Transmitter steering
I assumed that transmitter steering with app_rpt and RTCM would be well supported, but I'm not finding anything relevant with Google. Is anyone out there doing transmitter steering with app_rpt? How do you do it? Tom KD7LXL
Not sure what you mean by transmitter steering? On Jul 20, 2015 1:09 PM, "Tom Hayward" <tom@tomh.us> wrote:
I assumed that transmitter steering with app_rpt and RTCM would be well supported, but I'm not finding anything relevant with Google. Is anyone out there doing transmitter steering with app_rpt? How do you do it?
Tom KD7LXL _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
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Hi Tom, Do you mean for a multi-site system, steering the activated transmitter to the site where the loudest received signal originates from??? If so, isn't that more applicable for scenarios where you've got a central dispatch center and have clients (cars, etc.) only calling the dispatch? For ham applications, I'd think you'd want to blanket the whole region with a transmitted signal (basically simulcast)? OR, do you mean channel steering (frequency agility) for a given transmitter? 73, David KB4FXC On Mon, 20 Jul 2015, Tom Hayward wrote:
I assumed that transmitter steering with app_rpt and RTCM would be well supported, but I'm not finding anything relevant with Google. Is anyone out there doing transmitter steering with app_rpt? How do you do it?
Tom KD7LXL _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
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On Mon, Jul 20, 2015 at 10:54 AM, Sam Nabkey <sam.nabkey@gmail.com> wrote:
Not sure what you mean by transmitter steering?
Sam, Transmitter steering uses voted receivers to choose the best (single) transmitter. Here is a good explanation: http://www.signalharbor.com/ttt/00oct/ More below... On Mon, Jul 20, 2015 at 11:00 AM, David McGough <kb4fxc@inttek.net> wrote:
Hi Tom,
Do you mean for a multi-site system, steering the activated transmitter to the site where the loudest received signal originates from??? If so, isn't that more applicable for scenarios where you've got a central dispatch center and have clients (cars, etc.) only calling the dispatch? For ham applications, I'd think you'd want to blanket the whole region with a transmitted signal (basically simulcast)?
Yes, this is what I mean. You are right that this is not a typical ham application. The primary use of our repeater is in support of search and rescue. Usually, everyone participating in the search will be in the same general area, and therefore only the nearest receiver and transmitter site need be used. It would be advantageous to reuse the same repeater pair at every site, and the same tone, so users don't have to figure out which repeater is best. Currently, our transmitters do not have a timing reference input, nor do we have a fleet of GPSDOs. Simulcast may be a stage two plan, but at this point I'm looking at transmitter steering, since it will satisfy 99% of our use case. Tom KD7LXL
Hi Tom, AllStar nor RTCM's implement this functionality, as far as I know. Honestly, I'm not sure that this type of system would be a good fit for a ham radio repeater system--all it would take is one mischievous Kerchunker to greatly impair the systems operation (by "locking out" all but the site the Kerchunker is closest to). The Kerchunker might not even realize that Emergency Comms were in progress on a distant repeater, which they couldn't hear. Just being curious, what kind of repeaters are you currently running, and how many, over how big an area? 73, David KB4FXC On Mon, 20 Jul 2015, Tom Hayward wrote:
On Mon, Jul 20, 2015 at 10:54 AM, Sam Nabkey <sam.nabkey@gmail.com> wrote:
Not sure what you mean by transmitter steering?
Sam,
Transmitter steering uses voted receivers to choose the best (single) transmitter. Here is a good explanation: http://www.signalharbor.com/ttt/00oct/
More below...
On Mon, Jul 20, 2015 at 11:00 AM, David McGough <kb4fxc@inttek.net> wrote:
Hi Tom,
Do you mean for a multi-site system, steering the activated transmitter to the site where the loudest received signal originates from??? If so, isn't that more applicable for scenarios where you've got a central dispatch center and have clients (cars, etc.) only calling the dispatch? For ham applications, I'd think you'd want to blanket the whole region with a transmitted signal (basically simulcast)?
Yes, this is what I mean. You are right that this is not a typical ham application. The primary use of our repeater is in support of search and rescue. Usually, everyone participating in the search will be in the same general area, and therefore only the nearest receiver and transmitter site need be used. It would be advantageous to reuse the same repeater pair at every site, and the same tone, so users don't have to figure out which repeater is best. Currently, our transmitters do not have a timing reference input, nor do we have a fleet of GPSDOs. Simulcast may be a stage two plan, but at this point I'm looking at transmitter steering, since it will satisfy 99% of our use case.
