More frequencies for Bitchar?

[DrQuintezz]

Hello,

Our racingteam got 8 cars with 8 different frequncies.
27, 35.0, 35.6, 40, 45.0, 45.6, 49 and 57MHz
All cars are Bitchars except 35.0 and 45.0
they are Bensu (http://www.bensu.nl)

35.0 and 35.6 are working fine together.
There is no problem with control. 0.6MHz
difference works fine. When its less then 0.6MHz
then there is a problem. There is a possibility
to control each car 🙁
(We tested it when we bought a Bensu 49.2MHz)

Now my question.
I want to change an spare 49MHz car into 48MHz.
The crystal 48MHz is not a problem but adjusting
the receiver in the car is not so easy.
Is adjusting the coil clockwise adjusting a lower frequency?
Do i change a capacitor too?

We need more cars (12 cars and different frequencies)
because all my colleges want to race during lunch too 🙂

Greeting from a big racingteam in Holland

[micro_Amps]

It isnt that simple.
Adjusting the coil merely tunes the aerial.
You will find that you need to change a smt capacitor and possibly a resistor too.
I am surprised that a 35Mhz and a 35.6Mhz bit both work simultaneously. The Bensu must use a different signal coding chipset. I thought they were all Rx2c/Tx2c though!
Interesting that you say the Tomy BitCharg frequencies are 27, 35.6, 40, 45.6, 49, and 57Mhz.
The four I know for sure (Tomy BCG frequencies) are….
27.000 45.000 35.002 57.000Mhz
Where do the NN.6Mhz frequencies come from?
Just to let you know, we have experienced interference problems with transmitters that are less than 6 to 8 Mhz apart. The 35/40/45/49 combinations sometimes dont work real well. Have you found a way to counteract this?

[Impreza]

micro, maybe he has a microsizer or compact at 49 Mhz? And I have interference with running a Bensu and bit together, although I don’t think the Bensu Tx runs the bit car, but the reverse is true. Will have to check into it?

Impreza :smiley16:

[Impreza]

DrQuintezz, what are the stock Bensu motors rated at. I know this was discussed on the forum before, but can’t remember:sad:

Impreza :smiley16:

[spanky]

soon the microsizers will have 3 at 27mhz and 3 at 49…. just wait for the new pros.. they will be using subchanels!!!

Custom bodys: Ferari 250 GTO, 69 doge charger, Micro Cooper, Beemer 320i Turbo, Baha Beatle, New Beatle Rsi Porche 911
email: custombitbodys@attbi.com
website: http://custombitbodys.home.attbi.com

[DrQuintezz]

I am surprised that a 35Mhz and a 35.6Mhz bit both work simultaneously.

Q My scanner says that the transmitter is not so wide. 35.590 ? 35.610MHz. The ?problem? is the receiver. The receiver seems like +/- 0.25MHz wide.

The Bensu must use a different signal coding chipset. I thought they were all Rx2c/Tx2c though!

Q I don?t no. The sound is like the same when i listen to my radio-scanner

Interesting that you say the Tomy BitCharg frequencies are 27, 35.6, 40, 45.6, 49, and 57Mhz.
The four I know for sure (Tomy BCG frequencies) are….
27.000 45.000 35.002 57.000Mhz

Q Did you test it with a scanner / frequency counter? My frequencies are also written on the crystals.

Where do the NN.6Mhz frequencies come from?

Q I don?t no. 0.2MHz doesn?t work 0.6 is ok.

Just to let you know, we have experienced interference problems with transmitters that are less than 6 to 8 Mhz apart. The 35/40/45/49 combinations sometimes dont work real well. Have you found a way to counteract this?

Q You must stand 1 meter from the other drivers that will help a lot.
When you put al the transmitter and cars in a circle of 1 meter it will be a mass.
Our circuits lengths are 10 meters or more and then we can stand 1 meter from eachother.

micro, maybe he has a microsizer or compact at 49 Mhz? And I have interference with running a Bensu and bit together, although I don’t think the Bensu Tx runs the bit car, but the reverse is true. Will have to check into it?

Q We tested a Bitchar transmitter on a Bensu. It works only backwards = forwards. We don?t tested a Bensu transmitter on a Bitchar. I?ll test it this week..

DrQuintezz, what are the stock Bensu motors rated at. I know this was discussed on the forum before, but can’t remember

Q Bitchar 2.2 motor standard. The Bensu has 2.6 motor standard.
We put 2.6 in our cars and we put a variableresistor (50 Ohm 20-turns) between the motor and accu. When we changed the circuit we need another setup like tires, more/less speed and so on. I?ll think we are pro?s.

soon the microsizers will have 3 at 27mhz and 3 at 49…. just wait for the new pros.. they will be using subchanels!!!

