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Old 11-09-2009, 01:56 PM   #1
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Default amb counting system

Does anyone know how the connection between the couting wire and the coax cable has been made?There is a small black box connected to it with simple bnc m/f connectors,but is it a simple connection between the wire and the coax or are there some electronics inside off the box?
Our locale club placed new counting wires from the AMB system under the track and installed new 75 ohms coax cables,but we donīt know how to connect the 2.

Greetings Freddy.
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Old 11-09-2009, 02:25 PM   #2
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Does anyone know how the connection between the couting wire and the coax cable has been made?There is a small black box connected to it with simple bnc m/f connectors,but is it a simple connection between the wire and the coax or are there some electronics inside off the box?
Our locale club placed new counting wires from the AMB system under the track and installed new 75 ohms coax cables,but we donīt know how to connect the 2.

Greetings Freddy.
The "black box' is called the "pickup" and has a bit of electronics in it and is quite necessary. Also depending on which pickup it is....the older style, which was sold with the AMB 20, was connected to the coax via a BNC connector and connected to the loop wire with two screw terminals. The current style pickup sold since the introduction of the AMBrc (yellow coax) is molded to the coax and has two wires sticking out of it that can be soldered or use wire connectors to the loop wire.

Also if you're using a 75ohm cable like used for TV, that doesn't have bnc connectors you can get the gender changers from an electronics supplier.

Here's a link to the AMBrc manual; AMB MANUAL

Hope this helps!
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Old 11-09-2009, 02:57 PM   #3
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I'm with Bob on this.. you gotta have it! I've tried to eliminate the box... but the background noise is WAY to high... result.. hardly a car counts.

Whatever is in it will read 100k ohms from either end. Jeff (bigfix on here) sells the old stile box.. see it on eBay all the time.

I found you can make the loop... but need the box/COAX! But you might as well get them both... you only save like $20 buying just the COAX... probably about $15 plus time to make your own.

I've tried to buy the BNC connector from AMB... but they wouldn't sell it to me... wanted me to send the cable to them to fix it. Found the MFG... then the US importer, and was told "they don't import it any more as it was old and nobody uses it any more"

Found the specs on it and bought Pomona Electronics equivalent... so no problem to get the ends
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Old 11-09-2009, 03:43 PM   #4
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so,whe at the club use the latest ambrc system with a 20m yellow loopwire.
the connection from the decoder to the loopwire is done by a coax cable.no problem so far the coax cable is connected with the loopwire thrue a pickupbox???(the small blackbox).Inside the pickupbox whe have some electronics?right? any specs from the pickupbox elctronics?
You canīt simply solder the coax wire and the yellow loopwire?
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Old 11-09-2009, 04:10 PM   #5
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I only know one person that has got it to work without that box... I've tried it on-road, off-road, buried loops, bridges... 1/18 - 1/8 and had nothing but problems!

The manual reads "something" like this.... The transponder signal must be 60 points above the Background noise... Most TP's are about 113 - 130. With the AMB COAX my BG noise is around 24... no problems... as the signal is way above that. When I just try to use COAX, my BG noise is in the 80's... the TP's are no longer 60 points above.... the result... missed laps!

So like Bob said, you either need that old stile box.. came with the AMB20 and a black COAX with BNC connectors at both ends... Or the newer yellow COAX... it has the box molded to it.

Whats in it???? both old and new are filled with epoxy. Jeff (bigfix on here) has it figured out... he sells just the box on eBay all the time.

There are a couple threads on this on all the forums here... I've posted in them... shown pictures... have nice adapters.... it just doesn't work!

On another thread, someone suggested a TV antenna adapter... might work... only a couple $$ at radio shack


http://www.rctech.net/forum/electric...need-help.html

Last edited by Ed Anderson; 11-09-2009 at 04:28 PM.
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Old 11-09-2009, 05:35 PM   #6
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I beleive its just a matching transformer to adjust for the different resistance values.
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Old 11-10-2009, 07:33 AM   #7
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Quote:
Originally Posted by de_lange View Post
so,whe at the club use the latest ambrc system with a 20m yellow loopwire.
the connection from the decoder to the loopwire is done by a coax cable.no problem so far the coax cable is connected with the loopwire thrue a pickupbox???(the small blackbox).Inside the pickupbox whe have some electronics?right? any specs from the pickupbox elctronics?
You canīt simply solder the coax wire and the yellow loopwire?
Best to use the hardware as intended if you want trouble free racing! If the pickup box has been damaged get a new one and keep your racers happy.
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Old 11-10-2009, 07:50 AM   #8
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I beleive its just a matching transformer to adjust for the different resistance values.
This is a correct statement. The "Black Box" is a resistor. The loop needs to have a resistance from stop to start to be a consistent counting method. I have done test's just using speaker wire. It will work 95% of the time. LOL

Not worth the argument to the racer who gets cheated!!!

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Old 11-10-2009, 08:00 AM   #9
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I recently lost the motherboard in my PC so I have lost all my contacts; but if you Google AMB Repair, you should find a guy in Austrailia who sells the components and also repairs them.
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Old 11-10-2009, 08:30 AM   #10
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The place in Australia isn't cheap. Transponder Services I bought a coaxial w/pickup from AMBit-US for $120US (no loop wire) in February this year. Made my loop with 2-strand 18ga speaker wire. I leave the wire together so I end up with two loops just in case! AMB recommends a 470ohm .5-watt resistor in the center opposite the pickup in track widths less than 10m.
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Old 11-10-2009, 08:34 AM   #11
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There is a guy on EBAY from australia selling a replacement loop for AMB for fairly descent price check it out.
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Old 11-10-2009, 08:38 AM   #12
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Solder the 75 OHM resistor to each end of a 14 guage speaker wire then shrink wrap it for protection is doesn't matter how you do it. And it can be wired to Coax cable how ever you want it I use Deans plug to make it easier. There is no negative or positive side just hook it up and its done.
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Old 11-10-2009, 08:45 AM   #13
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Quote:
Originally Posted by fish4check View Post
This is a correct statement. The "Black Box" is a resistor. The loop needs to have a resistance from stop to start to be a consistent counting method. I have done test's just using speaker wire. It will work 95% of the time. LOL

Not worth the argument to the racer who gets cheated!!!

The black box is NOT a resistor. If you put a meter on it it will read 100K ohm... but there is more to it then that.

If you needed a loop... I (yourself) would have made a loop.

Before you keep throwing money at it.. What happened to your original box??

If your background noise is above 60... you have a problem (most of the time it's the COAX and/or the black box)

If you have the old stile black box, it should read 100K ohms across the two thumb screws or from the center pin of the BNC connector to the outer shell of the connector. If you have the newer yellow cable you should read the same thing... 100K across the two leads or center pin to outer shell.

The loop (you said its new)... that should read 470 ohms

If you need just the box.. you can't buy that from AMB anymore. You either have to get a box from Big fix... or buy the new cable.
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Last edited by Ed Anderson; 11-10-2009 at 08:55 AM.
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Old 11-14-2009, 06:46 PM   #14
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ok so just to clear things up for me. I am needind a loop for an AMBrc system. I can get a good deal on a complete loop with the old box (AMB20 thumb screws). Will this work with the AMBrc system?
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Old 11-15-2009, 08:58 AM   #15
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Simple answer... YES!!.. I know people doing it and it works fine. (was recommended by AMB)

Thats if its good. Test it with a meter.

Actually, I wouldn't mind having one of those boxes.... just not going to pay $120 for one.
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