Category: Software

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PI2NOS receiver mapOur local repeater in Hilversum, PI2NOS is undergoing some real exciting changes at the moment. Due to regulations this is one of the 70cm repeaters that is not bound to regional reach. That means it may be capable to receive and transmit in the whole country. Traditionally PI2NOS is situated in Hilversum with it’s antenna’s on a broadcast mast at 200 meters (656 feet) above sea level. It has a transmit range of almost all of The Netherlands. Receive range is a little bit smaller, especially of little local signals like hand helds. This is why the operators of the repeater adapted diversity to place more receivers for the repeater on high locations in the country. At the moment there are extra receivers in Utrecht, Amsterdam, Apeldoorn and Zierikzee. When you look at the map of The Netherlands, you’ll see that’s a nice circle around the center. There are plans to widen that circle and place even more receivers. There are plans to use extra transmitters to expand the reach of the repeater to the far ends of the country.

Mischa PA1OKZ, one of the operators of PI2NOS asked me if I want to develop a webpage to get a live view of the receiver status (for instance, which receiver is active at the moment). I did some coordination with Rob PE1CHL, the programmer of the repeater software of PI2NOS. Rob did write some excellent piece of code that is readable with JQuery on the client side. Rob did write a piece of example code to show how it works. Since Rob and me were talking about this subject on the repeater, more people who are able to code, listen in. Like René PC7X, Edwin PE1NMB and Rolf PE1PTP. In no-time they wrote excellent clients that plot the various receivers on a map.
Thereafter my mailbox exploded with mails from these guys. Day and night they are coding and exchange idea’s via mail. In the meantime the various pages become more and more beautiful and the users of the repeater more enthusiast.
These developments are great, many people are putting in their time and effort to benefit the greater good. In the meantime I’m designing a new website for this repeater which will hold the receiver map as well.

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Solution to APRS-holeThere is a APRS-hole in my daily commute route. On my daily bike ride of 18 kilometers (11,2 miles) one way I have APRS switched on on my Kenwood TH-D72. The Netherlands has a pretty wide network of APRS digipeaters. When my packets hits one of those digipeaters, I’ll show up on aprs.fi. Because of my low power and very small antenna not all of my packets hit a digipeater on my way to work or home. Near my QTH in Hilversum is the hardest, a real APRS-hole. When I’m half way near Maartensdijk, all my packets are picked up in Utrecht by PI1APU. I already tried to put on my own digipeater (my Kenwood TM-D710) at home. It doesn’t improve much. That’s because Hilversum is on a big hill and when I’m behind it near Hollandsche Rading, my TH-D72 can’t get it’s packets over it.
A solution would be to fill this APRS-hole with a APRS-receive point in or near Hollandsche Rading. Happens to be that Wilko, PA3BWK lives there and I asked Wilko if it is OK when I put up a APRS-receiver at his place. Wilko likes experiments so I’m glad he is willing to co-operate.
Now I have to find a simple cheap solution to set-up an iGate (APRS RF receive – internet link). Googling around gives me a Polish solution: a Raspberry Pi (or Cubieboard) with a RTL-SDR-stick.
I do have a Raspberry Pi laying around which I can use for testing. I think I will order a RTL-SDR-stick from Alibaba.com for around 10 euro’s soon. I will test this solution on my QTH first to see if it works properly. If it does, I move the setup to Wilko, PA3BWK. Hopefully my APRS-hole will disappear by then.
If it does, it might be interesting to build more of these simple iGates and place them in more APRS-holes. All it need is a little antenna outside and internet.

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This weekend I wanted to score some contacts in the Ukrainian RTTY contest. Saturday night at 21:00 local time I set down, opened a new log in N1MM with the appropriate contest and went off. But after 4 or 5 contacts I noticed N1MM keeps sending number 001. In the logging windows it shows the correct number but MMTTY keeps repeating 001 with each new contact. Aaargh, searching N1MM manual of several thousand pages didn’t come up with a solution. Double checked contest layout, all seems correct. Restart N1MM a few times. After an hour of searching I gave up. I didn’t had the time or the energy to search any more. I did want to participate in the contest for only a few hours anyway, now I blew the whole thing off.
Next time do some test sending exchanges first long before the contest starts!