What is "Spiking" a coil to check bandwidth?

[radeonut]

I've been restoring radios since the 1970's, but I have a few TV's kicking around to do, and have been doing a fair bit of reading, and restoring my vintage TV alignment gear.
I'm teaching myself alignment on a run of the mill RCA portable. So far, not bad. Learning the hard way about matching pads, detector jigs, etc. and most certainly the effect of ground loops around the gear.
My question is thus:
The instructions mention "spiking" a coil to check bandwidth. The coil they mention is a fixed, air core, between the tuner output and the 1st IF tube. I am thinking they are talking about adjusting the coil spacing. I tried fiddling with that, but the bandwidth shown on my scope didn't seem to change.
Am I on the right track with this train of thought?