Dave and all:
I wonder what all of you were thinking? If a commercial communication satellite were channeled on one of our mw ham bands, then we would be booted off.
C-band satellites used approx. 37-MHz wide channels with alternating linear polarity to afford more adjacent channel isolation. On most of the TVRO units one could manually adjust polarization angle for optimizing the signal. If you adjusted 90-degrees off then one often got a ghost of one of the adjacent channels. The feedhorns had a rotating probe with the motor on the backside of the feedhorn.
Typically in the mid-1980's these TV sats cost over $100M before launch. Your not going to convince the satellite company to include ham radio in any manner. AS has been hashed out many times previous on this reflector the path loss to the Clarke Belt orbit is prohibitive.
This topic is going no-where!
73, Ed - KL7UW
At 04:04 PM 1/29/2007 -0800, Dave hartzell wrote:
It looks like the commonly adopted block conversion for C-band transponders wouldn't land in our bands. There seems to be a delta for 2.2 GHz for the block conversion (e.g. 5.9 GHz up, 3.7 GHz down). We'd need more like a 4 GHz conversion to land in our S-band, given a 5.8 GHz uplink. I'm sure the filters aren't quite tuned to go below out of band, either.
Another issue I just realized is that these transponders use polarized signals (left, right, vertical, horizontal, polka-dotted)....this again makes using an old communications sat a bit more difficult (but not impossible) for us hams.
Looks like this was not meant to be!
73,
Dave NøTGD
On 1/28/07, Karl Bullock [email protected] wrote:
Dave hartzell wrote:
- Most of the uplink freq's are in the 5.9 GHz range (out of our
allocation) and downlink in the 3.7 GHz range, again, (out of our allocation).
That may be _the_ problem. I don't know the current capabilities of these birds, and if they have any capability of either "retuning" to a close amateur band, or if there are other assets on board, but inability to transmit/receive on one of our bands would probably make this a non sequitur. Those with more intimate knowledge of current flying technology would need to speak to this.
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Hi Ed,
You're right, the thread is going nowhere, other than to satisfy some intellectual curiosity. That was established early on in the thread.
Why not explore potential systems and alternatives, even if they are a dead-end?
Thanks for contributing! ;-)
73,
Dave
On 1/30/07, Edward R. Cole [email protected] wrote:
Dave and all:
I wonder what all of you were thinking? If a commercial communication satellite were channeled on one of our mw ham bands, then we would be booted off.
C-band satellites used approx. 37-MHz wide channels with alternating linear polarity to afford more adjacent channel isolation. On most of the TVRO units one could manually adjust polarization angle for optimizing the signal. If you adjusted 90-degrees off then one often got a ghost of one of the adjacent channels. The feedhorns had a rotating probe with the motor on the backside of the feedhorn.
Typically in the mid-1980's these TV sats cost over $100M before launch. Your not going to convince the satellite company to include ham radio in any manner. AS has been hashed out many times previous on this reflector the path loss to the Clarke Belt orbit is prohibitive.
This topic is going no-where!
73, Ed - KL7UW
Thanks, Dave. Nothing ventured, nothing gained, eh?
73, Karl, WA5TMC
Dave hartzell wrote:
Hi Ed,
You're right, the thread is going nowhere, other than to satisfy some intellectual curiosity. That was established early on in the thread.
Why not explore potential systems and alternatives, even if they are a dead-end?
Thanks for contributing! ;-)
73,
Dave
On 1/30/07, Edward R. Cole [email protected] wrote:
Dave and all:
I wonder what all of you were thinking? If a commercial communication satellite were channeled on one of our mw ham bands, then we would be booted off.
C-band satellites used approx. 37-MHz wide channels with alternating linear polarity to afford more adjacent channel isolation. On most of the TVRO units one could manually adjust polarization angle for optimizing the signal. If you adjusted 90-degrees off then one often got a ghost of one of the adjacent channels. The feedhorns had a rotating probe with the motor on the backside of the feedhorn.
Typically in the mid-1980's these TV sats cost over $100M before launch. Your not going to convince the satellite company to include ham radio in any manner. AS has been hashed out many times previous on this reflector the path loss to the Clarke Belt orbit is prohibitive.
This topic is going no-where!
73, Ed - KL7UW
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (3)
-
Dave hartzell -
Edward R. Cole -
Karl Bullock