Alternate antenna ideas! - Page 11

darkarchez · #**151** 12-06-2002, 11:35 PM

one quick one.... also if you read on the page 11... i add a foil onto the spring , when the foil on the spring it made it have better reception kinda like a super big attena... in other words imm trying to say is that if you add foil into your spring hard what ever wire you have you may recieve some feet like what i did i recive a extra 10 feet off of it

#**152** 12-06-2002, 11:56 PM

Cant wait until the 12th page!

GrimChild · #**153** 12-07-2002, 12:35 AM

I just found this forum a few minutes ago and ive been skimming through the articals everyone has been posting. anyhow, heres a little something to stimulate your mind.
I have one of those RC Microsizers that I myself have been playing around with. only, My results are quite a bit drastic.
my "Tiny" Microsizer now has a range of 30 feet.
Heres what i did...
I used the almighty 555 timer IC and some simple circuitry consisting of 6 transistors, 4 capacitors, 5 resistors and a voltage to frequency IC.
The 555 timer is used as a tuned frequency oscillator which works with the VTF IC. this itself creates an energy sucking antenna only it receives the signals, converts them to a voltage, and now with a couple of transistors and capacitors creating another oscillator, gets converted back into a much stronger amplified signal outputting to the factory installed antenna on the cars circuit board.
One thing that ive noticed is...
None of you are thinking of how radio signals work.
Any type of coil or resistant metal carries a frequency. Im sure youve all heard of power lines emitting small amounts of radio frequency, sometimes giving people tumors, cancer and so fourth.
Anyhow, the motor inside your cars obviousally contain a coil which revolves inside the motor within a magnet. This creates a what i like to call "Static interference". The Heat sink/motor casing is metal also touching the motor therefore carrying this static frequency. IT IS WISE TO KEEP YOUR ANTENNA AWAY FROM THE MOTOR AND MOTOR CASING.
Just food for thought.........

darkarchez · #**154** 12-07-2002, 12:44 AM

i dont get it?????

hmmm how did u really make your 30 feet???

GT-ahh · #**155** 12-07-2002, 01:27 AM

can u post a schematic for your amplifier?

nissan2S · #**156** 12-07-2002, 03:02 PM

myxstockxantennaxgoesx25xfeet

DavidDeLaurier · #**157** 12-07-2002, 04:44 PM

WOW! I made a coil antenna with insulator running up out of the car about half an inch to reduce "static interference" (as grimchild informed us of) and I got my car to go an astonding 65 feet. You may not get these results because my car came stock 35'.

I think it is the luck of the draw on how far your car will go stock. If you take off the cripple cap I got 3' 7" + and when I took the crip cap off my car I got another 1' 3"

I also took off the two FTCs or FCTs (whatever it is called) and got about 3 more feet.

But this mod takes the cake! I added 22' 1" when I added a simple 4.5" coiled copper wire to my circut board.

I am so excited. My Bit can go all the way accross my schools gym floor!

GrimChild · #**158** 12-08-2002, 12:00 AM

Glad I Got Through To Someone...
Obviousally You Have A Better Car Than Most Of Us And Still Doubled Your Range, I Just Have A Crappy 27mhz Microsizer, It was on sale so I Thought, What The Hell...

KFEdaddy2k · #**159** 12-18-2002, 12:44 PM

I want to elaborate on what Sonic said, I think he hit the nail on the head with this one. The LENGTH of the antenna is very important for any radio device. Just search the internet for HAM radio sites and see how much time (and money) these guys put into precisely tuning the length of their antennas. One thing that I remember form my HAM days was that the antenna needed to be an evenly divided fraction of the full wavelength for that frequency. In other words it needs to be 1/2, 1/4th, 1/8th, 1/16th, 1/32nd, 1/64th, etc. the length of the wavelength.

So being the nice guy that I am, I've calculated the length for the various RC frequencies used in our hobby. I've attached a TXT file with the lengths in it, that'll keep the columns in line easier than just pasting them here. Pay close attention to the 1/64th Wavelength lengths, as this is probably what most will use.

This length is the TOTAL length of the antenna, from the solder point on the PCB to the end of it. One trick that you can do is the "pig-tail" trick you've seen a few times here, just wrap the antenna around a small straw or something, creating a spiral if you will. The theory behind this is similar to the bottom-loaded CB antennas where you have a coil of wire at the bottom of the antenna, and a straight vertical wire the rest of the way up. The reason that is done is because all you are worried about is the total length of the wire, not the length of just the straight part. So you could get a 1/2 wavelength antenna int he space of a 1/4 wavelength antenna in this manner. However, as with any antenna, the higher it is the better reception it has.

Based on that, I'd suggest using the 1/64th or 1/32nd Wavelength length of antenna (depending on the frequency you have), then bottom loading the wire by wrapping a few coils around a small straw just as the wire comes out of the car body, then leave 2 inches or so sticking up straight. Note: when wrapping the wire, make sure that it is an evenly spaced coil, no wire overlapping the previous coil. Not so important on insulated wire, but extremly important if you use bare copper wire. If one coil of bare wire touches another, you've shorted the antenna out and created a length from the PCM solder point to where the coils are touching. The rest of the wire is useless.

This would account for the differences everyone is seeing in their antennas, as the different between a 27MHz car and a 57MHz car is quite a bit in terms of antenna length.

