GPS->Computer/OziExplorer->APRS/2m

[WhiteThaiGer]

Time to study this issue of transmitting the current position via 2m between vehicles. It would have come in handy on our recent Pinacate trip when we had 2 groups travelling a few miles apart, each group had one GPS/OziExplorer setup. To find out where the others were we had to describe our position verbally. Do we live in the stone age? This kind of thing should happen at the push of a button. So I started to browse the net a little.

Maybe some of you here know some thing about one the required components, etc. Please share. Here is what I have so far:

Basic setup: GPS->Computer with OziExplorer-> TNC or soundcard interface ->TNC/mic switch -> 2m radio

There seem to be at least 2 ways to connect the computer to the radio the: TNC (Terminal Node Controller) or an interface cable that uses the soundcard of the computer. With most of our radios we then have to connect to the mic terminal, i.e. only one can be connected at a time, that's where the TNC/mic switch comes in.

Some sites with info:
http://www.qsl.net/soundcardpacket/
http://www.packetradio.com/psk31.htm

There is a utility for Ozi: OziAPRS, still have to check what exactly it does and if it would work for us:
http://www.radio-active.net.au/web/gpsaprs/oziaprs.html

There are some intriguing possiblities. We need to have something like this http://www.4wdtrips.net/forum/emoticons/cool.gif


***************************************
http://www.confluence.org
http://www.usgo.org


Post Edited (WhiteThaiGer) : 2/21/2004 5:07:39 AM GMT

[alanh]

This is cool stuff, and I don't even have a ham radio! I did try a sample license exam a few days ago and managed to pass it without any studying though. Iused a little of what I remember from getting my EE degree years ago and guessed at a few. If I'm not careful I'll have another project on my list to add to all the other unfinished projects.</div>
This is a good site http://www.aprs.net/. You can select an area, zoom in,and see the positions of ham operators with APRS - in real time apparently since I see some moving. The link to the APRS virtual meeting looks like a good one to check out although some of the links on that page are broken.</div>
Fromthe checking I've done, there are also a few radios thathave the TNC built in.</div>
With a dedicated position transmitter and a stealthy install, APRSmight help locate a vehicle if its ever stolen too as long as they didn't remove the antenna used for the transmitter. I thinkthere is a handheld unit that has the TNC so all you need is the GPS and an antenna connection fora standalone system.There wouldn't be enough power out in the boonies, but around a city with repeaters,the signal would probably be picked up.</div>

Alan

[JackSilb]

Uwe,

This is something to support the Computer in 4WD project.
Sorry, I can't add much here now. I will be back.

-JACK


So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[BajaTaco]

I think this could be EXTREMELY helpful, and very cool too http://www.4wdtrips.net/forum/emoticons/cool.gif

Unfortunately, I have no time to devote to the subject. But I will certainly watch the progress from the sidelines for a while (kind of like the 4wd on-board computer)


http://www.bajataco.com

[JimWasson]

There is a new compactflash GPS from Garmin for PocketPCs:

Story is at --> http://www.brighthand.com/article/Garmin_cf_Que_for_Pocket_PC_Unveiled?site=PPC

The Garmin website for it is at --> http://www.garmin.com/products/cfQue/

Jack, do you have one yet?

Activated links - WhiteThaiger

Post Edited By Moderator (WhiteThaiGer) : 5/7/2004 3:38:47 PM GMT

[JackSilb]

Jim my man,

This is nice.
But my new Pocket PCs don't have the slot. I am not sure I can by them for the Ipaq and View Sonic I need.
BUT THIS what I have been waiting for a long time. And the price is right!

Let me read more about it.
Thank you.
-JACK


So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[alanh]

I got a Kenwood TM-D700 radio last weekend with a built-in TNC so it can send and receivethe APRS packets with GPS position. I lashed up a temporary connection to the PC and its displaying positions of a number of stations in WA and British Columbia with a program called WinAPRS as I type this. There are 86 stations reporting their positions.

I'm not sure I how easy I can repeat the setup again though since I haven't taken the time to read the directions any more than absolutely necessary as usual. I think there is some SW out there to make APRS reports work with OziExplorer, so I will have to try that. I haven't tried to transmit a position yet either.

