The first major project of the week was tearing down the old University Police Department's radio tower. UPD recently moved to a new facility, and CPARC volunteered to assist in the demolition of the old building. This doubtless saved the university a few thousand dollars on their quote from the demolition company, and we get a lightly-used 40 foot Rohn 45 tower for club use.
NVIS is an important capability for our shack in storm conditions, since we are an Emergency Communications Center for SLO county). To overcome this issue, we came up with a very clever and clean counter-weight design based on railroad catenary systems, where you have a pulley and weight at the end of a line to keep constant tension under varying lengths.
After working out the trigonometry, we figured the end of the dipole needed to move 15 feet as the tower went from fully retracted to fully extended. We then purchased two 20 foot pieces of 3" conduit, mounted a pulley on the end, and used 3' heavy-duty tent stakes as the weights. The weights are inside the conduit, and move from hanging two feet from the bottom of the conduit up to just below the pulley as the tower is extended. A very clean solution that works great and looks much simpler than it actually is. We were particularly impressed that once it was all built, our math for how long the lines and weights needed to be were off by less than six inches on both sides.
This was the biggest job of the week, so thanks again to everyone who helped out, and a huge thanks to our EE department head, Dr. Derickson, for allowing us to erect even more masts and towers on the EE building.
ARRL Field Day contest. We decided to activate our shack using the club vanity call N6CP as an emergency operations center with two active operating stations (meaning we were class 2F). I sent out a lot of the pre-weekend emails to drum up enough operators to keep us active most of the 24 hours (we were down for only 6.5hrs throughout the weekend), and helped Marcel with much of the final testing before the contest kicked off at 11am Saturday.
Thanks to all the club members and alumni who showed up and helped us have such a good time. Our rough contact count rounded out at 871, which we were really happy with. Here is our soapbox submission for the event:
The Cal Poly Amateur Radio Club W6BHZ/N6CP operated ARRL Field Day from the club shack as a 2F EOC taking advantage of the brand new 72ft antenna tower with a TH-7DX Tribander, XM-240 40m beam, and 80m inverted-V. Almost a dozen students and alumni activated the shack in the most active contest the club has seen in several years. Many brand new hams got to try out HF contesting and everyone did a wonderful job handling the pileups on both voice and digital modes. As a 2F station, we had the Yaesu FTDX-9000D and the FT-920 operating concurrently into the early hours of the morning. With only a four hour break at 5am, the station was on the air for a record 19 hours. Be sure to look for the Cal Poly station in upcoming contests and for Field Day 2014!