ORIGINAL: Love To build
Keeping the wire the same length while wrapping around the tube keeps the impedance the same. For 2.4 Ghz radio the hidden antenna should not be an issue. For the older radios as long as the wire length is the same as the original design your replacing, the only thing you will be effecting on your tank receiver is distance and possible interference issues by wrapping a coil and placing inside the vehicle.
Sorry but you are wrong antennas don't work in such way. If you wrap the wire around a tube you are making an inductance, then the impedance in the end will be absolutely different.
If you don't keep the vertical antenna in that position and leave a wire wrapen the impedance will change also.
There are two kind of antennas, dipoles 1/2 wave length and verticals 1/2 and 1/4. You can change the large of the antenna if you add a loading coil, then you can reduce the large of the dipoles and verticals.
In fact the verticals for 27Mhz should be around 2,75 mts and usually has 60 cm because the transmitter has a loading coil. If you remove the loading coil changing the output circuit and place a 2,75 mts and adapt the impedance you will have several db more of gain. Exactly the same works for a receiver.
Regarding to the antenna radiation pattern, 10 feet or 100 is the same, in fact most of the modelers have their radio’s antennas to 45° and there is not difference. The big problem with 27Mhz is the big interference and the fact that the radios are AM, citizen band is a very noise spectrum nowadays for AM.