Post by thread:RF application

Yes, as well as radiometrix, RFMD, and many others. Here are my recommendations(after 18 months of hell): If you are sending data in chunks of 100 bytes or more, go with LINX. They do not stick to their specs very well, but they're good for large data TX/RX. The 900 MHz HP modules are decent. If you are sending a few bytes here and there, and 1200 bps is OK, go with DVP. They exceed their specs across the board. If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice for European models. It requires a lot of attenuation for the U.S markets, making it impractical. If you run into anything out of the ordinary with these products, odds are that myself or someone else on this list can help. Justin Crooks, Interactive Horizons ---------- > From: Eduardo R. <spam_OUTeriveraTakeThisOuTUMEMPHIS.CAMPUS.MCI.NET> > To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU > Subject: RF application > Date: Wednesday, March 17, 1999 6:29 PM > > Has anyone succesfully tried DVP, LYNX or any other RF product to > interface your microcontroller applications sending RS232 signal or bits to > remote stations? > > I need advice about a reliable remote control link. > > Thank you.

At 11:44 AM 18/03/99 -0700, you wrote: Why not avoid 18 months of hell and go with an Indigo which does not require the RF knowledge to sit and try and drive it. Peter {Quote hidden}>Yes, as well as radiometrix, RFMD, and many others. Here are my >recommendations(after 18 months of hell): >If you are sending data in chunks of 100 bytes or more, go with LINX. They >do not stick to their specs very well, but they're good for large data >TX/RX. The 900 MHz HP modules are decent. > >If you are sending a few bytes here and there, and 1200 bps is OK, go with >DVP. They exceed their specs across the board. > >If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice >for European models. It requires a lot of attenuation for the U.S markets, >making it impractical. If you run into anything out of the ordinary with >these products, odds are that myself or someone else on this list can help. > >Justin Crooks, >Interactive Horizons > >---------- >> From: Eduardo R. <eriveraKILLspamUMEMPHIS.CAMPUS.MCI.NET> >> To: .....PICLISTKILLspam.....MITVMA.MIT.EDU >> Subject: RF application >> Date: Wednesday, March 17, 1999 6:29 PM >> >> Has anyone succesfully tried DVP, LYNX or any other RF product to >> interface your microcontroller applications sending RS232 signal or bits >to >> remote stations? >> >> I need advice about a reliable remote control link. >> >> Thank you. > >

So how many Aus dollars do these Indigo radio things cost ? Peter Grey wrote: {Quote hidden}> > At 11:44 AM 18/03/99 -0700, you wrote: > > Why not avoid 18 months of hell and go with an Indigo which does not require > the RF knowledge to sit and try and drive it. > > Peter > > >Yes, as well as radiometrix, RFMD, and many others. Here are my > >recommendations(after 18 months of hell): > >If you are sending data in chunks of 100 bytes or more, go with LINX. They > >do not stick to their specs very well, but they're good for large data > >TX/RX. The 900 MHz HP modules are decent. > > > >If you are sending a few bytes here and there, and 1200 bps is OK, go with > >DVP. They exceed their specs across the board. > > > >If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice > >for European models. It requires a lot of attenuation for the U.S markets, > >making it impractical. If you run into anything out of the ordinary with > >these products, odds are that myself or someone else on this list can help. > > > >Justin Crooks, > >Interactive Horizons > > > >---------- > >> From: Eduardo R. <EraseMEeriveraspam_OUTTakeThisOuTUMEMPHIS.CAMPUS.MCI.NET> > >> To: PICLISTspam_OUTMITVMA.MIT.EDU > >> Subject: RF application > >> Date: Wednesday, March 17, 1999 6:29 PM > >> > >> Has anyone succesfully tried DVP, LYNX or any other RF product to > >> interface your microcontroller applications sending RS232 signal or bits > >to > >> remote stations? > >> > >> I need advice about a reliable remote control link. > >> > >> Thank you. > > > > -- Peter Williamson | Phone: +61 15 898934 Waybeat Pty Ltd | Email: @spam@peterwKILLspamwaybeat.com.au

So, How much is the Indigo Anyway??? Kevin >Why not avoid 18 months of hell and go with an Indigo which does not require >the RF knowledge to sit and try and drive it. > >Peter > >>Yes, as well as radiometrix, RFMD, and many others. Here are my >>recommendations(after 18 months of hell): >>If you are sending data in chunks of 100 bytes or more, go with LINX. They >>do not stick to their specs very well, but they're good for large data >>TX/RX. The 900 MHz HP modules are decent. >> >>If you are sending a few bytes here and there, and 1200 bps is OK, go with >>DVP. They exceed their specs across the board. >> >>If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice >>for European models. It requires a lot of attenuation for the U.S markets, >>making it impractical. If you run into anything out of the ordinary with >>these products, odds are that myself or someone else on this list can help. {Quote hidden}>> >>Justin Crooks, >>Interactive Horizons >> >>---------- >>> From: Eduardo R. <KILLspameriveraKILLspamUMEMPHIS.CAMPUS.MCI.NET> >>> To: RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU >>> Subject: RF application >>> Date: Wednesday, March 17, 1999 6:29 PM >>> >>> Has anyone succesfully tried DVP, LYNX or any other RF product to >>> interface your microcontroller applications sending RS232 signal or bits >>to >>> remote stations? >>> >>> I need advice about a reliable remote control link. >>> >>> Thank you. >> >>

