While I applaud Ron's experiments, it would have a very long road to becoming something practical for the masses. Heck I can say the same for the NWDigital radio. They have been trying for quite some time to make the thing happen. I fear by the time either would come to fruition, the whole market / tech landscape could be different. (I.e, 56k is not as appealing at the price point as it was 10 years ago when they started, etc)
As for the ARRL, I am the only one who pounces on their staff virtually every chance I get (at ham fests and by email), about getting some of these changes though their heads? I think a coordinated approach, can help our cause. In addition, anyone can make comment directly to the FCC. How seriously they take things without someone waving money in their face is a whole another issue.
I wrote this paper quite some time ago, that covers quite a few of the issues: http://www.qsl.net/kb9mwr/projects/wireless/70cm-ATV-HSMM.html
Basically they way I see it, one has three ways to experiment: 1.) Pay for/file for a STA, which gives you 6 months 2.) Include some element of image transfer, so what your doing can be classified as an image transmission rather than data. (most logical/easiest to do) 3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide.
#3 is something I joked with friends about when I was in high school. That was long before SDR, so we envisioned taking a few TNC's and radio's on different frequencies, RF combiners and tons of filters to make it actually work, and from there channel bond/load balance all the data streams to achieve better throughput.
Do we have anyone who holds a ARRL position on this list?
Steve, KB9MWR
Mark Phillips <g7ltt at g7ltt.com> wrote:
"Maybe someone at ARRL ...."
Ha! Funny.
It's been many folks' experience that the ARRL does nothing that is not in its own interest. Unless they can be persuaded that XYZ technology is good for them and Ham Radio they won't lift a finger. It should also be noted that the ARRL speaks for less than 20% of the US ham population (see membership figures posted in QRZ). We are 700K+ hams here in the US. ARRL has less than 100K members. That said, they are the only group able to engage the FCC and push for changes etc. It's an expensive proposition!
"3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide."
We have that already. That's kinda how OFDM and COFDM work but with smaller bandwidth carriers. Indeed, many of the HF sound card data modes work that way too. So if someone with clever programming skills can work out how to bodge up PSK256K and shove it into the back of a Moto SM50 we might be on to a winner.
But there are still some hardware solution out there too that need to be investigated. The CM589 modem chip that D-STAR uses (found in AIS rigs too) can do up to 256K. Why have we not got an Arduino based modem that accepts this chip and allows us different speeds? I've also asked the MMDVM crowd to look at converting their modem stuff to higher speed packet (they said "what's packet?").
I'm full of ideas but lack any skills to implement anything.
On Sat, Sep 2, 2017 at 9:50 AM, Steve L kb9mwr@gmail.com wrote:
While I applaud Ron's experiments, it would have a very long road to becoming something practical for the masses. Heck I can say the same for the NWDigital radio. They have been trying for quite some time to make the thing happen. I fear by the time either would come to fruition, the whole market / tech landscape could be different. (I.e, 56k is not as appealing at the price point as it was 10 years ago when they started, etc)
As for the ARRL, I am the only one who pounces on their staff virtually every chance I get (at ham fests and by email), about getting some of these changes though their heads? I think a coordinated approach, can help our cause. In addition, anyone can make comment directly to the FCC. How seriously they take things without someone waving money in their face is a whole another issue.
I wrote this paper quite some time ago, that covers quite a few of the issues: http://www.qsl.net/kb9mwr/projects/wireless/70cm-ATV-HSMM.html
Basically they way I see it, one has three ways to experiment: 1.) Pay for/file for a STA, which gives you 6 months 2.) Include some element of image transfer, so what your doing can be classified as an image transmission rather than data. (most logical/easiest to do) 3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide.
#3 is something I joked with friends about when I was in high school. That was long before SDR, so we envisioned taking a few TNC's and radio's on different frequencies, RF combiners and tons of filters to make it actually work, and from there channel bond/load balance all the data streams to achieve better throughput.
Do we have anyone who holds a ARRL position on this list?
Steve, KB9MWR
Mark Phillips <g7ltt at g7ltt.com> wrote:
"Maybe someone at ARRL ...."
Ha! Funny.
It's been many folks' experience that the ARRL does nothing that is not in its own interest. Unless they can be persuaded that XYZ technology is good for them and Ham Radio they won't lift a finger. It should also be noted that the ARRL speaks for less than 20% of the US ham population (see membership figures posted in QRZ). We are 700K+ hams here in the US. ARRL has less than 100K members. That said, they are the only group able to engage the FCC and push for changes etc. It's an expensive proposition!
