Mikes Hobby Talk

by **awd** » Sat Jul 03, 2010 10:45 pm

I'll bring it tomorrow.

by **awd** » Mon Jul 05, 2010 9:07 pm

The loop is now out there. The height has been reduced as well. I am looking into getting a loop installed and connected to it as soon as I can.

by **awd** » Wed Jul 07, 2010 2:39 am

I tried with little success tonight. I was able to get the loop to detect transponders, but only if they were super close to the bridge.

I'll be back at trying to get it working after I get back from Memphis. The old loop is still in tact and operational in case anyone was wondering. It looks like the only reason the current loop is working is because the transponders are passing within inches of the loop. When I get back I will look more closely at the background noise figures we get from the old loop/coax. I suspect the problem lies in the original coax and/or connector box because the bridged loop isn't any less sensitive than the in-ground loop; its just farther from the cars and the difference between the background noise and the PT signal isn't great enough for the decoder to recognize the signal.

Here's some reading if anyone's interested.

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

http://www.rctech.net/forum/electric-of ... blems.html

http://www.rctech.net/forum/nitro-road/ ... ystem.html

http://www.rctiming.com/timing_systems.shtml

http://www.rctech.net/forum/electric-ro ... ost7638283

http://www.radioshack.com/product/index ... 2062320&cp

I would not be surprised if the $200 "box" AMB sells really is just an 89 cent RF antenna to BNC impedance matching transformer!

http://www.summitsource.com/product_inf ... ts_id=6656

by **adidasink** » Wed Jul 07, 2010 10:43 am

That is good reading.....I like the bridge design...way to go...

You dont think that because of all the signals going on inside Mikes that it somehow diminishes the transponder frequencies and causes some kind of dampening affect?

Just wondering though....is the purpose of the transponder bridge to eliminate the "bump" that the current under the tape/rug design gives us?

And I took a look at that Radio Shack RF antenna and I bet your right...the only concern would be that the AMB one might be tuned for those specific frequencies (if that is possible)?

Anyways..best of luck in Memphis!

by **awd** » Wed Jul 07, 2010 11:35 am

The bridge will allow us to move the loop where ever we please. Right now the loop in a channel cut into the concrete so there is no bump. For 88 cents I figure the antenna adapter is worth a try.
Thanks!

by **Team TQ** » Wed Jul 07, 2010 11:58 am

Andrew,

The loop bridge is a little too high. When you go to Memphis, you will notice that they use a similar get-up. The clearance between the ground and the top of the loop is just enough for a 12th scale with a standard roll-over antenna to go underneath with about a quarter to half inch to spare. Just an idea to think about.

by **adidasink** » Wed Jul 07, 2010 12:23 pm

Team TQ wrote:The clearance between the ground and the top of the loop is just enough for a 12th scale with a standard roll-over antenna to go underneath with about a quarter to half inch to spare. Just an idea to think about.

Well we also want to make sure that they also have enough for a 1/10 scale TC to go under....

by **Rysulrod** » Wed Jul 07, 2010 1:16 pm

adidasink wrote:Well we also want to make sure that they also have enough for a 1/10 scale TC to go under....

Awd has "some" experience in 10th scale. I'm sure he's considered them. The real question is how many pieces will it break into when a Slash hits it?

by **awd** » Wed Jul 07, 2010 1:18 pm

Team TQ wrote:Andrew,

The loop bridge is a little too high. When you go to Memphis, you will notice that they use a similar get-up. The clearance between the ground and the top of the loop is just enough for a 12th scale with a standard roll-over antenna to go underneath with about a quarter to half inch to spare. Just an idea to think about.

We tried decreasing the distance, but the loop still didn't pick up. The transponders literally had to be within 3 inches of the loop to read. I am going to be paying close attention to how they have it set up in Memphis for sure. I don't think the distance is the problem though as I have raced under loops that were much taller than ours is now without issue. PLus the current loop has the same issue. It jsut doesn't show up because the loop is within three inches of most transponders. The AMBrc manual even recommends 45 cm or less, roughly 18 inches. Currently the loop is about 14 inches I think ... We'll have to play with it and get it right! Thanks for the suggestions.

by **awd** » Wed Jul 07, 2010 1:23 pm

Rysulrod wrote:
adidasink wrote:Well we also want to make sure that they also have enough for a 1/10 scale TC to go under....

