433MHz remotes with >500ft range

Has to be 433 for 500ft I would have thought......I use Nordic nrf905....

You should also check how the link performs with nearby 5-50 W transmitters on the same or nearby (hundreds of kHz) frequency as your

In Europe, the 433 ISM band is in the actively used part of the 70 cm amateur radio band, so quite strong signals may also be present at that band.

At least the old keyfob system receivers had very bad selectivity, getting blocked by transmitters hundreds of kHz away. A person is approaching his/her car, a nearby handheld amateur radio transceiver is activated and the operator describes what the car owner is doing, when the doors do not open, people seem to do all kind of funny thing, when trying to get the car open with the remote control :-).

Speak to John Fairall at RF Solutions here in the UK. They have such a product range.

JB

$20 each for a custom controller? Ha!

More like $200 to $400 depending on options.

Also, very rarely do any two brands work together in this business. So they will not be providing IP for 'second sources' to profit from.

There are no standards and no consortiums for any that I know of.

Thanks, but that's a module and we are looking for a complete packaged product, with the required papers from agency approval labs.

Yes, Paul, I know. But what can one do? Europe doesn't allow the VHF bands we have here and the only common denominators worldwide are 433MHz and 2.45GHz. 2.45GHz often has range problems.

Thanks, I will. They have a US distributor and their products look a bit more bulky but I'll ask if they can supply one that sort of matches:

BTDT.

Oh no, it sure ain't :-)

Thanks, I bookmarked that. It's a module though and looks out-of-league financially, with a fancy gold plated jack and all that.

That is true, but many employ the usual Asian chips for encoding and the RF part itself is nothing more than a transmitter with a modulator. That's the kind we are after because then the code is the same, as long as both use FM or whatever modulation scheme.

Un bel giorno Joerg digitò:

EU regulations mandate a maximum transmit power of 10 mW eirp at 433 MHz for SRDs (short range devices). It is almost impossible to reach 150 m with this power in a reliable way, unless you have a directional antenna and a perfect line of sight (two things you can't rely on with a typical key fob application). With these regulations and a good antenna you can get a "real-life" reliable range of 50-70 m.

At 2450 MHz you can qualify your device as a "radio frequency identification device" rather than a generic short range device. This allows you to use powers up to 500 mW. To get 150 meters in a reliable way at 2450 MHz you will need a lot of power though, and this isn't good for a battery powered key fob.

On a sunny day (Fri, 29 Oct 2010 19:17:20 GMT) it happened dalai lamah wrote in :

I have a couple of 456 MHz PMT walky talkies. These are 500 mW, and range is about 3 km, and they are about 25 Euro for 2, really cheap. As you are not allowed to modify those, neither the ntenna nor connect anything, it does not even have a mike in or headphone out, I tried the following experiment, as the regulation specifies 'speech only': I did put one on RX on one channel, with a mike in front of the speaker, connected the mike to the PC (Linux) running perlbox voice. Then I gave voice commands from the other one :-) It works, at least most of the time, I could switch the house lights on and off from far away. Of course it is an open channel, so anybody listening in can hear the commands and copy those. But it was a fun experiment.

Even with a "good antenna" you are still fixed to +10 dBm EIRP. Maybe with the receiver having the good antenna, you can get better range but then it will make the receiver directional. About the only way around this is to use a slow data rate and very narrow bandwidth such as to lower the noise floor and improve the system gain.

tm

Yeah, sometimes I wonder what the guys in Brussels were thinking. Or whether they were thinking ...

EU operation on 433MHz would almost mandate AM mode and then tons of correlation. All we need is slow push-button control so an effective data rate of 10 bits per second or even less would be fine.

AFAIK they even have a 4W category when not inside buildings but that would require some massive battery. And we can't have that.

"Range" problems? Since that's close to the microwave oven freq's, there's got to be some kind of joke in there.

(In America, a "range" is an oven with a stove on top.)

Cheers! Rich

Suitable for cooking venison and antelope meat?

And seldom is heard A discourging word, Because what can an antelope say? ;-)

Cheers! Rich

Only if an insane hunter was responsible for somehow finding his way to the kitchen with the meat. "Home, home on, deranged!"

The Avalon RF stuff uses a QAM256 encapsulation.

The whole idea was to alleviate the dropouts that occur with Std FM stuff. It is like the DTV version of a stage microphone with very little latency, yet fully digitized, packetized, and encrypted, if need be.

We did a test where we replaced the reel-to-reel recorders on carriers with a belt worn "DVR" and all the deck traffic spoke through those links. All was recorded on the recorder device, and the Air Boss got clean feeds all the time without dropouts. It was pretty cool. Integrated it all into the colored deck vests and helmets they wear while up on the flight decks.

Or use diversity.