What radios are everyone using?

[sim600]

Just wondering what radios everyone's using and whether you've had any issues with them. Thanks.

[fasterthanspeed]

futaba 3pk

[Mod Man]

Spectrum DX3.

I have not had any problems with it. But, my Eagle Tree has recorded many glitches with the radio at long distances. However, none of those glitches has propagated into a servo twitch.

I have only run it out to about 800 to 900 feet, though.

Matt

[ki smoke]

futaba 3pjs pcm 75mhz"old school" but seems to work good.if it starts giving me any crap i'll go with spektrum.btw would i be better off upgrading my radio with a spektrum module and receiver or just buying a dx2 or dx3.if i upgraded would i lose any tuning features.i know i'll lose pcm and failsafe.

[ajlovering12345]

I have the 3PKS and have the Spektrum normal, Spektrum Pro and the Spektrum for HRS and the 40 mhz synthersised

Problem is the nerds at Spektrum made the telemetry sytem to ONLY fit the normal spektrum, it doesnt even work in the micro receiver! So if I want to use the telemtry module Im stuck with the normal system.

The best range was with the Spektrum for HRS. I had 0.4 miles or 2100ftwith no loss of signal. I have fitted 12 cells in the TX and 6 cells in the RX but have not tested the range to see if its any better or worse

[Craps]

When I tested last year for last years event I had alot problems using Spektrum with glitches and range. The Pro Version was worse than the regular Spektrum. I tested it with 2 complete systems of each the Pro and regular Spektrum in 2 different Futaba 3PK radios and ended up going back to regular 75mhz crystals that had range as far as you could see it and my car was the full 40" size too at 1,500'+ away from the radio. The Spektrum Pro version had problems at a little over 200' away and the regular Spektrum was good for about 300' of range. My problem may have been my using a 2 cell li-po as a r/x pack too.

If anybody is interested, I just put 1 of the large Tonegawa PS-050 servos on e-bay along with a schulze/plettenberg brushless system.

Good luck to all going to the contest!

[ajlovering12345]

The Spektrum is 2 way so the RX pack transmits and receives so you need the voltage at the RX side. If the RX votage is weak you will get glitches no mater what you do to the TX

Cheers

[GeoVW72]

M11 if i go, will probly make good use of traction control function

[myndseye]

:teacher:I have a Futaba T3VC that I made some adjustments to, and with it, I get range for days with the Spektrum Pro setup. I removed the antenna from the Spektrum module's plastic housing and unsoldered the two-stranded wire from the metal housing at it's end. Trying to stick with the 31mm rule, I rerouted the wire through the module's case, and cut it to length. Through some creative use of JB-Weld and a Dremel, I affixed a rp-sma connector at the radio's top, soldered the wire, and screwed on a 7dbi, rubber duck, omni antenna. My eyesight is now the range limiting factor.

http://www.hyperlinktech.com/web/24ghz_802.11_rubber_duck_antenna_7dbi_sm.php

[ki smoke]

nice mod

[Knight_B]

Hi I'm newbie
how about KO EX10,3PK or M11
any advice

[ajlovering12345]

:teacher:I have a Futaba T3VC that I made some adjustments to, and with it, I get range for days with the Spektrum Pro setup. I removed the antenna from the Spektrum module's plastic housing and unsoldered the two-stranded wire from the metal housing at it's end. Trying to stick with the 31mm rule, I rerouted the wire through the module's case, and cut it to length. Through some creative use of JB-Weld and a Dremel, I affixed a rp-sma connector at the radio's top, soldered the wire, and screwed on a 7dbi, rubber duck, omni antenna. My eyesight is now the range limiting factor.

http://www.hyperlinktech.com/web/24ghz_802.11_rubber_duck_antenna_7dbi_sm.php

This sounds like a decent soulution. Have you got any pics and more detailed description of what you did. Whats the 31mm rule?

