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# Re: Need alittle help JAS1 and 2..

```Hello This is Yoshi.

I had a huge number of unreading message of JAMSAT-bb now. Sorry
for delayed reply.

At 2001/05/11 19:05:06 Timothy Vermette wrote:
>  As I never used a SSB satellite before.. Im having trouble find answers to
> some questions. When TX'ing say at 145.950MHz on JAS1.. what will be my
> downlink frequency?

FO-20/29 has a REVERSE type linear transponder.

In the case of JAS-1b(FO-20) or JAS-2(FO-29), you can calculate your
downlink freq with this formula.

Downlink = 581.8MHz - ( Uplink(MHz)   + Dopp.Shift(145) ) + Dopp.Shift(435)
Uplink   = 581.8MHz - ( Downlink(MHz) - Dopp.Shift(435) ) - Dopp.Shift(145)

In the case of FO-29 at my QTH tonight,

UTC____________ 145MHz__ 435MHz___ Uplink_______ Downlink____
2001/5/14 12:00 +2.86KHz +8.55KHz  145.945MHz -> 435.86069MHz
145.950MHz -> 435.85569MHz
145.955MHz -> 435.85069MHz
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
2001/5/14 12:10 -3.07KHz -9.18KHz  145.945MHz -> 435.84889MHz
145.950MHz -> 435.84389MHz
145.955MHz -> 435.83889MHz

>  There was one guy who did a few contacts through AO-10.. How does its
> transponder change frequencies?

In the case of AO-10, It has also REVERSE type.

Downlink = 581.005MHz - ( Uplink(MHz)   + Dopp.Shift(435) ) + Dopp.Shift(145)
Uplink   = 581.005MHz - ( Downlink(MHz) - Dopp.Shift(145) ) - Dopp.Shift(435)

> How about any of the others?

There is a 2 type of transponder. FO-20/29 and AO-10/40 has a REVERSE
type. When you increase the uplink frequency, the downlink frequency
had decrease. But RS-12/13/15 has a NORMAL type. When you increase the
uplink, the downlink also had inclrase.

Please check the amsat web site to know the current informations of
any sat.

Yoshihiro Imaishi JF6BCC/KH2GR
GL:PM53JV, ex KC6IY(T88IY),V63BP
mailto:jf6bcc@jarl.com or jf6bcc@jamsat.or.jp
<http://plaza16.mbn.or.jp/~palau/> Sorry, Japanese only now.
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```

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