Awd has "some" experience in 10th scale. I'm sure he's considered them. The real question is how many pieces will it break into when a Slash hits it?

We'll be sure to get clearance for sedans. The flexible antenna in a sedan gives us some latitude, plus, most drivers are running DSM which doesn't have the same mile long antenna.
I haven't measured for Slashs, but if/when we need clearance for a Slash, it's not too hard to raise it up with blocks etc. Should still work well, as the PT in a slash is significantly higher than in a sedan or 1/12th.

by **Chris Adams** » Wed Jul 07, 2010 3:39 pm

I really dont think we should be too worried about slashes hitting it. They have a track on the other side of the drivers stand to drive on...

by **awd** » Wed Jul 07, 2010 3:57 pm

word yo!

by **awd** » Wed Jul 07, 2010 10:19 pm

Turns out thishttp://www.frys.com/product/4138653?site=sr:SEARCH:MAIN_RSLT_PG may be the solution. I tried the loop with the bridge attached to the RG-59 from the off-road track and it worked well at 14 inches away with a house PT. Last test will be to buy 100' of RG-59 and test everything in place. Lets hope the extra coax doesn't ruin the signal. Who knew RG-6 would cause problems. I figured since RG-6 and RG-59 are both 75 ohm it would work. Guess I was wrong! I am a little confused though as the AMB website says to use 75 ohm dual shielded coax, which according to wikipedia is RG-6. RG-59 is single shelded. Weird....

by **Rysulrod** » Thu Jul 08, 2010 1:47 pm

awd wrote:I haven't measured for Slashs, but if/when we need clearance for a Slash, it's not too hard to raise it up with blocks etc. Should still work well, as the PT in a slash is significantly higher than in a sedan or 1/12th.

You know I was being a smarty pants. Good work so far. I know you'll get it working.

by **awd** » Mon Jul 12, 2010 10:40 pm

http://www.rctech.net/forum/6702590-post15.html

One idea for a low cost drivers stand option ...

by **awd** » Tue Jul 13, 2010 7:48 pm

Well ...

I tried my 1/12th today with the bridge and I couldn't get a good strong signal. So after some calls to AMB and RCSP it sounded like we would need to buy a new digital connection box to replace the analog one we have now to get the loop to work above the cars. Because they want $130 for the digital connection box I am working on borrowing one to try and see if it gives us a larger signal area. Till then I think I have an even better solution. I found some ultra flat wire thats compatible with our current box and duct taped it down to the carpet. I ran my 1/12th scale on it and you can't see the car move over the wire at all. So for the ~$1 cost of 16 ft of duct tape for each track change we have an awesome solution. As an added bonus there is now nothing to obstruct our view of the track and there is no worry of running into the loop bridge. I think I like this better even after running on it.

by **awd** » Tue Jul 13, 2010 9:56 pm

Or ...

http://www.rctech.net/forum/attachments ... cf0217.jpg

by **markf3x** » Tue Jul 13, 2010 10:32 pm

Good job Andrew.

Do you think there would be traction issues accelerating across the tape (like the start of the Main)?

by **awd** » Tue Jul 13, 2010 11:43 pm

Believe it or not, the tape provides more grip than the carpet, even in high bite conditions. Just ask any of the guys from or that have raced at Adams Creek in Tulsa. They have tape all over in their sweeper and it gives them more steering when they get on the tape.On the tracks that get layed down and taken up and they tape the seams, the cars gain traction over the tape. Even if it were slippery, we will always have the option of placing it where ever we want. I ran on it today and started like I would in a main and can't imagine it being an issue. Not to mention , all of the cars will be behind the loop before the start and even TQ will be several feet from the loop at the start. By the time the first car gets there they won't have enough torque to make any difference. Good thinking though!

by **awd** » Tue Jul 13, 2010 11:50 pm

This was recommended to me by a guy who configures their carpet track loop the same way.

http://www.filmtools.com/gorilla-tape-o ... 61001.html

I like the black better than the white that's down now. I just grabbed whatever was laying in the hobby shop.

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