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Re: Why V/S in stead of U/S

>Maybe I have missed a discussion somewhere, but I do not understand why
>AO-51 is using V/S instead of U/S.

To operate in a U/S mode, AO-51 would have to employ it's SQRX tunable receiver. The command station has stated in the past that he considers it unnecessarily risky to operate the SQRX on U band receive with 2 high powered UHF transmit antennas 9 inches away. If one of the UHF transmitters was somehow powered up while the SQRX was on U band, we could loose the SQRX.

Additionally, The V band uplink requires no doppler correction for the entire pass. A U band uplink would require about +/- 10 khz of tuning. Combined with the +/- 60 khz of S band doppler correction it would almost make computer tuning a requirement for many operators.

On a personal note, I don't know any sat ops with S band that do not have a second 2m FM transmitter. Just about anything will work on the uplink, demonstrated by the dozens of QSOs made on just 5 watts and a rubber duck for uplinking during the last 2 V/S sessions. Visitors to the Dayton Hamvention demonstrations can attest to this.

I hope that helps answer your question.

73, Drew KO4MA
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