Cheers

[Hard Case]

Originally Posted by myndseye
I have a Futaba T3VC that I made some adjustments to, and with it, I get range for days with the Spektrum Pro setup. I removed the antenna from the Spektrum module's plastic housing and unsoldered the two-stranded wire from the metal housing at it's end. Trying to stick with the 31mm rule, I rerouted the wire through the module's case, and cut it to length. Through some creative use of JB-Weld and a Dremel, I affixed a rp-sma connector at the radio's top, soldered the wire, and screwed on a 7dbi, rubber duck, omni antenna. My eyesight is now the range limiting factor.

http://www.hyperlinktech.com/web/24g...na_7dbi_sm.php



This will adapt your antenna to Spektrum transmitter card.

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

Nic

[TheSteve]

The best range was with the Spektrum for HRS. I had 0.4 miles or 2100ftwith no loss of signal. I have fitted 12 cells in the TX and 6 cells in the RX but have not tested the range to see if its any better or worse


You do know the Spektrum receiver and transmitter both run on 3.3 volts, so adding extra cells to your transmitter will only produce more heat, it won't help the range at all.

[TheSteve]

The Spektrum is 2 way so the RX pack transmits and receives so you need the voltage at the RX side. If the RX votage is weak you will get glitches no mater what you do to the TX

Cheers

A Spektrum "receiver" never transmits anything with respect to controlling your car. The only time it will transmit is if you have telemetry enabled, and as I mentioned above it runs on 3.3 volts, so more voltage won't help with range.

[ajlovering12345]

Thanks for that Steve. I was groping in the dark on how to add range and now have the info I need.

I'll change the batteries back to standard and use the antenna you suggested.

Do you know how we could extend the range so we could use a much longer run with in car real time video??

:D:D:D:D:D

[Mod Man]

A number of people have suggested this. But, I have run RC cars with on-board cameras and I honestly do not think that is the solution. On and RC car, the camera is so close to the ground that even at 10mph, it looks and feels like you are running 60mph. The car is difficult to drive to say the least. Also, any rise in the surface at all looks like apporaching mount Everest. ;)

It is a good idea, but for high speed running, I think line of sight is the best option.

Matt

[ajlovering12345]

line of sight will soon become a problem.

[Mod Man]

I agree. But, trust me. On-board video is cool to mess around with. However, it is too difficult to drive the car with any amount of speed.

Now, if the camera would be raised about 3 or 4 feet off the ground, it could work. It seems like the big issue is being very close to the ground.

Matt

[myndseye]

The 31mm rule is not really a rule, its just the typically used length for 1/4 wave antennas in the 2.4ghz range. Actually the length is 30.5 mm which would make a 1/2 wave antenna 61mm and a full wave 122mm. When working with the wires on the spektrum, I tried to stick to those guidelines all the way to the solder points on the legs of the connector. (minus about 3mm to account for the legs themselves) The guys on forums like the ones I linked below, know far more about the technical on this stuff than me.

http://www.ocforums.com/showthread.php?t=480159

http://www.rcgroups.com/forums/showthread.php?t=657685

Sorry about the camera phone picture, but my digital Rebel went on vacation without me.

[ajlovering12345]

I just fitted a 9db antenna to the spektru with a pigtail like the one you posted and we tested the range. It worked but had a bout 400ft range as compared to around 2000ft with a normal setup. I must be doing something wrong.

I am charging the RX pack and have removed the switch and connected the battery to the RX with one servo. I havent re tried it yet.


Any suggestions??

Cheers

[myndseye]

It may be the 9db gain of the antenna. I thought that I might have been pushing it with the 7db because it was rated up to 50 watts transmitting power. I know for a fact that spektrum setups don't put out power like that. I would be suprised if they had 100mw. You may be under-driving an antenna so large. Also, make sure you have an rp (reverse polarity) connector added to the radio, and double check your solder connections for correct polarity if you soldered it. If you want though, there is a guy that runs with me that has a 11db omni, mounted to a base, with an inline amplifier transmitting at 1 watt. He is using an rf cable running from the connector he added, to the amp, then on to the antenna. It was powered initially by a 9v dc power adapter, so he just rigged up three A123's in series. Makes it through the day no problem. Going to such extremes just all seems a bit much to me though.