44Net mailing list 44Net@hamradio.ucsd.edu http://hamradio.ucsd.edu/mailman/listinfo/44net
Oh, and don't get me started on a "proper" KISS implementation on those so-called APRS "TNC's". I am now into my 9th different one and they all have the same issue - no large packets.
On Sat, Sep 2, 2017 at 10:16 AM, Mark Phillips g7ltt@g7ltt.com wrote:
"3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide."
We have that already. That's kinda how OFDM and COFDM work but with smaller bandwidth carriers. Indeed, many of the HF sound card data modes work that way too. So if someone with clever programming skills can work out how to bodge up PSK256K and shove it into the back of a Moto SM50 we might be on to a winner.
But there are still some hardware solution out there too that need to be investigated. The CM589 modem chip that D-STAR uses (found in AIS rigs too) can do up to 256K. Why have we not got an Arduino based modem that accepts this chip and allows us different speeds? I've also asked the MMDVM crowd to look at converting their modem stuff to higher speed packet (they said "what's packet?").
I'm full of ideas but lack any skills to implement anything.
On Sat, Sep 2, 2017 at 9:50 AM, Steve L kb9mwr@gmail.com wrote:
While I applaud Ron's experiments, it would have a very long road to becoming something practical for the masses. Heck I can say the same for the NWDigital radio. They have been trying for quite some time to make the thing happen. I fear by the time either would come to fruition, the whole market / tech landscape could be different. (I.e, 56k is not as appealing at the price point as it was 10 years ago when they started, etc)
As for the ARRL, I am the only one who pounces on their staff virtually every chance I get (at ham fests and by email), about getting some of these changes though their heads? I think a coordinated approach, can help our cause. In addition, anyone can make comment directly to the FCC. How seriously they take things without someone waving money in their face is a whole another issue.
I wrote this paper quite some time ago, that covers quite a few of the issues: http://www.qsl.net/kb9mwr/projects/wireless/70cm-ATV-HSMM.html
Basically they way I see it, one has three ways to experiment: 1.) Pay for/file for a STA, which gives you 6 months 2.) Include some element of image transfer, so what your doing can be classified as an image transmission rather than data. (most logical/easiest to do) 3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide.
#3 is something I joked with friends about when I was in high school. That was long before SDR, so we envisioned taking a few TNC's and radio's on different frequencies, RF combiners and tons of filters to make it actually work, and from there channel bond/load balance all the data streams to achieve better throughput.
Do we have anyone who holds a ARRL position on this list?
Steve, KB9MWR
Mark Phillips <g7ltt at g7ltt.com> wrote:
"Maybe someone at ARRL ...."
Ha! Funny.
It's been many folks' experience that the ARRL does nothing that is not
in
its own interest. Unless they can be persuaded that XYZ technology is
good
for them and Ham Radio they won't lift a finger. It should also be noted that the ARRL speaks for less than 20% of the US ham population (see membership figures posted in QRZ). We are 700K+ hams here in the US. ARRL has less than 100K members. That said, they are the only group able to engage the FCC and push for changes etc. It's an expensive proposition!
44Net mailing list 44Net@hamradio.ucsd.edu http://hamradio.ucsd.edu/mailman/listinfo/44net
Tony
On Sep 2, 2017, at 04:16, Mark Phillips g7ltt@g7ltt.com wrote:
"3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide."
We have that already. That's kinda how OFDM and COFDM work but with smaller bandwidth carriers. Indeed, many of the HF sound card data modes work that way too. So if someone with clever programming skills can work out how to bodge up PSK256K and shove it into the back of a Moto SM50 we might be on to a winner.
But there are still some hardware solution out there too that need to be investigated. The CM589 modem chip that D-STAR uses (found in AIS rigs too) can do up to 256K. Why have we not got an Arduino based modem that accepts this chip and allows us different speeds? I've also asked the MMDVM crowd to look at converting their modem stuff to higher speed packet (they said "what's packet?").
I'm full of ideas but lack any skills to implement anything.
