, though I have no idea how to quantify the reduction.




image




Quite happily, though, there was no need to make the connection any more reliable. I was more than willing provide antenna parts to improve the quality of the connection, but Nick's condition improved so much that inpatient treatment was no longer required.