How can I tell if my packet was digipeated by the ISS?

[K7XRL]

To give a little background,I am using a Baofeng UV5R V2+ at 4 watts output into a 3 element tape measure yagi antenna.

To connect the radio I am using a Mobilinkd TNC2 Blutetooth TNC.

The device is an older android phone using APRSdroid to send and receive packets.

I have 3 channels configured for Doppler shift at 2.5 kHz.

This setup works well for APRS ground stations, and it also receives packets from the ISS just fine as well.

I used the recommended path (from ARISS info I searched online) of ARISS,SGATE,WIDE and I did not see any packets returned to me from the station.

My packets did not appear on ARISS.net.

A packet did appear on APRS.fi but from the path it doesn't look like it passed through the ISS digipeater.

Here is the raw packet from APRS.fi:

2015-03-04 14:20:13 MST: K7XRL-6>APDR12,TCPIP*,qAS,N0AN:=3933. N/11024. W[ Hello from Utah!

Was my packet received directly by N0AN? Or was it digipeated by the ISS?

 

[OZ5MB]

To give a little background,I am using a Baofeng UV5R V2+ at 4 watts output into a 3 element tape measure yagi antenna.

To connect the radio I am using a Mobilinkd TNC2 Blutetooth TNC.

The device is an older android phone using APRSdroid to send and receive packets.

I have 3 channels configured for Doppler shift at 2.5 kHz.

This setup works well for APRS ground stations, and it also receives packets from the ISS just fine as well.

I used the recommended path (from ARISS info I searched online) of ARISS,SGATE,WIDE and I did not see any packets returned to me from the station.

My packets did not appear on ARISS.net.

A packet did appear on APRS.fi but from the path it doesn't look like it passed through the ISS digipeater.

Here is the raw packet from APRS.fi:

2015-03-04 14:20:13 MST: K7XRL-6>APDR12,TCPIP*,qAS,N0AN:=3933. N/11024. W[ Hello from Utah!

Was my packet received directly by N0AN? Or was it digipeated by the ISS?

I am not that experienced yet since I have only received packets through the ISS five times and transmitted twice. But I am using a setup not that different from yours: A homemade Yagi, a Wouxun KG-UVD1P 5W radio, a Mobilinkd TNC1 and APRSDroid running on a relatively new and high end phone. I do not make any effort to compensate for doppler shift.

When I had success sending through ISS I used a path of ARISS,WIDE2-2. The first time I sent a successful packet through ISS I didn't receive the digipeated packet myself but I could see on http://www.findu.com/cgi-bin/ariss/index.cgi that a station over 800 km away had received my packet. The raw packet looked like "OZ5MB-7>APDR12,RS0ISS*,WIDE2-2,qAR,SR5GK-3:=5523.87N/01021.25E$/A=000170 http://aprsdroid.org/". The second time I tried I received my own packet from ISS.

My interpretation of your packet would be that you inadvertently sent your packet directly over the Internet to APRS.IS and didn't transmit anything into the air at all. An explanation could be if you are not aware that you need to stop and start tracking in APRSDroid before making changes in the settings if the changes are to have any effect. In that case you might have pressed start tracking while the connection was set to TCP, changed the setting to Bluetooth which would not take effect. I usually use a seperate HT standing next to me tuned to the same frequency to allow me to hear that I actually transmit (and to hear the packets from ISS).

 

[K7XRL]

Thanks for the reply.

I interpreted the packet that way as well, because of the tcpip in the path. But I am 100% sure the APRSdroid app was configured to use the Bluetooth TNC. Unless the app itself had a glitch I don't know how or why it would have routed the packet over the internet.

I even went so far as to look at troposhreric ducting as a possible explanation, thinking the station might have received the packet directly if the conditions were right.

I will try again in a few minutes as there is another pass approaching.

 

[K7XRL]

Ok, I heard and decoded more packets on the most recent pass, but none of mine made it through this time either.

 

[OZ5MB]

My explanation on the settings could probably be a bit clearer:
If, for instance, I was tracking in TCP mode and wanted to change to Bluetooth I would first stop the tracking process from the log screen. Then I would go to the settings menu and make the change. After this I would go to the Log screen again and start the tracking process back up. Similarly it is also needed to stop the tracking to make any path setting changes take effect.


