Originally Posted by
speedracerntrixie
That one has the Hitec Optima 7 channel RX. Hitec Optima receivers have a boosted Omni Directional antenna. Only the last 1/2" is active. Installed as per manufacturers instructions. I have been flying the Hitec A9 TX ( I have 3 of them ) with the Optima 7 and 9 channel receivers since 2010. They have been in glow powered models, gas powered with CDI being run off RX power, Electric power and sailplanes. Almost all of those aircraft incorporated composite construction. Mostly fiberglass with CF re enforcement where needed. I have lost only one model due to signal loss. User induced. I placed the antennas ( Optima 9 channel w/dual antennas ) next to the fuel tank. It was either that or next to the digital elevator servos. I didn't really like either option but went with the one I thought best. That airplane did fly successfully for close to two years prior to the loss. As we both know, noise floor fluxuates.
So the antenna is essentially base loaded so it presents a 1/4 wave electrically to the RX. While electrical length is the more important measurement, physical length does play into it and I would suspect in a hard core test, the 1/2 inch would not have the same max range as the others with a full 4.92 inches.