D-Star and the ICOM IC-2820H

by N6XN

Updated February 2009

It's 18 months later and things have changed.  The IC2820H is still going strong and I've learned a lot about it's capabilities.  It has so many features that you have to play with it for hours to discover them all.

But what's new with DStar?  The most significant changes have come about by the introduction of Dplus, an add-on to the gateway software by Robin Cutshaw, AA4RC.  We are currently running version 2.2c and this rev provides some very significant changes to the way the radio is programmed.  In my opinion you can disregard most of the programming information shown below since Dplus provides for software linking of the DStar radio.  The biggest advantage to linking is that it allows the user to hear what's going on at the far end instead of just blindly calling. You can read about the new features http://www.opendstar.org/tools/readme.txt

Dplus is an evolving script and future releases are expected to do even more, but for now, the biggest improvement is the introduction of reflectors to the DStar system.  If you are familiar with IRLP you are already familiar with reflectors but if not, here's a brief description:  A reflector can be considered a "repeater repeater" meaning that it is a conference bridge into which any number of repeaters can be linked.  Any activity on any of the repeaters will be heard on all the other linked repeaters.  As an example, reflector-1C is located in Illinois at UI.  As of this writing there are 14 repeaters linked, most from the US but one in Canada and often there will be repeaters from the UK and Australia linked.  Any activity on any of these repeaters will be heard on all the others and users can talk to one another with no additional programming of their radios required.  The only requirement is that the operator program the UR: with CQCQCQ,  the RPT1: with the callsign and module* of the local repeater, RPT2: with the callsign and a "G" in the 8th position and finally his/her callsign in the MYcall position.
* The module is either A (1.2gHz), B (440 mHz) or C (144 mHz). The module letter always goes in the 8th position of the memory channel no matter how many characters there are in the repeater callsign.

Many/most DStar systems allow users to perform the linking functions as long as some common courtesies are observed.  If you are not sure, contact the administrator of your local repeater.  Let's say, as an example that your local repeater, W6XYZ module B is currently unlinked and you want to see if there is any activity on Reflector-1C.  If you have a PC handy you can look at the status of this reflector by going to http://ref001.dstargateway.org/  (change the 001 to any of the other 14  reflectors for other views)
Now change your UR: to REF001CL and press your PTT for one or two seconds.  If the link is successful you will hear a voice announcement saying "Remote System Linked".  Now switch your UR: to CQCQCQ and you are ready to make a call on the reflector or answer anyone you hear.  When you are finished with the reflector, return it to the state in which you found it.  To unlink, change your UR: to ^^^^^^^U (^=space and U goes in position 8). Press the PTT for one or two seconds and you should hear "Remote System Unlinked".  Once again, return your UR: to CQCQCQ.  It's a good idea to keep one memory channel setup like this so that you are ready to talk to anyone you hear.  You should have a second memory channel set up the same way but with the RPT2 blank so that you can talk on your local repeater without going out over the gateway.

Operators can also link to other repeaters instead of reflectors.  To do this, change the UR: to XXNYYYML Where XXNYYY is the callsign of the repeater to which you want to link, M is the module, and L is the command to link.  Once you hear the announcement "Remote System Linked", change your UR: back to CQCQCQ and you are ready to go. When you key up you will be using the remote repeater as if you were there.  When you are finished be sure to unlink in the same way as you did with the reflector example above.
Another big change brought about by Dplus 2.2c is the need to avoid callsign routing or "slash" routing if the repeater is currently linked.  Doing so won't really hurt anything but it can cause confusion.  For example, if you should use callsign routing and the station you are calling is on a repeater that is linked, he won't know if you are calling through the reflector or not.  He won't be able to answer you without pressing his one-touch button and even then, other stations on the reflector will only hear one side of the conversation.  There are many other features made available through Dplus so have a look at the readme file above and see for yourself.  Watch that website for future changes as they being released fairly often.  In just a few months, this entire page will probably be obsolete.

***

The 2820H is an amazing radio.  It looks a little like the 2720 and you can tell it's related but it's clearly the 2nd generation.  You still need a computer to program the thing but that's probably true of most of the newer multi-function radios.  The instruction manual, another classic garblespeak, has detailed instructions on programming the radio using either the buttons on the front panel or the HM-133 microphone.  Given enough time, I suppose you could do it but it would put an inordinate amount of wear on the knobs and buttons.  In Icom's defense, the manual programming is a quantum step beyond the 2720.  This radio has a pair of VFO knobs which double as momentary contact switches, and infinite-rotation dial knobs.  They provide the user with good tactile feedback on both push and rotate.  Nearly every function is menu driven with the menu being displayed on the front panel (3-5/8" x 1-1/4"). The main menu comes up with a single push of the Function button.  The sub menus line up with 7 buttons on the bottom of the screen; pressing any of them brings up a sub-sub-menu which can then be browsed by rotating the VFO knob.  The desired function is then selected by pressing the VFO knob.
I'll stick to the computer method thanks.  The programming software is very similar to the 2720 software except it has many more screens to cover since the radio does so much more.  The basic radio does everything that the 2720 does plus all the D-Star functions, plus APRS with a built-in GPS module.
Transmitter output has been upped to 50 Watts on both bands and provisions for diversity reception have been incorporated in the radio.  What this means is if you are in an area where multipath distortion is often a problem (like my location) a second antenna can be attached, which would be located in a slightly different place (within the limits of coax loss of course) and the strongest signal is automatically selected.  The examples Icom uses are in mobile operation where "picket fencing" is a problem.  It would be interesting to experiment with this but of course a second, identical antenna would be required.

