Interesting APRS transceiver with built in GPS & Bluetooth

[C2]

Maybe one bug. When paired with bluetooth to APRSDroid, and the USB/serial cable is plugged in, the bluetooth tx line does not work, but the device still receives fine.

Messaging in APRSDroid is as close to text messaging as it is going to get. It worked so well, it might as well replace SMS.

Now I need to discover how email works.

 

[C2]

OK, that was quick, but I'm not close enough to an iGate or repeater to test it.

The easiest way to send email is to send a message to EMAIL with the recipient's email address as the first "word" of the message. You may only send one line messages (67 total characters maximum).

 

[C2]

I noticed on aprs.fi, some of my hits reported in kph rather than mph. is that the device or the website?

Some of the hits had my call, but no data. Maybe the transmission was truncated or illegible?

The coverage is spotty, but this is just 1W. Some of the igates, however, pick me up far away but not when I'm closer.

I wish there was one more button or a switch so you could toggle on/off the beacon. I thought even a momentary switch would allow you to toggle between auto and manual pings. That came up when I just wanted to test the receiver and was too lazy to boot up the PC and program it. And it is not like you can just walk up to any PC and install a simple piece of software. To add complexity, it appears that the config program version must match (or be compatible) with the firmware version you have flashed. There are several versions of each floating around, as well as a firmware flash program.

After thinking about it for a while, while $120 is cheap, compared to the sub-fifty dollar UV-5R variants, it seems a bit pricey. Seems like those would be much more expensive to produce, but sure they'd have a much larger market base...

A good project would be to reverse engineer this and write up some new code. Maybe someone will leak the source...

 

[Moleculo]

I noticed on aprs.fi, some of my hits reported in kph rather than mph. is that the device or the website?

That's a setting on APRS.fi that you change under "preferences"

 

[Moleculo]

Some of the hits had my call, but no data. Maybe the transmission was truncated or illegible?

Yeah, probably. It sounds like you need either a bit more power or a better antenna to consistently hit your local digipeaters.

Your comments on this little APRS rig are pretty interesting, BTW.

 

[C2]

re: kph vs. mph, I thought this was changing on a single track, but it may have been two separate tracks, or maybe I looked at it once at work and then later at home, and the display is set differently. I'll have to check it.

I am just using the stock duck with it sitting on the dash. I recall I have a couple NMO mag mounts and at least one VHF co-linear antenna to try.

So far, the device has met every reasonable expectation I've had. I've run it for about 8 hours off the initial charge and the last voltage report was 3.66V

 

[C2]

I learned a few more things about APRS (and I need to add AP510 to this post for the search engine).

these are quotes from elsewhere:

Add NOGATE and RFONLY to the end of your path, and the information stays off the Internet. This still allows communication with other APRS users via the RF network without making location and messages available on the APRS-IS network.

AX.25 packet can suck becuase of the way it uses a checksum instead of forward error correction. If one bit is corrupted the entire packet is discarded and sent again until it is received intact.

 

[C2]

Oh, one thing I do not know is if I send a message to WKRP, how does the right iGate know to release the signal?

 

[Moleculo]

Oh, one thing I do not know is if I send a message to WKRP, how does the right iGate know to release the signal?

It's based on the last iGate he reported in at.

 

[C2]

OK, so the iGate will keep track. I guess the message has a half life once it goes into the system, or does it just die if there is no outlet?

I set my beacon from WIDE1-1 to WIDE1-1, WIDE2-1. That took almost half an hour because I had to get my PC to install the USB driver again. Why does USB always have to do this? Of course it did not work until I rebooted my PC and had the device plugged in at the right time. )You also have to realize that the USB plug they give you is not just a USB plug, but it has the usb/serial adapter in it.) After that, the software has a problem opening and closing comm ports. The headache should be obvious once you see links to programs to close Windows comm ports. I just reboot my PC. Anyway, you have to have the device plugged in, but off, when you launch the program, and then you have to turn the device on after pressing a button in the software, and you have to do it within a 20 second counter. Any screw up with that and your port is stuck. Then you reboot and try again, starting from the device driver. OK, I got it set the way I wanted.

Not one ping made it onto the network. I was trying the "improved" antenna from my GT-3M2. Maybe the antenna was not contacting. I could not remove the antenna when I got to where I was going because of the way they switched the connector genders. The male SMA is in the radio and that is the connector with the nut. So now, the nut just spins in the case as you twist the antenna. Proper procedure would have you holding the antenna and device, and just twisting the nut so the center pin does not rotate in the connector and cause wear issues. Now I have to take the daamn screws outta this thing already.

 

[C2]

Here is the insides. I was pleased to see the GPS module in a logical orientation. And there is the reason I took the covers off, the right angle SMA connector. I'm thinking of screwing something on there and then epoxying the nut in place. I'l also put something between the circuit board and the battery.

 

[C2]

Well, I tacked some solder around the SMA nut (with something screwed into the connector) so hopefully the antenna connector will not be giving me any more trouble. I don't think that was the problem since I was able to tighten it when I put it on.

Maybe the programming is not right for WIDE1-1, WIDE2-1 since now I cannot get any pings to show up. I am transmitting on the correct freq. I'm sure the Yahoo group will tell me to flash new firmware. I can't play with it now since I don't have the special cable with me, and I do not remember the cumbersome procedure for manually installing all the software and drivers, so I'll be driving 80 miles home so I can reprogram something, Maybe I'll just stick in WIDE1-1, WIDE2-2 and see if that fixes it.

 

[C2]

I just did a quick harmonic check, ~ -20 dBc (estimating about 10 mW conducted). I am just picking up the signal on an open coax, so take it with some sodium chloride.

 

[C2]

I measured the RF output with my Diamond cross needle SX144 something like that meter...I connected the AP510 using adapters and had a coaxial 2W load on the output. I was getting a solid 1.5W conducted output.

I fashioned a straight 1/4 wave whip and that improved transmission, not enough to be really usable around here so I'll need amplification, I think a solid 5W would be good enough.

 

[Moleculo]

How far away is your closest digipeater / igate? Is there a lot of APRS traffic on frequency that you're competing with?

I always have difficulty getting into the local digipeaters with my HT because I just get stomped on by other stations. Your issue sounds like a similar problem.