I'd also like to participate in this project - it sounds awesome! Norm KB2JRP
On Fri, May 23, 2014 at 8:35 PM, <[email protected]>wrote: > Send Radio mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://list.hackmanhattan.com/listinfo/radio > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Radio digest..." > > > Today's Topics: > > 1. 70cm GFSK project (Guan Yang) > 2. Re: 70cm GFSK project (Robert O'Connor) > 3. Re: 70cm GFSK project (David Reeves) > 4. Re: 70cm GFSK project (Max Nager) > 5. Re: 70cm GFSK project (Guan Yang) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 23 May 2014 17:48:27 -0400 > From: Guan Yang <[email protected]> > To: Hack Manhattan Amateur Radio Club <[email protected]> > Subject: [hmradio] 70cm GFSK project > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > I've been talking to a few of you about a project to finally make it easy > to do great digital on 2 meter or 70 cm. The use case is both emergency > communications, based on our frustrations with FM voice and our needs in > the Rockaways during Sandy, and APRS and similar modes, based on our > frustration with AFSK over FM in Manhattan. > > Right now I've ordered some RFM23BP transceiver modules, which can operate > on the entire 70cm amateur band and also 433 MHz ISM. The plan is to do > 9600 bps GFSK, and to test for compatibility with other chips, for example > ADF7023 from Analog. There's also a similar part from Silicon Labs. > > RFM23BP is easier to get started with since it has a single ended 50 ohm > RF output. It can't quite do GMSK with typical bit rates because deviation > has to be a multiple of 625 Hz. I'm thinking we might try 9600 bps with > 2500 Hz deviation. (That's carrier to peak, not peak to peak. I think.) > > The final product might be a circuit board with USB serial, possibly > Bluetooth LE for communication with phones, a battery charging IC, and a > lithium ion battery. > > ------------------------------ > > Message: 2 > Date: Fri, 23 May 2014 17:49:22 -0400 > From: "Robert O'Connor" <[email protected]> > To: Hack Manhattan Amateur Radio Club <[email protected]> > Subject: Re: [hmradio] 70cm GFSK project > Message-ID: > <CAPncwvJE1m3ho8LG3tEFd= > [email protected]> > Content-Type: text/plain; charset="utf-8" > > I'd be down > > --Rob > Sent from my phone...excuse any typos please! > On May 23, 2014 5:48 PM, "Guan Yang" <[email protected]> wrote: > > > I've been talking to a few of you about a project to finally make it easy > > to do great digital on 2 meter or 70 cm. The use case is both emergency > > communications, based on our frustrations with FM voice and our needs in > > the Rockaways during Sandy, and APRS and similar modes, based on our > > frustration with AFSK over FM in Manhattan. > > > > Right now I've ordered some RFM23BP transceiver modules, which can > operate > > on the entire 70cm amateur band and also 433 MHz ISM. The plan is to do > > 9600 bps GFSK, and to test for compatibility with other chips, for > example > > ADF7023 from Analog. There's also a similar part from Silicon Labs. > > > > RFM23BP is easier to get started with since it has a single ended 50 ohm > > RF output. It can't quite do GMSK with typical bit rates because > deviation > > has to be a multiple of 625 Hz. I'm thinking we might try 9600 bps with > > 2500 Hz deviation. (That's carrier to peak, not peak to peak. I think.) > > > > The final product might be a circuit board with USB serial, possibly > > Bluetooth LE for communication with phones, a battery charging IC, and a > > lithium ion battery. > > _______________________________________________ > > Radio mailing list [email protected] > > https://list.hackmanhattan.com/listinfo/radio > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > https://list.hackmanhattan.com/pipermail/radio/attachments/20140523/22ada61a/attachment-0001.html > > > > ------------------------------ > > Message: 3 > Date: Fri, 23 May 2014 20:10:11 -0400 > From: David Reeves <[email protected]> > To: Hack Manhattan Amateur Radio Club <[email protected]> > Subject: Re: [hmradio] 70cm GFSK project > Message-ID: > < > capvsgtxkwrievqt4tzsw9kysqaofxqtdt62t9rxuxpw-ock...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Ok, so is the reasoning here that some kind of direct FSK modulation will > suffer fewer of the propagation difficulties that we've seen with reception > of voice/AFSK? > > I'd assume this would be simplex only, which has in fact been by far the > most reliable over the few small-area (< 3 miles) urban nets I attended > recently. If we could get up to a 10 mile range somehow with some clever > digital processing, I'd think that would be very useful indeed for us > canyon-dwellers - do you think that might be possible? > > > > > On Fri, May 23, 2014 at 5:48 PM, Guan Yang <[email protected]> wrote: > > > I've been talking to a few of you about a project to finally make it easy > > to do great digital on 2 meter or 70 cm. The use case is both emergency > > communications, based on our frustrations with FM voice and our needs in > > the Rockaways during Sandy, and APRS and similar modes, based on our > > frustration with AFSK over FM in Manhattan. > > > > Right now I've ordered some RFM23BP transceiver modules, which can > operate > > on the entire 70cm amateur band and also 433 MHz ISM. The plan is to do > > 9600 bps GFSK, and