[myndseye]

I just thought about what you said above. If you have 2000ft range with your normal setup, isn't that enough. If you transmit from the center of your running area, it should give you 4000ft of coverage. 5280 feet in a mile.

P.S. - You are also the only person I know of with 2000ft range with an out the box Spektrum setup. Most of the ones I know of can't make 300'.

[ajlovering12345]

I talked with the guy who sold me the antenna. the antennas are designed for 100mw normal PC ise so should work perfectly with the spektrum. The problem is the E-plan angle. Its only 20 deg so both the tx and rx have to be fully vertical and not deviate more than 20 deg from each other. This is a problem with a car at hign speed as the aerial lays flat at speed. I found i lost the signal when it went part me and that makes sense now as coming towards me I had the antenna leaning towards the car and somewhere parallel to the RX. When it went past it was they were at 90 deg to each other. With a low E-plane antenna the problem would get worse.

I have ordered a 5db antenna with a 35 deg E-plane

The antnna has a magnetic base so I'll fix it vertically then use the very stiff fibreglass antenna from a 1/12th pan car on the rx. This will keep the TX and RX antenna parralel

The antenna has to be fully vertical from the RX.

[ajlovering12345]

If I use this I can get 1w output.

http://www.solwise.co.uk/wireless-export-outdoor-1w-booster.htm

I'll try it

[ajlovering12345]

Weird.... I just tried the 9 db antenna with the RX removed from the car and got 0.6 miles range, We actually ran out of space to test.

So the antenna from the RX has to be vertical from the case. If you first route it aound before coming up the antenna tube you loose about 90% range.

I'll install it in the car so its like that

[Mod Man]

I would love to do this to my radio. However, I must say, I already get 800 feet out of mine. But, I would love to see 1200 to 1300 feet. I will go back and reread this thread and order some equipment. :)

Matt

[ajlovering12345]

All you need is this

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

And this

http://www.hyperlinktech.com/web/24ghz_802.11_rubber_duck_antenna_7dbi_sm.php

Take the TX unit apart and remove the lead from the mother board and then the antenna from the case.

Plug in the pigtail and feed it through the hole where the antenna was and put the tx back together

Tape the rubber duck antenna to the old long antenna and plug the pigtail into the bottom....

Off you go!!

I'll post a pic on my blog.

[Mod Man]

OK, I ordered the pigtail. But, the antenna company requires a $100 minimum order. :(

Any thoughts?

Matt

[Mod Man]

If I use this I can get 1w output.

http://www.solwise.co.uk/wireless-export-outdoor-1w-booster.htm

I'll try it


That thing is spendy! Is an amp like that really useful for our application? If I knew it would make range pretty much limitless, I think it would be worth while.

Matt

[ajlovering12345]

OK, I ordered the pigtail. But, the antenna company requires a $100 minimum order. :(

Any thoughts?

Matt

The website mentions another shop for smaller orders. I used Solwise in the UK. I think they have a USA shop outlet.

I have the amp coming today so will try it out. I'll let you know. If it works really well i'll list all the stuff you need and how to rig it up and post it on my blog

Cheers

[Mod Man]

Turns out the Ebay store that I ordered the pigtail from also lists that antenna. So, I ordered it as well. If the amp works well for you, I may go that route also. I do not mind spending money on this if I know the range is beyond my needs. I would rather have extra range than not enough. :)

Matt

[Mod Man]

Oh, a computer hardware tech I know mentioned that an amp is really needed on the transmitter and reciever to really do it right. What are your thoughts?

Matt

[ajlovering12345]

I asked that question to the tech guys who sold me the stuff and they said its not needed on the receiver end. I was thinking it was needed both ends also. He said if your using it for computer data people only use one amp to hop to another building. They have a 7 day return policy so I'll check it out and if I dont get more than 2 miles I'll send it back.

