Changing Frequncies?

[Need4Speed210]

I just posted this here replying to their topic, just thought Id give everyone here a heads up. ......... Anyone have any ideas? Still thinking myself...

I wasnt going to let anyone know about my 'theories', but since I dont really have the resources right now I figured Id let someone else a try at it. First off im only 15 and my electronics knowledge is probably just the tip of the iceberg, but with what I do know, and common sense I thought of a few things... The car NEEDS atleast 1 component that regulates a frequency (27, 35, 57 etc) Even if this is not a full size Xtal, its most likely something that can be changed, seeing as it would make more sense. All the chassis seem to be exactly the same, same layout, just a different component governing freq. Theres only 1 Xtal, and thats for the tX. This means that there is most likely one component that changes frequency reception for the car itself. Although all the chassis seem the same, there must be a different component dictating freq. After all, you cant just change the tX Xtal, and the chassis will magically respond to that signal.- No, there needs to be something setting a base for it to understand. I dont want to sound like a scientist, but heres what I came up with-

Im thinking, this component must be, or must directly be related to the pot. As others have said, this seems to slightly adjust the freqeuncy with a seemingly small range (3-5Mhz?) From what I understand, pots are variable resistors, turning them does something like slide a connection point allong a resistant wire. This being said, I formed 2 possible answers.:

1- Frequency in the cars, must be wired in a way that different pots determine the frequency. Pots are variable resistors right? If adjusting one gives you a 3-5MHz sway, a say, different resistance wire, or guage, may determine the frequency.

2- A component directly related or very close to the pot determines the frequency, then sends it down to the pot for fine tuning. This could possibly be a mini Xtal, or something else. A schematic would REALLY REALLY help here.



Well anyways, thats what I thought up. Wouldnt it be DAMN cool if we could get like 10-15 cars going at once? (I KNOW I cant get whatever components required for different freqs, just determining what they are may take a while) Be welcome to critisize my thoughts, or try it yourself, just let everyone else here know!

[sine -''-..-]

yea ive been thinking about this as well, because if we can change the frequency on the car, we could make as many different frequency ranges as we liked (boo to fcc). anyhow, the pot is actually an adjustable coil as far as i know. im not sure if simply the coil governs the frequency of the reciever, it may be that or a capacitor. but adjusting the coil would definately tune the reciever to some degree.

drat. i wish i knew more about radios.

[e_lm_70]

Hi guys,

I think there are some mistakes on your assumptions:

- There is no POT in the car, it is a variable inductions simbol is L. Most probably in the car there is a simple LRC fraquency range filter.
- These cars for sure have a "filter" that is far to be narrow, so I expected that you can't use two indepentent frequences, closer then 7Mhz without generate interference.

So the limit of 4 cars with a range between 27-57 look the maximum.

What can be done, is just try to go in higher frequences, till 85Mhz, so other 3 cars can run !

My approch is to have 4 Bit + 4 Smartland (infrared) this bring up to 8 independent cars. But without mods, the Bits are more performing.

e_lm_70

[e_lm_70]

Just tried yesterday with my 27MHz OEM and the MultiBand controller.

I have turn in the two direction the little "POT" in the car PCB.

As result I can just increase or decrease the range, but no way to change the frequency !

It look to me that in the PCB must to be present a PLL, since once connected first with the signal the car can keep the signal even from more far.

e_lm_70

P.S: I tested it out, since on my electronic catalog, I have seen some componet similar to the PCB "POT", that state they can manage a frequence between 2 to 80 MHz !

[dtmracer]

yes you can change the frequencies. before bits, the smallest rc were the tyco canned heats, these were 1.32 scale and ran on mini 4wd motors. well they came in 49 mhz and 27 mhz. in the tyco canned heat forum a guy tried telling us how to do this mod. he took out the frequency in the controller and took one from a cordless fone i think, then using some radio wave reciever thing he tuned the cars coil to that frequency. he modded a 49 mhz car into a 45 mhz car.

[e_lm_70]

Hi dtmracer,

If I well understand the mod wasn't done over a Bit.

So far I tested over a OEM, the only result that I achieved it to broke the little "POT", now it doesn't turn any more.

I also seen that some original Bit has some glue over the POT, so no safe way to tuch it !

As well with my OEM I was just able to change (decrease) the range, so it could be that I change a little the frequence, I don't know how much, but for sure not enough for avoid interferences.

So guys, without a better clue about the RF part of the PCB, butter don't mess it around !

e_lm_70

P.S: I know it is not a POT, it is just a variable inductance

PP.SS: I would like to get a real Tomy Bit with 40 & 49 MHz, with Australian spec, where I can get it ?????