GPS, TNC & APRS

[Tom Stefanac]

Hi guys!

I have been a bit of a stranger these last few months I guess. What can I say, work + school can keep a guy busy!

I am not very familar with APRS but would like to have some form of an intergrated APRS system. My primary mobile radio is an Icom 208H dual band rig and I just use a simple Garmin Etrex Yellow for a GPS feed.

I read Stan Olson's post about using UI-View in conjunction with a data free APRS-IS server to save cell modem bandwidth and it is a great idea. I may endup just going that route since I only have one GPS unit and I use it in conjunction with Xport to emulate the nema feed across multiple ports.

Now here is my complex question...

How would I go about setting up APRS using the radio itself and how could I do something like that without having to use two GPS units?

Would a serial port splitter exist sort of like how there is a USB port splitter?

What type of TNC or APRS units would be best?

Do I have to dedicate the radio to 144.390 or can I use it between beacons?

Would 30 meter APRS be a better bet in general and not just in VHF the dead zones?

What is the typical beacon time interval (2 minutes)?

How much power should typically be used (full)?

Should I just buy the TM-D700 and save myself trouble (but I still have the GPS issue right)?

What APRS systems are popular today?

Does anyone use APRS for NWS text data?

Why is life and APRS so complex?

Thanks!
Tom

 

[Andrew Herron]

My father and all his buddies all have this set up at home and in their vehicles. I'll forward him your questions.

 

[cedwards]

I have a simple setup for APRS. I am using the TinyTrak. I have one radio dedicated for use with it I use an old Delorme trackmate gps modified to be used with this. Total cost: ~$120. If all your applications that use the GPS only get data one way, I don't see that there would be a problem using a splitter (You may need to make it yourself) The computer solution to use the same gps in two programs is a software slitter, so it wouldn't work with this. If somebody knows otherwise, let me know.

I will let somebody with more knowledge on the subject answer all your questions.

 

[Jeff Snyder]

Many chasers take out their laptop(s), which you can use in place of a TNC... Search "AGWPE", which lets you use the sound card on your laptop/computer to send and decode to/from your radio.

 

[Jarrod Cook]

Hello,

Since you already are using your laptop to split the port into multiple virtual ports (unless I mis-understood what you said), you can use UI-VIEW to receive the GPS data itself (rather than the TNC). Therefore, you wouldn't need any sort of serial splitter for the GPS. The next step would be to connect your laptop to a TNC...in this case, maybe you would need a serial splitter. What I do is use a USB-to-serial adapter since my laptop doesn't have any serial ports. My GPS is also a USB model. Finally you would need a cable to connect the TNC to your model of radio.

A good TNC is the Kantronics KPC-3+, but it's kinda pricey. Sometimes eBay has good deals on them.

Most mobile stations have their beacon rates between 1 and 2 minutes. Therefore, it will be hard to use the radio "between beacons."

I am not too familiar with AGWPE like Jeff suggested. That may work, too. I bougth a TNC because I can use it for all sorts of other things in the future.

 

[DMGullette]

Most mobile stations have their beacon rates between 1 and 2 minutes. Therefore, it will be hard to use the radio "between beacons."

I used to own a Kenwood D700 radio with the built in TNC for APRS.
I would set it up to beacon once once every 2 minutes.
It would beacon only if I was not talking.
So yes you can talk while beaconing.

 

[Ben Holcomb]

I've just got a Kenwood D710A and a GPS hooked up to that. It works great.

 

[Jason Foster]

I used to own a Kenwood D700 radio with the built in TNC for APRS.
I would set it up to beacon once once every 2 minutes.
It would beacon only if I was not talking.
So yes you can talk while beaconing.

When Bob Bruninga, WB4APR presented at a local ham radio meeting, he said that 2 minutes really is the maximum rate for any station to transmit their packet/data (beacon as you call it). Most mobile stations should really only set it for every 5 minutes. Stationary APRS stations should only transmit every 30 minutes. This allows for all the stations in that area to transmit affectively. There is more about APRS here:

http://www.aprs.org/

 

[Joe Dorn]

Hi guys!


Now here is my complex question...

How would I go about setting up APRS using the radio itself and how could I do something like that without having to use two GPS units?

Would a serial port splitter exist sort of like how there is a USB port splitter?

What type of TNC or APRS units would be best?

Do I have to dedicate the radio to 144.390 or can I use it between beacons?

Would 30 meter APRS be a better bet in general and not just in VHF the dead zones?

What is the typical beacon time interval (2 minutes)?

How much power should typically be used (full)?

Should I just buy the TM-D700 and save myself trouble (but I still have the GPS issue right)?

What APRS systems are popular today?

Does anyone use APRS for NWS text data?

Why is life and APRS so complex?

Thanks!
Tom

Would a serial port splitter exist sort of like how there is a USB port splitter?

I have made my own splitter cable for the Garmin GPS II+ and fed a TNC and computer with it. In my opinion it would be better to use one of the inexpensive 'button' GPS units now available.

What type of TNC or APRS units would be best?

We have a number of spotters in the area, including me, that use the Byonics TinyTrak III with the Byonics GPS II; cost about $120.00 plus radio. (I have multiple trackers, some are on loan)

Do I have to dedicate the radio to 144.390 or can I use it between beacons?

Depends on the radio... A single band radio (I like the Yaesu FT-1500, no longer in production but on E-BAY often or the Kenwood TM-271, still in production) should be dedicated. Most dual-banders can do both with APRS on one side and voice on the other. The FT-8800 you have to switch bands back and forth, the ICOM 2720 would take care of itself: I can not comment on other radios since I have no hands on with them.

Would 30 meter APRS be a better bet in general and not just in VHF the dead zones?

VHF is the only way to go in my opinion, I know of no spotter using HF for APRS.

What is the typical beacon time interval (2 minutes)?

Smart Beaconing is the way to go. A beacon is sent on significant turns and speed changes. The rate automatically slows down if you are parked. This might save a battery if you forget to turn the radio off... I carry a jumper battery... Yep... been there done that several times...

Without Smart Beaconing, a two to three minute interval is good...

How much power should typically be used (full)?

I run medium power on all of my trackers (10 to 25 watts). This will get you to a digi usually. High power puts an extra stress on the radio and power system with very little gain. Location, antenna(s) and height are more important.

Should I just buy the TM-D700 and save myself trouble (but I still have the GPS issue right)?

The TM-D710 is the latest Kenwood entry into the field. I have one and use the Byonics GPS 2 with the Kenwood cable with it: GPS2 costs about $70.00. (I have just recently installed this radio and it freed up a tracker to lend out.)

What APRS systems are popular today?

I don't know what you are asking here:APRS is APRS but there are MANY different ways to use it. APRS.fi is a good viewing program, free but it is a passive program. UiView is the most popular active (viewing and output) program. GRLx with Allison House's Spotter Network is what I use most of the time as net control operator.

Does anyone use APRS for NWS text data?

Not to my knowledge...

Why is life and APRS so complex?

Because God and Bob Bruninga made them that way...