Frequently Asked Questions - Packet Radio

Questions related to Amateur packet radio

Most of the major TNC manufacturers (MFJ,Paccomm, Kantronix) have 9600 baud capable TNC\'s. Any TNC-2 clone (MFJ-1270C, etc.) will work with the TAPR/G3RUH 9600 modem added. The Timewave PK-96 (formerly AEA PK-96) is my (N7IPB) favorite simply because it seems to work well. The YAM modem works well and is inexpensive ($75). Baycom, Symek,and Wimo are all selling 9600 baud TNCs. It is important to remember that you cannot connect a 9600 baud TNC to a microphone connector on a radio as you can for 1200 and 2400 baud TNCs. The 9600 baud modem requires a direct connection to the radio\'s modulator and discriminator to work.

Most hams get their introduction to packet radio via 1200 baud and tnc' s connected to standard voice radios. Unfortunately when you go to higher speeds voice radios just won't cut it.

Higher speeds require that the radio have a wider bandwidth, clean unemphasized output and rx and tx turnaround times that are well under 100ms. Despite what manufacturers claim, none of the '9600 ready' amateur radios work well at all.

That's not to say that there aren't radios out there that work, just that it's unlikely you will be satisfied with any of the typical radios provided by ham manufacturers.

So, what do you use?

First, there are numerous older commercial radio's that can be converted to the ham bands, and that will work well. Radio's like the GE MVP, GE MASTR II, Motorola MITREK, Motorola MICOR, Motorola MAXTRAC and others. A little bit of web searching and you can find all kinds of conversion info.

Second there are radios designed for data that we've determined will work well.

- The TEKK KS series http://www.paccomm.com/tekk.html data radio was among the first to be used. We have a lot of them inuse and they work well. It's a crystal controlled 2 watt UHF radio that originally sold for around $150. They are no longer being sold by the manufacturer but can be found on Ebay occasionaly.

- The TEKK http://www.tekkinc.com/products/data/sd-5200.html synthesized radio will also work, although we don't have a lot of experience with it.

- The MAXON SD-125 synthesized radio when modified with wider IF filters also works well. You can either do the mods yourself, or buy it already modified from PACCOM, or unmodified from outfits like RFWIZ http://www.rfwiz.com/Maxon/DataRadios/SD-125V_SD-125U_DataRadio.htm. Their latest price was $181.

- The WIMO http:www/wimo.com/frameset_e.htm PRD-70 synthesized radio is our current best choice. It's a 16 channel radio, with power selectable as 1 or 10 watts. It sells for 195 EUR (about $240 US), has fast turn around times and works great. RECOMMENDED

- Then for those that have a big budget there is the SYMEK http://www.symek.com/g/index-g.html TRX4S High Speed Data Tranceiver http://www.symek.com/g/trx.htm. This is an excellent example of a radio designed for data from the ground up. It has various filters to allow it to operate from 9600 to 153,600 baud. It's tx/rx turnaround times are under 200 usec. The downside is the price, currently it's going for 936 EUR for the UHF model which is about $1150 US. This might be just the thing if you're building a repeater and have a big budget, but is just a little out of line for the average station. The KeyTower site uses a pair of these for the repeater so we know they work well.

OBSOLETE: Refers to the old packet network.

From a posting on the seatcp mailing list

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1. RIP for NOS users

WA7NWP, KA7PBI and myself have been experimenting lately with a unix program called ZEBRA that manages various routing protocols including RIP. We finally figured out all the appropriate commands to make it work on our rf links and have started to bring it up on various lans.

The new parameters broadcast a little more often, (once every two minutes) but in exchange we get a more rapid response to network changes.

Most of the Linux boxes have been configured with ZEBRA and email outlining the settings for those remaining will follow in a later posting. This email is for those running NOS and outlines the changes you need to make in order to work with the new settings.

For a refresher about the NOS RIP settings I found my original email outlining everything about the use of NOS and RIP for both end users and those acting as routers. Those emails are now in the seatcp archives.

See:

OBSOLETE: This refers to the old packet network Since we have a subnet addressing system in use, we need to know what Local Area Network (LAN) you're going to use in order to issue the proper address. There are several ways you can determine which LAN is best for you. Probably the easiest way is to use your existing Terminal Node Controller (TNC) firmware to make AX.25 level connects to several of the stations on a given LAN. In particular try to talk to one of the gateway stations. Send several messages and verify that you have a good path for long messages. A good test is to issue several 'help' requests and monitor how well you receive them. If you find out that you have trouble, try another LAN if possible. Washington Area TCP/IP LANS

Subnet LAN served/Baud Frequency Geographic area
100 South 1k2, 145.67 MHz, South King, North Pierce Counties
101 North 1k2, 147.60 MHz, South Snohomish, North King Counties
102 Camano 1k2, 147.40 MHz, Arlington - N Everett
103 220 9k6 RPTR, 224.56 MHz, Rptr on Gold Mtn, East of Bremerton\
104 West Seattle 1k2, 144.41 MHz, West Seattle
105 East 1k2, 144.95 MHz,NE King County - Gtwy-Pine Lake
106 Aberdeen 1k2, 144.91 MHz, Aberdeen/Hoquiam, Gtwy Cosmopolis Hill
107 Baldy 9k6 2M RPTR, 146.98 MHz, Rptr on Baldy Mtn near Enumclaw
108 East 9k6 UHF RPTR, 441.975 MHz, Rptr on Pine Lake Plateau near Issaquah
109 South 9k6 UHF RPTR, 442.125 MHz, Rptr at Lake Tapps, near Sumner
110 Northgate 9k6 UHF R,441.825 MHz, Rptr on Roosevelt Hill in Seattle
111 Bellingham 1k2, 144.95 MHz, Greater Bellingham
112 Skagit 1k2, 147.44 MHz, Skagit Valley
113 West 1k2, 145.65 MHz, West King County - Gateway in Ballard
114 Bothell 1k2, 144.97 MHz, Greater Bothell/Woodinville\r\n
115 Tacoma 9k6, 145.09 MHz, South Tacoma
116 Aberdeen UHF, tbd MHz, Aberdeen/Hoquiam - rptr proposed
117 Ocean Shores 1k2, tbd MHz, Saddle VHF
118 Kent Valley 1k2, 145.03 MHz, Renton-Kent-Seatac-Auburn
119 Olympia LAN, 147.40 MHz, Greater Olympia area
120 Poulsbo, 430.55 MHz, West Central Puget Sound
121 Clallam County, tbd MHz,North Olympic Peninsula
122 SE Snohomish, tbd MHz, SE Snohomish Co, gateway near Monroe
123 Seattle ACS 1K2 441.025 MHz, Seattle, hub at Space Needle
124 Port Ludlow, 145.05 MHz, Port Ludlow area

The following temporary IP addresses may be used for testing. You may use one or more of these until a permanent address is issued officially:

44.24.[subnet].254
44.24.[subnet].253
44.24.[subnet].252
44.24.[subnet].251

Use the appropriate subnet number for the LAN/subnet you will be testing on. Use these addresses at your own risk since someone else may have picked the same temporary number. Address numbers 44.24.[subnet].0 and 44.24.[subnet].255 are RESERVED for broadcast and network use, as per TCP/IP conventions.

"AMateur Packet Radio\".org is the top level domain registered along with the class A IP network 44.x.x.x by Brian Kantor, WB6CYT. When you get an ampr.org IP address assigned to you the local IP address coordinator will generally also create a host for you in the ampr.org domain that is maintained to this day by Brian. Usually something like callsign.ampr.org although there is no requirement that it be your call, nor that it be assigned to a net 44 address.

Select the 'IP Address' entry from the Navigation menu. Then click on the 'Automatic IP Address Request form' link and follow the directions.