CAS-5A jpg trick?2023年03月04日 17時59分

CAS-5A jpg trick?
JE9PEL, Mineo Wakita
On Sat, Mar 4, 2023 at 7:14 UTC

I downloaded several jpg_file including *A07# or *A09# through the
DTMF request command to the satellite. Then the following message,
"Try to get another photos" or "Synchronization code not received"
appears on the cmd_prompt screen and I cannot proceed.
Is there any trick to making an image?

Re: CAS-5A jpg trick?
K4KDR, Scott

No trick, I'm afraid... I know it sounds simple (even though it is NOT),
but we just need to get ALL of the packets.

When you miss packet #1 (with the 'FF D8' bytes), that decoder will show
"Synchronization code not received". Here is an example from #22 last
night. These are the decodes from N6RFM (with the ax.25 header removed
so the sequence numbers are at the start of each line in my editor):

... you can see that he got every packet up until number '008e', but
then missed a number of packets until decodes started again with #00a2.

So, to make a complete picture, I looked at MY decodes and I had the
missing packets.  With copy/paste, I was able to fill in all of Bob's
missing packets from my decode.  Very lucky!

It would be a real accomplishment for ONE station to get a perfect,
100% picture with no missing packets... at least on a single pass.
But even if you don't get packets from another station, you can always
download again on the next pass - or even on the next day. Over 2
or 3 passes, you can accumulate all the packets and fill in the ones
that are missing. Good luck!!

Re: CAS-5A jpg trick?2023年03月04日 19時35分

トリックがあるわけではないです.... 簡単そうに聞こえるかもしれませんが、
(そうではないのに)、私たちはただ 全てのパケットを取得する必要があります。
パケット#1(含'FF D8' bytes)を取り逃すと、Decoder は次のように表示します。
 "Synchronization code not received".  次は、昨晩の#22の例です。N6RFM局
によるデコードです。 (ax.25ヘッダが削除されていますが、私のエディタでは

いることがわかります。そこで 完全な画像を得るために、私のデコードを見る

一人の局としては本当に快挙だと思います。しかし 他の局からパケットを得ら
れなかったとしても、次のパスで または翌日でも、いつでも再度ダウンロード