The pulsar antenna is now plugged into the pulsar receiver system, which consists of a pair of AirSpy SDR receivers, fed with a high-quality 10MHz OCXO timebase.
We’re running a pulsar-specific flow-graph, written by Marcus Leech, and using Gnu Radio underneath.
There are many unknowns–we don’t know if the ambient noise level is low enough without aggressive filtering, we don’t know if our antenna effective aperture is quite up to the task. This will be a useful test, but a negative result cannot be interpreted to mean “won’t work”.
The 3 x 4-bay UHF pulsar antenna was installed on the roof today, and is wired up to the entrance bulkhead. Checkout will start in the next few days.
Gary ATkins and Marcus Leech worked away this evening on making the first of two stands for our two UHF interferometer antennae.
We had planned to put the pulsar antenna “up top” today, but ran out of daylight hours.
Got one of two UHF antenna “modules” assembled.
Each of these modules consists of two “8-bay” UHF HDTV antennae, and each of those actually breaks down into 2 4-bay modules. By designing with modularity in mind, and leveraging the economies-of-scale of consumer items like these antennae, we can scale up individual antenna modules in a step-wise fashion.
It’s looking more like a lab every day.
Managed to scavenge a couple of 80s-era “printer tables”. From back when they knew how to make office furniture that would last. I had to explain to my daughter what a printer table was….
Our first live data feed is now up and running, showing the neutral hydrogen spectrum as seen by our 21cm telescope, aimed at a declination of +40 degrees. This will show interstellar neutral hydrogen twice a day, for a couple of hours each time, when the galactic plane passes through the main beam of the antenna.
Check out our “Live Data” page for information.
I did some local network improvements, including bring wired network into our lab/office, and setting up a more-reliable 2nd-floor WiFi connection, for visitors, etc. This doesn’t appear to interfere with our existing receivers in any noticable way, so, that’s good.
Finished building the two “stands” for the pulsar antenna, which is a stack of garden-variety 4-bay HDTV antennae. This arrangement will give ushttps://en.wikipedia.org/wiki/Right_ascension an asymmetric beam, with a roughly 2:1 ratio, with the declination axis having a narrower angle than the right-ascension axis, somewhat like an ellipse.
This asymmetry will allow us to “see” the target pulsar for long enough to integrate the pulses synchronously for an extended period, without having to move the antenna at all. This lowers telescope complexity enormously, but compromises on sensitivity. We may add a 2nd “stack” of 3 4-bay antenna if this proves to be insufficiently sensitive.
Gary and his son, Andrew came over today and we got the hydrogen-line monitor set up temporarily on the lawn, next to the office.
A quick pic of the hallway display was snapped on the way out this evening with a nice hydrogen-line “bump” on the doppler-view of the spectral display.
Some cross-bracing was added to the support stand for the 1m dish–should be ready to go up on the roof very soon.