Conway,
Let me tell you what I've done with a wire whip on a Wildman Jr. rocket. I stick my Beeline GPS in the forward part of the ebay on a carrier that has the deployment electronics aft which consists of a Raven II altimeter. I've lined up a hole on the forward bulkhead of the ebay so the wire antenna sticks up into the main chute bay.
So, o.k. under G forces the main chute will go aft and squish the antenna right?
Weeeeelllll, You know the cardboard tubes that contain the Aerotech wired igniters? I simply put a bit of removable clay around the antenna/bulkhead interface for a gas seal. I then slide the cardboard tube (that contained the igniter) over the wire and use clay and tape to hold the cardboard stent over the wire antenna at the bulkhead interface. I do use a micrometer to measure the wire antenna and choose a drill bit that will make a hole that will just let the wire go through the forward bulkhead. The removable clay or putty is more than enough for a gas seal.
Sure, the wire may be bent a little bit one side to the other but the antenna stays straight and not smushed down. It will track just fine via Rf. I've had no trouble with the low powered BLGPS at a couple of miles out though once it's down, the signal fades out.
No big deal as I have the last known position locked, go to it, get a new fix when I get closer and recover the rocket. Works like a dream.
Errrrrr, um, I did fly the rocket one time on a lower powered motor that I knew would keep it in sight without the stent and I can testify the wire antenna will get "smushed" and crunched down!
Signal was lost after launch but rocket came down in sight so recovery was no big deal. I thought the wire would get pressed against the inside wall of the tube, stay more or less straight but I was way wrong. At least I was smart enough to test it with a lower impulse motor to keep the rocket in sight for recovery. I straightened the antenna and brainstormed what to do.
After the main chute charge blows, if the cardboard stent is lost no big deal as one has a ready supply of more.
Actually, I've never lost a stent and they don't catch fire from the momentary flash. When they wear out, I replace them from a ready supply of cardboard tubes from my AT motor igniters.
It's a very easy remedy when ones rockets don't have enough room in the nosecone for a tracker bay.
Unless AT changed the tubes, mine are thick walled and strong. Make real nice stents to keep wire antennas straight inside main chute bays. The cardboard is radio-lucent.
Make sure the main chute bay is not painted with metallic paint as I've had it attenuate the signal terribly on the 400mhz Ham trackers. I don't know about the 900mhz stuff and I'm not going to try to find out how they behave with metallic paint.
As an aside, one could use a stent with an Eggfinder using a wire antenna. Just have to have an ebay that has enough room for the tracker, batteries and deployment electronics.
Best of luck,
Kurt Savegnago (also known as KC9LDH on hf)