Kenwood: Reusing old equipment, radio archeology, need advice.

[ve2ihs]

It's just 20 years old but very serviceable!

Hi all. I'm setting up an older kenwood TM-733 with aprs with a Nuvi 350 which I believe can be used to txt message, well that's the plan. I think byonics trak4 won't support this function and the argent OT2 is, well, rare. The plan is to use (mostly find) a OT2m, because I need the dual DB9 for GPS and Radio. I have the radio and the nuvi 350 and all the cables I believe, (hoping the pinout is good).

Any other options out there for this setup? I don't know a lot about TNC controllers manufacturers out there. Maybe Microsat? I still need an option to connect the TNC to the kenwood with some sort of PG-5A adaptor. Not sure if I require the RJ45 for aprs in this setup.

So questions are:

1-Any TNC compatible with nuvi 350 / tm-733 ( with garmin protocol for txt messaging ) ?
2-Cables assembly recommendation depending on answer to 1 ?
3-Do I need the RJ45 mic to run the aprs or the pg-5a will do ?
4-Will I keep the mic usable while aprs'ing ?
5-Can I crossband this setup somehow with my HT that have aprs ? ( that will come later and is a bonus )

I hope I made sense because it's a tad technical and I'm hardly keeping tabs on all this.



73 to all!

recycle for the planet.

 

[AK9R]

The Argent Tracker2 (and OT2) works with the Garmin nuvi 350 because Scott Miller at Argent hacked the Garmin Fleet Management Interface (FMI) and figured out how to make the nuvi 350 work as an APRS user interface. As I recall, Scott got virtually no support from Garmin to do this. Nobody else took the time to make it work, so your chances of getting your nuvi 350 to work as an APRS messaging device with any other TNC than an Argent Data unit is pretty much impossible.

The Byonics APRS devices work fine, but I don't think Byon is doing much development on them and isn't adding new features. The Byonics devices do not work with the nuvi 350 the way the Argent devices do.

Why is this? First, Kenwood, and Yaesu, killed the market for APRS trackers by building radios with TNCs and APRS user interfaces into radios. That was great for APRS users, but bad for Argent and Byonics. Second, a lot hams don't see the purpose of doing APRS via amateur radio frequencies. They'd rather run APRS apps on their phones and look at their position reports on a website. If you are running APRSdroid and looking at aprs.fi, you don't need a radio and a TNC.

If I was wanting to do what you want to do, I'd look at the Mobilinkd TNC. It can connect to your radio, with the proper cable, and you can connect it to your phone or tablet via Bluetooth. You'll have to run some sort of APRS client program on your phone or tablet. I think APRSdroid would work in this application, but I haven't researched it enough to know.

One other thing, the nuvi 350 is a really old GPS receiver. I'm surprised Garmin still supports it.

 

[AK9R]

Regarding your other questions:

3. Does the TM-733 have a "DATA" port? To use an external TNC, you need a way to get transmit audio into the radio, received audio out of the radio, and a way to key the radio (PTT). Some radios bring those signals to a connector on the radio. If your radio doesn't have that connector, then you'll have to send transmit audio and PTT to the mic jack (RJ45).

4. If the radio can receive and transmit APRS signals on one "side" of the radio while using the other "side" for voice transmissions, then yes.

5. Probably not. If you transmit an APRS signal from your handheld to a mobile radio set up as a cross-band repeater, your APRS signal probably won't remain intact. The cross-band repeater may cut off the very beginning of your APRS transmission and it may skew the audio frequencies and levels a bit.

 

[ve2ihs]

Thanks for the answer! I have indeed fiddled with aprsdroid and HT's with tnc in them. That specific project is for the kick. Reviewing your answer, I'll try to track down a OT2m indeed. May take a while. The 733 has a data port, which is the PG-5A connector in the image. Just below it, its the rj45 mic jack ( not pictured. ) I see that manufacturers have been impacted by that shortage, I noticed here, by your input, that kenwood discontinued a while ago some of their line of product, surely the shortage and this covid thing were part of it. I'll have to go second hand argent ot2m. I found that nuvi 350 on our "craiglist" and have to test something about updating the maps manually.

Thanks AK9R

On a side note, Bob Buringa's health isn't doing great noradays. Sad times.

 

[ve2ihs]

Well well I`ve managed to get this stuff working but with Byonics TT4. I don't have the texting ability but other stations shows on the nuvi 350.

I'll be continuing in this thread.

APRS wth TT4, Nuvi 350 and Kenwood TM-733

Greetings, I've manage to reuse old equipment to make it all work. This is my mobile station and I got it working this afternoon. I've notice things; my radio's fan now starts. Usually on listening only, the fan didn't start until I PTTed, but now it's running all the time low speed. My...

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