On 3/30/21 2:56 PM, Wes wrote:
You would know better than I, but I was thinking of physical size;
100m v. 70m.
Obviously a BIG difference in TX power.
Wes
It's all about EIRP, baby.
I know they're talking about half a megawatt for GB, but I don't see it
happening. They've spent so much time making it "radio quiet", putting a
big honkin transmitter there seems odd. Just think, a return loss from
the feed of -30dB (which is pretty good) is good fraction of a kilowatt.
I think a phased array of some sort is more likely (both for Tx and Rx)
- the cost of RF parts has come down a lot, and, as we on this list
know, phasing them all up to a fraction of a gnats eyelash is doable.
Fiber optics are cheap. And you can form multiple beams simultaneously
(the LEDA correlator at OVRO-LWA forms hundreds of beams).
What *is* a challenge (and hasn't really been solved) is how to do
cryogenic feeds in mass production. DSN looked at building an array of
100 receivers, and nobody would sign up to delivering 100 cryocoolers
that would have sufficient MTBF. But transmitting - that's easy.
On 3/30/2021 2:00 PM, Lux, Jim wrote:
On 3/30/21 6:40 AM, Wes wrote:
Was a pity. China's FAST is receive only. I believe that leaves
Green Bank as the biggest transmitting telescope.
More likely the Goldstone Solar System Radar function of DSN on the
70m (DSS-14) - 500kW in X band at 8560 MHz
There *is* a new transmitter for GB - but it's a demo - 700 W and
temporarily installed up at the feed for a test. I don't know what
frequency. People are pitching a 500kW system, but we shall see.
_______________________________________________
time-nuts mailing list -- [email protected] -- To unsubscribe
send an email to [email protected]
To unsubscribe, go to and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected] -- To unsubscribe send an
email to [email protected]
To unsubscribe, go to and follow the instructions there.
