Anybody have luck with hawk call to hold coveys?

Lots of birds but had a lot of coveys bust way out in front of us and out in front of the dogs. Any experience with hawk call to hold coveys? I've got an electric collar with a hawk call but I've never used it.
Any other techniques to help hold birds?

Ive seen them on collars, don't know that they work though.

Ive used red tail hawk calls since the 80's. Works great on running cotton tops.

Electronic call? Or hand call?
Who makes your call?
Can you use an MP3 player in the field for hawk call?

I haven't seen it work yet but I do carry a hawk whistle. Have only tried it a couple of times. You hunting public or private? Bobwhites can be like hunting blues after they've been pushed a few times. I know they pick up on us hunting them out of the Mule later in the season.

Private. Looks like the last rain moved a lot of the coveys and broke up some of the bigger ones. More water means less need for concentrating near tanks. Have a lot of blues on the lease that are very jumpy. But the bobs are starting to work the same way. Jumping early, way out ahead of the dogs.

hand call, I've actually witnessed a 30+ bird covey of blues freeze and squat at the sound of the hawk call in the middle of a plowed field.

that would be a great video

MP3 electronic quail call???

That tops the yuppie hunters guide to quail hunting

Any particular brand of call you guys like?