Mis-labeled Pico crystal? - RC Groups
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Feb 14, 2004, 08:36 AM
2ManyHobbies2LittleTime
jswayze's Avatar

Mis-labeled Pico crystal?


I was putting together my Mini-IFO and come to the point of testing my radio system. I turned on my radio and got nothing but a "blip" from the servos. Come to find out that the channel 31 "pico" rx crystal didn't match the package it came in (see attached photo.)

It seems very odd that the crystal would have mis-matched channels/frequencies printed on it. Am I missing something or did I just get a dud?

It's killing me because I wanted to fly this weekend, and the shop that sold this to me is closed. I'll try to hunt down another one...

Any ideas? GWS?
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Feb 14, 2004, 08:38 AM
2ManyHobbies2LittleTime
jswayze's Avatar
I guess if you preview the message you lose the picture... Here it is.
Feb 14, 2004, 08:54 AM
Registered User
that is really odd!
when i did a search on line for frequency lists, i found this:
chn 31 is 72.410... so the print on the box looks right. i actually couldn't find a 72.865... i did find a 72.870 which is channel 54.
i'd take it back to the store you got it from and have them check it out.
anybody know of a simple way to verify a frequency?
-beanie
Feb 14, 2004, 09:15 AM
2ManyHobbies2LittleTime
jswayze's Avatar
Oh boy, I win the bonehead award for today (at least for this morning )

The correct frequency is printed on the OTHER SIDE of the crystal! I also found a thread that says that the actual cyrstal frequency is .455 MHz less than the "channel" frequency.

The reason I jumped to the conclusion tha the crystal was wrong is that my setup didn't work, and still doesn't. Here's what I've got:

- Hitec Flash 5, ch. 31 crystal
- GWS ICS-100 ESC
- GWS 4-ch. Pico receiver
- 2x GWS Pico servos
- 2s LiPo battery

I turn on the radio first, then plug in the battery to the ESC. I hear the servos "blip" like normal, then I get nothing. No control from the radio. Any ideas?
Feb 14, 2004, 09:41 AM
Lookin' Good. Real Good.
larsy87's Avatar
Try reversing how you plug your servo and ESC wires into the Rx.

Cam
Feb 14, 2004, 09:42 AM
Lookin' Good. Real Good.
larsy87's Avatar
Wait - Is your Hitec radio negative shift???

There's no way a Negative shift transmitter will work with a Positive shift Transmitter.
Feb 14, 2004, 09:47 AM
2ManyHobbies2LittleTime
jswayze's Avatar
You got me there. I'd never heard of "shift" before today... I'll look into this. Thanks.
Feb 14, 2004, 09:49 AM
Just fly the darn wing!!!
ScYcS's Avatar
It is indeed a Hitec radio with a positive shift receiver (identified by the "J" on the receiver. The correct one will have a "F" on it). Your setup will not work. period. You will need a different receiver, one with "negative" shift.
Feb 14, 2004, 09:58 AM
2ManyHobbies2LittleTime
jswayze's Avatar
Well, lesson learned. This is my first non-Hitec receiver and I didn't realize there was a difference.

Thanks for everyone's help.

(Now I've got to find a LHS with these receivers so I can fly this weekend!)
Feb 14, 2004, 10:16 AM
Just fly the darn wing!!!
ScYcS's Avatar
Hitec also makes 2 versions, negative or positive shift. You should always state when buying a receiver for which shift it is. Hitec and Futaba use negative shift, JR and Airtronics and most others use positive. Some manufacturers make transmitters for both shifts (GWS for example).

Always make sure you tell the guy you buy from that it's for a Hitec radio with negative shift.
Feb 17, 2004, 10:46 AM
now that's a wattmeter...
simingx's Avatar
If your radio is an Eclipse it has both shifts selectable.. just go to the setup menu and select "SFT. P" instead of "SFT. N"...
Feb 17, 2004, 11:32 AM
Houng-wen Lin
GWS4CEO's Avatar
Quote:
Originally posted by jswayze
I guess if you preview the message you lose the picture... Here it is.
Pls don't be supprised the actual RX cyrstal frequency is .455 MHz less than the TX "channel" frequency.


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