You may want to look at the analogue links we are using on MeerKAT. ~
2GHz BW and good dynamic range.
J
On 17 Dec 2009, at 8:57 PM, Dan Werthimer wrote:
hi john, tom,
attached is a paper on the analog fiber links used in the ATA.
the work well at the ATA, which transmits the RF band
Alan reminded me I should have given the link to the supplier:
http://www.foxcom.com/index.aspx?id=2510
J
On 18 Dec 2009, at 12:53 AM, Tom Kuiper wrote:
John Ford wrote:
We've decided (Maybe prematurely?) that wide-band analog links are
not the
way to go, for single-dish, at least. The
Hi all,
In the old days the biggest problem was the very limited dynamic range of
fiber optic receivers. If you are thinking of using analog links you shoud
check if this is still true and if it isn't, what tricks have been used to
circumvent it.
Otherwise all the different standards are a
Hi
Roufurd Julie's M.Sc. dissertation should come out early in January 2010
(yes, Roufurd, just next year...) and he has a lot of practical measurements
of gain changes with ambient, phase changes, changes due to the antenna
cable wraps, and so on. Dynamic range, now specified at the 1%GCP, is
Hi,
OK, the dynamic range might be much better now, I remember something like
13 dB but it was year 1985 and first-generation 10 Mbps Ethernet.
The 45 dB sounds a bit weird, physics have stayed the same. Possibly some
tricks in signal levels?
So there is still the standard question we ask
Hi Dan,
On Fri, 18 Dec 2009, Dan Werthimer wrote:
You can use fiber optic cables on the iBob, Roach and Bee2 boards.
There are several vendors that make CX4 optical fiber cables; these cables
house copper to optical transceivers
in the connector body. Matt Dexter has tested several vendors
Hi Tom,
In my earlier life I designed some of the biggest fiber optic networks in
the world, before going into radio astronomy.
In your case, fibers are really cheap, digging costs a lot more. Cable
cost is insignificant.
For those lenghts I would use a 48 or 98- single mode fiber cable,
Dan Werthimer wrote:
Can you transmit the RF or IF through analog fibers, and then locate the
digitizers in
an electronics lab, where they are easy to service, upgrade, keep cool,
shield from the receivers, ...?
We can, in principal. The receiver being built first for Canberra by
Steve Smith
Hi Tom,
To save money on analog fiber transmitter/receivers, perhaps you could
transmit your full 10GHz band on a single
analog fiber, or as you suggested, convert the 10 GHz band to a pair of
5 GHz IF's, and transmit on two analog fibers.
After the analog fiber receiver (located in the
John Ford wrote:
We've decided (Maybe prematurely?) that wide-band analog links are not the
way to go, for single-dish, at least. The stability we need was not there
the last time I looked, when you factor in the twisting of the fibers, the
diurnal temperature variations, etc. Can you give me
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