W2MMD Satellite Blog

  The clubhouse satellite station has had steady incremental upgrades over the past few years but one factor had remained constant – the antenna and rotator system. The antennas were 1980’s style Cushcraft units that were probably average at the time and gave reasonable but not outstanding performance. Since “outstanding” is a goal of the Skunkworks team we were able to procure through a club member donation a pair of M 2 state-of-the-art satellite antennas – the 42-element   436CP42UG crossed yagi for 70 cm and the 22 element 2MCP22 crossed yagi for 2 meters along with the fiberglass boom to connect them. These are the top of the line satellite antennas from M 2 and promised to significantly improve clubhouse satellite operations. Figure 1 - Original Antennas Both antennas are 18 feet long and have considerable gain and would be a significant improvement over the existing antennas but the additional length created potential problems in clearing the clubhouse roof and the guy

With the plethora of new rocket technology these days it seems that someone is launching interesting new satellites every couple of days. Many of these are “microsats” the size of a Rubik’s cube and can be popped off of the top of a rocket or shot out of a slot on the International Space Station a half-dozen satellites at a time. Some are ham communications satellites that will allow FM or SSB communication, or will support APRS or PSK communication, while many others send down telemetry or images such as the recent SSTV transmissions from the ISS. Part of the fun of operating these satellites is the radio part – getting the antennas pointed in the right spot in space, correcting for the Doppler frequency shift in the signals, and tuning in and decoding the signals, but not everyone has the equipment or home space for the multi-element antennas and az-el rotators that we’re fortunate enough to have at the GCARC clubhouse. Luckily for these folks there’s a way for them to have

Below are some images that were copied by the W2MMD Clubhouse satellite station from the W5LFL memorial SSTV project. Some were copied live from the satellite while others were recorded by the clubhouse station and the audio was uploaded to SatNOGS. I downloaded the SatNOGS audio and decoded it locally.  This was an especially interesting session for me since I was involved in the first QSO with W5LFL's space shuttle mission. At that time no hams had ever had QSOs with any human who was in space, and a group over at the Franklin Institute gathered to try for a QSO led by Chief Astronomer Derek Pitts, KA3NQN (you probably know of him but didn't know that he was a ham) . Somehow I got enlisted to join them and we set up a station somewhere on the first floor. There was a lot of interest from the local TV stations and others, and Derek turned it into a great PR event for the Institute. We were unsuccessful for the first few tries, and one night I was unable to join them but w

Building the Raspberry Pi NOAA Satellite Station After building the station to receive the GOES geostationary weather satellite, constructing the NOAA satellite station was a relative breeze. The NOAA series of satellites (NOAA 15, 18 and 19) are much more similar to amateur satellites than the GOES satellite – they operate in the 137 mhz band, are in low-earth orbits and transmit analog images rather than the complex error-corrected digital images of the GOES satellites. I simply followed the “ Instructables ” project design and it mostly worked the first time. The overall concept is simple – the project uses a inexpensive RTL-SDR radio and a Raspberry P i computer along with free software that you install on the Pi. There are several components to the software – first it uses the Gpredict program to set up times (cron jobs) for each satellite based on the next pass for each of the three satellites. At the scheduled time the Pi runs a script that will enable the RTL-SDR receiv

APRS Weather from the GCARC Clubhouse “So now that we have a weather station at the clubhouse, why aren’t we broadcasting real-time weather thru APRS?” said John Zaruba K2ZA one day, signaling the start of another GCARC Skunkworks project. The weather station (a topic for another article) was up and running and its output could be viewed from a web server on the clubhouse network, but without a VPN connection to the clubhouse (or being physically present there) nobody could see it. And the clubhouse weather was getting increasingly important with the upcoming heat of summer since we wanted to monitor the temperature inside the satellite room because several computers are running 24/7 there. In addition, several of us are working with the Cooper Health System emergency communications team and planning to use APRS as a means to report from remote healthcare facilities, so it made sense for us to get familiar with creating customized APRS messages and figuring out how to transmit and

The GCARC 2018 Field Day Satellite Station Field Day brings out the creativity in hams since we have to adapt our typical operating configurations and practices to a completely different setting. This was also true for the satellite team (K2QA, K2ZA, N3PUU, KD2RPE and WB2MNF) as we prepared for the 2018 event. Under Field Day rules stations receive 100 bonus points for the first satellite contact, so obtaining this contact is significant to our point score. Last year we barely made it - we made our first and only contact on the last satellite pass of the event, so this year we wanted to be far better prepared. As in any ham station, there are three primary components - the receiver, the transmitter, and the antennas. For satellite receiving we long ago migrated to software defined radio, so I had to build out my laptop for SDR. This meant installing the PST Rotator program that manages the antennas and sets the frequencies on the radios, the SDR Console program for visualizing a