Parallax RFs distance.

Markus

Hi,

I need to send data using the 433.92 MHz Transmitter and
the receiver Items: 27986 and 27987.

I need to know the real distance of transmittion
because.


And the same question for:
item SureLink 900 MHz RF Module (item 30065)

Many Thanks,

Chris Savage

Hello,

·· The specs for the transmitter can be found at the following web page:

http://www.parallax.com/detail.asp?product_id=27996

·· The specs for the receiver can be found here:

http://www.parallax.com/detail.asp?product_id=27995

·· The specs for the surelink are available here:

http://www.parallax.com/detail.asp?product_id=30065

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Chris Savage
Parallax Tech Support
csavage@parallax.com

Joe

Yes,

The problem is that
PDF says 250 feet but realy is less than this.

Usually 50%.

I think that Parallax could test before selling.

Joe

Philip Gamblin

There are many variables to consider. We'll start with line of sight. As long as the transmitter and receiver have an unobstructed view of each other, you can expect optimum performance. Both antennae in a fixed· and vertical orientation· with as much ground plane as feasible will be a plus. Will either Tx or Rx unit be mobile?
Any of these variables,as well as many others, need to be considered. Even the type and frequency of data update can impact data integrity. For example FRS radios with a stated range of two miles means: two miles across water, probably ; two miles across a flat field, maybe; two miles across uneven terrain that is densely wooded, good luck. Your best bet would be to solicit·input from folks with a similar application.·Just remember RF has limitations and understanding those limitations can only help.

Chris Savage

Joe,

·· Definately consider Philip's response, as well as other types of interference, such EMI and stray RF noise in a given area.· Especially when between to relay towers.· The stated specifications are from the manufacturer and in some cases have been tested.· Of course, everyone's mileage varies.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

dandreae

I have actually tested these before.· Yes, you are correct about the given distance not as·accurate as documented in some cases.· The RF modules that you are referring to 27986 and 27987 are very close to the 250 feet (line of sight) as mentioned.· You can take away about·2/3rds the distance when communicating through walls.· As mentioned in the previous post, other factors can distrupt the signal and therefore shorten the distance of communication.

Dave

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Dave Andreae

Tech Support
dandreae@parallax.com
Http://www.parallax.com

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