The memory's  have been expanded from 212 to  522.  The Banks have been expanded from 10 to 26.  At first you wonder what to do with all that memory but when you see the way the D-Star system works, you begin to get the picture!

D-Star may or may not be the wave of the future.  If you are familiar with APCO or P-25   more info  you will see that from a design standpoint the D-Star system is very much like it. The big push behind the P-25 initiative is to get all the public service communications systems digitized so they can be operated closer together.  The D-Star only occupies 6.25 kHz of bandwidth and the measured deviation is around 1.5 kHz (not much more than some PLs on conventional FM radios).  As a result if you should tune across a D-Star signal (and you will eventually) it will be very low in "Volume" and it will sound like white noise, similar to the squelch noise in your FM receiver.

Reception is interesting when compared to an analog repeater signal.  I monitored the Mt Diablo system all day yesterday and only heard a few stations but the audio was very surprising.  There was absolutely no background noise.  No white noise, no ker-chunk, no courtesy tones, no squelch tails, just a voice which sounded like it was coming out of a very clean intercom system.  What was really surprising was some of the voices were in the Bay area, others on the East coast, Alabama and Georgia, and several from Canada.  They all had identical clarity. A few days later, Saturday, activity picked up and the channels were quite busy.  Eventually I did hear signals that were less than full clarity.  There is a type of noise that replaces the audio when the user is in a bad area.  One description of the noise was "It sounds like R2D2" (Star Wars).  When the station increased his power the noise went away and clarity was restored.

I'm not completely competent on D-Star yet (and may never be) but here's how I think it works: I have 62 memory channels programmed for the Mt Diablo system on UHF and another 62 channels for VHF.  All of the UHF channels are one frequency: 444.3750 mHz.  All of the VHF channels are another frequency: 145.610 mHz.  I can listen on any of them and any traffic that comes up on either frequency will be heard.  If I want to answer the station heard however, I need to switch to the memory channel that is programmed for the repeater the other station is using.  Referring to the chart below, If the calling station announces that he is on "K6SOA-B" that tells me that I need to switch to memory channel 7. K6SOA by the way, is the South Orange ARS in Mission Viejo CA..  If I am watching the screen on the D-Star User's report See it here  I will also see his callsign and routing information come up on the screen.
I have to put my callsign in the radio before I can use it.  Thereafter, every transmission has my callsign as the "from" call. (mycall).  On the 2820 you can also put a short message such as your name and location, email address etc. so the other station can see it if he has the appropriate radio.  I also need to put a "to" call into the radio before I can make a call.  The "to" call (urcall)  can either be a specific callsign such as a repeater or it can be CQCQCQ in which case anyone hearing me can punch in my callsign and answer me.  The callsign section has two additional spaces. Repeater 1 and Repeater 2.  Repeater 1 would be the local repeater, in this case the one on Mt Diablo.  Repeater 2 would be one of two choices: 1) crossband to another module on the same stack, 2) the local gateway which would put you into the worldwide system. The Mt. Diablo system is linked to all other repeaters via the internet gateway, and you need to be a registered user in order to pass through the gateway.  I did this by contacting the repeater trustee and he added my callsign to his IP directory.  Now I'm good to go and can contact anyone I hear, from the bay area to the East Coast to Australia, Hawaii or Europe.  The gateway registration is good world-wide.  If I should travel to Australia and want to use the system in Darwin, I'm all set. (like that's going to happen!)
Thanks to Mark, KE6O,  I got a copy of the programming files from Tim, K6BIV, the repeater owner Tim's email and its a good thing.  I had no idea this is how it works.  Here are the first 9 channels on his files, keep in mind that there are 513 channels that I'm not showing you!  There are similar files available for the other D-Star radios; the ID-800, the ID-1 and the ID-91AD.  The files are ready to run using the ICOM programming software.

There are various ways for the sysop to set up his D-Star repeater but there are certain conventions that must be followed:  The A, B, and C that you see after the callsign in the Yourcall and repeater columns refer to the D-Star stack ^{note 1}, with A being 23 cm voice and data, B is the 70cm voice and C is 2 meter voice.  In the Rptr2 column the G after the callsign stands for gateway which is the internet "gate" into the worldwide D-Star network.  By setting up his programming in the following manner, the user can talk to any of the stations heard just by flipping to the appropriate channel.  The callsigns shown below are all D-Star systems, mostly club stations but many are privately owned.  If I want to talk to someone coming in through W6HDD Port C, I switch to channel 5.  If I switch to channel 4, I will crossband to the UHF module at W6HDD.  All of the other users in the area can also hear the QSO if they have their radios set right, but they cannot break in unless they input the callsign information.  On most of the D-Star radios, that's just a matter of pushing one button.
K6BIV has about 22 additional stations/repeaters in his file occupying memory channels 0 through 62, and 100 through 162.  The UHF system uses a standard 5 meg split, but check out the split on the VHF system below.  The IC-2820H does not require presetting an offset  for the digital channels, that is taken care of in the memory programming shown below. (I've omitted several columns to save space).  The digital channels also do not require a PL.