Now all I need (once I get the details worked out) is someone else who has one to go on a trip to see if its of any value or just another gadget to play around with.


Forgot to note this is just by monitoring the APRS frequency of 144.390 MHz. If you monitor that in your area, you should hear the strange noises of the data packets if thereis any activity.

Alan

Post Edited (Alan H.) : 6/17/2004 3:40:02 AM GMT

[BajaTaco]

Alan H. said...
I got a Kenwood TM-D700 radio last weekend with a built-in TNC so it can send and receivethe APRS packets with GPS position. I lashed up a temporary connection to the PC and its displaying positions of a number of stations in WA and British Columbia with a program called WinAPRS as I type this. There are 86 stations reporting their positions.
emoticons/bounce2.gif WOOOHOOO!!! That is great! I think there are a few members who have this capability (I think Uwe is one of them, and he has OziExplorer on a laptop). I think MrS is another.


BAJATACO.COM (http://bajataco.com)

[WhiteThaiGer]

BajaTaco said...



Alan H. said...
I got a Kenwood TM-D700 radio last weekend with a built-in TNC so it can send and receivethe APRS packets with GPS position. I lashed up a temporary connection to the PC and its displaying positions of a number of stations in WA and British Columbia with a program called WinAPRS as I type this. There are 86 stations reporting their positions.
emoticons/bounce2.gif WOOOHOOO!!! That is great! I think there are a few members who have this capability (I think Uwe is one of them, and he has OziExplorer on a laptop). I think MrS is another.




Well, I only have the Ozi part going. What I need:

1) TNC

2) Connection from TNC to notebook

3) software to interface WinAPRS (or similar) to Ozi.

Alan, how did you connect the TNC and notebook?

I really need to get back to this and look into getting all the hardware. I'll have YukonBob to test things.
So maybe you get a chance to test your setup when you come down here in October.[/quote]



***************************************
http://www.confluence.org
http://www.usgo.org

[YukonBob]

I'm in. Let's see if we can make it work.

[alanh]

My radio has an RS-232 port that must be similar to what the external TNCs have. I just wired it to the com port of my PC.

There are a couple of ways to get the APRS data to and from the radio and the PC.

External TNC - prices seem to be $150 and up.

Sound card interface - a web search for APRS and sound card will turn up some software that uses the PC sound card - I ran across one site that had some discussion of good and bad sound cards, but don't have the link. I don't know if the average laptop sound card would be considered good or bad.

Either way, you have to connect to the radio.

It may have a data connector meant to hook to a TNC. On the PC, most of the TNCs seem to be RS-232, so you'll need a com port or an RS-232/USB adapter. For sound card, you hook to sound card i/o instead of the TNC. My data port doesn't seem to need a push-to-talk to transmit, but I see that mentioned on one site that talked about sound card interfaces. That may be for cases where there is no data port so you have to hook the mic in and speaker out to your sound card out and in.

For Ozi-Explorer, you need some extra software (not winaprs). There is some out there and I will start looking into that since I have the setup already to provide it data. I'll report back with results when I have some.

I'm not quite sure how you get your own GPS position into the APRS software for the sound card or external TNC methods and in to Ozi at the same time. All the software I've tried complains if you try to connect to a com port already in use, so I don't know how that works. I will see what I can find in the documentation.

I can feed the GPS directly into the radio's internal TNC through a separate connector. I already have an adapter I made thatprovides my GPS outputto two separate RS-232 drivers so I shouldn't have a problemsupplying it tothe PC and radio.




Alan

[WhiteThaiGer]

Thanks Alan. Looks like things are much easier for your radio. On mine I'll have to use the mic input for the link up, i.e. a mic/data switch.


Then there are the serial/USB port issues on how to connect radio and GPS at the same time...


For software.... Ozi has some programming interface, maybe some of the functions provided allow for the GPS data to be passed out.




