[robocup-small] Two frequency radio module

[Andy Bardagjy]

Zach,

The spectrum at RoboCup is quite crowded. It is essential that you are
able to change frequencies to accommodate other teams. 

We (the GT RoboJackets) and many other teams use the Linx HP3 modules
which operate on the 900MHz band. We use them in the serial channel
selection mode.

I would strongly suggest operating outside of the 2.4GHz band. It is
extremely crowded (due to wifi - we saw 100+ networks). If you are in
the US and at the required bandwidth you are looking at either 900MHz or
5.4 or 5.8GHz bands. 

While we have used Linx modules in the past (with varying degrees of
success) we are looking to a suitable replacement. We saw a high degree
of failure in the transmitter this year, and definitely recommend
socketing it (in a high quality socket) as it is difficult to replace.
Also they are large and expensive. 

We are looking to replace the modules with a DIY solution using a highly
integrated ASIC (look at TI, Nordic, Atmel, and MAXIM). This solution,
while much cheaper and smaller, will take some development and RF
expertise. This is probably not a good path for a first year team. 

In the future when our server is up (our server is changing physical
locations) you can look at our wiki for more information. 

wiki.robojackets.org

Good luck!

Andy Bardagjy
RoboJackets SSL Team Leader


On Fri, 2008-08-15 at 11:07 -0400, Zachary Noyes wrote:
> Hi robocup,
> 
> How serious is the rule that we have to have two frequencies available
> so as to not interfere with the other team? Radiometrix, a company
> that Cornell references using modules from, doesn't sell ANY
> two-frequency radios. I talked to a sales representative directly who
> said so. The frequency I was thinking of transmitting on was 914.50
> MHz
> 
> Also, because I like radiometrix as a company: they are friendly/have
> good customer service/and are innexpensive, here's a model of theirs
> that I was concidering:
> 
> http://www.radiometrix.co.uk/products/rpm3.htm
> 
> Of course, it only has one frequency, but it is only $98
> 
> Thanks.
> 
> --Zach
> 
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