Have you read the manual on http://www.mobilinkd.com/wp-content/files/MobilinkdTNC2UsersGuide-101.pdf .

Some other things I practice that I believe improves my conditions:
- The power saving setting in my radio is turned off. (This will only help with reception though)
- I operate with an open squelch and the mobilinkd carrier detect setting on. (This will also only help with reception)
-I turn off the dualwatch feature on the radio (This will also only help with reception)
- I followed the manuals recommendations on finding the proper RX volume setting and have marked this setting on my radio with a small cut in the plastic made with a knife. (This will also only help with reception)
- I found that the default TX volume setting matched the recommendations in the manual and did not adjust it.
- I was a bit unsure if the antennas on ISS would be horizontally or vertically polarized. To guard against picking the wrong of thse two options I keep my yagi in my hand and flip it between vertical and horizontal sending a packet in each position.
- To make this more manageable I suggest bringing a friend along. This allows me to press the single shot button at regular intervals while my friend tries to track the ISS while keeping a smartphone in one hand and the yagi in the other. It would be cool to have a pan-tilt unit to automatically track the ISS, but for now a friend is way cheaper - it only costs a couple of beers
- On http://forums.radioreference.com/amateur-radio-antennas/308728-my-take-wb2hol-tape-measure-yagi.html you mention two passes at 29 and 30 degrees. The passes where I got packets through were between 40 and 45 degrees at the culmination. These passes are the best ones possible at my geographic location (JO55fj). What are the highest passes possible at your location?
- On the thread mentioned above you have tried "a Nagoya whip on the radio, a 1/4 wave ground plane, a magnet mount mobile antenna, or a TV twin lead slim jim". I have pretty god reception (but no successful transmissions) using a Nagoya NA771 whip and a what I think is a Nagoya UT-106 mounted on the roof of my car.

 

[K7XRL]

Thanks for all of your suggestions!

I actually have marked the the volume knob with a couple of dots using a center punch, and I do have dual watch, squelch and power save turned off. I am aware that the app must be made to stops and restart tracking for changes to take effect.

What I haven't yet tried is hand holding the antenna. I like your idea bout sending packets with both horizontal and vertical orientation and I will try that the next opportunity I get.

The best pass I have seen to date was over 70 degrees. I think there is a 66 deg. pass later today so I will have another opportunity.

I have read the Mobilinkd manual, and I have it working fine for terrestrial APRS, so I don't think it is a configuration issue. I have an old unused phone set up for the satellite attempts so that I don't confuse the settings between the two.

It will happen eventually. It is just a matter of being in the right place at the right time, and getting a packet through the QRM.

 

[K7XRL]

Ok, I have had success!

I tried hand holding the antenna this time instead of using it on the tripod, and I took your advice about sending a packet with the antenna polarized both ways and it worked! I got through and the packet showed up on APRS.fi here:

Station info for K7XRL-6

And also I received it back at my station as well. This is the most fun I've had with radio since I got licensed!

Thanks for the suggestions!

 

[jzilla80]

Hi K7XRL,

First off, congrats on getting thru the ISS. Ive been fooling with it myself. Im RX'g just fine, however, my packets arent being seen either.

I know this is slightly old, so I can only hope you'll be able to reply, but I wanted to ask you if, for your succesful Tx-Rx, did you have your Digipath set to the same as you mentioned above in your OP (ARISS,SGATE,WIDE) or did you change it?

Thanks for your help! And anyone elses help, that wishes to comment or explain, or offer a good source for ISS Path choices.

Good day
N8TIP

 

[K7XRL]

It has been a while since I did this, but I think I used ARISS, WIDE.

One thing that helped was using the ISS Detector app on my phone to give an idea of where to point my antenna, and sending packets in both horizontal and vertical orientation with the antenna. Also I remember when I finally got one digipeated it was as the ISS was on its way down toward the end of the pass, and I had corrected for Doppler shift.

That said, I wouldn't wait until the end of the pass to try. But Doppler correction does seem to make a difference.

 

[jzilla80]

Ok, Thanks. That helps me! I was a bit confused.

Have a good one.

Sent from S5