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RE: Mode B vs. Mode S



I haven't heard of anybody LATELY who thinks AO40 is dead.  After all, there was a QST article a few months ago about successful AO40 transponder operation.  But the QST article still doesn't motivate the average ham to invest in equipment that can only be used to hear ONE satellite that has a history of problems.

I don't know much about the alleged politics of "Mode B" vs "Microwave", other than that the original P3D plan didn't include 2m until a lot of people said they refuse to contribute money unless it has a 2m transmitter.  That's not politics.  It's a natural evolution from a theoretical design to actual development of a customer-driven (and customer-funded) product.

2m and 13cm downlinks are so different that they are VERY complementary.  For any given problem one is "strong" while the other is "weak".  Depending on the unique circumstances of each ground station, some people will prefer 13 cm some or all of the time, while other people will prefer 2m some or all of the time.  A lot of people need BOTH for reliable operation.  Use 2m to go through trees.  Use 13cm when in the clear.  Use 2m if a neighbor starts using a 2.4 GHz cordless phone.  Use 13cm if there is 2m QRM or a nearby thunderstorm that raises the noise level on 2m.  Use 13cm if antenna length is a problem.  Use 2m if antenna wind loading is a problem.  Use 13cm if your 2m preamp blew up.  Use 2m if your downconverter blew up, or if downconverters aren't available in your location.  Use 13cm if restrictive covenants force you to use an indoor antenna pointing through a window, or if a balcony is your only place for antennas.  Use 2m if Doppler is driving you crazy, or if you!
!
're using a mode that doesn't tolerate rapid Doppler changes.  I can't think of a single ground station downlink problem that affects BOTH bands.

I've already contributed generously to Project Eagle.  If the project plan includes a "definite" 2m downlink I would be motivated to contribute even more.

Wayne Estes W9AE
Mundelein, IL, USA

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