Tom KD7LXL
On Mon, Jul 20, 2015 at 12:54 PM, David McGough <kb4fxc@inttek.net> wrote:
Hi Tom,
AllStar nor RTCM's implement this functionality, as far as I know.
It's not a terribly complex operation, just activating a single transmitter instead of many. Maybe this configuration could be adapted: http://ohnosec.org/pipermail/app_rpt-users/2015-April/011662.html
Honestly, I'm not sure that this type of system would be a good fit for a ham radio repeater system--all it would take is one mischievous Kerchunker to greatly impair the systems operation (by "locking out" all but the site the Kerchunker is closest to). The Kerchunker might not even realize that Emergency Comms were in progress on a distant repeater, which they couldn't hear.
Just being curious, what kind of repeaters are you currently running, and how many, over how big an area?
We have a few homebrew repeaters with S-COM 7330 controllers. The transmitters and receivers are various from Motorola and Kenwood. We would standardize on just one model before implementing voting. We'd probably eliminate the 7330 too, in favor of just RTCMs and app_rpt. We'd like to serve a ring around Mt. Rainier. The area is mostly wilderness with no inhabitance and deep valleys. There would be almost no overlap between transmitters--just at the tops of ridges. Many similar systems in the region use a different tone for each repeater. We could do it this way, but I'd prefer to let a computer make the decision about which site is best. Tom KD7LXL
Given that the repeaters don't overlap you might benefit to setup simulcast even though you're not syncing the transmitters. Anywhere you do have overlap, like on the ridge tops, you're going to get out of sync signals but I'm guessing that is a low percentage of coverage area. If you could get one transmitter to capture your receiver, even just a little, you should have mostly intelligible reception at those locations. Maybe walking down from the ridge top a little ways. Alternatively, do you have a location that can cover all the ridge tops? Use a different transmit frequency to cover those spots that the psuedo-simulcast causes interference at. Instead of the many different channels you would end up programming and using with separate input tones, you would now have only two, the main channel and the secondary transmitter channel. The receiver at this alternate site could be the same frequency and voted, or just have transmit only since the other voted receivers would be providing coverage. -------- Those commands in your linked message look to be easily scripted from an external control script. I haven't played with the RTCM's yet but can you somehow see which site is being voted from the command line? Doesn't AllMon do this? If so it should be relatively easy to watch the voted sites and pick the appropriate transmitter. Might need a little special logic built-in. Brett KQ9N On Mon, Jul 20, 2015 at 3:46 PM, Tom Hayward <tom@tomh.us> wrote:
On Mon, Jul 20, 2015 at 12:54 PM, David McGough <kb4fxc@inttek.net> wrote:
Hi Tom,
AllStar nor RTCM's implement this functionality, as far as I know.
It's not a terribly complex operation, just activating a single transmitter instead of many. Maybe this configuration could be adapted: http://ohnosec.org/pipermail/app_rpt-users/2015-April/011662.html
Honestly, I'm not sure that this type of system would be a good fit for a ham radio repeater system--all it would take is one mischievous Kerchunker to greatly impair the systems operation (by "locking out" all but the site the Kerchunker is closest to). The Kerchunker might not even realize that Emergency Comms were in progress on a distant repeater, which they couldn't hear.
Just being curious, what kind of repeaters are you currently running, and how many, over how big an area?
We have a few homebrew repeaters with S-COM 7330 controllers. The transmitters and receivers are various from Motorola and Kenwood. We would standardize on just one model before implementing voting. We'd probably eliminate the 7330 too, in favor of just RTCMs and app_rpt.
We'd like to serve a ring around Mt. Rainier. The area is mostly wilderness with no inhabitance and deep valleys. There would be almost no overlap between transmitters--just at the tops of ridges.
Many similar systems in the region use a different tone for each repeater. We could do it this way, but I'd prefer to let a computer make the decision about which site is best.
Tom KD7LXL _______________________________________________ App_rpt-users mailing list App_rpt-users@ohnosec.org http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
To unsubscribe from this list please visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users and scroll down to the bottom of the page. Enter your email address and press the "Unsubscribe or edit options button" You do not need a password to unsubscribe, you can do it via email confirmation. If you have trouble unsubscribing, please send a message to the list detailing the problem.
participants (4)
-
Brett Friermood -
David McGough -
Sam Nabkey -
Tom Hayward