Two Frequencies on Same channel # !

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Iantos - 30 Nov 2003 07:25 GMT

Can someone explain how can two cars run simultaneously having the
same frequency, I saw that last weekend. The guys told me that both of
them are having channel#4 on their JR radios BUT the second car was
having the TX & RX crystals locations switched which (what it seems)
produces them a new frequency.

That was cool :)

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kenji - 30 Nov 2003 16:15 GMT

> Can someone explain how can two cars run simultaneously having the
> same frequency, I saw that last weekend. The guys told me that both of
[quoted text clipped - 3 lines]
>
> That was cool :)

they probably didn't have the same frequency.

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Iantos - 01 Dec 2003 04:37 GMT

> > Can someone explain how can two cars run simultaneously having the
> > same frequency, I saw that last weekend. The guys told me that both of
[quoted text clipped - 5 lines]
>
> they probably didn't have the same frequency.

yes they had the same frequency and i tried it my self ! it worked
without any problems.

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kenji - 01 Dec 2003 05:04 GMT

> > > Can someone explain how can two cars run simultaneously having the
> > > same frequency, I saw that last weekend. The guys told me that both of
[quoted text clipped - 8 lines]
> yes they had the same frequency and i tried it my self ! it worked
> without any problems.

You actually pulled out both sets of crystals and could see the
frequency numbers stamped on them were the same? Or were you trusting
what the plastic adapter (holder) said on the outside?

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Decrash - 01 Dec 2003 18:50 GMT

That is impossible to have to cars run on the same freq.
One of them probably had an synthesized RX or just changed th
crystals in the TX and RX with a different frequency cyrystal....whic
means then second car was no longer on channel 4

-
Decras
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Decrash - 01 Dec 2003 18:50 GMT

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Iantos - 02 Dec 2003 17:47 GMT

> That is impossible to have to cars run on the same freq.
> One of them probably had an synthesized RX or just changed the
> crystals in the TX and RX with a different frequency cyrystal....which
> means then second car was no longer on channel 4.

Try it your self and see.

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kenji - 02 Dec 2003 18:33 GMT

> > That is impossible to have to cars run on the same freq.
> > One of them probably had an synthesized RX or just changed the
> > crystals in the TX and RX with a different frequency cyrystal....which
> > means then second car was no longer on channel 4.
>
> Try it your self and see.

If you thught you had a live one, you do. I tried it with 4 different
radios. It didn't work with any of them.

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Olev Pihl - 01 Dec 2003 06:54 GMT

Tx and Rx crystals are on different frequencies (they differ by
something that's called an intermediate frequency, which is related to
Rx design and IIRC is several hundred kHz in model radios). Effectively,
when you swap the Tx & Rx crystals, you 1) change the transmitting
frequency and 2)may end up outside the frequency band. The thing may
still work (as it obviously did in this case), but there's no guarantee
that it will. So, it's not really a smart thing to do.

BR,
-olev-

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Model Forum / Radio Controlled / Land Models / December 2003

Two Frequencies on Same channel # !