First, we have a dual-band feed design update from Paul Wade W1GHZ.
He reports that what he’s come up with looks like it would work pretty well for an offset dish like the DSS dishes, with good efficiency at both bands. Simulation says the isolation from 5.8 GHz to the 10 GHz port is about 80 dB.
Performance plots are attached. He is going to work up a sketch for 3D printing.
He recommends a filter (like the ones in his QEX articles) that can easily provide 60 dB of second harmonic rejection. He believes that the second harmonic from any decent amplifier is 20 or 30 dB down, so that’s at least 80 dB down. Unless the signal is actually inband, a signal that far down won’t hurt.
He added that as for push-pull amps, we may be underestimating the difficulty of keeping them balanced at microwaves. Using a push-pull amplifier as part of the dual-band solution may not provide the performance we need.
Second, there’s plenty of action in the transmitter RF chain with results from measurements at the VHF super conference. Thank you to Eric Nichols, Mike W4UOO, John Petrich, W7FU, John Toscano, Mike Seguin and several others for stepping up to volunteer on this part of the project. We’ll be increasing our use of google forms to coordinate parts of the project, maintaining a list of all the forms on github, and possibly setting up a webpage to increase project findability.
Third, San Diego Microwave Group demonstrated the results of a project that Drew and Kerry Banke have been working on these last couple of weeks. It is the combination of a $4.24 Arduino processor board with a $29 ADF4350 PLL board to provide a programmable fixed LO in the 137-4400 MHz range. Once programmed, this set of off-the-shelf boards comes up on frequency at power up. The programming software utilizes the Analog Devices ADF4350 evaluation software to calculate the PLL data. This is entered by hand in to an Arduino program(sketch) written by Drew. This then is uploaded to the Arduino and that’s it. Kerry reports that the software is easy to use and free. Check out this video report from Paul KB5MU.
March 10, 2016: Today the Amateur Radio on the International Space Station team (ARISS team) proudly celebrated its 1000th school radio contact!
The very first ARISS contact took place in 2000, and Astronaut Tim Kopra, amateur call sign KE5UDN, on the International Space Station (ISS) did the honors for today’s 1000th link-up to the University of North Dakota. Kopra spoke in real time to excited scholars in Grand Forks at the event organized by the North Dakota Space Grant Consortium (NDSGC). An additional program milestone—this was the first amateur radio contact with the ISS that has been hosted in North Dakota.
On February 18, 2016 NASA announced the selection of RadFxSat-2, the Space Radiation Effects CubeSat, for participation in NASA’s CubeSat Launch Initiative. RadFxSat-2 (Fox-1E) is another partnership opportunity between Vanderbilt University ISDE and AMSAT, similar to RadFxSat (Fox-1B) which is scheduled to launch in January 2017. Vanderbilt University, with cooperation from AMSAT, submitted the RadFxSat-2 CSLI proposal in November 2015.
Out of 21 proposals, NASA is recommending 20 for participation in the CSLI opportunity. RadFxSat-2 is prioritized #1 out of the 20 selected and has been offered an opportunity for a launch date. The opportunity is being evaluated by Vanderbilt University and AMSAT to determine if it meets our mission and orbital parameters.
RadFxSat-2 (Fox-1E) will carry a radiation effects experiment similar to RadFxSat (Fox-1B) but will study new FinFET technology.
The Fox-1E spacecraft bus will be built on the Fox-1 series but will feature a linear V/U (Mode J) transponder “upgrade” to replace the standard FM repeater which Fox-1A through D have carried. The downlink will feature a 1200 bps BPSK telemetry channel to carry the Vanderbilt science in addition to a 30 kHz wide transponder for amateur radio use.
Further details of the mission and timeline will be published as they become available and are cleared for public release.
Dave Swanson, KG5CCI reported that on February 10th, at 2009UTC he made a scheduled contact with Eduardo Erlemann, PY2RN, using AO-7 Mode B, from Shinnal Mountain just west of Little Rock, Arkansas. His 10 digit grid locator for the contact was EM34ST20SC, and Eduardo’s station is located at GG66LW77JQ in Vinhedo/SP, Brazil. Using this mapping website for reference, this equates to 8030.895 km which we believe to be a new record for AO-7 Mode B.