PDA

View Full Version : Extending CORE loop for 3 wide tile?


Sinister_Y
2007.10.09, 10:49 AM
Hi All,

I will be starting a Nascar (i-series) oval series for my club shortly and wanted to run 3 tiles wide the whole circuit. The challenge is that the CORE loop is really meant for 2 tiles wide. Has anybody extended the loop and if so, what were the risks/disadvantages to this setup?

Thanks in advance.

briankstan
2007.10.09, 11:03 AM
I know this has been done, I'm not sure who it was exactly but I talked with them on the phone about a year or so ago.

what he did was replace the loop with some speaker wire of similar gauge. He said he didn't have any issues with it reading the transponders.

Risks, I guess would be damaging something in there, or possibly it not reading.

byebye
2007.10.13, 09:09 AM
I cracked open my core box and inside I saw a soldered connection for the cable. Now I'm wonder why it was the way it was. I found that although it was a shielded cable the only part that was soldered was the shielding??? I'm no expert on radio transmission but I'm assuming you can use any kind of cable and any length. I would take caution desoldering as not to over heat the board.

The cable used for my system is pretty durable. I'm thinking I'll have to find a similar or slightly larger gauge shielded cable and put a groove in my start/finish tiles. Maybe reinforce the bottom and cover the box somehow.

Anyway I'll update this thread when I do make the extension.

Kris

pinwc4
2007.10.13, 12:15 PM
Don't do it. After changing the size of the loop you would have to retune the circuit. If the circuit is out of tune enough you could damage parts, although in this case I would doubt it is possible.

I assume that since the Core lap counter has just a fixed loop that it does not even have adjustable capacitors and resistors inside to tune it for different sizes. So you would have to do some soldering of different value capacitors and resistors to get a different size antenna to work.

Soldering the shielding is the correct way to go though. The greater the surface area you have to transmit the signal the stronger it is and easier it is to tune.

I think with the Core lap counter the only way to get this to work would be to bypass the antenna circuit altogether with you own. For example you could use this module from Feig
http://parts.digikey.com/1/parts/639075-rfid-manual-tuning-brd-1356mhz-rridiscmata.html

But even then you need the right tools to tune it. An antenna analyzer, oscilliscope and multimeter would be sufficient.....

One remote possibility is that some combination of larger antenna size and wiring would lead to the circuit needed to be tuned at the same spot. Very unlikely though.

The other is that the Core lap counter has amplified the signal greater than what just the TI S6350 puts out meaning it could work at small ranges even when somewhat out of tune.

theplanethobbys
2007.10.19, 09:53 AM
Don't do it. After changing the size of the loop you would have to retune the circuit. If the circuit is out of tune enough you could damage parts, although in this case I would doubt it is possible.

I assume that since the Core lap counter has just a fixed loop that it does not even have adjustable capacitors and resistors inside to tune it for different sizes. So you would have to do some soldering of different value capacitors and resistors to get a different size antenna to work.

Soldering the shielding is the correct way to go though. The greater the surface area you have to transmit the signal the stronger it is and easier it is to tune.

I think with the Core lap counter the only way to get this to work would be to bypass the antenna circuit altogether with you own. For example you could use this module from Feig
http://parts.digikey.com/1/parts/639075-rfid-manual-tuning-brd-1356mhz-rridiscmata.html

But even then you need the right tools to tune it. An antenna analyzer, oscilliscope and multimeter would be sufficient.....

One remote possibility is that some combination of larger antenna size and wiring would lead to the circuit needed to be tuned at the same spot. Very unlikely though.

The other is that the Core lap counter has amplified the signal greater than what just the TI S6350 puts out meaning it could work at small ranges even when somewhat out of tune.
I have found that the loop itself can be somewhat smaller. About 8" instead of the full 12"
Todd

Blackno3
2007.10.20, 11:25 AM
WARNING!!!! THIS IS A BAD BAD IDEA!!!!!!!

I beta tested the core sys for them. The loop is not just a loop it is an antenna that is specifically tuned to work with the system. I had them send me a core with a tuned antenna loop that was big enough to go 3 tiles wide and it didnít work every well. I sent it back to have a regular tuned antenna loop put back on. Trust me no this one, bad bad idea.

There are only two ways to make it work on a 3 tile wide track.
1. Narrow the loop down to 8 to 10 inches as theplanethobbys suggested to make it a little wider.
2. Create a choke point in the track were the antenna loop goes.

pinwc4
2007.10.20, 12:09 PM
Narrowing it to just 8" wouldn't get you far enough to cover 3 tiles would it?

The primary things that impact tuning the antenna are the length and surface area of the conductor. I think you could tune it for 3 tiles wide you would just need a different conductor. Having a greater surface area would help tremendously. You could use larger shielded cable but this would create a jump in the track. I think the best option to tune an antenna that is 3 tiles wide would be to use copper tape. It would be very flat but have greater surface area.

byebye
2007.10.20, 02:35 PM
Narrowing it to just 8" wouldn't get you far enough to cover 3 tiles would it?

The primary things that impact tuning the antenna are the length and surface area of the conductor. I think you could tune it for 3 tiles wide you would just need a different conductor. Having a greater surface area would help tremendously. You could use larger shielded cable but this would create a jump in the track. I think the best option to tune an antenna that is 3 tiles wide would be to use copper tape. It would be very flat but have greater surface area.

Thanks for the info guys. I'll hold back until CORE or some engineer comes up with a proper solution.

Kris

byebye
2007.10.23, 07:00 AM
I just thought of another question in regards to the loop tuning. Is it possible to solder up some male female plugs? Will that affect tuning?

I could test different lenght loops but that wouldn't be the purpose of the plugs. Just trying to stay on topic ;)

Thanks!
Kris

CoreAnalog
2007.10.25, 12:33 AM
Hi Guys,

I wouldn't touch the loop on the current core systems.

Sorry, for the long absence from the forums. We've been extremely busy with our engineering projects. We will be releasing a new system that can be used for larger scale cars. It's being used in private testing now and will have to be put through FCC/CE certification once the tesing period is over. We'll have it ready for purchase early next year. The system and transponders will be much cheaper (approx 50% price reduction from retail prices).

Current core stuff is also 50% off on the website.

Regards,
--Core

arch2b
2007.10.25, 08:50 AM
Hi Guys,

I wouldn't touch the loop on the current core systems.

Sorry, for the long absence from the forums. We've been extremely busy with our engineering projects. We will be releasing a new system that can be used for larger scale cars. It's being used in private testing now and will have to be put through FCC/CE certification once the tesing period is over. We'll have it ready for purchase early next year. The system and transponders will be much cheaper (approx 50% price reduction from retail prices).

Current core stuff is also 50% off on the website.

Regards,
--Core
awsome! glad to have you back, there are lots of questions in the 'ask' forum;)

1wizard
2007.10.29, 07:03 PM
great looking forward to the new system

racer_18x
2010.03.30, 11:05 AM
does anyone know what is the actual length of the wire that core uses for its loop cause i have to change mine. the previous owner actually shorten the wire and it doesnt seem to detect the transponders well. and is there any chance that we can change this loop to a strip instead like the kyosho system? we we could wat kindna strip is it and what is the length

thanks for the help!