Re: [Advisors] Re: Re: [Fwd: Re: S band and Eagle: an appeal for ahig...
In a message dated 9/17/06 3:08:03 PM Greenwich Standard Time, kd6ozh@comcast.net writes:
Path loss is 15 dB less at 435 MHz than 2400 MHz and antenna gain is 13 dB less. However, the noise figure is 5 dB higher, so almost twice the EIRP wll be required on a U uplink than an S uplink. The 70 cm receiver has a 200 kHz bandwidth so some class 2 (4800 bps) uplinks could be accomodated. Since they will be BPSK and use FEC, I assume that they will occupy at least 15 kHz each and will have to be spaced at least 25 kHz apart. This could allow 4 uplinks. It's not good to increase the receiver bandwidth as it will let in more PAVE PAWS interference.
John,
I was thinking in terms of an additional 70 cm receiver to accommodate several conference-grade channels, for those users who may be prohibited from using BOTH L-band and S-band uplinks (think Europe). Yes, PAVE PAWS is there, sometimes, but it would still be better than no digital access at all. Also, it's not a certainty that PAVE PAWS will even be there in 2020.
73,
Ray
PAVE PAWS is part of the ballistic missle defense system so it will remain active. We didn't allow for much loss between the U antenna and U receiver so the use of two receivers would require some changes.
73,
John KD6OZH ----- Original Message ----- From: RaySoifer@cs.com To: kd6ozh@comcast.net ; K3IO@verizon.net ; bod@amsat.org ; Senior-officers@amsat.org ; advisors@amsat.org ; eagle@amsat.org Sent: Sunday, September 17, 2006 15:21 UTC Subject: Re: [Advisors] Re: [eagle] Re: [Fwd: Re: S band and Eagle: an appeal for ahig...
In a message dated 9/17/06 3:08:03 PM Greenwich Standard Time, kd6ozh@comcast.net writes:
Path loss is 15 dB less at 435 MHz than 2400 MHz and antenna gain is 13 dB less. However, the noise figure is 5 dB higher, so almost twice the EIRP wll be required on a U uplink than an S uplink. The 70 cm receiver has a 200 kHz bandwidth so some class 2 (4800 bps) uplinks could be accomodated. Since they will be BPSK and use FEC, I assume that they will occupy at least 15 kHz each and will have to be spaced at least 25 kHz apart. This could allow 4 uplinks. It's not good to increase the receiver bandwidth as it will let in more PAVE PAWS interference.
John,
I was thinking in terms of an additional 70 cm receiver to accommodate several conference-grade channels, for those users who may be prohibited from using BOTH L-band and S-band uplinks (think Europe). Yes, PAVE PAWS is there, sometimes, but it would still be better than no digital access at all. Also, it's not a certainty that PAVE PAWS will even be there in 2020.
73,
Ray
Keep in mind that anything susceptible to Pave Paws will also be subject to the APS-145 based on Hawk Eye and P3 aircraft, which operates a higher power anywhere in the world, typically at sea.
73 JI K1KSC
On Sep 17, 2006, at 12:01 PM, John B. Stephensen wrote:
PAVE PAWS is part of the ballistic missle defense system so it will remain active. We didn't allow for much loss between the U antenna and U receiver so the use of two receivers would require some changes.
73,
John KD6OZH ----- Original Message ----- From: RaySoifer@cs.com To: kd6ozh@comcast.net ; K3IO@verizon.net ; bod@amsat.org ; Senior- officers@amsat.org ; advisors@amsat.org ; eagle@amsat.org Sent: Sunday, September 17, 2006 15:21 UTC Subject: Re: [Advisors] Re: [eagle] Re: [Fwd: Re: S band and Eagle: an appeal for ahig...
In a message dated 9/17/06 3:08:03 PM Greenwich Standard Time, kd6ozh@comcast.net writes:
Path loss is 15 dB less at 435 MHz than 2400 MHz and antenna gain is 13 dB less. However, the noise figure is 5 dB higher, so almost twice the EIRP wll be required on a U uplink than an S uplink. The 70 cm receiver has a 200 kHz bandwidth so some class 2 (4800 bps) uplinks could be accomodated. Since they will be BPSK and use FEC, I assume that they will occupy at least 15 kHz each and will have to be spaced at least 25 kHz apart. This could allow 4 uplinks. It's not good to increase the receiver bandwidth as it will let in more PAVE PAWS interference.
John,
I was thinking in terms of an additional 70 cm receiver to accommodate several conference-grade channels, for those users who may be prohibited from using BOTH L-band and S-band uplinks (think Europe). Yes, PAVE PAWS is there, sometimes, but it would still be better than no digital access at all. Also, it's not a certainty that PAVE PAWS will even be there in 2020.
73,
Ray _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
participants (3)
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John B. Stephensen -
John Isella -
RaySoifer＠cs.com