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Re: THoughts on minimum ERP



John, Jerry and the group,

I am not at the position to permit (or prohibit) an FM QRV on the FO-20
or FO-29, but let me allow to give you a suggestion as a project member
(co-designer/constructer of JTA & JTD) of JAS-1a & 1b (FO-12 & FO-20).

 >> Hmmm, here's a crazy idea...  What about designating an FM day FO-20 or
 >>  FO-29 from time to time on a day that has been typically vacant?
 >
 >John,
 >I like that suggestion.  Would we need to obtain permission/concurrance
from
 >the JAS-1/JAS-2 team in Tokyo to try such an experiment?  It would open up
 >new opportunities for a lot of people.

As the transponder is linear transponder, it is possible to convert
any kind of modulation, needless to say. But, please consider up/down
link budget, S/C power budget and employed device in transponder.

We chose BPSK modulation for down link of JD. If we could have
enough link budget, we had chosen FSK (= FM). Regarding S/C power
budget and device, the transmitter chains employ Class AB1 amplifiers.
This is not ideal, not high efficient amplifier for FM modulation.
If you have an SSB high power amplifier, then please try key-down
continuously at maximum output, or try  AFSK (RTTY). You might kill
your devices. Yes, I killed couples of transistor during my bread-board
test of transponder.

Thanks for your consideration.

Yoshi Takeyasu / JA6XKQ
ex member of JAS-1 project
SCOPE project member
JAMSAT



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