April 8, 2001

MAREX News, ISS Amatur Radio packet is on the AIR

Miles Mann MAREX-MG

(Manned Amateur Radio Experiment, North American Division)

Note, the proper call sign of the ISS has not been configured at this time.

On Sunday April 8, the call sign was NOCALL (that’s a O not a zero).

The call sign will eventually be programmed for R0ISS.

ISS UnProto mode

The ISS PMS (Personal Mail System) supports the Digital-repeating mode called UnProto. I am not going to get into too much detail about UnProto, for more information check Amateur radio handbooks and back issues of Amateur Radio magazine. Basically UnProto is a way of sending packet messages without requiring an acknowledgment from the other station. This mode is similar to RTTY in that, you can have several stations in one big QSO at the same time. Set your UnProto command in your TNC, on my KAM the syntax is " U CQ V R0ISS ". Then switch to Converse mode (enter K at cmd: prompt). Now everything you type will be transmitted in UnProto Mode. If the ISS station hears your transmission, the ISS PMS Digi will rebroadcast your information with a range of over a 1000 miles.

Snip from this weeks ISS

Don’t let the asterisk * after the call sing fool you. The call is not NOCALL*

It is NOCALL. The * means the packet was repeated by the station with the * after the call sign.

WB4APR-9>APK101,NOCALL*,RZ3DZR [04/08/01 19:55:14]: <<UI>>:

:BLNB :Its been a long time coming.0Mucho TNX to ARISS!

N4ZQ>ID,NOCALL* [04/08/01 19:55:34]: <<UI>>:

heard wb4apr-9

KB3GGU>SYPX0P,NOCALL* [04/08/01 19:56:55]: <<UI>>:

'h?"l "K\]testing via ISS

WB4APR-9>3X5Y8V,NOCALL*,RZ3DZR [04/08/01 19:57:00]: <<UI>>:

'h9Ql "v/]Welcome to ISS APRS!


Snip from a Mir QSO

WF1F>CQ,R0MIR*/V [04/21/93 22:22:09]: <UI>:

hi Tim can you work OSCAR 13?

N8DEU>CQ,R0MIR*/V [04/21/93 22:22:30]: <<UI>>:

Hi miles, yes what freq?

WF1F>CQ,R0MIR*/V [04/21/93 22:22:40]: <UI>:


The UnProto mode does not guarantee you message will ever be heard, but if the ISS Digi does rebroadcast your line of text, then you can be assured that someone saw it. The line of text you send will be repeated with an Asterisk after it, "R0ISS*/". If you do not see the Asterisk, then ISS did not hear your packet. UnProto does have its drawbacks, but it is much more efficient to use on ISS than the Direct two-way connect method. Full two-way packet connects via the ISS PMS are not recommended because they use up too much resources and excessive "Retires". Before you try Unproto on ISS, I recommend that you practice on a Terrestrial Digi first before attempting to use the ISS station for Digi-repeating. If you make a few UnProto calls and do not get any echoes back from ISS, it is probably because UnProto is turned off or because of a collision. Occasionally the System Operators may turn off Unproto (Digi = OFF) to improve the MailBox traffic flow. The Mailbox access should always have top priority over other traffic. Also there is a good time and a bad time to use the UnProto mode with ISS PMS.

Do not use UnProto when:

1. The ISS crew is operating in Voice mode.

  1. When the ISS PMS is connected to another station that is actively sending/receiving information from the Personal Message System (PMS). Any Index packets going to the R0ISS-1 address.

The only real safe time to use UnProto, is when the ISS PMS is in its 2-minute time-out mode. This time-out is caused when the station connected to the ISS PMS is out of range and cannot log out of ISS. No one can log into PMS Mail box (R0ISS-1) until the connected station times out. Time-outs are the best time to use UnProto. Before using UnProto, monitor ISS’s down link to see who is using the PMS Mail box port "R0ISS-1". If you do not seen any Index packets from ISS PMS to the ground station using to the "R0ISS-1" port for 60 seconds, you can assume the connected station is out of range of the ISS PMS and its "UnProto time".

The shorter the Unproto sentence, the greater your success of a PMS repeat. Long sentences may get clobbered by other stations. If you are in the middle of an Unproto QSO and you see someone connect to the PMS Mail box " R0ISS-1", you should end your Unproto QSO and let the Mail box users have access to the PMS.

Previous Testing of Two-way Connects via Mir:

In 1993 WA2GSY in New Jersey (now W2KQ) and I WF1F in Boston made arrangements to test the efficiency of FULL-TWO-WAY packet connects verses Unroto messages. Unfortunately I have lost the original logs from the test, but I do clearly remember the results. We made arrangements for the Mir Amateur Radio station to move to a private channel for a weekend. Then Joe and I attempted a Full-TWO-WAY packet Digi connect via the Mir PMS on a perfectly clear channel. The orbit was a perfect pass, traveling from Texas to Maine. The 10-minute pass had good elevation. Both of our stations were similarly equipped and running high gain antennas with approximately 1200 watts ERP of transmit power each. At the beginning of the pass, we sent a few Unproto packets, and then Joe issued the full two-way connect to my station. After the initial log-in we each sent each other two simple lines of ASCII text and then logged out. Now you must remember we had a perfectly clear channel. There were NO other stations on frequency because we had moved the PMS to a private channel. There was no interference from any ground stations.

It required over 4 minutes for us to exchange the 2 lines of text. The total number of packet transmission from all three transmitters was over 200 packets. Every packet, which I sent, had to be heard, acknowledged and retransmitted by the Mir PMS. The same packet was then sent to WA2GSY and had to be heard and acknowledge. The acknowledgment from WA2GSY then had to go back to Mir and Acknowledgement had to be re-broadcast from Mir back to my TNC. Four transmission are required for each original packet. However since my station in Boston cant hear when Joe’s system in New Jersey was transmitting, there were dozens of packet collisions. These collisions are what causes the efficiency of two-way packet to drop. With a full two way connect each packet sent must be acknowledged. This causes a tremendous amount of over head in this particular satellite configuration. The efficiency of full two way connects via Mir is less than 10% on a perfectly clear channel. Now if you add in the normal amount of traffic to the Mir public channel, you can see that full two way connects are a complete waist of time. The efficiency of Unproto on the other hand is greater than 50%. And Unproto is more band friendly.

The existing design of the TNC on ISS does not allow us to filter out the difference between Unproto and Two-way connects its just all or nothing. So we need to rely on your courteous corporation and for people to help spread the word on the correct operating procedures.

Good luck and let’s be courteous to everyone.

Remember, Only 1 station can connect to ISS's PMS at a time, and try avoid using UnProto when someone is actively using the PMS Mail Box.


Space Station Alpha gets a new Amateur Radio call sign:

The ISS ALPHA is keeping the international flair by hosting several amateur radio call signs from around the world. So far the ISS ALPHA has four calls signs from three different countries, Russia, USA and Germany. Also each of the crewmembers of expedition 1, has their own personal Amateur Radio call sign. The newest call sign is now R0ISS (R Zero ISS). The new call sign will become the official call sign of the Space station. You can expect the ISS crew to be using this call sign on both voice and packet operations. The new Club call signed was issued by the Russian government on December 12, 2000.

Russian Module call sign: RZ3DZR / R0ISS

Other club call signs ISS used: NA1SS, DL0ISS and ALPHA

Ground Station Link:

What will you need to Hear the ISS ALPHA Amateur Radio 2-meter Station.

That’s a tricky question because there are good orbit pass and poor low orbit passes. On a good 45 degree orbit pass, since the ISS ALPHA is only 250 miles high, you will be able to hear the 2-meter signal from the space station with a very small antenna (0 dBd to minus 12 dBd (rubber duck)). During a very low orbit passes under 20 degrees you may need a much larger antenna.

The Amateur Radio station on ISS ALPHA will be transmitting in the satellite 2-meter band (ITU 144.000 – 146.000 mc). I have listed a frequency chart below. The ISS ALPHA transmitter power output is approximately 3 watts, into a pair of co–phased vertical antennas rated at minus 3 dBd. There is one antenna on each side of the Service module. Both antennas are then connected to a power divider to split the transmit power evenly between the two antennas. The co-phased installation provides a good transmit and receive patter, with very little blocking of the signals by the bulk of the space station it’s self. I do not have the coax loss values at this time. This combination of power and antenna gain will provide an ERP rating of approximately 1.5 watts. The 1.5-watt value is not that bad, many stations have reported hearing the ISS crew talking to pre-arranged schools with the ISS Amateur Radio station and the signal reports were very good. If you only have a zero dBd gain antenna and a police scanner you will still be able to hear the ISS ALPHA on some good orbits. I have even heard ISS with a HT and Rubber duck (not recommended for quality reception).

(note: if your antenna is rated in dB rather than the correct dBd value, subtract 3 to convert the dB value to the correct dBd rating. The higher the dBd rating, the better the antenna.)

Suggested receiving station:

Casual listening for ISS ALPHA and Mir

2-meter vertical or scanner antenna (0 dBd or better)

Police scanner or amateur radio with the ability to receive in the 144 – 146 mc or MHz range, FM mode. Antenna cable should be a low loss RGפ style cable less than 100 feet long (RG-213 best choice). You will not need to mount the antenna very high, just try to get above the roof ridgeline. And of course you will need to find / buy a satellite tracking program. I recommend the InstantTrack 1.5. It’s a simple easy to use program, which can be purchased from Amsat.


ISS ALPHA frequencies:

The Amateur Radio frequencies for ISS ALPHA have been posted.


Worldwide downlink for voice and packet: 145.800

Worldwide packet uplink: 145.990

Region 1 voice uplink: 145.200

Region 2 & 3 voice uplink: 144.490

You will need to dig out the manual for your radio and program in the following frequency combinations. Note that some of the older FM mobile and Walkie-talkie HT style radios over 15 years old may have some difficulty in saving these combinations into memory. The channels listed below will help you compensate for the speed of the space station, called Doppler. If the smallest channel step your radio supports is 5k, then only program in channels 2, 5 and 8. If your radio supports the smaller 2.5k channel step, then program in all channels listed. After you have determined your smallest channel step supported by your radio, then program in the channels. You can either use the procedures for storing ODD-Splits or you can reprogram your repeater off set for each of the channels and then save the new combination in a new memory location. This channel procedure has been successfully used on the Mir Amateur Radio program for years and is the choice of usage for school schedules (you do not want to fiddle with VFO’s during a 10-minute pass). I also recommend you program in all channels, no mater what part of the world you live in. The World Map ISS ALPHA location display used by the ISS ALPHA crew is not located next to the Amateur Radio station.

Voice operations Region 2 & 3 (North and South America and Pacific)

Chan Receive Transmit Offset (Meg)

1 145.802.5 144.488.5 -1.314

2 145.800.0 144.490.0 -1.310

3 145.798.5 144.492.5 -1.306

Packet operations Regions 1, 2 & 3 (Europe, North and South America and Pacific)

Chan Receive Transmit Offset (Meg)

4 145.802.5 145.988.5 +0.186

5 145.800.0 145.990.0 +0.190

6 145.798.5 145.992.5 +0.194

Voice operations Region 1 (Europe)

Chan Receive Transmit Offset (Meg)

7 145.802.5 145.198.5 -0.604

8 145.800.0 145.200.0 -0.600

9 145.798.5 145.202.5 -0.596

Usage Example:

Lets assume ISS ALPHA is approaching for a good 10 minute over head pass, running Packet. When ISS ALPHA comes over the horizon the Doppler frequency error will initially be 3.5k plus 145.800 + 3.5 = 145.803.5. This means the frequency ISS ALPHA will appear to be transmitting on is 145.803.5. Set your radio to channel #4 for the first 3 minutes of the pass (145.802.5 is close enough). Then for the next 3 minutes use channel #5 and for the last three minutes use channel #6. Follow the same procedure for Voice operations. Since we are using the Mode FM, we do not have to have our Transmit and receive frequency exactly on frequency. We can be off frequency 1-2khz and still get reliable Voice and Data. The MAREX-MG team has been using this procedure for 10 years with excellent results.

QSL card:

A QSL card is a post card, which you can request to confirm you made a two-way or heard the crew on the Amateur Radio band. The QSL procedure for ISS ALPHA is under development, please check the AIRSS web pages for the latest updates and QSL procedures for ISS ALPHA.


New MAREX Web page

Please check out our new MAREX web page with updates on the new SpaceCam1 SSTV project


Copyright 2001 Miles Mann, All Rights Reserved. This document may be freely distributed via the following means - Email ( including listservers), Usenet, and World-Wide-Web. It may not be reproduced for profit including, but not limited to, CD ROMs, books, and/or other commercial outlets without prior written consent from the author.

Images received from the MAREX-MG SSTV system on the Russian Space Station Mir are considered public domain and may be freely distributed, without prior permission.