I managed to tune the engine today. I found the best way is to disconnect the spur gears and tune each one on the bench until it runs at the right temp and picks up instantly.

I got the 45 shore tyres tody also. They should stand more speed than the 37s

[ajlovering12345]

I just spoke to the tech guy at Horrizon Hobbies. He seemed to know what he was talking about. He said on the car system NO information is passed from the receiver to the transmitter. This means as long as you boost the TX you can add as much range as you want. It is of course totally illegal to do so.

GREAT!

[Mod Man]

S W E E T ! ! ! :D

Matt

[ajlovering12345]

If you look at the rules we cant use any radio mods

:confused:

[Mod Man]

They do not say the radio cannot use any accessories. It just must be commercially available. I would assume that commercially available antennas and amps should be OK, especially if they bolt right on because anyone could buy that item and simply install it.

Anyone see a problem with that? I think it sould be OK. ;)

Matt

[ajlovering12345]

I agree. Whats worse using a radio with a long antenna or a car weighing 10lbs out of control at 150 mph?

As soon as I get the stuff i'll see if it works. I can return it if it doesnt

Cheers

[Mod Man]

That is the way I see it. It is a safety issue, more than anything. That is exactly what I just told Nic.

From my perspective, if a mod increases the safety margin, it sould be encouraged.

Matt

[ajlovering12345]

You can see a pic of the 9db antenna on my 3pk system on my blog

http://ziggy12345-myspeedattemptcar.blogspot.com/

Cheers

[trailranger]

What about 2.5Ghz repeaters?

[myndseye]

The FCC states that the maximun un-licensed transmitting power (in the US);

(3) For systems using digital modulation in the 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz bands: 1 Watt. As an alternative to a peak power measurement, compliance with the one Watt limit can be based on a measurement of the maximum conducted output power. Maximum Conducted Output Power is defined as the total transmit power delivered to all antennas and antenna elements averaged across all symbols in the signaling alphabet when the transmitter is operating at its maximum power control level. Power must be summed across all antennas and antenna elements. The average must not include any time intervals during which the transmitter is off or is transmitting at a reduced power level. If multiple modes of operation are possible (e.g., alternative modulation methods), the maximum conducted output power is the highest total transmit power occurring in any mode.

excerped from Section 15.247(b)(3) of the document located at:
http://www.fcc.gov/oet/info/rules/part15/part15-5-4-07.pdf
---------------------------------------
Spektrum's specifications

Output Power: 10 mW
Antenna: 2 dBi
Modulation: Digital GFSK 160kHz dF

heres a calculator and some great links for anyone interested
http://www.bessernet.com/jobAids/dBmCalc/dBmCalc.html

[trailranger]

I am sure someone has a firmware flash for the wrt54g routers to make them a singal repeater, i own two of the routers, one had 9dbi antenna with 34mw output

[Mod Man]

So, it sounds like a 1 watt amp should be allowed since it is an off the shelf item and is also legal for an unlicensed individual.

Matt

[trailranger]

OK, 1watt amp,
15' fiberglass pole (linman chicken stick or something)
30' of HF RF cable
and $10 per use fee to use.

[ajlovering12345]

Does it work?

Cheers

[Mod Man]

OK, 1watt amp,
15' fiberglass pole (linman chicken stick or something)
30' of HF RF cable
and $10 per use fee to use.

Not a bad idea. But, everything you gain with the amp, you lose in the long cable. ;)

Matt

[ajlovering12345]

Just got the amp. I plugged it in and it works but the signal can be coming from the pigtail so I need to test the distance.

Cheers

[Mod Man]

Cool. Keep us posted. ;)

Matt

[ajlovering12345]

Well thats the range problem solved!!! I found the longest road I could around here and that was a good 1.1 miles line of site before dissapering over a hill. You have to remember I live in a hilly area with lots of twisty roads.

I plugged the amp in and stuck the 9 db antenna on the car using the magnetic base. At 1.1 miles the signal was clear and strong and didnt flinch when a big heavy truck went between me and the car.

