Modded TX for top speed use.

[Mod Man]

Here are pics of my modified DX3. It is running a 9DB gain antenna and (obviously) a new steering assembly. The reason for the antenna is range. I get 1500 feet uninterupted with the antenna. The big mod, though is the steering assembly. The story behind the assembly is an interesting one. Basically, I have my top speed car setup for normal daily driving, I.E. good handling and neutral steering. However, when setup that way, over 100 mph the steering is far too touchy. I have tried expo and I do not like dual rates. What I really wanted is farther steering wheel throw to give me finer control at speed, but still have full steering lock. This steering assembly a 3 to 1 reduction ratio. That gives me 3 times farther steering wheel travel, though still fully controllable. I love it! Oh, another reason I made the steering wheel assembly is simply because I can. It is nice to have my own CNC machine shop. :)

The assembly is comprised of carbon fiber, machined aluminum and a ball bearing supported titanium shaft. The steering wheel is a pink compound Jaco L4 rear wheel that is narrowed and trued down.

Anyway, I know this is not exactly a mod that everyone will want. But, I made it from scratch with materials I have on hand from my heli business. So, it cost me nothing and solves an odd top speed issue in an interesting way.

At this point, this transmitter is perfect for my particular needs.

Oh, it is more comfortable with the wheel in its current location. I love it!

Matt

[CrazyPhantom]

Wow, that is really cool. Handle alot better that way?

[Mod Man]

It makes the steering less twitchy while retaining full steering travel. Kind of hard to explain. Basically, modern transmitters have way too short steering wheel travel. That makes them hard to use for high speed because of the relatively far servo movement per degree of wheel travel. I found that setting my steering servo to 30% travel made the car easy to drive fast, but killed my turning radius. This eliminates that problem making the car easy to drive fast or slow with servo travel set at 100%. :)

Matt

[microrcdude]

I see it now.

"My belt is slipping!"

"Uhh, your car doesnt have belts"

"On my transmitter you silly!"


Very innovative, makes TONS of sense.

[Mod Man]

Thanks, Another nice thing about it is; it is adjustable. I can change pulleys to alter the ratio to suit my needs.

This is definately a "Think outside the box" sort of mod. :)

Matt

[tcolesen]

If you ever wanted to upgrade to a different radio, you could get something like the Nomadio React that has a servo speed function. On my HV Savage, I dialed down the servo speed rather drastically, and although I haven't brought it to full speed yet, I noticed a huge improvement in steer-ability. I could turn the truck such that it would be lined up for a full run even while accelerating, yet I still had full control.

[Mod Man]

I have a React also. You are correct about the stability. If I were setting up my car for top speed only, I could do that along with adding trail and making the car push. However, that would kill the handling. Also, I have a gyro and super fast servo. The car is plenty stable under accelleration and cornering. However, above 100 (actually closer to 110mph) ANY steering input I give gets translated into too much servo movement. I could never seem to give the steering small enough movements to give small corrections at extremely high speeds. This, however, allows me to give very smally corrections without sacrificing any other aspect of the car's driveability. I know a top speed car is normally built with top speed ONLY in mind and can, therefore, be setup for very sluggish steering to make it controllable at speed. But, consider my car the Bugatti Veyron of the RC world. It is a tad heavy, but wildly fast and still very good handling, That is what this car was designed for.

Next year's car is a straight line only, top speed only car. :D

Matt

Oh, the React does not have the range I need, either. Awesome radio, though. I am using it in another car that does not require 1/4 mile range.

[ajlovering12345]

Thats awsome. Somebody asked me why i want to put 3 engines in a car and the answer was " Because I can!" Same with your radio. It gives you all the control you need PLUS you have 100% servo travel if you want it! Great solution.

The margins for success are getting smaller. Next year you wont see a runaway winner. I bet the winner is above 5-6 others by about 6 or 7 mph. there should bve more competition in IC as well. I'm helping out as many guys as I can.

See you there

Cheers

[Mod Man]

I totally agree. Many of the "Secrets" are out and alot of people will be learning more and more about top speed running.

I honestly think that once the 150 mph mark is achieved, the record will be broken a few MPH at a time rather than 20 or 30 mph. It may get (very soon) to the point that 1 or 2 mph increases will be what we are striving for. But, who knows!? I think 150 is possible with existing designs and technology if fine tuned to the limit. That is why I am doing things like this TX mod. I want to eliminate any and all road blocks (or even minor irritations) that limit my speed and make the car more driveable.

Matt

[ajlovering12345]

Exactly. The record will be limited to the run up and radio range as I said before this years comp. That needs to be sorted before you see real jumps in speed

[DrtFrds1]

Matt,Is the 9db gain antenna a bolt on for range? or did one have to re-calibrate radio/receiver to use it?
Thanks.