Hi there, Justin Crooks wrote: {Quote hidden}> Yes, as well as radiometrix, RFMD, and many others. Here are my > recommendations(after 18 months of hell): > > [...] > If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice > for European models. It requires a lot of attenuation for the U.S markets, > making it impractical. If you run into anything out of the ordinary with > these products, odds are that myself or someone else on this list can help. I would not recommend Radiometrix if you don't want to have an effective random number generator... We did a remote controlled robot with it (using some 8051 derivate) and enjoyed '6 months of hell'. But maybe we had bad luck and they got damaged when we ordered them (at least that was our conclusion after hours, days and months of debugging). Most of the time they did work but then there were lots of (non-reproducible) errors that made only _very_ low effective transmission rates (few bytes/s) possible. We checked all configuration words, disabled all possible noise sources but it didn't even transmit over some centimeters. Stefan Sayer > > > Justin Crooks, > Interactive Horizons > > ---------- > > From: Eduardo R. <spamBeGoneeriveraspamBeGoneUMEMPHIS.CAMPUS.MCI.NET> > > [...] > > I need advice about a reliable remote control link.

I'm not sure that that is possible at all with off-the-shelf (read not REALLY expensive) RF stuff. The main problems are #1)preventing collisions #2)key-up delay #1) If 2000 individuals try to transmit within 4 seconds,there are LOTS of collision possibilities. Most likely, there would have to be lots of retransmissions (AFAIK) #2) Even a transmitter which is VERY high speed may take a 100 milliseconds to key-up and BEGIN to transmit. This is related to the settling times of amplifiers,any switching circuits which must change,etc. This is MAINLY true with transceivers which must do a T/R switch (change the antenna from receiver to transmitter) so if you only need to transmit or if you can deal with separate antennas for transmit and receive,you may be able to reduce this problem. For 2000 individuals to key-up and send in 4 seconds, they will each only have a 2 millisecond slot for each one to key-up,transmit,and stop transmitting,AND somehow the others have to know not to try to transmit at the same time. And if they do,then there is a lost slot. I'm sure there is an RF way to solve this problem,but I don't think it is going to be easy. Can you implement a wired network? Possibly,you could have the base station have several receivers on separate freqs and group the 2000 stations into several freqs. If you had ten freqs,then you have just reduced your problem to a 200 user network instead of 2000. Can each individual hear its closest neighbors? How fault tolerant does this need to be? Assuming that you can aleviate the key-up delay,you may be able to prevent collisions by using a token passing system. However,the network may become disabled if one of the stations goes down. You may have to pass the token in both directions and maybe even do it multiple times to ensure that you get every station. Just some things to consider, Sean At 04:15 PM 3/18/99 -0700, you wrote: >Can I gather information (4 bytes) from 2000 individual sources in under 4 >seconds with an Indigo? I have unique needs. But there are several RS-232 >transceivers out there, and I would agree that if RF timing is not an >issue, by all means they are the way to go. > | | Sean Breheny | Amateur Radio Callsign: KA3YXM | Electrical Engineering Student \--------------=---------------- Save lives, please look at http://www.all.org Personal page: http://www.people.cornell.edu/pages/shb7 TakeThisOuTshb7EraseMEspam_OUTcornell.edu ICQ #: 3329174

At 04:15 PM 18/03/99 -0700, you wrote: The max baud rate for teh Indigo is 9600 and you require about 64Kbaud. I will have a frequency hopper out in about 2 months - operator controlled power levels (say by a PIC, 2 line interface) to 320mW; 2"x1"; 48 channels of info;micro on board; all CRC and auto resends handled automatically; etc etc. This would definitely do the trick for you. You could have a number operating side by side. Give me a buzz in a few months or keep in contact with my web site. Sorry I could not help right now. Peter {Quote hidden}>>Why not avoid 18 months of hell and go with an Indigo which does not >require >>the RF knowledge to sit and try and drive it. > >Can I gather information (4 bytes) from 2000 individual sources in under 4 >seconds with an Indigo? I have unique needs. But there are several RS-232 >transceivers out there, and I would agree that if RF timing is not an >issue, by all means they are the way to go. > >