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Setting up a digipeater

diamond

Well Known Member
I've read some good posts here on setting up an igate, but what if I just want to set up a digipeater? Are the equipment requirements the same as for an igate? What computer/software requirements, if any, are needed?
 
Digipeater Required Equipment

You'll need a radio (capable of transmitting), antenna, and an appropriate TNC. A digipeater doesn't necessarily need a computer or software (except for the initial setup).

While I don't have firsthand experience with it, if I were putting up a digi today I would choose a TNC-X (http://www.tnc-x.com/XDigi.htm). The group I was last involved with used the ubiquitous Kantronics KPC-3s on their standalone hilltop digi.
 
Thanks Joe
What would you recommend for a radio and antenna? Currently I have neither. My digipeater needs to be able to transmit a strong ground signal over relatively flat land for a minimum of 30 miles (the closest igate).
 
Radio and Antenna

I haven't bought a radio or even an antenna in years but that's a good question to ask some of your local ham buddies. The one who runs the digipeater you're trying to hit should be knowledgeable.

My own station (an Igate that I occasionally allow to digi) uses a converted commercial radio and a quarter-wave groundplane antenna. I felt it was important to have a decent radio to co-exist with all my other RF stuff but YMMV. High on my list of criteria is a radio that's easy to pipe audio in and out of (i.e. existing rear apron connectors or at least a schematic so I can solder in my own).

I also feel it's important to have solid-state transmit-receive switching instead of a mechanical relay as there will be a lot of changeovers in digipeater service.

That said, nearly any radio with 5-10W or more of output will do the job. But again, I'd suggest talking with some local hams. Often a radio can be obtained for free or cheap, and the antenna can be homebrewed.

73,
Joe (K7JD)
http://www.mail2600.com/cgi-bin/position.cgi?call=K7JD-7
 
Digipeater

Our MT-TT4 combines a low power radio and a controller in one 5 X 5 inch package. You only need a computer to program it; it runs as a standalone hardware Digipeater. We have a 10 Watt amplifier for these, but you can use any amp that can handle a 500 milliwatt drive level. Mirage makes some excellent amplifier models. www.byonics.com

Allen
VHS
 
So what's the difference in capabilities between the tnc-x and the mt-tt4 other than the fact that the mt-tt4 is more than 3X the cost of the tnc-x with xdigi board? Guess I need to go back and read more on these 2 units.
 
Differences between TNC-X and the MT-TT4

The TNC-X, when combined with a uDigi board, is a TNC (terminal Node controller) Together, these products cost $116.00. These are roughly comparable in function to the Byonics TT4, which sells for $65.00 in kit form, and $75.00 assembled. The TNC-X has a nice metal case, the TT4 is sold as a board level product

The MT-TT4 combines a radio transceiver operating on 144.390, with the TT4 controller, packaged in a small plastic enclosure. This can function as a tracker, a digipeater, an APRS weather station, and other functions, including sending multiple channels of radio telemetry. The MT-TT4 allows you to plug in a PS/2 keyboard for sending APRS messages, and for changing the configuration of the tracker/digi. The MT-TT4 has an output to allow you to hook up an external LCD display, which is handy to have when you set up your digi, since it will display the received signals from other stations.

The TNC-x uses a modem chip to decode 1200 baud data-the only format it can receive. The MT-TT4 (and the TT4) use software decoding , so it can process any type of signal ( different baud rates, TouchTones, etc) and it can transmit pretty much anything that Byonics can write for it.

The TNC-X is a nice unit, but its just an encoder/decoder for APRS, adding the uDigi board makes it a digipeater, but you need to have it connected to a transceiver to make it work as a digipeater.

Either of these two techniques, (TNC-X, plus Digi module, plus radio) or the MT-TT4 ( self contained unit, or two parts if you want the 10 Watt amplifier) are good approaches to building a digi without having to dedicate a PC to the job. The MT-TT4 eliminates most of the difficulties you might encounter with trying to mate a radio to a TNC ( which can be a pain with either the regular TT4 or the TNC-X) and all you have to do is set up the configuration on a PC, add power and an antenna, and you are on the air.

Allen
VHS
 
Allen
You say the MT-TT4 can function as an aprs weather station. What equipment would be needed in order to run this as a weather station that measures and reports wind, temperature, and rainfall? Would such equipment be cost prohibitive for the small scale operator like myself?
 
Weather Stations

Since I am not actively involved with the weather station end of things, I would steer you to Byon at Byonics to answer compatibility questions. Basically you can plug in a hardware based weather station with an RS-232 serial output. Peet Brothers I, believe, makes compatible units. Also, since the MT-TT4 has telemetry inputs, you can read a number of sensors connected to these ports as a voltage level of 0 to 5 volts. I understand that a number of people are using these to monitor sensors at remote cabins, etc. and you don't need a weather station to make that happen.

Allen
VHS
 
Wow, now you got me thinking of all kinds of APRS possibilities. When you said "remote cabin", I thought of my own remote cabin and how cool it would be if I could install a motion-activated camera connected to a controller and radio to transmit photos via APRS/digipeater/igate, etc. Is that within the capabilities of APRS or is that just fantasy?
 
APRS transmissions

The APRS network is set up to handle relatively short, small (packets) of data. The amount of information sent in image files is enormous, but you could certainly use APRS to send you notifications, and then monitor or trigger SSTV ( slow scan TV) or more conventional ATV (amateur television ) video. There may even be a video repeater in range of your cabin if you are lucky, or you could build one yourself. I would check out hamtv.com, they are sometimes a little..... well, short, shall we say with newbies, but they have good gear and good info.

Allen
VHS
 
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