Q Subchannels 26.9, 27.5, 28.1 and so on. I?ll think it?s possible. We need more information
about the receiver. Is there a radio amateur in da house?
Each frequency with 3 subchannels = 18 cars.
A race with 12 drivers or more is great. When we have 20 drivers we can do the formula one 🙂

[spanky]

they are only doing the american 27 and 49 frequencys this way.. at least thats all ive heard. i emailed microsizers and they verifyed this. 6 cars will run simeltanesouly on two frequencys.. but they were unsure about the release date.. sometime in june or july. the reason for doing this is that they can only sell those two frequencys in the United States per FCC rules… One would think that the new tomy bit char-g’s will be the same way. Unfortnately at this time the reports are that only the microsizers will have these new frequencys…:shock:

Custom bodys: Ferari 250 GTO, 69 doge charger, Micro Cooper, Beemer 320i Turbo, Baha Beatle, New Beatle Rsi Porche 911
email: custombitbodys@attbi.com
website: http://custombitbodys.home.attbi.com

[micro_Amps]

They must have altered the Rx pcb then. To run more than one car on 27Mhz would require precise rx circuitry (a crystal) which the current model of BCG does not have.

[ph2t]

DrQuintezz, welcome to ausmicro, good to have another propellor head onboard, micro and I were getting lonely!:smiley2:

See my thread here about the RX boards on these cars. Also in this thread there are datasheets for all the different chipsets used in these models.

The recievers aren’t very selective, as micro said, more circuitry is required to decrease the bandwidth on the RX’s. Possibly the addition of an extra IF stage, or the inclusion of a PLL (Phase Locked Loop) will make the RX more selective. But in the current config of these cars they only have the single RF reciever stage at the moment.

As for Bensu .vs Microsizer controllers, the TX/RX chipsets might be on a different base oscillator (set by the 220K resistor on the OSCO/OSCI pins on the RX and TX chips respectively) which would then created a different modulated signal. This is a “theory” that I will try (when I get enough time of course) one day to get two cars on the same freq operating together. But then again the Bensu’s might be on a different revision of the same chipset (tx2b, tx2c, etc…) which could then change the OOK (On-Off Keying) encoded signal for each function, Left/Right/Fwd/Rev…..

Cheers,

ph2t.

[DrQuintezz]

We did some research on the transmitter
schematic and the Bitchar and Bensu transmitter.
The transmitter schematic is the schematic
from the Bensu and not the Bitchar.
The Bitchar transmitter has less components.
The bandwide of the Bitchar transmitter is
smaller then the Bensu transmitter.
We’ll change the bandwide of all the transmitters
because we want to race with 12 drivers or more.
Please give us some time for research.
When we’ll find some tips and tricks
we’ll post it here.

[ph2t]

I case of the schematic being different, do you mean for all the circuitry or for just the timing part of the circuit..? I’ve been told that the original MS’s / BitChar-G’s had what is shown in the schematic BUT the new transmitters use an LM293 voltage comparator in a time delay config.

ph2t.

[Impreza]

More nfo spanky pls. Do you have a link for the freq subchanel cars coming out? Thanks:)

Impreza :smiley16:

[spanky]

well i emailed microsizer and they verified it a couple weeks ago to me. however they were still unsure about a release date then… you can go to this site
http://www.microsizers.com/points-schedule.html

scroll down and you will see some frequencys like 27xA, 27xB…. and so on..
i copyed and pasted the cars from that page below…

HCAC0461 100 Honda NSX – Pearl Orange – 27mhz xA
HCAC0462 100 Toyota Supra – Silver – 27mhz xB
HCAC0463 100 Toyota Celica – Blue Metallic – 27mhz xC
HCAC0464 100 VW Beetle – Double Yellow – 49mhz xA
HCAC0465 100 Nissan Skyline R34 GTR – Midnight Purple – 49mhz xB
HCAC0466 100 Nissan Fairlady – Black – 49mhz xC

Custom bodys: Ferari 250 GTO, 69 doge charger, Micro Cooper, Beemer 320i Turbo, Baha Beatle, New Beatle Rsi Porche 911
email: custombitbodys@attbi.com
website: http://custombitbodys.home.attbi.com

[PandaBear]

Quote:

…the new transmitters use an LM293 voltage comparator in a time delay config.

So that’s like the separation between CH1, CH2 etc etc in real RC gear? :blush:

[ph2t]

Nah, this was just the charger part of the circuit on the controller that charges up the battery. The original controllers used the transistors in the known schematic, but the new revisions use this IC (LM293) to perform the same operations. Hell, I’m looking at a Bensu clone TX board right now and they use a 4013 CMOS chip.

So we have transistors/LM293/4013 CMOS all doing the same function: charging the battery.:)

So imagine how different the RF freq part of the circuits will be, damn…….!

ph2t.

[micro_Amps]

Yeh, but it is only a matter of time before we get schematics for those too. I hope.
:)uA

[DrQuintezz]

PH2T

There is a difference between the Bensu and
the Bitchar Transmitters.

The Bitchar transmitter is without
C8 and C5 and they use different
resistor values around 2 transistor
Q1 and Q2. There is also difference between
the coil values in the Bensu and Bitchar
transmitters. We think if we change
this components we will have a smaller
bandwide. We will wait for the new components
now. If we have new results i’ll put the information here.

