Comments on: Long range R/C on 868Mhz

By: Mike Berg

Mike Berg — Tue, 13 May 2008 18:27:19 +0000

The Pololu micro servo controller mentioned in my previous post should be this model:
http://www.pololu.com/catalog/product/207
The Scott Edwards SSC2 works as well:
http://www.seetron.com/ssc.htm

By: Mike Berg

Mike Berg — Mon, 12 May 2008 20:42:24 +0000

By combining a RC transmitter to serial interface with a Digi long range wireless serial link and a Pololu serial to servo controller you can do the same thing.
RC to serial
http://www.ringolake.com/pic_proj/servo/rc_trans/rc_trans.html

Pololu servo controller
http://www.pololu.com/catalog/product/727

Digi wireless
http://www.digi.com/products/wireless/

By: TJHooker

TJHooker — Sat, 10 May 2008 14:59:59 +0000

There is a cool set of tested protocols to broadcast digital over 12Mhz SW. I forget what they're called though.

There is almost -no- public implementation literature on them though.

By: albertocvr

albertocvr — Fri, 09 May 2008 23:33:15 +0000

Actually the 868 DMD system is under beta testing and they have flown Â¡Â¡16.5Km away with an easy-star elapor plane !! , the actual limit is the plane battery capacity . They will have available the system in 2 versions , 868 Mhz for Europe ISM band ,and 900 for USA .For more info take a look here : http://www.dmd.es/rc_&_fpv_e.htm

By: DietFig

DietFig — Fri, 09 May 2008 19:22:05 +0000

Neat, it would be more interesting though if it wasn’t a commercial kit…

By: twistedsymphony

twistedsymphony — Fri, 09 May 2008 15:07:18 +0000

This is the perfect hack for building that Full sized RC car I’ve always wanted to build!

By: dmang

dmang — Fri, 09 May 2008 08:07:30 +0000

ya, lots of place online willing to sell you tx/rx equipment for 868mhz tho...

from wikipedia:
# 824â849 MHz: AMPS A & B franchises, terminal (mobile phone) (formerly TV channels 73â77)
# 849â869 MHz: Public safety 2-way (fire, police, ambulance â formerly TV channels 77â80)
# 869â894 MHz: AMPS A & B franchises, base station (formerly TV channels 80â83) (one translator is still in use on channel 83)
# 902â928 MHz: ISM band: cordless phones and stereo, radio frequency identification, datalinks, amateur radio (33 cm band)
# 928â960 MHz: Mixed studio-transmitter links, mobile 2-way, paging, other.

from the ism page, it looks like AMPS spectrum has mostly been abandoned as of feb18 2008. maybe this will get auctioned or opened soon?

"The receivers of 11 series of 868/902Mhz are designed for the band ISM of 868-870Mhz of agreement to the European procedure ETSI EN 300 220 and availables for the band ISM 902-928Mhz in agreement with the procedure FCC of the USA."

looks like the US version will only be 902-928mhz? and "changes for soft (setup)"??? maybe a software setting or jumper that changes it between bands? would 40mhz lower make much of a difference?

been thinking about getting a ham license for ages now. last time i checked, the morse code requirement is gone for the tech class.

By: Bill

Bill — Fri, 09 May 2008 07:34:20 +0000

900 Mhz is licensed but for low power stuff (like a cordless phone or other r/c devices) you dont need one. For the things he is talking about you do need a HAM radio license in the states.
"The receivers of 11 series of 868/902Mhz are designed for the band ISM of 868-870Mhz of agreement to the European procedure ETSI EN 300 220 and availables for the band ISM 902-928Mhz in agreement with the procedure FCC of the USA."

902-928 is the 33cm band and should not be used without a license. If you are interested in getting one, check out the ARRL and QRZ websites, they will help you get your license. Its not very hard to get the basic one which is needed for this band (technician).

I know he is talking about 868Mhz but it is not legal to use this in the states for any reasonable amount of power.

Also, if you want more range, try a lower frequency. Once you've got your ham license you can use a huge range of them!

http://www.arrl.org/FandES/field/regulations/bands.html

http://www.qrz.com/

Enjoy
-Bill
KC2RST

PS If you are ever in the Newark NJ area listen for me on K2MFF, the repeater at NJIT.
http://web.njit.edu/~k2mff/

By: dmang

dmang — Fri, 09 May 2008 07:16:21 +0000

cool. i know the 900mhz band is mostly open/unlicensed (cordless phones, etc). but 868mhz i dont know much about.

By: strider_mt2k

strider_mt2k — Fri, 09 May 2008 05:33:11 +0000

That's _nice_!

I'd like to use something like that with a wheeled ROV but real time video over those kinds of distances over the ground...ouch. :(

This is an awesome project.