Here is a posting from another forum reguarding the antenna modification:
"heavyaslead ...Grand idea!
Just tried it with my 75MHz receiver, and I must say it does work very well, range was improved by almost 2X
Now I will fine-tune it for CH90 which will make a coil about 13 feet in length.
Also as a side note, my initial test also proved to cut down on the interference (since the entire antenna helical coil can be located away from motors and electronics or other metal parts)."