ECLECTIC AETHER - Adventures with Amateur Radio

Operation via QO-100 Es'Hail 2

Notes relating to Es'Hail / QO-100 operation.

Block Diagram

Block diagram of Ground Station


I used a Global  L-Band upconvertor

Which will take in 432MHz and output 2400MHz (plus images, so it needs a filter).

The conversion gain at 2400MHz is right on the edge of the mixer performance, but the output level can be increased by diverting the signal via the LO output amplifier stage.

Some more notes can be found at https://forum.batc.org.uk/viewtopic.php?t=4118


Band Pass Filter

Constructed using this information https://www.qsl.net/g0ory/2.3g/bpf/13bpf.html


This was my first quick attempt at a linear feed using a PBC Log-Periodic.
Then a 5 turn helix which gave approx 4.5dB better performance.
The Helix was copied from G6LVB's AO40 S-Band design Modify an Anologue Sky TV Dish for AO

Helical feeds - read the notes on optimisation inc. axial ratio, beamwidth and feepoint adjustment  http://www.g6lvb.com/60cm.htm

I think it would be better to use a larger diameter outer support tube around the helix acting as a radome.

The helix reflector plate could probably be made a bit smaller, but it didn't seem to degrade the RX S/N by any appreciable amount, so I didn't bother chopping it down. I used PCB because I had it to hand, but aluminium, brass or whatever would be OK. 

The underside of the 1/4 wave impedance matching line one the first turn of the helix has got self adhesive Mylar foil on it so that it doesn't short against the body of the N connector, when it is bent close to the reflector in order to achieve the best Return Loss.
The foam at the back is just to help keep the LNB short term drift under control when the sun goes behind a cloud.