Next test I dropped my mate off on top of a hill and drove over to the next hill at 3.1 miles. Strong signal with 100% operation!!!! As long as it was line of sight.

The amp is 12vDC Powered so this makes it easy to rig up in the car or using a car battery. I'll take the rig to the comp and if anybody want to use it they can.

[Mod Man]

So, that is a 1 watt amp correct?

They can be obtained in a small enough size to mount to the transmitter.

Matt

[myndseye]

3 miles, one way.....geeze!

[myndseye]

Hmmm....1 watt at the amp with a 9db gain antenna........


don't stand too close.

[myndseye]

this should clear it up:

:teacher:In absolute terms there is no such thing as one antenna that is more powerful than another because antennas are passive devices (radiators) and they do not create energy, however, antennas are most often rated in dB gain and as such, most people believe that a high gain antenna is better or more powerful than a low gain: for example a 3db gain antenna versus a 0db gain antenna. An antenna without gain (0db) radiates energy in all directions equally and an antenna with gain redirects or concentrates energy in a certain direction and the gain performance is measured in the direction of the energy concentration. A vertically mounted, high gain antenna, will concentrate energy more parallel to the earth, however its vertical radiation will be lower than a low gain antenna. The 0db gain antenna is designed for mountains or urban centers with lots of tall buildings and radiates energy vertically very well. In flat, open terrain, higher gain (5db to 9db) antennas that radiate energy primarily horizontally work the best. A 3db gain antenna is a nice compromise for general use.

http://www.marcspages.co.uk/tech/antgain.htm

[Mod Man]

I just installed my new 9 DB gain antenna and pigtail on my Spectrum DX3. I will post pics soon.

Here are a couple links. I got these from the same vendor (great service, by the way).

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=019&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=290079945271&rd=1&rd=1

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=019&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=290096282140&rd=1&rd=1

Thanks to AJ for the antenna link and Nic Case for advice on the pigtail.

Anyway, I did a range test with the steering servo only. Previously I had a good 800 foot range with the stock antenna. I had a couple lockouts at that distance (no reception) with the stock antenna. So, I am sure that was the maximum range. However, I just came in from two separate range tests and got 1200 feet while broadcasting through a house (my wafe was in my front yard watching the car and a house was in the way while I walked away). Then with line of sight, I got 1600 feet. I finally stopped walking away because I ran out of road and could not see my daughter at all anymore (she was barely a spec on the horizon).

So, I would say this is a wonderfull mod for those looking for great radio range. The total for this mod was less than $30 US.

Now, AJ was correct in his comment about antenna angle. I found that as long as the antenna is held straight up, the range is almost unlimited. However, 20 degrees is the maximum angle of declination without loss of reception. However, that 20 degrees only applies at long distances. When I was 600 feet away, angle made no difference (or at least none that we could detect).

So, I mounted my antenna on my transmitter in such a way that it is straight up when I am holding the trasmitter at the most cumfortable angle for driving.

I am very happy at this point. I need no more range.

The only question mark for me is if the range is affected with the car driving.

Matt

[Mod Man]

I just came in from a road test of the new antenna. All I can say is WOW. I ran the car untill all I could see is a tiny dot on the pavement (about 1200 feet out). I still had full control without any issues at all. I took it further and it was still fine. At that point, I could not really tell which way the car was going.

It is fantastic!

Thanks to everyone for the input on this. What a great mod!

Matt

[ajlovering12345]

Same with my car. I am going to paint the left and right different colours so you know which way its heading.

Looks like we can get through the comp with no radio issues.

Cheers

[Mod Man]

I would say so. ;)

Matt

[wqqdster]

I just put a Fast system module in my old 1024 PCM and I got 1000 feet of crisp radio reception. There may be more available but that's as long as my test site is. That would give me 2,000 feet of useable distance to accelerate and decelerate.....more than enough.

Gary O

[ajlovering12345]

I have to get one of those