I know that posting this is a bit hypocritical, since I have not personally tried this, but I'm an very confident that it'll increase the range of your car. I will be trying it myself later this week/weekend, and I will post my results. Currently I only have an OEM Bullet (RallyRacer), but I have two Bit Char-G's (Nissan Gloria and Black Celica) coming within a week. Yea, I know, I'm hooked already.

Hope this helps,
KFEdaddy2k

DavidDeLaurier · #**160** 12-18-2002, 02:55 PM

WOW! This has really helped the range of my car! Thank you!

KFEdaddy2k · #**161** 12-20-2002, 10:45 PM

Well gang, I'm not sure what to make if this. I'll just tell you what I did, the results and then let you make your own assumptions.

This is all on the brand new 45 MHz Bit Char-G Nissan Gloria, right out of the box with no other mods at all:

First I fully charged the batt and it ran 8 feet and stopped.

The first thing I did was to open 'er up and re-route the antenna out the back of the PCB and un-knot it. That gave me a total of 12 feet before the car quit.

I then de-soldered the antenna and added one that was 7.8 inches long (the gloria is 45MHz). I used solid core CAT5 cable. At first I zig-zag'd the antenna inside the car body with only about an inch or so sticking out. That got me a total of 8 feet. I then had the antenna coming straight out of the car with all 7.8 inches sticking straight up. That got me around 25 feet or so (didn't measure this one). Good distance, but it was almost 8 inches of antenna sticking up. 25 feet isn't bad, but my clone did that right out of the box, or right out of the bullet I should say.

Next I cut the antenna down to 3.8 inches (the 1/64th wavelength for 45 MHz). I was back to 8 feet.

Next I de-soldered the cripple cap on the car itself. No change, still 8 feet.

Next I de-soldered the cripple cap in the transmitter. I have a Rev 5 board, and from everything I could find, it's c11 that is the cripple cap. I took it off, but it made no difference at all, still at 8 feet.

So, I tried the twisted pair of CAT5 and solder the top end together thing. The length of the antenna is about 6 inches or so, twisted. I've got the top ends soldered together. So in theory the total length of the cable is about 12 inches (from the PCB out to the soldered ends and back). The end that comes back into the car is not soldered to anything. Guess what this gave me...yep, 8 feet. I tried it sticking straight up and I also zig-zag'd in inside the car for aesthetic reasons, no difference.

So that's where I stand now, all that work and I'm back to 8 feet. The plus side is that the orange twisted pair looks cool, and it's very ridged so it can take a fall off the coffee table pretty well and not bend the antenna most times. I would just like more than 8 feet out of it. If anyone else has any suggestions, I'd appreciate them.

One side note, I also have a 35 MHz clone bullet. Tonight when messing around with them I noticed that the 35 MHz transmitter from the clone would control the 45 MHz Bit Char-G. I'm wondering if the cripple cap on the car itself is the cause of this? Maybe removing it allowed the car to "see" more of the frequency band, and actually see into other bands. I don't know, it's kind of weird. I guess that blows my reasoning behind getting a different frequency, so I can race them.

Oh well, back to the science books and back to the drawing board.

KFEdaddy2k.

baleisen · #**162** 12-21-2002, 05:14 AM

Folding the antenna cuts its effective length. Coiling the antenna changes its effective length. My solution is to use an OEM transmitter until I map out the differences between the two x-mitters. Changing the final x-istors for higher output ones would be illegal but work well. BAE

DensityMan · #**163** 12-21-2002, 09:33 PM

Background: I have three different brands currently at home... all have used the Bit char-G type spooling antennae on the transmitter.

This past weekend the wife and I babysat for some friends and their child had the "bullet" variety car (27Mhz) with the telescoping antennae on the transmitter.

His car was obnoxiously loud, slow and had HORRIBLE wheel alighment... BUT I could not get the car far enough away from me to lose range (through three rooms... call it 45-50ft)...

That was all well and good, but the car itself was not acceptable... I stopped "testing" his car and got mine out to drive with him...

Meanwhile my wife (frustrated because her car was a 27Mhz as well), got hers out in the kitchen (lets say 30ft away - through a wall) turned the controller on and started to charge her car. While it was charging she was startled due to the car spinning tires while charging... the telescoping antennae from the bullet car was able to reach her un-modded antennae to control it (stutter-free) from 30ft away through at least one wall)...

Gonna work this week on modding my non-race abled Lxx with the internal antennae and a telescoping transmitter antennae...

Food for thought: The transmitter may have FAR more to do with the range then the receiver antennae of the bit

???

I2ed · #**164** 12-21-2002, 10:44 PM

what gauge is good for a nekkid copper wire? or cat5 wire?

GrimChild · #**165** 12-21-2002, 11:40 PM

I've been meaning to post this discussion for quite some time..
The transmitter DEFINATALLY has some issues.. I used a transmitter from and old R/C Airplane i hardly ever use and popped in a 27mhz cap to allow it to control my microsizer. The controller didnt work at first, the car needed to be tuned a bit to match the controller, but once i got it working the car was capable of going further than i could even see.. i dont have an exact distance, but the plane the controller came from obviousally had to have a great distance all its own..
To tell you all the truth, i dont beleive these cars are really worth the effort. Even if you Can get them to go more than 50', what good is it gonna do ya ? you need decent flat surface to run them on which limits out a lot of fun. I would pay big bucks for a miniature R/C hovercraft. If anyone comes across one, send an email, i'd much appreciate it.....