***************************************
http://www.confluence.org
http://www.usgo.org

[alanh]

I did a bit of experimenting this evening, and have OziExplorer displaying APRS positions. I can't tell exactly where they are because I haven't loaded a local map yet, but its displaying them. There is a program called OziAPRS available here http://radio-active.net.au/web/gpsaprs/oziaprs.htmlthat makes the connection. I downloaded the full install, started both OziExplorer and OziAPRS, executed the "connect to TNC" command under Options in OziAPRS and it starts displaying the APRS stations. I think I need to understand the connect to TNC option a bit better, but at least its progress. As far as I can tell, OziAPRS turns the APRS reports into waypoints.

Now, I have to decide how to proceed. I have an old Dell 233MHz laptop with windows 98. It has one com port, so I can't connect the GPS and the radio at the same time. I can either get an RS-232 to USB adapter for the existing laptop, go the build-it-myself carcomputer route with a VIA CL10000 board that has 4 com ports, or maybe get a newer laptop (which still will need the RS-232 adapter).

Has anyone here used OziExplorer with windows 98? I've only used it on my desktop machine with Windows 2000 for experimenting. In the 4Runner I've used the laptop with ExpertGPS and USAPhotoMaps. ExpertGPSseemed to have problems running very long. It gradually slowed down to the point where it didn't respond to commands well at all and I never successfully stored a track log because it would invariably fail to store or shutdown properly. I suspect it may have a memory leak or some problem caused bythe thousands of small files it uses for an area of any size. IfOziExplorer runs OK on an older machine with Win98, I may pospone the computer upgrade since I've already spent a fair amount this year toys and have a couple more must-haves on the list.

Alan

[BajaTaco]

WoooHOOO!! Alan has the ball rollin' emoticons/yeah.gif


BAJATACO.COM (http://bajataco.com)

[WhiteThaiGer]

Alan, you are way ahead of us here!


I wish I would have looked out for this stuff when I got the radio, i.e. look for the right connectivity features.


Now my notebook is in pieces also, one of the hinges broke and I took it appart to see what can be done. I may have to make some hardware decisions here. It's good to know from your success what works!




***************************************
http://www.confluence.org
http://www.usgo.org

[alanh]

The built-in interface certainly made it easier. The only thing I worry about is that some change to protocols will be made or it doesn't have some minor feature I might want later that an external box might have. TNCs are used for a number of things besides APRS. I guess if that happens, I can always go with and external box or a sound card interface.

I've been wondering what I will do for a base station if I get into the ham radio stuff. I've got a mounting bracket for my radio under the passenger seat, but it won't be real easy to get out to go back and forth. If I get a home radio, it will probably be one without the TNC since I can use my desktop or maybe even dedicate my old/slow laptop to something like that if I upgrade toa better computer for navigation.

Ifanyone wants to try the PC sound card interface, here is a box that should make the job easier. http://www.powerwerx.com/product.asp?ProdID=1947&amp;CtgID=1952

It will take care of the job of making the connections to the radio if you're not into DIY electronics stuff. You can go to http://www.eham.net/reviews/detail/1741for some reviews. Most seem to be positive of those I read except for the one guy who said it smoked his radio. Don't know what happened there, but I guess there is always some risk.

I haven't bought anything like that from Powerwerx, but I got some of the Powerpole connectorsthere and they've sent my stuff without any problems so I think they're reputable.


Alan

[WhiteThaiGer]

I'll have to check that out, looks better than that cable setup that I've found (see link in first post).



***************************************
http://www.confluence.org
http://www.usgo.org

[YukonBob]

[quote]

Alan said...
Has anyone here used OziExplorer with windows 98?

I've used OziExplorer on 233mz Compaq with Windows 98SE for years. Worked fine.

Nice work guys. I haven't taken it all in yet, but I see you have been busy while I have been gone.

[alanh]

Thanks for the report Bob,


I've sent my payment into OziExplorer and hopefully I will give it a try this weekend. Probably won't have APRS and my own position at the same time unless I manage to get an RS-232/USB adapter in the next couple of days (and time is running out), but I'll at least see if Ozi runs for a few hours without problems.


If so, I will put off investing in new computer gear. Icheck the Via site occasionally and they keep coming out with new mini-itx boards and even have some smaller ones out now.


Alan

[YukonBob]

Alan

When on the road, I usually let Ozi run twenty-four hours a day. I think you'll like the amount of information (tracks) that you will be able to store.