Dan

[ajlovering12345]

The 9db antenna fits on as long as you have the pigtail from the spektrum TX unit.

http://cgi.ebay.com/Pigtail-cable-RP-SMA-H-FL-WIRELESS-WiFi-mini-PCI-CARD_W0QQitemZ290096282140QQihZ019QQcategoryZ45000 QQtcZphotoQQcmdZViewItem

[TheSteve]

Just don't show the FCC...

[ajlovering12345]

Just don't show the FCC...

The antenna is legal in the USA as it does not increase the power only focus the output in a flat plan.

Also you can amplify the signal in the USA up to 1 watt legally. This is how I got 3.2 miles range with my spektrum

[Lito Reyes]

Matt: You are probably the only other person I've ever heard note that "modern radios" don't have much wheel travel. Older high-end radios, like the Airtronics/Sanwa 3P/PS and XL/CS2P and the old Futaba Magnums, had 85- to 90-degrees of wheel travel lock-to-lock. Most radios these days have only about 60-degrees of travel. I've been complaining about this for years.

Nice work on your ratio and relocation mod -- good stuff!!

Lito

[Mod Man]

Thanks Guys! This is one of those "I will get to it one of those days...." Kind of mods. Well, finally I got around to it. I must say I love the feel of the radio. I can change the ratio to whatever I want from 4 to 1 up to an overdrive (if that were ever desireable). I may try 2 to 1 also for kicks. But, the 3 to 1 seems best.

I have a react running a Tamiya Dark Impact off road car. I may mod that radio for a bit mroe wheel travel too. I am getting spoiled to this. It is far easier to hold a drift and just control the car overall with more travel. Obviously it takes longer to go from lock to lock. But, that is a minor sacrifice for being able to adjust my TX as I want.

The antenna was a simple plug and play item with the correct pigtail. I got both parts from E-Bay for $26 total.

The range is awesome! The only issue is at the farthest distance the antenna must remain pretty much straight up. But, the closer the car is, the less angle sensetive it is. In fact, at normaly running distance (maybe less than 500 feet), the antenna angle means nothing. Up at 1000 feet, the antenna must be held within 20 degrees of straight up. This, I found, is far easier than you might think. I never really had a problem keeping the antenna straight up without even thinking about it.

Matt

[B4Maz]

Thats the coolest mod ever. I dont think anyone has even thought about doing that kinda thing to their transmitter. Good job Matt. Its good to know that the parts to increase the range are about 30$ so any one could do it.

[k_sw31]

thats pretty sweet, but I'd really like to see a custom made waveguide can mounted on there, like such:
http://www.turnpoint.net/wireless/cantennahowto.html

;)

[Mod Man]

Hmm, I am kind of partial to spam myself! ;) :D

Matt

[crazyjr]

Will this antenna mod/ upgrade work on a nomadio sensor?

[Mod Man]

It may. I no longer have my Sensor. So, I cannot comment on how the wire connects within the transmitter. But, from what I remember of my old Sensor, the antenna should be compatible. However, don't quote me on that! ;)

Matt

[speedracer1129]

The antenna is legal in the USA as it does not increase the power only focus the output in a flat plan.

Also you can amplify the signal in the USA up to 1 watt legally. This is how I got 3.2 miles range with my spektrum


where do you obtain the antenna?? would it be compatible with the new Futaba FASST system??

[ajlovering12345]

Hi

You can get the antenna here

http://www.solwise.co.uk/wireless-indoorantenna-omni-9osc.htm

But the i dont know if the cable from the motherboard on the fasst system is the same as the spektrum. If it is then you also need this

http://cgi.ebay.com/Pigtail-cable-RP-SMA-H-FL-WIRELESS-WiFi-mini-PCI-CARD_W0QQitemZ290096282140QQihZ019QQcategoryZ45000 QQtcZphotoQQcmdZViewItem

[ajlovering12345]

http://www.teamassociated.com/shusting/CatalogHub/radio/xp3d_radios.htm

This radio system uses the Superhet system. It can theoretically increase the range 10 fold of a normal system. Has anybody used one yet?

Thanks

[trailranger]

I havent taken the plunge just yet for an wifi amp but I was thinking that using an directional antenna would be better. Currently I just have the Pigtail and a 7 DBI omni antenna.

The setup would require two people to operate: DRIVER and CAMERA MAN. Yes Camera Man. When you mount the video camera on a tripod, go ahead and mount the directional antenna there too. Setup your drivers stand about 1/3 down the driving lane and a few meters/yards to the side. As you drive your car the camera man follows the car and since the directional antenna is mounted with the camera it follows the car too. If you are setup too close to the track as the car passes it is possible to lose reception by not being able to follow the car fast enough. Following the car is also the reason for being 1/3 down the track, you will have better view of the starting trajectory and the car will pass by you slower than at the 1/2 way point.

http://cgi.ebay.com/3in1-12dBi-WiFi-Antenna-6ft-RF-Cable-Amp-Booster-500mW_W0QQitemZ160109385282QQihZ006QQcategoryZ4658 4QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

[Mod Man]

Nic Case tried a directional entenna with mixed results. You may want to PM him to ask his perspective. :)

Matt