Will the board work with my radio?

The short answer is -- if your radio provides access to the receiver's discriminator without filtering, and access to the transmitter's modulator without filtering, then yes, your radio will probably work.  By far the easiest way to ensure the above is to use a radio that supports 9600 Data, typically for Packet.  Many of these radios provide a standard 6-pin Mini DIN connector on the back, but some radios use a DSub9 or other connector. 

If thinking about buying a particular radio for your Hotspot, find that radio's manual on the internet and check the back panel documentation for a Data connector.

You can also check the Radio Files section of the gmsk_dv_node Yahoo Group to see if anyone has already documented that radio for use with a Hotspot.

Note: if you are adept at reading schematics and can add a small modification to a radio, you usually can find the tap points for discriminator and modulator and convert radios lacking the 9600 Data port.

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What's Linking?  What are the different linking systems?

DPlus was the first and arguably still the most popular linking system.  It was developed by Robin Cutshaw AA4RC to make it easy to connect repeaters to other repeaters.  He also created the DPlus Reflectors, named REFnnnx as in REF001C.  Hotspots running DVAR, WinDV, G4KLX and similar software can be configured to link the Hotspot or homebrew repeater to DPlus Repeaters and Reflectors -- as a DPlus Client.  So you can link OUT to DPlus systems.  Normally you cannot have ICOM G2 repeaters find your homebrew system and link IN.  DPlus authenticates by verifying the callsign is registered at a G2 repeater/gateway.  See more about registration here.  You can see a list of REF reflectors here.

DExtra was created by Scott Lawson KI4KLF. DExtra reflectors are named XRFnnnx as in XRF001A. It does authenticate to the G2 database, so registration is less of a problem. It uses different procedures to "talk" between a client the the reflector.  XRF reflectors will also support DPlus-style link requests, to allow DPlus-only clients to connect and talk.  Ramesh Dhami VA3UV now supports DExtra as part of the FreeStar system.

DCS is an extension of DExtra, but DCS reflectors do not support DPLus linking requests.  DCS reflectors are popular in Europe, but can be found worldwide.  You can see a list of DCS reflectors here.

DVAR can link to DPLus systems.  WinDV, G4KLX and some other homebrew software support linking to all three types of reflectors.

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What's callsign registration? What should my Node Callsign be and must I register it?

Most people want their Hotspot to be able to issue DPlus Link requests so they can connect to DPlus-enabled repeaters and connectors, so this answer will focus on that need.  However, if you don't plan to do DPlus linking, rather DExtra to XRF reflectors or DCS linking exclusively, this answer does not apply to you.

DPlus is an application that repeater administrators add to their gateways, and most reflector owners choose to utilize the DPlus Reflector application.  DPlus, in an attempt to ensure only authentic callsigns are allowed to connect and transmit over remote repeaters, checks to make sure the callsigns involved are already properly registered terminals on a US Trust-connected repeater.  See Step 1 at http://www.k6jm.com/hs-setup.htm. 

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What is Callsign Routing and what is ircDDB?

Callsign Routing is an excellent feature of the D-Star specification, but it is a little harder to use that first time, so many (most?) people get started using only DPlus linking.  But as they get more knowledgeable, many people also learn to use Callsign Routing.  There are two major reasons:

• You can Callsign Route to a friend who is mobile or travels, and you don't necessarily know what repeater or reflector he's hanging out on right now.  Callsign Routing allows you to ask the D-Star network to find the most recent repeater where he's been heard, and route your transmission there.  This is neat stuff.

• You can use the STARnet Digital system of creating or joining various groups, so that you can easily contact hams in a group without having to know where in the D-Star world they are right now.  Click here to join the STARnet Digital Yahoo Group.

Your Hotspot can be configured to do callsign routing and accept incoming callsign routing transmissions.  DVAR software does not support this, but the DUTCH*Star WinDV does, since it supports ircDDB (learn more).  In addition to WinDV, people also use Jonathan Naylor G4KLX's Repeater Controller with his ircDDB Gateway software, but for simplicity, this FAQ will focus on WinDV. The following assumes you want to be able to do both Callsign Routing and Dplus Linking.

ircDDB requires that your Hotspot or full duplex repeater must have a different callsign from your own personal MyCall callsign.  This is your "gateway callsign."  These callsigns are obtained in different ways in various countries.  For example, in the US, this is gotten by forming a club and requesting a club callsign (http://www.k6jm.com/usasetupclub.htm).

Summary:

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I have enabled ircDDB in WinDV, but it keeps disconnecting me.  Why?

See the above question, but the short answer is you need to register you callsign in the ircDDB database.  Click here to go to their registration page.

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I'm trying out my Hotspot for the 1st time, and I can't get the receive test to work.  What should I do?

• Start out with RX trimpot in the middle
• Using your receive test tool (e.g. NAWinTOOLS RF Read) transmit with your D-Star radio, typically an HT, but it doesn't have to be. 
  • You want to see the callsign headers decoded at the top of the window, and for NAWinTools, you want to see the received data scroll in the RF Data section of the window.  And, you want to see on the right, the first line of each data block highlighted in green.
  • If you don't like what you see, or you don't get anything, then go into your firmware config program (e.g. NAWinCFG) and toggle the RX Invert setting, then go back to your RF Read test and try again.
  • Once it kind of works, you can tweak the RX trimpot if you think it needs it.  In my experience, the RX trimpot in the middle works with most radios.

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I'm trying out my Hotspot for the 1st time, and I can't get the transmit test to work.  What should I do?

• Once the receive test (e.g. RF Read) works, move on to the transmit test (e.g. Echo Test). 
  • When you transmit, the window should say it is recording
  • When you let up on PTT, it should have your Hotspot radio go into Transmit mode, and hopefully your D-Star radio can decode it. 
  • If it doesn't work, first thing is to go into the firmware program (e.g. NAWinCFG) and toggle TX Invert, then go back to Echo Test and try again
  • Once it kind of works, tweak the TX trimpot for best decoding.  Kenwood radios almost always give garbled or R2D2 audio when the TX trimpot is centered, and you have to turn it up almost to max.  Other radios need to be backed off, and still others have a very narrow sweet spot.  Setting the TX trimpot is more critical than the RX trimpot, but only worry about it once you get TX Invert right.
  • If you use DUTCH*Star firmware, I recommend you uncheck AutoPolarity and manually test until you find the correct RX and TX Invert settings for your radio.

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I can connect my Hotspot to a repeater and hear them, but they can't hear me.  Why?

The cause is either DPlus authentication or your hotspot software is rejecting your RPT1 or RPT2 settings.

Authentication -- Remember that the MyCall in your D-Star radio must be a registered terminal, but also your Node Callsign and your Auth Callsign must also be registered terminals. Note: when Hotspots were starting up, the Node Callsign did not have to be registered, but DPlus was changed to now require this.  (The easiest way to comply is to use your callsign with a blank suffix for all three of the above.  But many people prefer a different convention and end up setting up three terminals with different suffixes.  See the callsign registration question above.)

RPT1 & RPT2 -- Programs like DVAR and WinDV have a setting which will check if your RPT1 and/or RPT2 values are valid or "proper."  If your D-Star radio is set for simplex operation (not DUP), then remember the radio ignores what you programmed in RPT1 and RPT2 and simply transmits "DIRECT" for those values.  The quick fix is to uncheck the setting ("Require proper RPT...").  Another way is to program your radio for DUP mode with a zero offset. 

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When my Hotspot transmits, the audio is a little garbled/R2D2.  What is causing this?

• Hotspot's transmitter is running too much power and overloads the D-Star radio's receiver.
• Hotspot's transmitted signal is disrupted between antenna and D-Star radio -- for example, if the Hotspot has an outside antenna placed fairly far away from the shack, and metal objects or even a metal roof disrupt the path of the signal, resulting either in a weakened signal or multipath -- note that mutlipath is probably the biggest enemy of a GMSK modulated signal.
• TX trimpot not quite adjusted to the sweetspot. Sometimes a bit of one of the above is combined with this problem.
• A variation of the above, rare but it does happen -- the radio's required TX audio level is outside the range of the TX trimpot. In that case, people have placed an appropriate resistor in the TX audio path to further reduce the audio level, or in extreme cases have had to change a resistor on the board to allow more drive to the transmitter. Again, this is rare.
• Analog radio's VFO is not quite on the exact same frequency as that of the D-Star radio. Some older analog fm radios have been measured and been off enough to cause this. In one case (my own Hotspot), instead of setting the hotspot's radio correctly, then locking the controls, I left lock off and accidentally banged the VFO knob and was transmitting slightly off frequency without realizing it.

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The text message on my D-Star radio is often garbled and not what was transmitted. Why?

In the D-Star protocol, the user message data is transmitted without error correction.  

Normally when people test at their QTH, their HT has excellent signal strength, so typically garbled text is not caused by a weak signal.  Some possible causes:

• TX trim pot, which controls FM deviation, is not set optimally.
• Too much power out of the analog FM radio that overwhelms the HT’s receiver.
• Multipath.  Metal roofs, house wiring or other metal obstructions can sometimes cause some multipath.  We have seen improvements by moving outside antennas to another location.