I was wondering if you could give any reccomendations on radios. I was at Watkins Glen this past week and some of the teams had problems keeping in contact over the 3.4 mile long course.
I was wondering if you could give any reccomendations on radios. I was at Watkins Glen this past week and some of the teams had problems keeping in contact over the 3.4 mile long course.
Morgan<br />Zetec Championship
For the Glen or Road Atlanta you almost need a repeater broadcasting off an antenna up on a high mast. All the big pro teams do it. The rest of us learn to live with the dead zones.
I've never understood why we can "talk" to a satellite on the edge of our solar system - but I can't talk to somebody that is 1/3 mile away...
The Motorola GP300/350's are pretty good - The SP50's are not that great... You will not get the big distance unless you follow Frog's advice. I would first check out a the links for a vendor that sells radios - after that check Ebay (always tons of Moto stuff on there) Also - I just saw an ad at the Usf2000 pro site from DSTP for a bunch of stuff.
2006
2007
What is a minimum number of channels needed to be safe from overlay?
There is a fine line between "hobby" and "mental illness."
4 should doOriginally posted by Tim Reed:
What is a minimum number of channels needed to be safe from overlay?
It really comes down to having a good antenna on the car. The quarter wave antenna that comes with most radio kits is designed to be mounted on the metal roof of a race car. The metal roof acts as a ground plane which is essential for the antenna to function properly.I've never understood why we can "talk" to a satellite on the edge of our solar system - but I can't talk to somebody that is 1/3 mile away...
The ground plane must be perpendicular to the radiating element, at least a half wavelength in diameter and attached to the coaxial cable ground braid at the point where the cable connects to the radiating element. Hard to find this mounting configuration on a Formula car.
If you can't fabricate some kind of ground plane for the antenna, you might find that you get better results with the "Rubber Duck" antenna that comes with the radio as it is designed to be used with the handset directly without any ground plane required.
Dennis Cleary
VD RF94/95
NER #37
Use the lowest frequency available or buy radios in the lowest frequency band that you can legally use if you go to a lot of hilly areas. The lower the frequency, the more the ground wave bends to acommodate loss of line of sight. There's a drawback to this strategy though - you will need a bigger ground plane and a longer antenna or find that the shorter ones available are very inefficient. Ground to ground radio in hilly terrain is always a very hit and miss proposition.
I noticed once a prototype car had a large piece of copper foil stuck to the inside of the bodywork - where the antenna was mounted. Maybe putting foil under an upper nose section and mounting the antenna there would work better??
We improved our radios 200% this season by fabricating a thin aluminum sheet about 15" in diameter that we mounted the antenna on. We use velcro to hold it on the frame in front of the front roll hoop. Drilled one small hole for the antenna to stick up through the body work.
Hey Frog,
Could you post a picture of that? Sounds like a neat setup.
We have not used an external antenna for at least 3 years. We just use the rubber ducky with the radio mounted between the front shocks. We have good reception every where, even at Road America and Mid-Ohio. We have 2 channels but have only needed the second channel once in 5 years.
While you're paying attention to the ground plane, don't forget the cable. It has to be 50 ohm stuff (RG-58) not the stuff the cable guy uses (75 ohm RG-59) . Depending on who's connectors you use, they may have to be matched to the cable type. Keep it short and tie it down so that vibration doesn't flex the braid at the backshell and leave you with no ground.
Frog,
Did you ground the aluminum sheet ground plane?
Also,
Our radio reception improved dramatically when we rewired our ignition, using shielded twisted pair for the 12V power wiring to the MSD box and the coil-to-MSD box wiring. We did this to improve the reliabiliy of the ignition, but another result was no noise at all in the radio, except when Don was passing or being passed by another car.
Randy
Randy
It is not necessary to ground the antenna ground plane to the chassis. It's only necessary to connect it to the coaxial cable shield at the point where the center conductor connects to the radiating element.
Dennis Cleary
VD RF94/95
NER #37
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