[R-390] R-390a Part Of First ELINT Satellite Recon System

[Glenn Little WB4UIV]

The satellite that this payload was on was TRANSIT. This was a navigation 
satellite that transmitted on about 150 MHz and 400 MHz. The frequencies 
were a few Hz below this. We used the satellite to give us a Doppler curve. 
We knew where the computer thought we were and we tracked the satellite 
based on the predicted Doppler curve. When we finished the pass, the 
computer compared the acquired Doppler curve with the predicted Doppler 
cure and computed Latitude and Longitude offsets. The reason for the two 
frequencies was to know if there was anomalous propagation. There was at 
least one ground station that controlled the satellites. I think that it 
transmitted to the bird in the 400 MHz range. I highly suspect that the 
antenna in the pictures is UHF.

We did have problems at times with the secondary payload interfering with 
the navigation signals.  We would usually get a message advising us of the 
times that the satellite was unusable. Probably when the secondary payload 
was active.

73
Glenn
WB4UIV

At 08:09 AM 01/04/07, Tim  Shoppa wrote:
>Cecil Acuff wrote:
>  > One of the R-390A's looks to have a frequency
> > counter mounted above it.
>
>Almost certainly not a frequency counter but
>a "digital clock" (really a timecode generator).
>It might have synchronized to other base stations
>via HF radio.
>
>Look at the heights of the neon stacks:
>Leftmost digit counts to 2, then up to 9, then up to
>5, then up to 9, then up to 5 then up to 9.
>
>You're right, those sorts of counter modules were also used
>for frequency counters from the 50's onward.
>
> >  Not sure what the other is unless it's a mixer of some sort to put
>the
> > audio from both radio's on tape...
>
>The standard for rocket telemetry puts timecodes into
>or alongside the analog data stream and then puts it all
>on tape so a mixer is very plausible.
>
> > http://ncst-www.nrl.navy.mil/HomePage/GRAB/GRAB_Photos.html
>
>Tim.
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