On Sat, Sep 2, 2017 at 9:50 AM, Steve L kb9mwr@gmail.com wrote:
While I applaud Ron's experiments, it would have a very long road to becoming something practical for the masses. Heck I can say the same for the NWDigital radio. They have been trying for quite some time to make the thing happen. I fear by the time either would come to fruition, the whole market / tech landscape could be different. (I.e, 56k is not as appealing at the price point as it was 10 years ago when they started, etc)
As for the ARRL, I am the only one who pounces on their staff virtually every chance I get (at ham fests and by email), about getting some of these changes though their heads? I think a coordinated approach, can help our cause. In addition, anyone can make comment directly to the FCC. How seriously they take things without someone waving money in their face is a whole another issue.
I wrote this paper quite some time ago, that covers quite a few of the issues: http://www.qsl.net/kb9mwr/projects/wireless/70cm-ATV-HSMM.html
Basically they way I see it, one has three ways to experiment: 1.) Pay for/file for a STA, which gives you 6 months 2.) Include some element of image transfer, so what your doing can be classified as an image transmission rather than data. (most logical/easiest to do) 3.) Develop a data mode that uses multiple carriers, as each carrier can be 100 KHz wide.
#3 is something I joked with friends about when I was in high school. That was long before SDR, so we envisioned taking a few TNC's and radio's on different frequencies, RF combiners and tons of filters to make it actually work, and from there channel bond/load balance all the data streams to achieve better throughput.
Do we have anyone who holds a ARRL position on this list?
Steve, KB9MWR
Mark Phillips <g7ltt at g7ltt.com> wrote:
"Maybe someone at ARRL ...."
Ha! Funny.
It's been many folks' experience that the ARRL does nothing that is not in its own interest. Unless they can be persuaded that XYZ technology is good for them and Ham Radio they won't lift a finger. It should also be noted that the ARRL speaks for less than 20% of the US ham population (see membership figures posted in QRZ). We are 700K+ hams here in the US. ARRL has less than 100K members. That said, they are the only group able to engage the FCC and push for changes etc. It's an expensive proposition!
44Net mailing list 44Net@hamradio.ucsd.edu http://hamradio.ucsd.edu/mailman/listinfo/44net
With regards to this mode, I collected a stack of 20 or so evolution 3 idirect satellite modems that output in the 950 megahertz range up to 2gig with intent to mod with a transverter or lnb/a for ham use. They put out -35dbm from what I read and I have located the software to mod these to use for ham. These use dvb s2 modulation from what I remember. They also feature full routing and a Linux kernel built in. Also do both transmit and receive.
All the modems were working pulls and should be easy to mod. Not sure if this would solve the issues of expensive hardware as these are bound for trash in most satellite operations due to newer tech coming out and go for sub 100usd on eBay.
I have made two talk in bridge mode across coax with attenuators. Substitute coax for transverter and feed horns and I think a point to point solution is easy.
I have not started to experiment more but was able to link at 20mbits. In scpc mode and transfer data.
The modems are small and self contained as well.
Anyone wanting to experiment I will gladly share the info I found on these. Or even share the hardware for the good of experimentation.
Qpsk, tdma, and ofdm are some modes they do and while encryption is an option, it can be turned off completely.
Spec sheet: http://www.idirect.net/~/media/Files/Spec%20Sheets/iDirect-SPEC-SHEET-Evolut...
Best Regards,
Elias Basse KD5JFE
Sent from my iPhone
While I applaud Ron's experiments, it would have a very long road to becoming something practical for the masses. Heck I can say the same for the NWDigital radio. They have been trying for quite some time to make the thing happen. I fear by the time either would come to fruition, the whole market / tech landscape could be different. (I.e, 56k is not as appealing at the price point as it was 10 years ago when they started, etc)
I'm all for working on FCC rule changes. History shows that if you go to them with a real problem and a real solution, they will bend. In other words, let's get a viable commercial product out there that hams can use throughout the US. In other words, demonstrate that there's a need for more than just a few experimenters. Until then, it's just an academic exercise.
Here in Silicon Valley, a "medium" speed data radio would have far wider appeal (and sell far more units) than a high speed streaming radio. It would be a much more compelling use case because far more people could make use of it.
GHz frequencies and Mbps speeds suffer from line of sight and multi-path problems. With so many locations around here surrounded by trees and or other buildings, it's a problem. Case in point: we had to move a packet system out of a 2-story building with a 30 foot tower on the roof. Due to trees in some directions and new apartment buildings in another, it had no line of sight to any of the surrounding mountains! Most locations here in the valley have a similar problem.
A lower bandwidth radio on UHF (70cm) would provide much better coverage, allowing many (,many) more people to participate.