to test for compatibility with other chips, for > example > > ADF7023 from Analog. There's also a similar part from Silicon Labs. > > > > RFM23BP is easier to get started with since it has a single ended 50 ohm > > RF output. It can't quite do GMSK with typical bit rates because > deviation > > has to be a multiple of 625 Hz. I'm thinking we might try 9600 bps with > > 2500 Hz deviation. (That's carrier to peak, not peak to peak. I think.) > > > > The final product might be a circuit board with USB serial, possibly > > Bluetooth LE for communication with phones, a battery charging IC, and a > > lithium ion battery. > > _______________________________________________ > > Radio mailing list [email protected] > > https://list.hackmanhattan.com/listinfo/radio > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > https://list.hackmanhattan.com/pipermail/radio/attachments/20140523/9a47feab/attachment-0001.html > > > > ------------------------------ > > Message: 4 > Date: Fri, 23 May 2014 20:18:39 -0400 > From: Max Nager <[email protected]> > To: Hack Manhattan Amateur Radio Club <[email protected]> > Subject: Re: [hmradio] 70cm GFSK project > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > Ditto. Sounds awesome. > > Max > > > On May 23, 2014, at 5:49 PM, "Robert O'Connor" <[email protected]> > wrote: > > > > I'd be down > > > > --Rob > > Sent from my phone...excuse any typos please! > > > >> On May 23, 2014 5:48 PM, "Guan Yang" <[email protected]> wrote: > >> I've been talking to a few of you about a project to finally make it > easy to do great digital on 2 meter or 70 cm. The use case is both > emergency communications, based on our frustrations with FM voice and our > needs in the Rockaways during Sandy, and APRS and similar modes, based on > our frustration with AFSK over FM in Manhattan. > >> > >> Right now I've ordered some RFM23BP transceiver modules, which can > operate on the entire 70cm amateur band and also 433 MHz ISM. The plan is > to do 9600 bps GFSK, and to test for compatibility with other chips, for > example ADF7023 from Analog. There's also a similar part from Silicon Labs. > >> > >> RFM23BP is easier to get started with since it has a single ended 50 > ohm RF output. It can't quite do GMSK with typical bit rates because > deviation has to be a multiple of 625 Hz. I'm thinking we might try 9600 > bps with 2500 Hz deviation. (That's carrier to peak, not peak to peak. I > think.) > >> > >> The final product might be a circuit board with USB serial, possibly > Bluetooth LE for communication with phones, a battery charging IC, and a > lithium ion battery. > >> _______________________________________________ > >> Radio mailing list [email protected] > >> https://list.hackmanhattan.com/listinfo/radio > > _______________________________________________ > > Radio mailing list [email protected] > > https://list.hackmanhattan.com/listinfo/radio > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > https://list.hackmanhattan.com/pipermail/radio/attachments/20140523/f90fea11/attachment-0001.html > > > > ------------------------------ > > Message: 5 > Date: Fri, 23 May 2014 20:34:45 -0400 > From: Guan Yang <[email protected]> > To: [email protected] > Subject: Re: [hmradio] 70cm GFSK project > Message-ID: > <[email protected]> > Content-Type: text/plain > > On Fri, May 23, 2014, at 20:10, David Reeves wrote: > > Ok, so is the reasoning here that some kind of direct FSK modulation will > > suffer fewer of the propagation difficulties that we've seen with > > reception > > of voice/AFSK? > > Yes; certainly on a per-baud basis. I've found that a lot of the time > under bad propagation situations you can actually hear voices if you > open the squelch. Something not mediated by the FM voice thing should be > better. > > RFM23BP has a best case RX sensitivity of -120dBm, which is well below > the noise floor at these frequencies. Of course we will have to test it. > But even if propagation is just as terrible as FM voice, it will be > easier to copy a digital transmission because we can do aggressive > forward error correction and easily repeat transmissions many times. > > It's frustrating to be able to hear that there's *some* voice without > understanding the words. Also talking to people is horrible even under > ideal circumstances. > > > I'd assume this would be simplex only, which has in fact been by far the > > most reliable over the few small-area (< 3 miles) urban nets I attended > > recently. If we could get up to a 10 mile range somehow with some clever > > digital processing, I'd think that would be very useful indeed for us > > canyon-dwellers - do you think that might be possible? > > We could have digipeaters. That alone would help a lot. A 2m or 70cm FM > voice repeater is a big hassle to move around and set up. With a $50 > digipeater we could just plant them in various locations in the field > and cross our fingers that they won't get stolen - and it won't be a > huge deal if they are. > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Radio mailing list > [email protected] > https://list.hackmanhattan.com/listinfo/radio > > > ------------------------------ > > End of Radio Digest, Vol 11, Issue 13 > ************************************* > -- Norm Sutaria (646)580-9749 [email protected]
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