# Kenwood TH-D72 APRS and Big Red Bee question

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#### manixFan

##### Not a rocket scientist
All,

I have a Kenwood TH-D72 and I have to admit I can't quite figure it out. I had it working and now for some reason I can't get it to display the APRS data. When I turn on the BRB I can hear the packets being received by the Kenwood but the display doesn't change to show me the APRS data. I've watched several videos and tried to read the manual but no joy. The display shows all the right settings (APRS12, iGPS, D symbol).

Any help would be greatly appreciated. I hope to use this at Airfest.

Thanks,

Tony

#### ksaves2

Number one: Tune to 144.390 and make sure you turn on the TNC and it's not it packet mode. The "D" should be after the frequency.
You should start to see positions coming in from other stations unless you are so far out in the boondocks there is no digipeater nearby.

Second: Make sure you know the 70cm frequency your Beeline GPS is tuned to. Turn on and put the Beeline GPS outside, out in the open and let it sit for 20 minutes. It needs to acquire the GPS satellites Ephemeris in order to "find out" where it's at. Make sure you have programmed the Beeline GPS to transmit a packet once every 5 seconds. You have to learn how to program the Beeline GPS to get it to work properly. Read Greg's instructions on how to do that.

First hurdle: Get the 72 decoding APRS packets on 2 meters if you have traffic on 144.390 in your area. You do that and all's you have to do is change
bands, go from 2 meters to 70cm (420 to 440Mhz) and if the BLGPS is transmitting position packets, you'll see them decoded.

You get this done, read the 72's instructions on how to get the GPS in the rig working. I think a better way though it connect up an external GPS
in the fashion of a Garmin 60Cs or 60CsX and use it for your local position. A single cable will get your rocket's position into the Garmin 60Cs(X)
from the D72A and you will have a rock steady tracking and navigation solution to track your rocket. This is the cable: https://www.gilsson.com/garmin_gps/cables/rk.htm

The points of interest database isn't really good at all but the maps are and they're free. Good enough for rocket tracking. You'll have to get
a Garmin 60Cs or CsX off ebay or used someplace. A cheap Garmin legend will work: https://buy.garmin.com/en-US/US/p/173
but it uses a different cable, the monochrome map isn't as nice and new maps aren't available for it. It will find your rocket on the cheap though.
Ebay prices $33.00 but again, there is a different cable for it. Kurt #### Zebedee ##### Well-Known Member Just to double check - you definitely have the GPS BRB and not just the RF Beacon BRB? #### manixFan ##### Not a rocket scientist Thanks for the info so far, I'll have to wait until after work to try the suggestions. I can hear the radio getting the packets, have the TNC opened, the GPS on, and all the right displays. I'll try Kurt's suggestion of 144.390 and see if it decodes any packets that come in on that frequency. If that doesn't work I will reset the radio to the factory defaults and start from scratch. I'll let you all know how it goes. It's one of the first BRB's with GPS so it looks a bit different than the new ones. Tony #### ksaves2 ##### Lifetime Supporter TRF Lifetime Supporter #### manixFan ##### Not a rocket scientist Success!! Thanks to Mark and Kurt. The thread Mark linked to had a lot of great info including a quick setup sheet. From that I decided to do a reset of the radio. Then I used Kurt's suggestion and made sure I could decode packets. That worked so I knew my radio was now in GWO. But still no joy with the BRB. So I re-read the manual I got with mine and realized that some of the settings were different, most notably the preamble. The manual showed a default value of 1. I set mine back to that and presto, success the next time I tried it. Not sure it was exactly that setting but at least it now works. It looks like there are a lot of the Garmin 60CS units on eBay fairly cheap and I already have the cable. But I have a couple of the eTrex units already that would only require a$25 cable. For now I'll probably just key the numbers in by hand since I won't really have time before Airfest to mess with anything new. But good info to know.

Thanks again for taking the time to help out,

Tony

#### ksaves2

Success!!

Thanks to Mark and Kurt. The thread Mark linked to had a lot of great info including a quick setup sheet. From that I decided to do a reset of the radio. Then I used Kurt's suggestion and made sure I could decode packets. That worked so I knew my radio was now in GWO. But still no joy with the BRB. So I re-read the manual I got with mine and realized that some of the settings were different, most notably the preamble. The manual showed a default value of 1. I set mine back to that and presto, success the next time I tried it. Not sure it was exactly that setting but at least it now works.

It looks like there are a lot of the Garmin 60CS units on eBay fairly cheap and I already have the cable. But I have a couple of the eTrex units already that would only require a \$25 cable. For now I'll probably just key the numbers in by hand since I won't really have time before Airfest to mess with anything new. But good info to know.

Thanks again for taking the time to help out,

Tony
Be careful with the Etrex units. I have a Vista HcX and it won't work via USB for tracking. Works for programming only and they use Garmin's proprietary communication protocol.
If you have the Legend that will work with the appropriate cable.

If you get an Etrex Vista to work, post your setup. The USB cable for the D72 works with programming and for packet radio use. If you wanted to
have a "base" station to "record" a flight, you could use any Ham tracking app and put the 72 in "packet" mode. In that case the laptop program
would control the TNC.

If you get a 60Cs or CsX (the CsX has the "sight 'n go" option that lets you shoot a line on a rocket you have a visual on descent) You have to change the communication protocal to NMEA for the serial round port to get it to work with the D72.
Kurt