[barto_85]

you guys are too smart! yeah C5 and Q1 and Q2?????

[DrQuintezz]

Look at the schematic of the transmitter
and you will find C5, Q1, Q2 and so on.
Easy way

[DrQuintezz]

Yes here we are again.
We learn a lot about the Bitchar last weeks.
and YES we can make use more frequencies.

When you buy a 35MHz Bitchar you can change
it to 32MHz. You only must buy an 32MHz Crystal
and you must adjust the coil in the car.

Take of the 35MHz crystal of the transmitter an place the 32MHz crystal in it.
The car does not work any more.
Adjust the coil of the car (anti clockwise)
till you have the best receiving. (see also topic
on this site to adjust for the best distance)

Easy way

Now we want to try this with a 49MHz car
and put an 53MHz crystal in it.
A 53MHz crystal is not easy to find but
we will try.

We also want to use Infrared communication
Is there somebody who can help us.
There is a Chines site but we cannot understand
Chinese 🙂

[ph2t]

I’ve got a 20Mhz crystal, and I’m currently trying out some theories to get my 27Mhz RX7 MS to operate at 20Mhz giving me an extra freq for my Gran Prix, lol! :smiley2:

ph2t.

[barto_85]

hey, i have a question about these frequencies. on bitheds website, the frequencies are 27mhzA, 27mhzB, 27mhzC etc. what does this mean, how does it work?

[ph2t]

Seems that they might have changed the design of the receiver on the car to be more “selective” on what frequency it responds to. eg A=27.08, B=27.12, C=27.16 in Mhz. This is just an example, don’t take these freq’s as kosher…..

[barto_85]

oh ok, thanks. why would they do that?

[ph2t]

3*27 and 3*49 equals 6 cars running at one time….:shock:

[barto_85]

the reception on my compact is so much crappier than my friends bit. are the “real” ones made better quality? he can drive his car anywhere on the pool table, even with his remote underneath it, whereas mine, even with the remote above the table can’t go all over the table, it always seems to have a weak spot at the same spot on the pool table, even when im driving by myself.

sorry that was so long

[barto_85]

but why wouldn’t they just spread the frequencies out more?

[ph2t]

Is your friend’s car a clone or the real deal? Clones are known to have great range. Otherwise is your friend’s freq higher than yours? ie: he’s running 40MHz and you’re on 27MHz? These are the only two *legal* frequencies for Australia. I’ve found that higher freq cars have a greater range out of the box, but then again this could be because they have been tuned better than the other freq’s. See Micro_amps’ posts in my “Crip cap in the car” mod for more info about this…

They can’t spread the freq’s out more due to restrictions on what TOMY can legally run these cars on in Japan. Hence the extra selections in the 27MHz band……

Edited by – ph2t on 21 May 2003 23:24:57

[barto_85]

he’s on 35mhz and im on 27mhz.

[barto_85]

and yeah his is the real deal bit char g. it was a black celica originally i think.

[barto_85]

too scared to do the crip cap thing, everything is too small and dont wanna screw it up totally.

[DrQuintezz]

ph2t

I’ll hope that the coil in the car can change 7MHz
(27 – 7 = 20) and watch out when you use a 40 MHz
car (2 x 20 = 40)

The bandwide of al transmitters is more then
400KHz. I said this some weeks ago.
The modulation is AM and not FM
When I use an FM receiver i’ll measured
400 KHz but when i’ll use a FM-receiver it’s
more.

On the chip RX2 and TX2 you can change
the control pulses. When 1 car has
100K ohm and the other uses 180K ohm
then you can jam the other car
but you cannot control the
other car.

At this moment we only can change frequencies
in the neighbourhood (35 to 32 and 27 to 22)
There is a possibility (i don’t no
at this moment) to change a capacitor in the car
and you can change the receive frequency
in every frequency you want. bUt how and which one???

Which car frequencies do you got ph2t???

[DrQuintezz]

53MHz crystal got a problem with the
27MHz car (2 x 27 = 54) Stupid!!!

Now we want to try 60 MHz
We take an 57MHz car and change this
to 60. A 60MHz crystal is not
a standar crystal. 🙁
there is a company that can make this
crystal but it takes weeks.

Waiting……………………

[DrQuintezz]

Waiting……………………

Yes we received the 60MHz Crystal.
We use a Bitchar 57MHz for modification.
We put the Crystal in de Tranmitter and we
adjusted the coil in the car for maximum range.
And now we have frequency number 8
and there are 8 cars in compettion now 🙂
Number 9??? This wil use infrared (38KHz).
There is no rf (wide) frequency free anymore

[DaveF]

Got any photos or movies of the 8 car races?

[DrQuintezz]

Dave,

What’s your email adress?
I’ve got 2 pictures for you

Dr.Q

[ph2t]

Mail them to me dude and I’ll post them in this thread.:D. mail to ph2t@prahranpianos.com

Great work on the 60Mhz!

ph2t

[micro_Amps]

Good stuff Quintezz, how about posting a pic in this forum.
:)uA

[ph2t]

Pics have been posted, you can see them HERE.

ph2t.

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