Like many topics in the amateur radio world, there is a mix of what is prescribed in protocol versus how it's applied in the real world.
Bob's right here. There are excess packets created by using APRS messaging vs a simple "one time" packet being sent as a UI.
The weakness in using the built-in APRS functions of Kenwood, Yaesu, or other traditionally-terrestrial messaging systems is the load of 'waste' packets generated vs using a simple UI packet. The APRS messaging functions will often continue to transmit until they receive an acknowledgement. This can be problematic in a short-duration LEO satellite pass, especially when one station tries to message everyone in their HEARD list!
Many people who operate solely with a radio such a Kenwood are oblivious to 'waste' packets being digipeated (repeat ACK's, REJ's, etc.) Unless you're sitting at a terminal and viewing all the packets, your view of what is passing by is extremely limited; not just by the tiny display of your radio. For fun, I suggest running a terminal attached to your radio and monitor all packets at Field Day.
I've observed passes when 10-15 stations were able to exchange packets and I've observed other passes when 2-3 struggled because one or two other stations were over-beaconing and sending messages repeatedly.
It's like the many new stations incorrectly assuming the best way to be digipeated is to keep pressing BCON on their Kenwood radio until the glorious "MY POS" flashes and they hear a beep! OUCH. Those are typically people on omni antennas or in their car that have no idea they've been digipeated every time but their station is not hearing.
Not everyone has the luxury of sitting in their shack to operate a packet/APRS-capable satellite. At home, I use UISS. By default UISS does not request acknowledgement or require it. It will only transmit a message or position packet upon pressing the appropriate function key. This helps limit the amount of "rapid-firing" typically employed by many of the folks using transceivers with built-in packet/APRS capabilities.
Occasionally I like to make contacts via ISS or other satellites with packet digipeaters using either one of my Kenwood mobile or HT transceivers. Do I use the status text method? No. I use the MSG function like others on this thread have described. I keep it short and sweet.
Do you want to strictly adhere to terrestrial protocol rules for acknowledging messages, often resulting in the logjam of packets, or do you want to increase efficiency and send the minimal frames necessary to get a clean exchange via satellite with another station? I leave that up to the operator.
Have fun.
73 Clayton W5PFG
P.S. I think the unattended beacons remain my favorite nit-pick of packet/APRS satellites' use. :-)
FYI, the application APRSIS32 has an explicit control of acknowledgments, and, to some extent, the path, on each message being sent. Look to the lower left in the Message Sending window. I believe the default is to include Ack processing (box checked).
Greg KO6TH
Clayton Coleman W5PFG via AMSAT-BB wrote:
At home, I use UISS. By default UISS does not request acknowledgement or require it. It will only transmit a message or position packet upon pressing the appropriate function key. This helps limit the amount of "rapid-firing" typically employed by many of the folks using transceivers with built-in packet/APRS capabilities.
Here is what I was suggesting. You keep an exchange in your status text like this:
1D MDC QSL XXXXXX
And that is transmitted in each of your APRS position packets (which also is displayed as a gridsquare on everyone's screens). Each time you want to QSL another contact you see in the STATIONLIST, you use the MENU button and 5 presses to then edit in the new call in place of the XXXXXX. Press BCON and wait for a response.
I am *not* a contester and have no idea if this constitutes a valid exchange, but the 1D and MDC are my usual FIeld Day excahnge. What would be best for APRS use?
So, I receive a packet from station X, I send my QSL, he sees it and sends his QSL. Aren't excahnged grids and exchanged QSL's a valid contact?
No ACKS and only manually controlled retries.
If I am missing something, correct me, thanks bob
On Sat, Apr 13, 2019 at 2:57 PM Clayton Coleman W5PFG via AMSAT-BB < amsat-bb@amsat.org> wrote:
Like many topics in the amateur radio world, there is a mix of what is prescribed in protocol versus how it's applied in the real world.
Bob's right here. There are excess packets created by using APRS messaging vs a simple "one time" packet being sent as a UI.
The weakness in using the built-in APRS functions of Kenwood, Yaesu, or other traditionally-terrestrial messaging systems is the load of 'waste' packets generated vs using a simple UI packet. The APRS messaging functions will often continue to transmit until they receive an acknowledgement. This can be problematic in a short-duration LEO satellite pass, especially when one station tries to message everyone in their HEARD list!
Many people who operate solely with a radio such a Kenwood are oblivious to 'waste' packets being digipeated (repeat ACK's, REJ's, etc.) Unless you're sitting at a terminal and viewing all the packets, your view of what is passing by is extremely limited; not just by the tiny display of your radio. For fun, I suggest running a terminal attached to your radio and monitor all packets at Field Day.
I've observed passes when 10-15 stations were able to exchange packets and I've observed other passes when 2-3 struggled because one or two other stations were over-beaconing and sending messages repeatedly.
