Does anyone know anything about the 1st AR HQ Division A Co signal intelligence at Fort Riley?

Have you researched it on the usual links* yet? If not, I'd start there.

It's been a few years, so they could have reorganized (again), but there was a combined signal/MI company last I interacted with them (2020) that was the Signal, Intelligence & Sustainment (SIS) company. Wasn't aware that the HHBN had an "Alpha Company".

1ID publishes their own online magazine called "Danger Forward"*. Suggest you read through a few issues as that will give you a much more comprehensive feeling of their OPTEMPO, focus, etc.
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* Links to start with to get an overview of the Big Red One (1AD) and Ft. Riley
https://www.1id.army.mil/
https://installations.militaryonesource.mil/in-depth-overview/fort-riley
https://home.army.mil/bliss/about/leadership/1st-armored-division-and-fort-bliss-command-policy-letters
https://www.facebook.com/1stArmoredDivision/
* Danger Forward magazines - https://www.1id.army.mil/Newsroom/Danger-Forward-Magazine/

Call them up. Ask if there is a sponsor for you.

Enjoy Custer Hill