Narrow Band Signal Reflected Off Moon on 3 March

[VK2XAX]

Hi all,

This popped up on the Amateur DSN list. Jim Lux works at JPL...

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There will be a narrow band signal at about 2041 MHz illuminating a spot
on the moon (probably centered on Tycho) about 1000km in diameter early
in the morning of 3 March. From about 0630 to 0900 UTC. JPL will be
transmitting about 20kW from a 34 m aperture. We'll probably have 3
distinct transmit modes, 2 CW carrier, and a third where there's a PN
ranging code on the signal, probably changing every 45 minutes.

The signal should be easy to detect with even a small receive antenna,
at least the narrow band signal.

If you have a wideband recorder, the ranging code should be easy to
recover with post processing. Standard ranging code as defined in 810-005

http://deepspace.jpl.nasa.gov/dsndocs/8 ... /214-1.pdf

as with all PN ranging that DSN does, the PN code rate is coherent to
the transmit carrier, probably 1.9931640625 MHz (or half that) in this case.

I'll find out more about the exact options on the ranging, and things
like the mod index.
Posted by: Jim Lux <jimlux@earthlink.net>
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I'll update this info when Jim sends more info.

regards

Tim

[VK2XAX]

UPDATE -- FREQUENCY CHANGE ----

From Jim Lux at JPL....

The frequency and schedule has changed slightly..
As before, we're going to aim at Tycho from DSS-24 (34m antenna)
We'll radiate at 2115 (not 2041).. from 0630UTC to 0900 UTC

For the first hour (until 0730UTC) we'll just have a CW carrier, should
be easy to see.

For the next hour, we'll be transmitting a JPL ranging code with the
chip rate at 2115/2048 MHz (a bit more than 1 MHz)..
See the 810-005 handbook for details
http://deepspace.jpl.nasa.gov/dsndocs/8 ... /214-1.pdf

You can probably see not only the carrier but the +/-1 MHz ranging tones
(and probably at +/-2 MHz, too), and also the PN sequence if you've got
enough SNR (or post process.. the code period is about 1 second.. it's
about a million chips long)

Then, at 0830UTC we'll stop using the PN ranging, and go to Doppler
compensating the uplink so that the received signal at JPL will have
zero Doppler.

This is all "we hope".. it's experimental and a sort of procedural shake
out as well as giving me a chance to test my ground copy of a Software
Defined Radio that is flying on ISS.

Jim Lux
W6RMK

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cheers

Tim