Whether I tap or press and hold the key fob button for this particular vehicle (KIA Sportage), the key seems to only emit a very short signal which looks like a piano key in the display. Though the flipper picks up and records the signal, sending the signal does not work. I am assuming that the signal is too short or is missing some critical component. This is the 433.88 freq, by the way.
Any ideas as to why this replay is not working?
Thanks!
That is a rolling code. Rolling codes change each time. It’s specifically meant to stop replay attacks which is what you are attempting. Stop what you are doing and become familiar with rolling codes before you go any further. You may de-sync your fob from your car. Best case in a de-sync you have to do a re-sync. Worst case you might have to hire a locksmith or have your car towed to a dealer.
Those Tik-Tok videos don’t explain how you can break your car if you don’t know what you are doing.
Appreciate the information, and the concern. Now, I have looked into the rolling codes and encountered it on other cars but what I had not yet seen was the narrow signal. Previously, with other fobs, I had been able to capture a longer signal by simply pressing the button for longer (unlike in the situation I previously described). All of these types of signals I could capture and replay the one time before the code ‘rolled’. Are you saying that the narrow signal that I am seeing with this particular car is in fact characteristic of rolling codes in general?
We typically use the term narrow to describe the frequency domain but I think you’re describing the time domain because you mentioned holding the button. Either way I wasn’t suggesting rolling codes as being characteristically shorter to static codes. In most cases the transmission length(time) is longer because the transmission is repeated.
Understood, sorry, I was having a little trouble describing it without a picture, but yes the fob only allows me to send a very short burst, in terms of the time interval of the signal, before shutting off. And the capture appears to be unusable. Again, that is in comparison to other fobs I have tried. I thought of trying to mash the button continuously during the recording… but was concerned about getting into the situation you mentioned in your your initial reply and having to resort to auto jigglers or something.
No reason to apologize. We aren’t as judgmental as those Stack Exchange people. 
Kia has FM modulation. 4 code repetitions are transmitted, in Manchester encoding. the duration of the transmission in full is enough