I had the same problem with com ports a few years ago. I bought a PCMCIA serial card. I don't know if this will help your situation but I see they are in the fifty dollar range. Here is one example. (http://www.buy.com/retail/product_jump.asp?sku=10352671&amp;SearchEngine=ya&amp;Sear chTerm=10352671&amp;Type=PI&amp;Category=Comp&amp;dcaid=17194)

I still haven't digest all the information that you have posted but I really like the direction.

Thanks

If you are looking for topo maps of Oregon or Washington to use with Ozi, check out the Oregon BLM site (http://www.or.blm.gov/). The FTP site is here. (ftp://ftp.or.blm.gov/gisweb/download)They have done a nice thing by merging the the maps into one degree grids.

[JackSilb]

Alan H. said...
I did a bit of experimenting this evening, and have OziExplorer displaying APRS positions. I can't tell exactly where they are because I haven't loaded a local map yet, but its displaying them. There is a program called OziAPRS available here http://radio-active.net.au/web/gpsaprs/oziaprs.htmlthat makes the connection. I downloaded the full install, started both OziExplorer and OziAPRS, executed the "connect to TNC" command under Options in OziAPRS and it starts displaying the APRS stations. I think I need to understand the connect to TNC option a bit better, but at least its progress. As far as I can tell, OziAPRS turns the APRS reports into waypoints.

Now, I have to decide how to proceed. I have an old Dell 233MHz laptop with windows 98. It has one com port, so I can't connect the GPS and the radio at the same time. I can either get an RS-232 to USB adapter for the existing laptop, go the build-it-myself carcomputer route with a VIA CL10000 board that has 4 com ports, or maybe get a newer laptop (which still will need the RS-232 adapter).

Has anyone here used OziExplorer with windows 98? I've only used it on my desktop machine with Windows 2000 for experimenting. In the 4Runner I've used the laptop with ExpertGPS and USAPhotoMaps. ExpertGPSseemed to have problems running very long. It gradually slowed down to the point where it didn't respond to commands well at all and I never successfully stored a track log because it would invariably fail to store or shutdown properly. I suspect it may have a memory leak or some problem caused bythe thousands of small files it uses for an area of any size. IfOziExplorer runs OK on an older machine with Win98, I may pospone the computer upgrade since I've already spent a fair amount this year toys and have a couple more must-haves on the list.


Good job sir.

What cable did you use to connect to your radio?
Can you talk and still use the APRS deal? Sorry I did not read about the technology yet.
Were you listening to a repeater when you got to see the other folks? Is there a special repeater that is needed to translate the positions or we will be able to do that in simplex?

-JACK




So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[JackSilb]

Did a bit of reading. It seems that the netAPRS software can work as a server and/or client. Cool!
-JACK


So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[JackSilb]

Got an Yeasu cable today. Need to plug the DB9 connector so I can start playing.

-JACK





So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net


Post Edited (JackSilb) : 12/14/2004 11:44:35 PM (GMT-8)

[alanh]

I keep browsing the web for APRS stuffandfound this (http://www.coastalchipworks.com/)site today. The TNC-X he sells looks like a good start at a fairly cheap APRS setup. Its real inexpensive if you're capable of assembling an electronic circuit board, and the assembled version isn't too bad (looks like $85 plus some shipping).

There are some really cheap gadgets out that go between the gps and a radio for transmitting the position, but I haven't seen any that also receive data.This looks like it will do that. The full-featured TNCs I've seen all seem to be pretty expensive for the use most of you would get out of them.

You'd have toconnect the tnc-xto the radio which involves some research and assembly (pretty simple or more difficult depending on whether your radio has a connector for a tnc) and hook it to a pc. The pc would have to have the gps hooked up to it with software to send the position data on to the tnc sincethe TNC-X doesn't have the smarts totake the NMEA input and tx it. I think that Ozi-APRS willdo that, so you wouldn't need another box.

I'm tempted buya kitmyself to add to my ever-growing collection of unfinished projects. I just bought an older model 2m handheld for about $45total incl shippingoff Ebay so I'd have a radio to hook it up to to play with.The radio has 5w output &amp; was made by Maxon and also sold by Radio Shack in the 90s as the HTX-202. I thought the radio might come in handy on a trip some day as a way to keep in touch on foot or even for a spotter to use.

