RaDAR Challenge – Defining your four hours

My satellite pass list

We all live in different parts of the world. The choice of four hours within the twenty four hour time frame is each operator’s own choice, what suits him / her best. Synchronizing these times can be done with others via forums and social media ahead of the challenge. Like planning an ops, a RaDAR ops.

For example I have chosen my four hours to start at 10:00 local time and to finish at 14:00. For me it’s easy, I need to coincide with the FM satellite pass times for my grid location.

I will start walking to my first location starting at 10:00 local time and deploy my SatComms station to be ready at 10:23 when the AO-92 cubesat comes over the horizon. I’ll print this info and keep it in my “RaDAR Signals Instruction” folder, because the app, ISS Detector, likes to be in contact with the Internet and if not prediction info could fail! Because I walk I’m classified in this instance to be a moving RaDAR station, “on foot”.

If I started and communicated from home, I’d be a fixed station. If I started and communicated from a camping area I’d be a portable station. These deployments can be mixed. For example after the five portable QSO’s you could ride a bicycle for two kilometers to the next deployment point and classifed, in this instance, as a moving RaDAR station.

The ISS is in the list. One could play APRS if any SatGates are within the footprint. That could possibly count as a contact. Digipeating via the ISS using packet radio and communicating with someone would definitely win you some “Points”. I’m not sure if the ISS’s BBS RS0ISS-11 is active anymore?

I would have a whole hour to walk and deploy at the next position before the AO-91 cubesat will come into range. Well that is if I made five QSO’s on the previous satellite otherwise I’d need to stay put! Tough if that happens. It worked for me in April, I hope this time round it goes as well. Having HF facilities could certainly fill in the gaps.

For the next session I’ll have over an hour for the next deployment if all goes well up to this point. In the meantime I’d enjoy the bush and nature in general. PO-101 is a tricky satellite to work having a 70cm uplink and VERY sensitive to doppler. My TH-D7A(g) can only move in 5 kHz steps.

PO-101 overlaps slightly with the times for SO-50. I could switch between the two but I’d have a better chance with SO-50 which is also a tricky bird. Luckily it has a 70cm downlink so doppler settings are easier.

I work full duplex on the TH-D7A(g) using the SA-AMSAT antenna design mounted on a tripod. I use a 12 v 7 A/Hr SLAB to power the system so I’ve always got a decent 5W on the uplink. I use a remote mic and headphones, the left and right speakers wired in parallel so I can hear properly using both ears.

I write all the info down by hand on my RaDAR logsheet with the satellite info printed on a separate sheet of paper, all stored in the RaDAR Signal Instruction folder.

From then on I have forty five minutes to pack up and walk back home. If all works out as it should with the necessary support from other hams, it will be a successful ops.

Oh, I carry a Lensatic magnetic compass so I can determine true north. Then I place my smartphone or paper image on the ground under the tripod so I can follow the satellites movement reasonably accurately throughout the pass from horizon to horizon.

My FT-817ND needs another finals replacement so HF is out for me presently. Ordering could be problematic as the postal system has come to a standstill here in South Africa since the lock down started over three months ago.

Hoping all are surviving the COVID-19 pandemic. Here in South Africa the infection rate is climbing rapidly.

Stay safe and have fun. Looking forward to hearing all the stories in blogs and You Tube videos.

73 de Eddie ZS6BNE

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