Turnigy 9X8Cv2 Receiver antenna weak point

[trauma50]

Turnigy 9X8Cv2 Receiver antenna weak point

Has anyone replaced the coax antenna with a stronger coax cable? Mine get swapped out and used alot in Multirotors. I believe with the prop wash from being exposed to constant movement, the antenna fatigues were it comes out of the receiver. The shielding cable can have intermitted contact causing glitches, and loss of control. I have shortened the cable and re-soldered 3 receivers to date. I have tried hot glue to reinforce the coax cable were it exit's the receiver, heat shrink tubing, with minimal results. I know they are 10 bucks a apiece. But when you have 3 perfectly good receivers on the bench except for the antennas, $30 bucks add up.

First question: dose the length of the coax cable affect range as with the 72mhz radios?

Second: Can I use thicker coax cable to make a stronger antenna ?

Third: The copper tubing at end of the antenna is soldered to the shielding of the coax cable. Does the size and length have any affect on range?

Thanks for any guidance as how to fix this issue.

Joe

[Daedalus66]

The length of the antenna is critical (about 31mm but varies a little) but not that of coax, which is simply a connecting cable. Transmitters on 72 don't use coax -- the whole wire is the antenna.

The coax is a specific type with the required impedance and must not be changed.

The sleeve has specific dimensions that should not be changed.

[trauma50]

Thanks, posted this question on 2 different forms and you were the only one to reply. So I can make the connecting coax cable as short as I want with out affecting the range. It's the short 31 mm wire that exits the copper tube, that's the active antenna.

You mentioned that a 72mhz antenna is not coax cable. A nubee story, the first time I went to repair a antenna that was ripped from the board, I did not know that. So I solder the whole wire to the board in one spot it looked like it came from??? After closer inspection under a magnifying glass I saw that it was coax cable. Lesson learned.

Thanks again. Joe

[Daedalus66]

The simplest extended antenna is a piece of coax with the outer shield removed from the last 31mm. The sleeve is not essential (though it does improve range modestly). For many purposes where maximum range is not essential, this simple antenna is entirely adequate. The only problem with shortening the cable drastically is that the antenna may be less effective if closer to the receiver, but this in not usually a problem.

An even simpler approach is used by receivers such as the Orange 610, which have a single wire (not coax) soldered directly to the circuit board. This is usually adequate for "park flyer" type models.

By the way, the following statement from the HK web page is misleading: "Only RX-9X8Cv2 receiver is comptible with TX-9X(v2) transmitter module." What it should say is "The RX-9X8Cv2 receiver is compatible only with the TX-9X(v2) transmitter module." Meaning, really, that the old v1 receiver is not compatible with the v2 module (which is the one they have been selling since 2010). Another receiver that is compatible with the v2 module, and has the advantage of being smaller, is the six-channel HK TR6A-v2:
http://www.hobbyking.com/hobbyking/stor ... Ch_V2.html