Alan
KE7AXC
2000 4Runner

[JackSilb]

We need to resume this talk.
I got a cable for my radio but nothing done with it yet.
Lets see if this move forward when Uwe comes back from vacation.
-Jack





So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[alanh]

I built the cable I needed to connect my GPS directly to MY TM-D700A transceiver and did some experimenting with the transmit side of APRS today. It took at least 3 times through the APRS setup instructions in the radio programming manual, but I finally got things set correctly so I can transmit the position.

If you go to aprsworld (http://aprsworld.net/) and enter KE7AXC-1 into the individual station under the database search you should see a couple of position entries from this afternoon. I think the database retains them for about 10 days. I wasn't moving, so there isn't any interesting track to follow, but thats my evidence that it was working. Now on to the OziAPRS software to see if I can get the moving map display working on the laptop like I had it on my desk machine a few months ago.

Alan
KE7AXC
2000 4Runner

[alanh]

I've been doing some experimenting with APRS and sound card interfaces and thought I'd report on my results so far.

I have a Kenwood TM-G707 at home that doesn't have a TNC built in, but it does have a data connector. Not all radios have these, but I know the Yaseu FT-8800 does.

I bought an interface box so I didn't have to make the cables and connected the radio to my old laptop. I then got a software utility called AGWPE (see www.soundcardpacket.info (http://www.soundcardpacket.info)).

I already had OziExplorer and OziAPRS loaded. With a little bit of setup, the attached file shows an OziExplorer map of Washington state and the APRS stations that were being reported this morning on the 144.390MHz APRS freq.

I haven't studied this enough to know exactly what goes on, but basically its Radio->soundcard->AGWPE->OziAPRS->OziExplorer.

I haven't tried the transmit side yet. I tried it on my desktop machine, and have not made that work yet either. It came right up on the laptop, so I don't know if there is a sound card issue on the desktop or what.

The interface uses a com port for push-to-talk on transmit, which is a bit of a drawback since there is a limited supply of those on most laptops, but a USB/serial adapter can be used for the GPS interface. The AGWPD software has an option to use a printer port for transmit PTT, so I may see what it takes to create an adapter. Unfortunately, I don't think many laptops have those either.

Alan
KE7AXC
2000 4Runner

[WhiteThaiGer]

Looks like you are making progress. I never get farther than looking into which cables I would need to order.... Then I always see something different or read that it didn't work for some. That's when I get distracted and stop /forum/emoticons/cry.gif I read somewhere about a box that someone used to sell which would send out the position with every transmission. That would be ideal, I don't like the fact that with my current radio I would have to switch between voice and data.



***************************************
http://www.confluence.org
http://www.usgo.org

[JackSilb]

Alan, I was wondering what you were cooking these days. Too quiet.
This is all good progress to one day we have the ultimate goal accomplished.
I am starting to think that having an old dedicated VHF radio will make our life much easier ...
-JACK


So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[alanh]

Jack,

Most of my projects this year have been around the house. I have to try really hard to stay focused on one thing. My list of unfinished house and hobby projects is a mile long.

You may be right about the radio. One could get a radio pretty cheap for APRS use. There are quite a few older used single-band 2m rigs without all the bells and whistles for low prices. But then you'd need another antenna, etc.

I haven't kept real close track of who has what, but I think a significant number of the people on the forum who have 2m radios have single band models. A few with dual-band like the Yaesu FT8800 and as far as I know, one (me) with something like the TM-D700.

I think what would work best here is a device that would transmit APRS on the same frequency as voice comm. The idea would be to transmit a short position report at the end of tx, or after x minutes. I think the data burst can be on the order of 1/2 second or less for a short position report so it probably wouldn't be too objectionable.

There is a group called TAPR (Tucson Amateur Packet Radio) that made a device called the MIC-E that sounds like it would do that if if I remember correctly. The interface was through the microphone connector so you didn't need a data (actually its analog) connector. It was TX only though. I'd have to check to remember if it inhibited transmit if there was RX audio or the mic PTT was pushed, but that would be a must. Unfortunately, they don't make it any more and have another device called the PIC-E which seems to work differently. Its a kit and has a small PIC processor, so one might be able to modify the software and combine that with the sound card for RX.

