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Icom DD Mode - ID-1, RP-1D/2D and D-Star L-Band General Advice
DD Mode data "repeater" modules are very easy to set up in standalone or "bring your own Linux server" mode.  Plug it in, set the callsign, frequency and IP address/mask via the USB connector and Windows software. Set the Ethernet to "on" and turn off the gateway and links (unless you have some). Then you are good to go. Computers using ID1 radios in the same IP subnet as the repeater can now talk to the repeater, and the Ethernet on the back. We are not fans of DHCP at this point. If your radio does not talk the repeater assume you have RF path problems - the repeaters and protocols seem bulletproof to us. Do not put an ID-1 or a repeater controller on a busy Ethernet hub. They can act like bridges and will bridge all kinds of trash onto the RF path

This frequency band (L-Band) does not provide the "bonus propagation" we have seen on 2 meters. On 2 meters, in our experience, if you put a radio and an 18 inch piece of coat hanger in the air you are good to go. On microwave bands you need line of sight coverage and good antennas and connectors and feed lines.

We have not had good luck with NMO mobile antenna mounts on 1.2G-Alan says they do not look good on his analyzer. The Comet N base mobile antenna systems work great. Radio City stocks them. I have used the Comet 1.2 mobile antennas for years- they are rated to 2.4Ghz.

Invest in an SWR bridge for this band. The Comet CM-120 was about $70.00. You put your ID-1 into FM mode, and press the Push to talk button and ID and you get 10 watts of RF to test your antenna. The lack of obvious adjustments on the repeater (none) is good news and bad news. The bad news is you can't tweak anything. The good news is these are plug and play RF wise and you don't need to tweak them.

The ID-1 settings are a little mysterious. For one to work you need to set it up, and have a good signal to the repeater. On the left is the signal going up then the right is the signal coming down. If you are not seeing displays like this it is likely you have an RF problem. You can test SWR- get an SWR bridge (Comet makes one) and put the rig into FM simplex, tune to a proper FM simplex frequency, key the mic and ID. It's tricky to test SWR on the digital signals. In the case here, KE8TX is the repeater.
1. Computer set with an Ethernet interface on the right fixed IP address and subnet. We do not use DHCP currently (other groups might be).... So for the Mining ARC system you might use 172.16.0.56 as an address for your PC (2-254 are legal, skip .20) and 255.255.255.0 as the subnet mask. We have tended to set the default gateway to the base address of the repeater or the Ethernet on the repeater 172.16.0.20 - no data here on what is best- you can set a DNS server- use the Ethernet address 172.16.0.20 Turn off all the other services on the interface- Netbios, 802.1x, etc. For starters, turn off your other Ethernet interfaces, Internet, etc just until it works the first time. This seems to work both with and without a default gateway set.

2. Use an Ethernet cable not a crossover. And not a switch or hub unless you are the only station(s) on it.

3. Turn on the ID-1 and put in your settings - you need to set your personal callsign "my" TwinsLAN/3M repeater: Your: KC0TQI A RPTR1: KC0TQI G GW: checked - the gateway symbol tells the repeater to direct traffic to the Ethernet interface on the repeater, which is either off, running the Icom Gateway Software or in our case, a Linux appliance running our web server and DNAT etc.

4. The Ethernet should come up (layer 1/2) on the computer, and the lights on the radio should flash when you ping the repeater, and you should see a little boxed lightning bolt flash (xmit) and a little three bar s-meter symbol flash (rx data). The callsign of the repeater should flash on the radio display.

5. If that works you can try the repeater web site - 172.16.0.20 - if that works you are good to go.

I have this working on Windows Server 2008 RC0 in my lab here, and it works with XP and Linux. The ID-1 programming software does not yet support Linux. I have the Internet going on one computer interface and D-Star on the other today - that is pretty cool.
Don't even think of antennas with less than about 11-14 dbi of gain - losses are everywhere on this band- discones are rated for 1.2 but are useless.

Long cable runs are not your friend. This equipment will not work on towers with the gear at the base unless you have top end hardline (1 5/8" like the cell phone folks use).

We think remote mounting of the ID-1 base unit is a good idea. It draws 7 amps and is rated for 14f to 140f - not bad.

Use only N/SMA/BNC/DIN connectors (there in an N plug out that is like a PL259 and easy to solder on), and avoid RG8/RG58 etc. Each adapter or jumper adds loss. 

Make sure lightning arrestors you use are rated for this band

Slight antenna movement /adjustment might help - we aim antennas with ping- fire up "ping -t" under Windows(r) to your repeater, and aim the antenna until you get the fewest lost packets. The inventors of ping might be surprised by the use of their software for aiming antennas.

Our experience is the general behavior of radios, repeater range, etc of 1.2G is like 440M - NY9D designed and built a 1.2 FM voice repeater years ago from scratch and ran it for years - even published an article in 73 Magazine on it. Accept no "advice" on this band from people who do not own/use/build equipment for it. There are many myths around.

ID-1s do not have IP addresses - they just use callsigns - your data goes encapsulated in callsign headers . We are not using DHCP- your computer on the ID-1 needs a fixed address in the same range as the address on the repeater/gateway you wish to reach or other station you wish to reach. Other repeater owners may be using different systems. We are using fixed IP subnets, a different one per repeater. The idea is then we can use a router to link the back end Linux systems.

We see around 100ms of per hop RT latency on ID-1s

L-Band DD mode is not duplex- it's simplex, so excess broadcast packets, unattended data streams, linking on the same channel are not good. These are called "repeaters" but are not in the FCC sense of the word.

