TL;DR: How would one send a fixed radio signal at 447,54MHz with Arduino?
Background: I recently purchased a (receive only) SDR and recorded my garage door fob. I found it sends a fixed signal at the frequency 447,54MHz, which I was able to decode. Now I want to try activating the garage door via Arduino. The standard 433MHz senders obviously don't work, since they have a totally different frequency.
I tried searching for senders of my frequency (447MHz) and also for senders with different or variable frequencies. I didn't really find much. Also I read in some post (that I don't remember currently), that building an own sender circuit is not easy (since the exact PCB design plays a big role in the behavior in the ciruit). It didn't seem, that this would be a valid way for me.
Has someone here experience with such frequencies? While I know, that this site doesn't do product recommendations, maybe I just searched for the wrong term and you can help me with that. Or maybe there are no (or very very few) "maker-ready" products for this out there currently. Maybe the creator of the garage door system wanted a non-standard frequency for security-through-obscurity (since that doesn't protect against attackers with a sending SDR).
Also I researched about frequency bands. Normally I would think of a garage door fob as a Short Range Device (SRD), but instead my frequency is right above (and outside) of the band PMR. Maybe this is because the system is really old (can easily be between 15 and 30 years).
I'm kinda lost on how to proceed here, or if proceeding is even viable here.