There is a small USB TNC (see www.elcom.gr/ (http://www.elcom.gr/) ) thats reasonable in price (to me anyway), but I don't know off-hand how one would make it coexist with voice use on the same freq.

Still needs some more work to come with something.

By the way, I've done some studying on the FT8800. It seems to receive independently on one half, but will only transmit data coming in on the data connector if that half of the radio is the 'main' band meaning the one you'd be using for voice. That means you can't use one half for voice and the other for APRS on possibly a different frequency. The TM-D700 can do that with its built-in TNC, but I don't know if an external TNC would work the same as the Yaseu. Seems like they could have done it, but maybe there is an issue with internal switching that causes problems.

Alan
KE7AXC
2000 4Runner

[JackSilb]

Alan,

The solution we choose would need to be flexible enough to work on any radio. So we get people to use it. Or be cheap that people will buy the other radio and antenna.

The periodic transmission idea is something I bounced with Uwe while back. The problem is that if the radio transmit while someone is talking, it will interfere with it. Multiply by 6+ radios that may be in the same trip and you have a mess. Unless it is smart to check if someone is using the frequency.

I like better the idea of having a subtone added to your regular transmission. Something you can not hear but is going with your voice on each transmission. All the radios would be listening at the same time and decode the subtone that comes with your transmission. If you have not transmitted for a time, lets say 5 min, then the radio send a signal as you illustrated above if there isn't activity in the frequency.

While back I would be actively working with you and Uwe in the project. But, work is really busy this year and the kids are taking most of my weekends. I hope to be with more time for personal projects by July 06.

-JACK


So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[alanh]

I think the external TNCs and the sound card software will not transmit if a transmission is being received. That is pretty much a basic requirement for any implementation to avoid people stepping on each other's signal and causing chaos.

Its a little more straightforward with a data jack because that gives you a signal when the receive signal has exceeded the squelch threshold. With the sound card, I assume the software samples and measures the audio signal and has some threshold that when exceeded indicates someone else is transmitting.

I haven't gotten around to trying the sound card interface to verify this yet. I have a dummy load and a gadget to tap off a small signal so I can hook two radios together for off the air experiments. I haven't used this setup yet, but it should work. I thought I would experiment with that before going 'live' on the air.

To my knowledge, the sound card software doesn't have any way to trigger a transmit of position data when the PTT is released. I'm not sure the TNCs have that either, but have not verified this.

Alan
KE7AXC
2000 4Runner

[JackSilb]

What you do know about coding and decoding of non-audible tones?

-JACK


So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net

[alanh]

Jack,

I'm not sure if this is what you're talking about, but Continuous Tone Coded Squelch System (CTCSS) can be used simplex much like with a repeater. Everyone in the group sets up to TX the selected tone and receive only when the tone is present. All other signals are ignored.

If you want to use sub-audible tones for position reports, that's something different, but it seems like it could be used. My communication theory is a bit lacking, but a low frequency tone, or tones would limit the rate you can transmit data at since you'll need more time to get enough cycles in to decide what kind of bit (0 or 1) it is. I will see if I can find anything on slow data transmissions. I know the HF people use 300 bps for data, but thats still a lot faster than you're going to get using tones that are 250Hz or less. (The CTSS tones seem to be between 67 and 250.3 or 254.1 Hz from a couple of sources.)

Alan
KE7AXC
2000 4Runner

[JackSilb]

> If you want to use sub-audible tones for position reports, that's something different, but it seems like it could be used.

That is what I am talking about. I am not sure what frequencies (higher or lower than audible) and its implications. But the principle is what I am proposing for us to talk about.
While you talk you are transmitting information about your position. Nobody hear it but the decode on the other radios.

What do you think?
How many bytes do you need to transmit your ID and position?
Lets say a 3 digits ID then whatever GPS coordinates you may be using. No need to transmit time since you can use the clock from the receiver computer.

-JACK





So much to see, so little time. Try using your 4WD tosee and do more.
Tread Lightly! empowers generations to enjoy the outdoors responsibly...
http://www.4wdtrips.net