It's like the many new stations incorrectly assuming the best way to be digipeated is to keep pressing BCON on their Kenwood radio until the glorious "MY POS" flashes and they hear a beep! OUCH. Those are typically people on omni antennas or in their car that have no idea they've been digipeated every time but their station is not hearing.
Not everyone has the luxury of sitting in their shack to operate a packet/APRS-capable satellite. At home, I use UISS. By default UISS does not request acknowledgement or require it. It will only transmit a message or position packet upon pressing the appropriate function key. This helps limit the amount of "rapid-firing" typically employed by many of the folks using transceivers with built-in packet/APRS capabilities.
Occasionally I like to make contacts via ISS or other satellites with packet digipeaters using either one of my Kenwood mobile or HT transceivers. Do I use the status text method? No. I use the MSG function like others on this thread have described. I keep it short and sweet.
Do you want to strictly adhere to terrestrial protocol rules for acknowledging messages, often resulting in the logjam of packets, or do you want to increase efficiency and send the minimal frames necessary to get a clean exchange via satellite with another station? I leave that up to the operator.
Have fun.
73 Clayton W5PFG
P.S. I think the unattended beacons remain my favorite nit-pick of packet/APRS satellites' use. :-) _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Hi Bob,
For those of us with a non-D710 radio (e.g. the D74A), what are those 5 menu items you're pressing through?
Greg KO6TH
Robert Bruninga via AMSAT-BB wrote:
Each time you want to QSL another contact you see in the STATIONLIST, you use the MENU button and 5 presses to then edit in the new call in place of the XXXXXX. Press BCON and wait for a response.
I guess the difference is that I was thinking in terms of efficient channel use while making a demo contact or so. It does take more work. But if your goal is only to make a demo contact, then it is easy enough.
On the other hand, those trying to maximize contacts per pass will find messaging easier, though adding a significant load of ACKS on the channel. Fortunately, Patrick's guidance does attempt to manage that. The key being, to CANCEL a message as soon as one knows it has been digipeated and NEVER wait on an ACK.
Say the channel is running at 25% success, then the chance of an ACK is 25% of that or only 8% or meaning the ACK might need 16 transmissions to be heard. (though the APRS radios stop at 5).
To answer Greg's question, the first press is Menu, Select APRS, Select status, Select number, Select Rate, begin editing. But all of those are already in line since the last time it was used, so it is just 4 rapid presses of the SEL (ok) key. But then you have to manually enter the other persons call (while remembering it).
Bob, WB4APR
-----Original Message----- From: Greg D ko6th.greg@gmail.com Sent: Saturday, April 13, 2019 11:58 PM To: Robert Bruninga bruninga@usna.edu Cc: AMSAT-BB amsat-bb@amsat.org Subject: Re: [amsat-bb] Tutorial on Working APRS Contacts on Kenwood TM-D710
Hi Bob,
For those of us with a non-D710 radio (e.g. the D74A), what are those 5 menu items you're pressing through?
Greg KO6TH
Robert Bruninga via AMSAT-BB wrote:
Each time you want to QSL another contact you see in the STATIONLIST, you use the MENU button and 5 presses to then edit in the new call in place of the XXXXXX. Press BCON and wait for a response.
So, on a Kenwood TH-D74 it would be Menu, APRS, Basic Settings, Status Text, Enter (use up/dn to pick the one you want first), then the Down arrow to move from Rate to the Text, and Enter to edit. Hit Enter to finish the editing, then Menu to clear all the way out.
I presume you'd want a Tx Rate of 1/1, in order to improve your chances :). Default is 1/4.
Thanks,
Greg KO6TH
Robert Bruninga via AMSAT-BB wrote:
To answer Greg's question, the first press is Menu, Select APRS, Select status, Select number, Select Rate, begin editing. But all of those are already in line since the last time it was used, so it is just 4 rapid presses of the SEL (ok) key. But then you have to manually enter the other persons call (while remembering it).
Yes, definitely 1/1 bob
-----Original Message----- From: Greg D ko6th.greg@gmail.com Sent: Monday, April 15, 2019 2:03 PM To: Robert Bruninga bruninga@usna.edu; AMSAT-BB amsat-bb@amsat.org Subject: Re: [amsat-bb] Tutorial on Working APRS Contacts on Kenwood TM-D710
So, on a Kenwood TH-D74 it would be Menu, APRS, Basic Settings, Status Text, Enter (use up/dn to pick the one you want first), then the Down arrow to move from Rate to the Text, and Enter to edit. Hit Enter to finish the editing, then Menu to clear all the way out.
I presume you'd want a Tx Rate of 1/1, in order to improve your chances :). Default is 1/4.
Thanks,
Greg KO6TH
Robert Bruninga via AMSAT-BB wrote:
To answer Greg's question, the first press is Menu, Select APRS, Select status, Select number, Select Rate, begin editing. But all of those are already in line since the last time it was used, so it is just 4 rapid presses of the SEL (ok) key. But then you have to manually enter the other persons call (while remembering it).
participants (3)
-
Clayton Coleman W5PFG -
Greg D -
Robert Bruninga