APRS packet traveled 104.7 miles

K7XRL · Feb 20, 2015

I have been messing with my radio and Bluetooth TNC today, just experimenting. It looks like I can access 2 digipeaters from here. One of them is over 100 miles away using a 4 watt handheld radio! This is fun stuff!

Station info for K7XRL-7

If you scroll down the page you can see "stations which heard K7XRL-7 directly".

Unless I am misinterpreting the data it looks like one of those mountaintop repeaters heard one of my packets from pretty far away.

Thunderknight · Feb 21, 2015

I think you are correct. Looking at that stations's list (Station info for ELLEN) it appears to hear many distant stations, so it's probably a good site.
Isn't radio cool?

I used aprs.fi to test the footprint of my igate. I could see where it was able to hear my portable, so I figured out the limitations.

K7XRL · Feb 21, 2015

Yep!

There are a lot of mountain top repeater sites out here that have great coverage. I happen to live at the base of a plateau on some elevated land so it is easy to communicate with stations to the south and west of me. But once you drive down the hill it becomes more difficult.

I drove to town today with a handheld radio and didn't get a single packet into the system. Granted, a handheld radio antenna inside a vehicle is pretty dismal. But the little tracker radios that use the same antennas and only put out 1 watt wouldn't get in either.

I am lucky to have a good site for LOS to several 2 meter phone repeaters. But I think the area could us a few more digipeaters.

kayn1n32008 · Feb 21, 2015

K7XRL said:
I have been messing with my radio and Bluetooth TNC today, just experimenting. It looks like I can access 2 digipeaters from here. One of them is over 100 miles away using a 4 watt handheld radio! This is fun stuff!

Station info for K7XRL-7

If you scroll down the page you can see "stations which heard K7XRL-7 directly".

Unless I am misinterpreting the data it looks like one of those mountaintop repeaters heard one of my packets from pretty far away.

Just wait until there is a 2m band opening. In Alberta we have regularly seen single paths of 200+km or more. With our digipeater network on a normal day we can see a huge chunk of the province, and even regularly see activity in northern Montana.

2m APRS is a great indicator of enhanced propagation. When you start seeing activity 400-700km away, start tuning the band to see what else you normally can't hear. Lots of fun. One particular day I was able to access a voice repeater 200km away with 5watts. On any other day I would not be able to use it even with full legal limit.

Sent from my iPad using Tapatalk

Jay911 · Feb 21, 2015

This map shows propagation based on long path APRS packets...

VHF Propagation Map

kma371 · Feb 21, 2015

You should try contact with the international space station. It's generally over 200 miles

prcguy · Feb 21, 2015

I routinely get a direct APRS path of 167mi (that's one hundred and sixty seven miles!) using a 1w AP510 tracker with stock rubber duck antenna when hiking at a local park. The park is at around 700ft altitude on a coastal peninsula near Los Angeles, CA and the other site is south of Ensenada Mexico at about 700ft.
prcguy

K7XRL · Feb 21, 2015

kma371 said:
You should try contact with the international space station. It's generally over 200 miles

Van Halen fan?

The ISS was next on my list. I am trying to decide whether it would be easier to build a cable to interface the TNC with a mobile radio for more power, or to build a yagi for my handheld for more gain.

n9mxq · Feb 21, 2015

When I first put my APRS digi up here at the new house (950' asl with the antenna 50' agl) I got a little rambunctious and had the radio set to 60 watts.. And received complaints from an OP in Montana that he was hearing too much from my station..

So, I switched to mid power and he told me he only heard me "occasionally". Your long path is no real surprise.

Jay911 · Feb 21, 2015

n9mxq said:
received complaints from an OP in Montana that he was hearing too much from my station..

Did you tell him about the new concept called the tuning knob, which allows him to go to another frequency? Or even the off button?

Sounds like an OF who needs to get out of his shack more often.

Thunderknight · Feb 21, 2015

K7XRL said:
I am lucky to have a good site for LOS to several 2 meter phone repeaters. But I think the area could us a few more digipeaters.

Could you put one at your house and fill in the gap below?

w9xxx · Feb 22, 2015

You don't really need a yagi for the ISS. I easily hit it with a 2m 1/4 wave While mobile. Any other vertical won't do as well. It's a radiation angle issue. 5 watts at a time and day when most people are doing something else is all you need.

AK9R · Feb 22, 2015

Jay911 said:
Did you tell him about the new concept called the tuning knob, which allows him to go to another frequency?

Not really an option on APRS since most APRS traffic is on one frequency across the U.S. and Canada. If the Montana operator was trying to copy local APRS traffic, it wouldn't have been practical for him to "spin the knob".

Jay911 · Feb 22, 2015

W9BU said:
Not really an option on APRS since most APRS traffic is on one frequency across the U.S. and Canada. If the Montana operator was trying to copy local APRS traffic, it wouldn't have been practical for him to "spin the knob".

I missed the part about it being a digi. I thought the post was about dxing - my mistake.

n9mxq · Feb 22, 2015

Jay911 said:
Did you tell him about the new concept called the tuning knob, which allows him to go to another frequency? Or even the off button?

Sounds like an OF who needs to get out of his shack more often.

Back then, yes, there were other APRS frequencies, but 144.390 was being adopted as the nationwide frequency. Where was he supposed to go?

n9mxq · Feb 22, 2015

Jay911 said:
I missed the part about it being a digi. I thought the post was about dxing - my mistake.

Well, that'll teach me to scroll all the way down before replying...:roll:

K7XRL · Feb 22, 2015

W9BU said:
Not really an option on APRS since most APRS traffic is on one frequency across the U.S. and Canada. If the Montana operator was trying to copy local APRS traffic, it wouldn't have been practical for him to "spin the knob".

Yeah, I occasionally pick up a packet from a station named "Area 51" in NV. It has "WIDE5" in the path!

Though that is not an RF issue.

Jay911 · Feb 22, 2015

K7XRL said:
Yeah, I occasionally pick up a packet from a station named "Area 51" in NV. It has "WIDE5" in the path!

Though that is not an RF issue.

Wanna kill APRS for a day or two? Toss a balloon with WIDE7 enabled.

AK9R · Feb 22, 2015

WIDE5 or WIDE7 only impact the network if the digipeaters are configured to respond to those aliases. If a digipeater is configured to act on WIDE1-1, WIDE2-2, or WIDE2-2 and someone comes along with a packet containing only WIDE7-7 in the path, the digi will just ignore it and listen for another packet.

My WIDE1-1 fill-in digi will only act if there's a WIDE1-1 in the path.

The high-profile digi that I maintain will only act if there's a WIDE1-1, WIDE2-1, WIDE2-2, or IN in the path.

Where balloons can kill a network is if they transmit with "WIDE anything" in their path from an altitude of 10,000 feet or more. Every digipeater in a very large radius will respond. High altitude balloons should not use any path when they are at altitude. Once they get close to the ground, switching to a "normal" path is a good idea.

mikewazowski · Feb 22, 2015

I don't think many digis have supported anything higher than wide3-3 for many years.

Mine only supports wide3-3.

APRS packet traveled 104.7 miles

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