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Re: ISS Packet with Kenwood THD7A

A point to remember:  Let's say the ISS is passing over,
but you only hear a packet from it every 20-30 seconds.
This could mean either:

1: Hardly anybody is trying to transmit to it, and they
do it only every 20-30 seconds.

2: So many people are trying to transmit, that they are
all stepping on one another, and the ISS can only hear
a clean packet every 20-30 seconds.

I suspect the second case is the most common by now
(at least in the USA).

And to make it worse, when all these people fail to hear
their own packets repeated on an apparently clear
channel, they all try over and over.

The digipeater is unfortunately worse in this respect
than a regular repeater, because with a regular repeater
you can at least hear all the QRM and understand what is

Some tips:

1: Keep your packets SHORT!  They will interfere less with
those of everybody else, and yours are less likely to get QRMed
themselves.  (Maybe the ISS should use 9600 baud?)

2: Try again on those really late-night passes.

3: Use some restraint about how often you transmit (sort of idealistic).

4: Have more ERP than everybody else.  (sort of cynical.)

Good luck,


At 01:54 PM 4/10/01 , you wrote:
>Last night I tried to contact ISS with my Kenwood THD7A.  I was
>successfull at RX, however I don't think my TX got there...

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