Case in point: We have lots of packet users -- many, many times more than we have WiFi or mesh users. (User group of 230, with 30-50 active weekly). Because it's on VHF, it works from virtually anywhere with just a roll-up J-pole. And, because we have a packet-to-email gateway, it provides a relevant, useful service from literally anywhere in the county (and beyond). But it's obviously very limited in functionality due to 1200/9600 baud. Plain text only, no attachments -- not because we can't, but because it's just too slow for that.
Those same people and locations could benefit greatly from a 56k to 128k radio on 70 cm. It provides enough speed to allow functional IP connectivity for mass appeal applications like standard e-mail (standard POP/SMTP clients, rich text formatting, reasonable-sized attachments), while maintaining close to ubiquitous coverage. It's a ubiquitous application with near ubiquitous coverage. That equates to many more radios sold.
And, most important, it would be an viable solution that could be run at 56K under the current rules and then used as a proof point to the FCC that the rules need changing. Then, turn up the speed when the rules are changed.
That's why I've been excited for the NWDigital UDRX radio. But ... well ... They say they're still working on it. But that story grows less and less believable each passing month and year.
Michael N6MEF
A couple of decades ago, the "GRAPES" WA4DSY 56kbit modem kit was available for a moderate price. They weren't too difficult to put together. Alignment did take a scope, but took only a few minutes. About five people in San Diego had them. As far as I know, only three ever made it onto the air here.
It generated and received at 29 MHz, and you used an off-the-shelf transverter to put it on whatever band you wanted to actually use -- in my case, 70cm. We operated them on 433.05 MHz to put them in the (barely)-suppresed lower sideband of the ATV folks on 434 MHz. You talked to it with KA9Q NOS. Once you got the multipath problems worked out, it worked rather well when the military radar wasn't eating the band.
There's an archive page for the device at http://www.wa4dsy.net/rfmodem.html if you want to know more about it.
But you had to build it. It didn't come all put together in a cardboard box. You couldn't just buy one, some coax, and an antenna and put it on the air.
I built two of them. We put one up on at our repeater site on a 3500 ft mountain, hooked to a very sophisticated multiport packet controller, which also had 9600, 4800, and 1200 bps ports, on 70cm (439.05), 6m, and 2m. I tried to get an internet connection working on the 56k port via UCSD, but the 70cm multipath problems smeared the symbols enough that it never really worked. Eventually I turned my interest to other things.
A few years later, when the controller succumbed to an excessive accumulation of rat urine, no one noticed it wasn't there for months because the 1200 bps digipeater function still worked. Eventually it all went to the metal recyclers.
Perhaps I'm wrong, but I don't believe there is any future for a 70cm 56kb radio in the ham market. It's too slow and too-range-limited to be interesting. The only people I can see who would buy them are foreign military and government users. - Brian
On Saturday, September 2, 2017 9:21:45 AM PDT Brian Kantor wrote:
A couple of decades ago, the "GRAPES" WA4DSY 56kbit modem kit was available for a moderate price. They weren't too difficult to put together. Alignment did take a scope, but took only a few minutes. About five people in San Diego had them. As far as I know, only three ever made it onto the air here.
The problem with the GRAPES modem was cost, the kit was reasonable but add in all the other pieces and it was more than many of us could afford.
We had a few GRAPES modems here in the Pacific Northwest but very few ever made it on the air.
We did have a dedicated 56k link over an 80 mile path between Camano Island north of Seattle and a 56k repeater on Mount Seymour in British Columbia. The repeater and the link radio used a 56k modem designed by Dennis, AC7FT (then VE7BPE). It was compatible with GRAPES but was a completely separate design.
That link provided additional connectivity for the 1200/9600 IP network in central Puget Sound for several years and was reasonably reliable.
Those were fun times
The modems in Vancouver were GRAPES modems, but may have come from a different supplier, and they were fully built rather than kits. Dennis designed a new transverter and power amplifier to connect to the modem.
The repeater on Mount Seymour (at the CBC television transmitter site) was linked to the Internet using 900 MHz radios across Burrard Inlet to Simon Fraser University on Burnaby Mountain (where I worked at the time). I had a station up the Fraser Valley in Maple Ridge, and although I did not have line of sight, it worked just fine bouncing off a nearby mountain. Dennis had a station in Chilliwack, and there was another repeater at the Industry Canada (Canadian version of the FCC) monitoring station near there. As to mobile - Dennis put a station in his car, and had good connectivity and speed driving in from Chilliwack to Vancouver (about 30 miles).
