RX Single Conversion Crystal
01-03-2007, 06:47 PM
#1
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RX Single Conversion Crystal
Hi folks!
I'm a bit uneducated when it comes to TX and RX xtals.. I have some basics, but still not totally clear.
I have a number of helis and want to control them all with my Futaba T6EXHP. Since each heli that I've purchased has come with a different channel RX, I was thinking I'd buy all Ch 53 crystals (as that's the channel my TX is on) and pop them into my different helis.
To make sure this idea would work, I took the Ch 53 crystal out of my X400 and put it in my Blade CP, configured the TX and everything was fine. So I went ahead and ordered a HiTEC HRC#6647253 72mHz Single Conversion Receiver Xtal (72.850 MHz, Ch #53), and it doesn't work in the blade... however the Futaba Rx Crystal Short 72-12 (FUTFRC553) works fine.
The question is this: Should the HiTEC xtal work, or is it different than the crystal short Futaba? I thought I only had to match SC or DC, and the Ch #. I just don't know enough to tell if I got a junk crystal or if I purchased the wrong item.
Any and all advise would be greatly appreciated.
I'm a bit uneducated when it comes to TX and RX xtals.. I have some basics, but still not totally clear.
I have a number of helis and want to control them all with my Futaba T6EXHP. Since each heli that I've purchased has come with a different channel RX, I was thinking I'd buy all Ch 53 crystals (as that's the channel my TX is on) and pop them into my different helis.
To make sure this idea would work, I took the Ch 53 crystal out of my X400 and put it in my Blade CP, configured the TX and everything was fine. So I went ahead and ordered a HiTEC HRC#6647253 72mHz Single Conversion Receiver Xtal (72.850 MHz, Ch #53), and it doesn't work in the blade... however the Futaba Rx Crystal Short 72-12 (FUTFRC553) works fine.
The question is this: Should the HiTEC xtal work, or is it different than the crystal short Futaba? I thought I only had to match SC or DC, and the Ch #. I just don't know enough to tell if I got a junk crystal or if I purchased the wrong item.
Any and all advise would be greatly appreciated.
01-04-2007, 02:17 AM
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RE: RX Single Conversion Crystal
I do not know what you mean by “SC and DC”. Some manufactures use “positive swing” and some use “negative swing” but as far as I know Futaba and Hitec are compatible. The fact that the Futaba crystal works in the Hitec suggests to me that the Hitec crystal is faulty. But don’t think that the Futaba crystal will be as good as a Hitec crystal in a Hitec receiver. As a rule don’t use different brand crystals, they may seem to work but because of design differences they may be slightly off frequency.
01-04-2007, 09:11 AM
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RE: RX Single Conversion Crystal
ORIGINAL: Piet Le Roux
I do not know what you mean by “SC and DC”. Some manufactures use “positive swing” and some use “negative swing” but as far as I know Futaba and Hitec are compatible. The fact that the Futaba crystal works in the Hitec suggests to me that the Hitec crystal is faulty. But don’t think that the Futaba crystal will be as good as a Hitec crystal in a Hitec receiver. As a rule don’t use different brand crystals, they may seem to work but because of design differences they may be slightly of frequency.
I do not know what you mean by “SC and DC”. Some manufactures use “positive swing” and some use “negative swing” but as far as I know Futaba and Hitec are compatible. The fact that the Futaba crystal works in the Hitec suggests to me that the Hitec crystal is faulty. But don’t think that the Futaba crystal will be as good as a Hitec crystal in a Hitec receiver. As a rule don’t use different brand crystals, they may seem to work but because of design differences they may be slightly of frequency.
What I meant by SC is Single Conversion and DC, Dual Conversion. The Eflite receiver on the blade cp is a single conversion receiver. Maybe I wasn't too clear on my question. What I'm trying to find out is if the HiTec xtal and the Futaba xtal should work the same, or if they are indeed different things (other than the manufacturer). Basically I'm trying to determine if I got shipped a bad crystal, or if I just purchased the wrong one.
Both crystals are single conversion, and ch 53 (72.850 Mhz). The Futaba one calls it's a 72-12 Short, and the HiTec one just said single conversion, ch 53. I just don't know enough about this aspect of the hobby yet to determine if I am just buying the wrong stuff, or if I'm getting shipped defective parts.
01-04-2007, 11:01 AM
#4
RE: RX Single Conversion Crystal
I'm not an expert on this stuff as some who post on the forum are, but from what I've read there are/can be differences between the manufacturer's crystals. Therefore you should use only crystals from the manufacturer of the rx, but some others do occasionally work.
Having said that, I was really surprised when I found out the my Blade was using a negative shift radio considering where/who it came from. I couldn't find out who actually manufactured the radio stuff, so I opted for the Futaba short crystal and it works fine with my Futaba 9C Super radio. I didn't try the Hitec crystals.
Having said that, I was really surprised when I found out the my Blade was using a negative shift radio considering where/who it came from. I couldn't find out who actually manufactured the radio stuff, so I opted for the Futaba short crystal and it works fine with my Futaba 9C Super radio. I didn't try the Hitec crystals.
01-04-2007, 04:46 PM
#7
RE: RX Single Conversion Crystal
A single conversion reciever requires a single conversion crystal of the correct channel and manufacturer. Same with dual conversion.
Some manufacturers use positive shift signal (jr, airtronics) and some use negative shift (Futaba and Hitec) some transmitters are shift selectable like the 14mz from Futaba and some receivers (some hitec models) are shift selectable.
Crystals should generally be of the same manufacturer as the reciever but hitec and Futaba are generally accepted as compatible, though its really best to get the correct crystal.
One other aside, crossing manufacturers, say a Futaba TX and Hitec reciever, can only be used in PPM Mode, pcm is proprietary and you need that companies reciever because the frame format differs.
Some manufacturers use positive shift signal (jr, airtronics) and some use negative shift (Futaba and Hitec) some transmitters are shift selectable like the 14mz from Futaba and some receivers (some hitec models) are shift selectable.
Crystals should generally be of the same manufacturer as the reciever but hitec and Futaba are generally accepted as compatible, though its really best to get the correct crystal.
One other aside, crossing manufacturers, say a Futaba TX and Hitec reciever, can only be used in PPM Mode, pcm is proprietary and you need that companies reciever because the frame format differs.
01-04-2007, 07:30 PM
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RE: RX Single Conversion Crystal
Don't mix different brands of crystals with unlike brands of Rx's and Tx's. Hitec does not, and can not recommend using our crystals in any product other than Hitec.
Period.
Glen Merritt
Marketing Manager
Hitec/Multiplex
Period.
Glen Merritt
Marketing Manager
Hitec/Multiplex
