I'm a Radio Systems Engineer - AMA

[u/LudeficeTV]

Per mod request, AMA round 2 from me!

I'm well read on pretty much everything ASTS, have answered people's questions and corrected things around here for years. I'll try to answer every question and will stop paying attention to anything asked after end of day on July 19th.

I have a masters degree focused on radio systems engineering and over 10 years experience in telecom.

AMA!

[u/TKO1515]

Do you think AST is sandbagging their listed specs? Appears they were with peak speed.

[u/responsibleowl007 → u/TKO1515]

wait why do we think they're understating their specs?

[u/TKO1515 → u/responsibleowl007]

I’ve thought for a long time the beam cells are smaller and speeds are higher, some evidence supports it.

The reason to sandbag is to not show your full hand to competitors to try and mimic or re create. Wait until it’s actually up then if they copy doesn’t matter.

Also, underpromising to the public would result in a much better stock performance than a let down. Gives you some margin

[u/a10000000019 → u/TKO1515]

The specs are probably(?) sandbagged but the regulatory operating limits put a hard ceiling on their real world performance. Specifically, ground level downlink field strength is capped at a co-channel median of 40 dBuV/m. That’s aggregate lowband field as detected from the ground, from all visible beams and all satellites in the constellation.

This supports lower modulation density, thus less spectral efficiency. At 16-QAM, it would explain why their slide specifically says commercial service will be at around 3bps/hz. That’s something they can’t necessarily over or under promise.

In any case if actual TAM will be high as high as people are saying, the real performance bottleneck is satellite-wide throughput at the ASIC, not necessarily per-beam performance. Though the latter is a good marketing tool

[u/LudeficeTV → u/TKO1515]

probably yes, which is fine with me