Antennas are plug and play devices from the point of view of your Jetpack. If they are configured correctly the Jetpack will start to notice an improved reception immediately.
What you should be watching is the reception of VZW signal, not the scores from speedtest.net. In theory your reception and performance will go up and down together but not always. The antennas are impacting the Jetpacks 4G LTE reception. If there is no improvement then you might not have the right antennas or have them configured correctly.
There is also no guarantee that antennas will produce a noticeable benefit. There needs to be a signal in the air for the antenna to work correctly. Some areas are just deadzones and there isn't anything you can do to improve unless you move out of it.
Your Jetpack should have some kind of Diagnostics area. Take a peak at this area with and without the antenna to see if there is a noticeable difference.
More info on antennas and site surveys here: