Try adjusting for Doppler. When the signals are strong over S3, should not have much of an issue decoding intact packets. However, if the signals are dipping below S3 and you are experience Doppler greater than 2k, then you can improve your decoding performance by adjusting for Doppler. On 2 meters, ISS Doppler will be plus and minus up to 3.3 kHz.

For 2-Meter FM Use three pre program channels with Odd-split frequencies stored in advance. Set Channel #1 Receiving frequency plus 2k. Set Channel #1 Transmitting frequency minus 2k.

Set Channel #2 Receiving frequency plus 0k. (No Doppler correction) Set Channel #2 Transmitting frequency minus 0k. (No Doppler correction)

Set Channel #3 Receiving frequency minus 2k. Set Channel #3 Transmitting frequency plus 2k.

During an ISS 9 minute pass. Use Channel #1 for the first 3 minutes. Use Channel #2 for the Second group of 3 minutes. Use Channel 3 for the last three minutes of the pass.

Icom 910H: This radio has a Blinking light that will tell you when your FM receiver is Off frequency. It does not tell you if you are high or low. If the light blinks while receiving Packet/Voice from ISS, then it’s time to change channels. With FM, you do not need to be exactly on frequency.

Some radios such as the Yasue FT736R have a FM Tuning center meter. The FM center meter is great for tracking FM satellites. Too bad none of the satellite radio manufactures sell this important feature any more.

--- On Mon, 6/10/13, [email protected] [email protected] wrote:

From: [email protected] [email protected] Subject: [amsat-bb] Re: Improving performance of packet communications through the ISS To: [email protected], [email protected] Date: Monday, June 10, 2013, 8:46 AM Les...

I forget the command...maybe PASSALL? Typically the default settings only display complete verified packets...I think if you turn it on it will display partial and unverified packets which allows you to see everything received even if  incomplete and can you can figure out the content.

Roger WA1KAT

-----Original Message----- From: Les Rayburn [email protected] To: AMSAT Mailing List [email protected] Sent: Mon, Jun 10, 2013 12:39 am Subject: [amsat-bb] Improving performance of packet communications through the ISS

I've got my Icom IC-910H working with it's SignaLink interface, through Packet Engine Pro and UISS. I've been able to receive lots of stations through the ISS, and managed to have short QSOs with a couple. Fun!

But I notice that this combination seems to do a poor job of decoding weak signals. I hear packets in the speaker that seem plenty strong enough to decode, but they don't show up on UISS.

I'm wondering if I used a traditional TNC, such as a Kantronics unit, if I'd get better performance? Does anyone in the group have any experience along these lines? Or could someone provide other suggestions on how to improve my ability to communicate through the ISS?

Thanks in advance. Having a ball on the birds.

-- 73,

Les Rayburn, N1LF 121 Mayfair Park Maylene, AL 35114 EM63nf

6M VUCC #1712 AMSAT #38965 Grid Bandits #222 Southeastern VHF Society Central States VHF Society Life Member Six Club #2484

Active on 6 Meters thru 1296, 10GHz & Light

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Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb