APRS | Mark-Rodgers

APRS digipeater in a box

February 20, 2013 MRodgers No comments

I am planning on deploying a few more APRS digipeaters in the Mid-Michigan area.
I hope to be able to fit everything inside a 12 x 12 x 6″ outdoor weatherproof box, for each site. The only external connections will be 110v power and antenna. I still have do do all the wiring and solder up some connectors, but this will give an idea of how it will look inside.

Contents:

110v outlet
12v 3amp power supply
12v 7ah battery
MFJ-1207C TNC
Vertex FTM-2011 commercial VHF mobile
Wiring for power / data

I hope to get some much smaller TNC’s like the Byonics TinyTrack4 for some future kits.
I am not sure which site this will be installed at, but I will update my website with the new location and installation pics, when done.

FSK Decoding from a Caller-ID unit.

November 16, 2012 MRodgers No comments

Mobile APRS Tracker & Hidden Electronics

April 28, 2012 MRodgers No comments

A quick video of the APRS tracking system in my truck and other electronics hidden in the back storage compartment.

Upgraded Digipeater Antenna

March 16, 2012 MRodgers No comments

New Antenna installed behind me. I LOVE tower climbing!

On Sunday, March 11th I upgraded thye VHF antenna at the ELSIE Mi APRS digipeater site. My brother had bought me a new 3 point climbing harness and lanyard as a gift the week before and I was itching to use it.

The previous antenna was a mobile 5/8wave VHF, attached to a “L” bracket and then mounted to the highest point of the grain leg (tower). It used about 10′ of RG-58 coax to a barrel connector, and then to the 100′ run of RG-8 going into the shack.The antenna has about 3dbi gain.

I had a VHF 5/8wave x2 mobile antenna at home, that the digipeater previously used. It has 6dbi gain. I got a 6′ long 1/2″ thick electrical conduit pipe from my step dad. He had some laying in his junk pile. that was nice, since I didnt have to use my 10′ section that I had planned for another project.

At the site I noticed that I had a long coax run into the shack and I could easily re-route it at the bottom to save some coax. Redoing it gained me about 12 feed of extra length, so I slid it up, as I climbed the tower.

At the top I disconnected the existing antenna and left it in place, for future/backup use, for my live scanner feeds at that site. I mounted the 6′ pole and new antenna to the top of the silo leg rail. The bottom of the antenna is now above head height, in case anyone happens to be working at the top, while it transmits. I happened to have almost exactly the right amount of extra coax. It has about 6-8″ of extra room, so it turned out perfect.I removed 1 barrel connector and 10′ of RG-58. This should help reduce some line loss.

Before the antenna upgrade, it was hearing a digipeater (KB8VEE-11) from 94.8 miles away. I was hoping to break the 100 mile distance. After the antenna upgrade, I am now hearing multiple stations regularly, around 103-130 miles away. This is a great improvement. Sure they are other tall digipeaters, but it proves that the extra 3dbi gain and less coax loss really helps out.

I still plan to upgrade the antenna 1 more time, to use a dual-band antenna, for APRS and GMRS. The farmer who owns the site wants to use a GMRS repeater, so Ill set one up for him. Id like to share 1 antenna, to avoid using another coax run.

Old Antenna On Left, New Antenna On Right

Update your APRS position via Text Msg

February 19, 2012 MRodgers No comments

APRS can be confusing for a beginner and even some experts. Equipment can be found easily, but it can cost a lot to buy and piece together. Some new handhelds like the Yaesu VX-8 and some D-Star radios can do APRS positioning right out of the box, but they still cost $500+ new.

Want to post your APRS position for FREE?
Want to do it without any software to download and learn?
Want to do it anywhere?
Want to do it easily?
That’s what I was thinking too!

Introducing APRS via Text Message!

I wrote an script using Tropo, (a voice, sms, Twitter and IM cloud server) that enables you to simply send a text message to a phone number, with your callsign and position, and it will be automatically posted to the APRS network.

Want to know how to do it? I bet you do…

My 1st tower site

December 20, 2011 MRodgers No comments

I have been looking all over the surrounding counties, talking to local farmers, asking them if I can use their grain silos for an antenna tower site for Ham Radio use.

I talked to one generous farmer, who instantly said YES to allowing me to use his site. I didnt even need to show him the paperwork with what I wanted to do and install. He is allowing me unrestricted access to the site and the “shack” at the bottom.

It is 90′ tall, with a ground elevation of 720′. It is located on a hill of aprox 60′, so the coverage is good. The grain leg has a ladder that goes up to 3 different levels,which 2 of them are easily usable.

So far I have just installed a VHF 5/8 wave mobile antenna at the top level with 120′ of RG-8 coax. Both will be upgraded later with better equipment. For now, they will serve their purpose for scanner feeds and a APRS receiver /iGate.

: Farm Silo Ham Radio Antenna Site

: Looking up at platforms

: Looking up at silo platforms

: 2Meter 5/8 wave antenna for scanner feeds & APRS

: Looking up at VHF antenna

: 5.7Ghz Ubiquiti Nano WISP antenna

: Equipment “shack” at bottom of tower

: Equipment “shack” at bottom of tower

Repeaters can be digipeaters too

September 28, 2011 MRodgers No comments

Almost every Ham Radio club has a 2meter repeater. Lots have 440 repeaters. Only some have a APRS digipeater. If they even do have a APRS digipeater, its almost always an afterthought and not a great setup.Why is it that the repeater gets the nice 200+ foot tower location and the digi gets the mag mount stuck on someone’s mobile home roof?

APRS Map Widget for WordPress

August 02, 2011 MRodgers No comments

APRS Map Widget for WordPress
This Plugin widget allows you to easily display your APRS location on your WordPress blog, without editing any code. Simply add your Callsign-SSID, add a title, and edit the height and width, if needed.

Digipeater Status Script

July 28, 2011 MRodgers No comments

I wrote this code so I can check the Working / Down status of my APRS Digipeater.
I have made this code very easy for anyone else to use for their systems.
It checks the Callsign-SSID on APRSsearch.net for the last status update time.
You simply need to enter the following:

Callsign-SSID
Your E-Mail info for the alert to be sent to
Your Working / Down time

KC8GRQ-1 APRS Digipeater

July 26, 2011 MRodgers No comments

KC8GRQ-1

This is my main digipeater. The callsign is KC8GRQ-1.
The system runs an older, but rugged Azden PCS-4000 mobile radio. I got the radio for $5 at a local swap, because the mic audio didnt work. It turns out it was just a bad mic element. It didnt matter since I dont need the mic anyways.
Its on a small 2.5 amp power supply, which is enough for the 10w output power that I have it set at.