We have had good luck with two multiband antennas here- the Comet GP95 *** ($160) and MFJ 1532N ** ($99)- 4.5db (2m), 8.3db (440) and 11.7 db (1.2) - both are one piece and suited for building tops and tall places

Doug Reed N0NAS (9/9/07) thinks ID-1's don't mind having home type routers attached to them- you can support multiple TCP/IP sessions through one radio-radio (callsign to callsign) "tunnel" in essence- not a hub/switch with a lot of devices on it...The radio otherwise takes all it hears with an IP address on the Ethernet wire and sends it out the RF end.

Windows Update is a good thing but not with D-Star + Internet gateways. If your computer wants to check for updates and it thinks there is Internet someplace on your D-Star system it will fire up and go- the Marine Corps Marathon folks found this out during their race
Project List 2/12
If you combine the requests of our various served agencies, a Statewide buildout of D-Star repeaters makes sense.  In many "sunny day" scenarios, such as flood relief, you can have live contact between a helicopter in Moorhead and the State EOC in St Paul.  You can move a lot of messages.  On a wide (State/Region) area this of course assumes the Internet is up.  Our systems can be linked via private fiber/microwave/RF etc.  The D-Star systems (as we have now proven) are very useful in unlinked mode- for high speed data and voice/data in area wide deploments.  There is again an article in March 2012 QST (Oregon ARES P.80) suggesting the message handling rates on the current "accepted" emergency communications systems (Winlink/Pactor) are insufficient.  The math is fascinating - they had a 120 operators, and handled 5 messages/minute.  Our system, per DD repeater, can handle 5 messages per second.  In the Twin Cites, any given emergency van can "see" up to three of our repeaters as a time - 3x90 kbps = 15 messages/second. 

1. Get TWINSLAN to buy a D-Star controller for their lab.  We do keep taking every piece of gear and putting it up on our sites on the air.  This has limited our bench R&D capabilities. 

2. Get the State EOC set up with a DV Dongle.  They are in range of STPONE - which is unlinked.  The good news- STPONE cannot be taken offline from the Internet. 

D-Star DD Mode FAQ 2/15/12
1. Why are you using separate IP subnets for each unlinked DD repeater? This makes us reconfigure the Ethernet on our computer when we change repeaters. We don't understand the linking protocol Icom uses, and can't afford to buy the official link radios @$5000 per end. So we will have to link the Linux appliance computers themselves. You can't IP route easily between the same subnets. So we are setting up separate subnets per repeater. You just pick an IP address ( not .1 or .20) and go.

2. What about Kenwood and Yaesu? Kenwood has announced a D-Star radio in Japan. My take is they are doing everything they can to fight D-Star. They have plenty of support in this battle. The full page "Packet is the Future" ads from Kenwood. are a hoot. We'll see who wins :-)

3. What is the range on 1.2? It's about like UHF. Line of sight - so 10-12 miles from a big rooftop for tower-tower. It is whatever the RF Path Study says. There is no magic.

4. What do you mean by Internet? We use "The Internet" to refer to the commercial information service. We use TCP/IP over Amateur Radio to refer to our plans for linking, and is the underlying protocol at some level for DD Mode. We use TCP/IP over 802.11 (Part 15) as a linking and short range option as well. The use of Part 15 off the shelf technology and frequencies allows encryption, Internet access and does not require licensed control operators.

5. The cost of ID-1s is a big impediment for home stations and casual user adoption. Yes that this true but we want to build credible shared infrastructure and deployable assets. You can get on AX.25 packet radio for $50- but almost no one does. The role of casual home users in tactical, large scale emergency services is not clear to me. In Pandemic Influenza under quarantine type conditions, this is of course different, but home users would not need high bandwidth? So existing packet, low speed data, Airmail, Winlink 2000 would seem fine.

6. Can you use D-Star DD for routine public Internet access? No - it's not legal. Other/commercial radio services (Satellite, 2G/3G, 802.11 etc) offer commercial Internet over essentially the entire USA.

FCC Part 97.113:. (prohibited Part 97 operations)

(5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services.

7. Do you support encryption?  Read the Part 97 rules.  You don't need encryption to provide many forms of backup emergency communications. All forms of commercial communications support encryption, and if they are calling us (Ham Radio) things are bad. You can creatively solve some short term message authentication problems with one time pads of unique message sequence numbers, and tactical names for sites, etc. Operators of digital message forwarding systems on the other hand are required by the FCC to authenticate users to limit their liability on illegal traffic. For that we think a digital signature aka "digital callsign" is a good idea. A digital callsign does not obscure anything. And we can see an agency wanting to use an SSL protected website. This is fully legal in an emergency, and not legal on a routine basis so we are covered.

9. What do you tell served agencies? We say we are the fifth tier emergency communications network for them. "If all else fails" as the ARRL bumper sticker says.

Normal commercial data services > Normal commercial voice services incl. Fax > Normal commercial wireless services > Sat phones > US

10. Do you worry about having a single platform vendor. No. 80+% of the routers in the world are from one vendor (Cisco) so it has not been an issue there either.

11. Is this network a "Common Carrier" that competes with other Common Carriers? No. A Common Carrier (see Wikipedia) serves the public. This network only serves FCC licensed Amateur Operators on Part 97 frequencies.

Our main software, Trivnetdb, is available here: http://kb8zqz.org/trivnetdb/