I'd say that the GRAPES modems did well in both mobile and multipath situations.
Dennis' radio and duplexer designs were so clean that Industry Canada let us put the antenna for the repeater at the top of their tower - they said that they had never measured *commercial* equipment that clean. 70 cm was like DC to Dennis - his commercial work went up into the tens of GHz. :-)
- Richard, VE7CVS
On 9/2/2017 10:17 AM, Ken Koster wrote:
The problem with the GRAPES modem was cost, the kit was reasonable but add in all the other pieces and it was more than many of us could afford.
We had a few GRAPES modems here in the Pacific Northwest but very few ever made it on the air.
We did have a dedicated 56k link over an 80 mile path between Camano Island north of Seattle and a 56k repeater on Mount Seymour in British Columbia. The repeater and the link radio used a 56k modem designed by Dennis, AC7FT (then VE7BPE). It was compatible with GRAPES but was a completely separate design.
That link provided additional connectivity for the 1200/9600 IP network in central Puget Sound for several years and was reasonably reliable.
Those were fun times
Perhaps I'm wrong, but I don't believe there is any future for a 70cm 56kb radio in the ham market.
- Brian
I think you're wrong. Well, actually, I know it! ;-)
Very few, if any, hams that I know would have any interest in the kit you mentioned. Including me. Far too much work. Too costly. Far too complicated for the average one-day ham-cram technician-class, appliance operator ham. So even if a few might be willing to do the work to put those at the "server" location(s), you won't have many/any? "clients".
In contrast, we've had about 30 or so folks waiting for an appliance-like device, such as the NWD UDRX. Probably more over time. And that's just ones that I know about in this one county. Why? Because it would provide a practical solution to a very real problem - how to get modern messaging connectivity for the appliance-operator ham. Because their price-point was about the price of a dual-band mobile - very reasonable. And because, as I mentioned earlier, faster/higher frequency just isn't an option for most of those people due to line of sight problems.
Michael N6MEF
On Sat, Sep 02, 2017 at 10:21:04AM -0700, Michael Fox - N6MEF wrote:
about the price of a dual-band mobile - very reasonable. And because, as I mentioned earlier, faster/higher frequency just isn't an option for most of those people due to line of sight problems.
Unless they've come up with a modulation scheme which overcomes the multipath distortion of transmitted symbols, I believe line of sight is practically a necessity.
But I'll be the first to admit that my communications theory knowledge is now many decades old. Perhaps there is a way around it. - Brian
Unless they've come up with a modulation scheme which overcomes the multipath distortion of transmitted symbols, I believe line of sight is practically a necessity.
Hmmm, I don't think so -- at least not in the strict sense used for microwave. A proper line of sight would certainly reduce both attenuation and multi-path. Both are a problem at microwave frequencies. Which is why n*GHz radios won't sell many units to the average ham at home.
But UHF has the advantage of not being hampered so much by attenuation from trees and the like. That's why it's attractive for us, even if the bandwidth is lower. And, UHF multi-path isn't as much of a problem as for GHz, but still more of a problem than at VHF. So it will work will without clear line of sight, but not from all the places that VHF packet would work. FEC will be essential.
As for new modulation schemes: I believe NWD was going to be using a chipset from a commercial data radio (I don't know the details). The "not reinventing the wheel" approach sounded good to us, because we pride ourselves in our uptime/availability for EmComm use. But one would also hope that the radio would be capable of software upgrades to modulation schemes as well. That would be attractive to those who are into experimentation.
Bottom line: Many projects fail because they focus on speed or some other esoteric means to an end, but not on the end itself -- the application. And without an application, there are no users. And without lots of users, the idea will die. So we don't look at a potential 56k-100k UHF radio as much slower than microwave and narrower coverage than VHF packet. We look at it as way to carry what is probably the most ubiquitous application in the world today: e-mail. And, by the way, it happens to have MUCH, MUCH broader coverage than microwave (the ONLY possible coverage for many), AND be MUCH, MUCH faster and more feature rich than packet.
Michael N6MEF
OFDM is about as good as it gets with regards to multipath. Right now to reduce latency, I'm using the 4K carrier mode (3409 active carriers) which has a symbol duration of 448 microseconds (in 8 MHz bandwidth). That means a reflection from less than 134 km away will be in the same symbol.
