Great input ! , thanks... Now How do I get the best Q ?...
As stated the type of Ferrite is extremely important. I normally use antennas taken from transistor radios and rewind them. The type of ferrite in mid 50s Zenith and Motorola tube portables is what Ive found to be the best.
Space winding is an art. It really takes a LOT of experimentation with turns so be warned. If you look at the second picture you posted, near the one end of the loopstick, the windings are fairly close together. They did this for fine adjustment to be able to get the inductance just right. The loopstick was then covered in wax to keep the wire in place. Candle wax works great for this. I have to say, if the antenna is already space wound, take advantage of it. Slowly peel off turns until the desired tuning range is desired. Most Tube radio antennas are made for 500 or 365pf variables. Transistor sets are usually 135pf.
If that sounds like too much work you can always wind the coil on the end of the loopstick normally. Start with 75 Turns or so then slowly take off turns until the tuning range is what you want. Many of the transistor radios were done this way especially Zenith. Look at the Royal 500s. For smaller loopsticks (3 inches or less) winding the coil on the most center of the bar is best. That only works if the winding will cover 70% or more of the loopstick. It acts similar to the space wound effect.
The Ferrite material is available Via Ebay but the frequency range of the material may not be fit for AM BCB or SW.
The shape of the material has a big effect. If you notice,
To sum it all up:
Space wind if you positively absolutely need Q. Lets say for a crystal set. Take advantage of space wound antennas when you can if pre wound.
Wind a coil on one end of the loopstick if you are winding a loopstick for a radio with an active device. The difference between Space wound and standard spaced as far as Q is not that much. The difference can be compensated for with larger litz. DO NOT DOUBLE BACK ON THE WINDING!! Only 1 layer of wire on the loopstick is really needed. DO NOT LATICE WIND COILS. The Q suffers greatly. They only did that originally to save space. Notice how only cheap radios and radios limited on space use them.
Look out for old damaged transistor and tube portables that are too far gone. Especially Zenith and Motorola.
Regen sets also benefit from a high Q front end. Adds to selectivity.