[R-390] R-1247 Nasa Receiver info

[William J. Neill]

Yes, you would've needed the R-390(  ) for HF diversity comms in  
1965, either in space or frequency diversity configurations.

The benefit of HF diversity operation is that if the signal goes down  
on one antenna/receiver, it'll still be up on the other and therefore  
you'll still be functional.  And the ancillary equipment, whether it  
be a CV-116(  ) or CV-157, has the capability to compensate for minor  
signal drift, thereby further enhancing quality of the signal.

I still run HF diversity although there ain't a helluva lotta traffic  
left that merits such operation, especially TTY.

Bill Neill
Conroe, Texas


On Feb 25, 2010, at 10:19 PM, Bill Hawkins wrote:

Group,

I'm glad to know that the R-1247 functions as an R-390A by default.

I bear the seller no ill will. NASA sets do not grow on trees.

But I really wonder about the need for precise frequencies, when
the R-390A is so well adapted to multichannel RTTY diversity
reception all by itself.

Does anyone else know about the need for secondary conversion
from microwave to precisely discover the Doppler shift from the
microwave signal on the spacecraft?

Would I really have needed the R-390A for SSB diversity comm in
1965? Who would I be talking to? I can understand the military
adopting precise frequencies to get closer to perfection, but
did NASA need it for site communication?

Thanks in advance,
Bill Hawkins