DVB-T2 has six carrier modes. 1K, 2K, 4K, 8K, 16K and 32K. 1K is used for high Doppler applications (mobile) and 32K is used for high multipath. Almost all DVB-T2 television transmitters in Europe and Asia use the 16K or 32K mode. The BBC uses 32K for their multiplexes in the UK.
The new proposed US digital TV standard, ATSC 3.0, is almost identical to DVB-T2. It's basically DVB-T2 with some tweaks added to get another dB of S/N performance.
Ron W6RZ
On 09/02/2017 10:29 AM, Brian Kantor wrote:
Unless they've come up with a modulation scheme which overcomes the multipath distortion of transmitted symbols, I believe line of sight is practically a necessity.
But I'll be the first to admit that my communications theory knowledge is now many decades old. Perhaps there is a way around it.
- Brian
Regarding 56k+ on UHF it can be done, at east commercially. I worked for DataRadio which was owned by Bob Rouleau VE2PY; and Norm Pearl VE2BQS of the Montreal Packet Net originators of ham radio packet. When I worked there in 2000 we were implementing 56k on UHF using parallel decode technology that used 3 Z80 processors in the radio. I installed a system in MT and conducted drive testing in a police car at speeds up to 108mph (guaranteed to 80mph but you tell the guy with the gun to slow down). It worked with few dropped packets even in areas where multi path was a problem on their voice systems. I don't know what they had going on in the DSP and the parallel decode it was all kept very much from us in the Atlanta office, however it almost seemed to like the multi-path exceeding the coverage plots generated by the very expensive software predicted.
The radios were manufactured in WI (they were dumb radios at this point with no firmware to speak of. The radios were then shipped to DataRadio Canada for DSP and firmware loading then shipped back to DataRadio in Atlanta for distribution to the specific customer. (not shure but I think there was some sort of tax advantage to this process or they must not have wanted the DSP process that was radio specific to go out to the US companies. We then built the base stations (Tait repeaters with 2 RX units and a DataRadio Base controller) and shipped them to the local installer. One of the engineers would show up for testing after the first 10 cars were installed as well as the base stations. If you see one of these radios for cheep on Ebay or at a ham fest it is likely 800mhz, but pick one up just for disection. They will be labeled Gemini PD, or PD+ I would love to look at the code for what all they were doing with Z80 processors.
http://www.amateurradio.com/upcoming-37th-anniversary-of-packet-radio/
Lin N4YCI
Regarding 56k+ on UHF it can be done, at east commercially. I worked for DataRadio ...
Lin N4YCI
Wow. Thanks for this info Lin!!! (Especially the part about the ability to deal with multi-path at 80 MPH!)
It looks like DataRadio has been purchased by CalAmp, which now offers the Gemini G3-UHF.
http://www.calamp.com/products/private-radios-narrow-band-equipment/private- mobile-networks/gemini-g3-uhf
I just called and left a message requesting more info.
Michael N6MEF
Michael, Big money, but the history is very interesting. I am guessing the new stuff is even better, but in reality LTE is going to work much faster and better especially now that the channels have gone to 12.5khz.
Lin
On Wed, Sep 6, 2017 at 2:11 PM, Michael Fox - N6MEF n6mef@mefox.org wrote:
Regarding 56k+ on UHF it can be done, at east commercially. I worked for DataRadio ...
Lin N4YCI
Wow. Thanks for this info Lin!!! (Especially the part about the ability to deal with multi-path at 80 MPH!)
It looks like DataRadio has been purchased by CalAmp, which now offers the Gemini G3-UHF.
http://www.calamp.com/products/private-radios- narrow-band-equipment/private- mobile-networks/gemini-g3-uhf
I just called and left a message requesting more info.
Michael N6MEF
44Net mailing list 44Net@hamradio.ucsd.edu http://hamradio.ucsd.edu/mailman/listinfo/44net
Big money, but the history is very interesting. I am guessing the new stuff is even better, but in reality LTE is going to work much faster and better especially now that the channels have gone to 12.5khz.
Lin
Yeah, when I saw the police application, I figured the price would be high.
It will be interesting to see if there's a way to fit them into a ham radio application.
M
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Antonio Querubin -
Brian Kantor -
Elias Basse -
Ken Koster -
Lin Holcomb -
Mark Phillips -
Michael Fox - N6MEF -
Richard Chycoski -
Ron Economos -
Steve L